Apostila - Medicina de Emergência

I Simpósio Internacional de Medicina de Emergência - Anclivepa MG

08 de abril de 2001

Belo Horizonte -MGBrasil

ON THE FRONT LINES - ANIMALS IN CRISISPractical Emergency Procedures

Readiness, Triage, Rapid Assessment, General Resuscitation and Emergency Respiratory and Abdominal Conditions

Dennis T. (Tim) Crowe, Jr., DVMDiplomate, American College of Veterinary Surgeons

Charter Diplomate, American College of Veterinary Emergency and Critical Care

Chief of Staff, Surgeon and Emergency - Critical Care Specialist Western Nevada Veterinary Specialists,

Carson-Tahoe Veterinary Hospital and Emergency and Critical Care Center3389 South Carson Street

Carson City, Nevada 89701775-883-8238

Emergency Medical Technician and Fire FighterStation 6

East Fork Fire and Paramedic DistrictMinden, Nevada

Formerly Chief of Emergency and Critical Care Services, Georgia Veterinary Specialists, Atlanta, Georgia

Chief of Surgery and Co-Owner, Animal Emergency Center, Milwaukee, WisconsinDirector of Clinical Research, Veterinary Institute of Trauma, Emergency and Critical Care, Milwaukee

Associate Professor of Surgery and Chief, Emergency and Critical Care ServicesUniversity of Georgia, Athens, Georgia

INTRODUCTION

Its 7 PM and as you are about to leave your practice you see a man carrying a dog rushing in through the front door. While trying to look in control but obviously very shook up the man exclaims that his dog of 10 years has just been hit by a car only minutes ago and knows he has been badly injured… You quickly survey the situation. The Golden Retriever the man is carrying appears motionless and unconscious with blood dripping from his mouth. The man appears in emotional shock and you sense your own pulse quickening. You feel a sense of urgency as you know the Golden Hour of Trauma is ebbing away…The man exclaimed "do all you can to save him, I just lost my wife and he is all I have left!" This pressure scenario is unfortunately not an uncommon occurrence in veterinary practices today. Despite leash laws and many educational campaigns pets are still getting injured and pets are still getting severely ill…requiring veterinarians and paramedical personnel working together effectively and efficiently to provide the best care.

The purpose of this address is to provide information that will help the practicing veterinarian make correct decisions concerning the emergency and critical care of the seriously traumatized or ill patient and provide information about how to perform life-saving procedures. Emphasis will be placed on practical procedures involving readiness, assessment, resuscitation, and treatment of emergency respiratory and abdominal conditions. Guidelines on monitoring, nutritional support, and emergency wound and fracture care will also be discussed. Guidelines that can be referred to in the "heat of the battle" when faced with the serious patient

are provided. New treatment protocols, based on scientific experimental and clinical investigations will also be discussed.

OVERVIEW AND THE GOALS OF EMERGENCY MANAGEMENT

The Golden Hour

"The Golden Hour" has been referred to the first hour after severe injury. In research conducted in a human civilian trauma center R Adams Cowley, MD found that most preventable deaths occurred because surgery was delayed either because of a delay in diagnosis (such as a simple bleeding spleen that continued to bleed) or a delay in being able to get the patient to the operating room with a competent team able to operate. In my experience as a fellow at the Shock-Trauma Center in Baltimore and in a large level one trauma in Ohio (Riverside Methodist Hospital) supports this concept. My experience is parallel to Dr. Cowely's but with an emphasis on even less than an hour in some cases to surgically intervene. I believe this is because our small animal patients have higher metabolic rates than adult humans and generally have less volumes of blood to loose and less critical mass to absorb the energy imparted. Pediatric human trauma surgeons have also suggested this idea in their patient population. Airways, especially those of cats are also at more risk because of their small size and reactivity of obstruction. Similar to an infants or young child's, the cat airway becomes obstructed more rapidly from blood and foreign material giving only a matter of minutes in which to act. Therefore readiness is key if we are going to be as successful as we can when faced with emergent conditions.

Factors that Influence Survival

Factors that influence survival in the seriously traumatized or ill small animal patient include: 1. The extent of the injury or the severity of the illness as seen physiologically by the patient.2. Number and depth of injury or illness regarding specific organs.3. Patient's physiological condition and medical illnesses prior to the injury.4. The time laps between time of injury or onset of illness and treatment.5. Abilities and readiness of the team treating the patient and team numbers.6. Facilities, equipment, drugs and supplies available for the patient's care.7. Availability of blood, plasma, oxygen carrying colloids and necessary.8. Amount of financial commitment the owner has toward the patient's care.9. Ability of the veterinarian regarding diagnostics and therapeutics.10. Ability to provide continuous 24-hour care and the supportive care needed.

Immediate goals of resuscitation

The immediate goal of resuscitation of most serious medical or trauma patients is to reverse the state of shock and tissue hypoxemia by improving the delivery of oxygen (O2) and nutrients to the tissues, and to arrest the cause of the shock. This involves the ABC's of emergency medical care: A - opening the airway; B- ensuring adequate ventilation; C-controlling hemorrhage, providing volume replacement as required, and support of the cardiovascular system; D- correcting anatomical defects caused by the injury that affect function (repairing the ruptured urinary bladder) before its consequences impart serious life-or limb (locomotion) threatening complications. The final goal is to have a comfortable and functional pet return to their owner. Multiple factors affect oxygen delivery to the cells; however, in general terms O2 delivery depends on O2 being delivered to the alveoli, effective gas exchange, the presence of sufficient hemoglobin to carry the O2, cardiac output, and adequate flow to the tissues. Cardiac output is determined by circulating blood volume, cardiac muscle strength, vascular tone and heart rate. "High Priority Resuscitation" that is resuscitation issues involving the trauma patient that can not wait which MUST be addressed immediately upon arrival are those aimed at maximizing oxygen delivery. The treatment must be appropriate and must be provided in a timely manner.

Research has shown that if cellular hypoxia to the gastrointestinal tract in dogs continues beyond an hour even though global resuscitation appears adequate death from organ dysfunction and sepsis from gastrointestinal bacterial translocation and endotoxin absorption across the gut wall will likely occur a day to several days later (Shoemaker). Irreversible cellular apoptisis (programmed cellular death) may also occur as an aftermath of the cellular stresses secondary to the global effects of the injury.

THEREFORE successful care reiterated requires timely and accurate patient examination, assessment and treatment in proper sequence according to physiologic priorities. Since all three of these components occur simultaneously in the injured, all three are included in the decision making that must performed accurately and in as short of times as possible. One thing that can not be bought is TIME. Therefore the decisions not only have to be accurate but also with expedience.

PRACTICAL READINESS

Facitilites, Equipment and Supplies

Ideally to be the most ready to handle emergency patients requires an ongoing effort that begins each morning and continues for the following 24 hours. Supplies and drugs are checked and stocked; and equipment is checked to ensure good working order. All is made ready. When anything is used it is restocked as soon as possible. Areas of particular concern are emphasized:

READY AREA: To treat a seriously injured or ill patient urgently in need of immediate care, soon enough to prevent catastrophic consequences, requires the hospital to be maintained in a state of readiness. For efficiency one centralized area for initial assessment and management should be used. Often the best central "ready" area is usually near the operating room, and is ideally the anesthesia induction and surgical prep area. All seriously injured or ill animals are initially examined and treated in this area. This location should be the area where in-patient emergencies are also treated, except for those that occur in the operating room. The operating room must also be equally as equipped for immediate surgery.

OPEN SYSTEM & CHECK LIST: All resuscitation equipment and necessary drugs should be organized in this area. These materials should be packaged or stocked to facilitate ease of location and use. Open shelves and bins with needed items and drugs is ideal as it allows rapid procurement by all staff. Doors and drawers do not have to be opened or labels read in the open system. The use of a daily check-off list of the ready area's equipment and drugs will insure that the area is always prepared. Following any use of the area for patient resuscitation the check list is reviewed again. Any materials needing restocking are then charged to the client involved and the restocking is completed.

CRASH CART: It is suggested that drugs, instruments, and equipment that may have to be shared between the ready area and the operating room should be kept on a mobile "crash cart. Drawers in the cart are organized into Airway, Catheters, Drugs, Instruments (to open the chest and cross-clamp the aorta), Special Items (such as tracheotomy tubes, chest tubes, Heimlich valve, doppler flow detector, back-up items, etc.)

WALL CHART: A wall chart indicating drug dosages, standard fluid administration volumes/rates, and direct current watt-second defibrillation levels (based on estimated body weights) is recommended.

LIGHTING: The ready area requires good lighting, similar to that required in the operating room. Dual lights that can be directed at divergent angles are especially important for the care of the seriously injured patient. These patients frequently require emergency surgical procedures that demand this availability of good illumination, e.g., venous cutdown and slash tracheostomy. A focusing high-intensity cool beam light (very useful for close/exacting or deep cavity work) and a wider beam reflecting dish light for general full-body illumination are recommended. A back-up emergency flash light system should be readily available in the even electrical power is interrupted. A "Snake Light" is recommended to be stored in the crash cart.

KEY EMERGENCY ITEMS: Key items that are mandatory for the care of catastrophic injuries or illnesses include suction, oxygen, laryngoscope, major surgery pack including a curved Mayo scissors and a Balfour retractor. Assorted catheters, suture, sterile towels and drapes, and emergency drugs such as epinephrine, atropine, and lidocaine are required. These will be discussed later in more detail.

MEDICATIONS, FLUIDS, BLOOD, PLASMA, COLLOIDS: Other drugs and biologics such as a first generation cephalosporin, dextran 70 or hetastarch for plasma expansion, plasma and whole blood (or a walking donor program where blood for transfusion that can be collected on an emergency basis), are also key and irreplaceable. The availability of fresh homologous whole blood, in particular, is paramount in the treatment of most catastrophic injuries because severe blood loss is a common problem in the cases. Even in the shock patient (not suffering from severe blood loss), the need for plasma or some other colloid for volume replacement is vital. Recent studies have shown that vascular compartment expansion or replenishment is only short lived if a crystalloid such as lactated Ringers solution (LRS) is used . In less than an hour over 80% of the LRS is no longer in the circulation and instead is found in the interstitium. The use of oxygen carrying colloids like Oxyglobin for blood volume resuscitation is also recommended when whole blood is not immediately available. In the multiple trauma patient, particularly in those with lung or head injury, and there are many, the over-expansion of the interstitial space, (common with the rapid administration of "one blood volume" with a crystalloid) may be especially damaging. Increased amounts of interstitial water over normal values, clinically evident as edema, have been associated with higher morbidity and mortality in humans suffering from multiple trauma. This is in contrast to vascular volume replenishment with a colloid where only a few percentage points of the material are in the interstitium after 12 hours. Therefore the bottom line tells us that there is no substitute for blood and blood components, such as plasma, in the successful resuscitation of the catastrophic injured patient.

In the drug drawer all should be in multiple dose vials or in containers that are easily accessible. A section of foam rubber should line the drawer and holes cut out that hold the bottles on their side with the label on the outside. Next to each bottle a space should be made that holds 2-3 syringes that are loaded with hypodermic needles. Whenever a drug is needed the syringe is used to pull-up the drug from the bottle and it is administered intravenously, introsseously, transtracheally, intracardiac, or deep intramuscularly in the epaxial muscles. The following drugs are those needed in emergency situations:Epinephrine for cardiac arrest, anaphylaxis, extreme hypotension, severe bradycardia, severe bronchospasmAtropine for bradycardia, vasovagal reflex hypotension, bronchospasmLidocaine for ventricular tachycardiaGlucose for severe bradycardia, severe shock, severe hyperkalemiaMethylprednisolone sodium succinate for severe shock, head or spinal cord injury, anaphylaxis, asthmaDiltazem for malignant hypertension, supraventicular tachycardiaDopamine for hypotension, spanchnic blood flow support, bradycardiaDobutamine for cardiac failure, shockMannitol for cerebral edema, spinal cord edema, shock .Adensosin for supraventricular tachycardiaMidazolam for severe seizuresHetastarch for colloid fluid supportInsulin for hyperkalemia and hyperglycemiaPolyvalent antiserum for rattlesnake biteMagnesium sulfate or chloride for arrhythmiasSuccinylcholine hydrochloride and Atricuruium for muscle blockagePentobarbital for head injury or seizure control

SPECIAL EQUIPMENT: ffective treatment of serious injuries demands the availability of key equipment that is usually not required for the management of many other conditions. There is also often no substitute, and the lack of this equipment directly jeopardizes the patient's chances for recovery. Key equipment required is listed in the Veterinary Emergency and Critical Care Societies publication Guidelines and Standards of Emergency and Critical Care Facilities in the United States. An example of a key piece of equipment that is required is a suction unit for the evacuation of vomitus, blood clots, thick exudate, or saliva from the pharynx, larynx, and trachea to gain a patent airway. This instrumentation includes: the suction trap bottle, suction tubing, several types of aspirator tips (Yankauer aspirator tip for pharyngeal aspiration, dental

tip for rima glottis and tracheal suctioning, and tracheal-whistle tip-catheters for tracheobronchial tree aspiration), and suction capable of generating up to 300mmHg of vacuum that can be obtained within 4 seconds of clamping the tube. The dental suction tip is used for the aspiration of large pieces of vomitus and clot from the while the whistle tip catheters are used for the aspiration of frothy secretions, vomit, exudate and blood. An endotracheal tube with suction applied to the connecting end can also be used to evacuate particulate debris from the pharynx and upper airway.

Interposition of a suction trap at the base of the dental suction tip or endotracheal tube "suction tip" device will prevent clogging of the latex connecting tubing with large amounts of debris or blood clots. A trap has been described that fits directly onto the endotracheal tube. This allows effective suctioning during the act of intubation and can save valuable seconds. It is recommended that for the "state of readiness" that either a Yaukauer tip, medium sized dental suction tip, or endotracheal tube (with an inflatable cuff) be attached to the suction unit via a 6' section of 5/8" tubing and that the other suction attachments be close at hand so exchange can be done quickly. A section of suction tube with a side hole. This tubing can be used to aspirate the pleural space that is continuously accumulating air or air and blood in spontaneous pneumothorax or trauma cases.

OPERATING ROOM AND IMAGING: Maintaining facility readiness in regards to the management of the seriously injured patient applies to the operating room, intensive treatment (care), x-ray, and laboratory areas as well. In some cases the patient may go directly to the OR for resuscitative management. Ideally, effective use of diagnostic radiology requires capabilities for rapid radiograph exposure and development, thus the need of at least a 200 to 300 MA X-ray unit and an automatic film processor. Ultrasound capabilities are paramount for emergency assessment. It has been life-saving in the diagnosis of diaphragmatic hernia, traumatic ventral hernia, necrotizing pancreatitis, liver and splenic mass hematoma and hemorrhage. Readiness should also include the operating room where everything should be laid out and ready for the execution of a resuscitative thoracotomy or celiotomy or both as well as cross-clamping of major arterial or venous bleeding sources. Operating room equipment includes suction, good lighting, surgical headlight, sterile instrument pack, lap pads, silicone sheeting, polypropylene on taper needles size 2, 1, 0, 00, 000, 4-0, 5-0, 6-0 and cutting needles size same as the taper sizes. Maxon and Vicryl, and 0, 2-0 silk free ties. 5-0, 6-0, 7-0 polypropylene or polybutester.

SURGERY CAPABILITIES: Because major surgery is often required as part of the resuscitation of patients with catastrophic injury, it is important to have an operating room and the equipment and supplies necessary to perform such surgical procedures that may involve the "acute chest or acute abdomen patient". These are as follows:

* resuscitative thoracotomy (performed w/in 30 second)* pericardotomy* aortic cross clamping* exploratory thoracotomy* lung lobectomy* chest tube thoracostomy* wound exploration* repair or ligation of major vessel bleeding* tracheal repair and tracheostomy* exploratory laparotomy with autotransfusion* liver lobe resection* splenectomy and partial splenectomy* intestinal resection and anastomosis* nephrectomy* cystorrhaphy (continued)* diaphragmatic herniorrhaphy* abdominal wall herniorrhaphy

LABORATORY: In-house determinations of hematocrit, total serum solids, platelet numbers, white blood cell counts and differential cell counts is a standard requirement. Capabilities for determination of blood

glucose, activated coagulation time, blood urea nitrogen, serum electrolytes, blood pH and blood gases and cytologic evaluation of urine, body cavity fluids or lavage samples are life saving in many cases. Hospitals that can't perform these tests should make alternative arrangements e.g., setting up a protocol to have the tests performed at a local human hospital or reference laboratory.

Personnel

PERSONNEL AND MENTAL READINESS: Readiness requires that hospital personnel be mentally and physically prepared. In-hospital training and drill sessions are recommended. Assessment and resuscitation team skills are practiced. When catastrophic traumatic emergencies happen everyone on the staff must know their assignment and be able to perform it well. Drill sessions facilitate the practice of psychomotor skills and working as a team, providing for effective and efficient treatment of critical patients. Ideally at least three experienced professional and technical personnel should be present and involved in the treatment of animals presented following serious injury (polytrauma), particularly chest injury with ventilation compromise. Some of the required technical support can often be provided by receptionists, maintenance workers, or bookkeepers. These individuals can be trained to assist with restraint and to perform basic life support tasks. If an adequate number of professional or paraprofessional members of the team are not present alternatives might include:

1. The enlistment of bystanders or the owner. Although this involves an increased risk of liability and more effort on the doctors part concerning communication and direction for these individuals.

2. Calling other professionals off duty or from another practice. This can work in all but the most catastrophic conditions, especially if an "on - call roster" and agreement is worked out ahead of time and the "response time" is usually under 15 to 20 minutes.

In veterinary medicine logistics play a huge roll in the ability to successfully treat as well often because the manpower and facilities are quite limited and 24-hour care is not possible. Solo practitioners may have to use the owners and family members as part of the team needed to accomplish the care required. The author also has used high school and college students on an "on call bases". This "shock-trauma team" becomes "activated" by a pager system after school, week-ends and holidays after a short training program that includes basic anesthetic monitoring, assisting in surgery, circulating in the operating room, and basic ICU examination and skills. They are placed on call and receive both financial and educational rewards when team members are called in.

Other less optimal methods of providing the help needed to be able to operate a critical trauma case involve using an on-call schedule of the regular employees at the hospital, involving untrained volunteers, or even using the patient's own owners in a crisis situation such as having them sitting on a stool and providing positive pressure ventilation buy manually squeezing an AMBU or resuscitation bag during repair of a diaphragmatic hernia done under intravenous oxymorphone (an opioid agonist) and atricurium (a non-depolarizing muscle blocker). (Note A depolarizing muscle blocking agent such as succinylcholine can also be used to cause rapid physiologic myoneurojunction blockade allowing intubation and uncompromized ventilation) . The suggestion to use owners as part of the "resuscitation teasm" is of course not the best. However it does provide at least someone that can assist in a life-or-death situation. There are risks that must be weighed into the decision to involve owners in the care of their own pets in these life-and-death cases however.

Training of the staff can not be overemphasized and a method of training that makes it enjoyable and in which the staff retain much of the information that is taught is to use case based scenarios. Drill sessions in the Ready Area can also be done to hone skills and teamwork. Weekly half-hour service training sessions is also a method of introducing new methods of management and new equipment.

Emergency patients that require definitive body cavity surgery as part of the resuscitation should be managed by a team that includes at least three personnel in the operating room; surgeon, assistant surgeon, and anesthetist - circulating nurse. Ventilator assistance and careful anesthesia monitoring is always required in

these patients and having assistance in surgery greatly facilitates intraoperative effectiveness and speed. Provided that mechanical ventilatory assistance is available then one person may be able to function as anesthetist and or circulator. But this is still not ideal

DRILLS: A stuffed toy dog can be used to simulate an "HBC patient" presented in shock and unconscious. Review sessions are held at the conclusion of the drills to evaluate team performance in a positive and constructive manner. These sessions can also be used to introduce and test the feasibility of new treatment protocols

PROTOCOLS: Emergency and critical care protocols for general assessment, management, treatment for specific catastrophic injuries or illnesses are recommended. These protocols should be printed and reviewed at staff meetings. They may also be posted in key areas in the hospital or the "ready" area where they can be referred to easily. They act as guidelines and mental reminders for the staff and clinician in-charge; increasing team efficiency, and helping to prevent assessment and management mistakes.Each protocol may be organized in a numerical or alphabetical list of steps to follow, or in an algorithm. Protocols should be reviewed and revised as required periodically to insure they remain current, easily understood, and effective in the setting they are used.

TRIAGE

The term triage, derived from the French verb trier (meaning to pick or cull) was used originally by French wool traders as they sorted wool into various quality categories. Larrey, a French military surgeon in Napoleon's army used the term triage to identify the act of sorting solders that were injured. His military triage was used to identify those injuries that could be repaired urgently and easily to hasten the solder's return to battle. Although for quite different reasons the system of triage is now used in both human and veterinary medicine for prioritizing care according to urgency in order to save lives and to decrease morbidity.

The act of triage in the management of the emergency patient involves three steps:

1. Evaluation of the facility and team that will be providing the care . The level of care that can be accomplished was proposed and published by Crowe et al in 1985. Level 1 = 24-hour full care facility with ICU manned and with ventilatory support. Level 2 = 24-hour care w/o ventilatory support. Level 3 = non-24-hour facility with advanced emergency equipment. Level 4 = non-24-hour facility with basic emergency equipment. Knowing ones capabilities allows for accurate decision making and honesty in receiving patients and making referrals. It also encourages a good working relationship among practices in a local or regional area. It is highly recommended by this author.

2. Preparing for emergency patients ahead of time . This involves identifying an area in the facility where the critical patient will be immediately taken upon arrival, called the Ready Area, and preparing this area as best as possible for the patient's admission. The area should include as a minimum those items listed in table 1. Preparation should also include procurement of a supply of blood products and oxygen carrying colloid, preparation of the operating room immediately after each surgery is over for eminent use for an emergency medical or trauma patient, and preparation of other key areas of the hospital for STAT use: imaging (radiology and ultrasound), clinical laboratory, anesthesia and surgical preparation, ICU. The development of protocols and team training are also ideally part of the preparation of a facility for the care of the major-trauma patient.

3. Care of the "incoming patient" with the initial act of assessment and management beginning at the scene of the accident by owners or bystanders. Assessment and care often starts with the answering of the phone by veterinary hospital personnel. If an owner with an injured pet calls the call should be immediately forwarded to a doctor or experience VMT (veterinary medical

technician), unless the receptionist has the training to be able to give suggestions for at-the-scene care and transport. Basic life-support instructions can be given over the phone. Experience has proven that owners can provide effective rescue breathing and stop major external hemorrhage. They can be instructed to on how to transport the injured pet on a flat object which globally splints and immobilizes the abdomen, spine pelvis, and limbs. Experience and research has proven this treatment to be important in the management of internal hemorrhage, fractures, luxations, and spinal injuries.

First-aid courses, given by veterinarians and VMTs, are recommended as a community service to teach knowledge and skills to lay personnel that can be life-saving in the care of injured pets. Morbidity has also been lessened through the use of first-aid measures applied at the scene of the injury, e.g., the muzzling of the dig before transport decreases the incidence of human bites and splinting of an obviously unstable radius and ulna fracture decreases continued soft-tissue injury and the incidence of open fractures.

4. Assessment and sorting of the patient according to the priority of need when the owner and patient arrives at the hospital. As the pet arrives the receptionist immediately announces their arrival by intercom or overhead and a VMT or doctor is immediately summoned to perform 'triage' in the reception area.

The patient is quickly assessed and a brief history is gotten the patient is placed into one of four categories:

Code red: Immediate Life-threatening. Category 1Code blue: Possible impending life-threatening. Category 2Code yellow: Emergency but not impending life-threatening. Category 3Code green: Stable and sure is not life-threatening Category 4Code black: Not salvageable, requires euthanasia or is dead. Category 5

TRIAGE ASSESSMENT: The professional (dcoctor or veterinary nurse) upon arrival begins assessment by noting the following: LOC (level of consciousness) and AVPU scoring is made (see below) Airway patency by listening for increased or absence of airway sounds Breathing rate and effort is determined by watching the chest movements Strength and rate of central pulses or heart tones by palpation/auscultation Color of mucus membranes and capillary refill time. Examination for any outward abnormalities that place the patient in category 1-3 such as active

hemorrhage, sucking wounds in the neck or chest or an expanding abdomen.

The above steps are only done if it is determined that assessment can be done with reasonable safeness. If safety appears in jeopardy then only assessment from afar is performed while a history is obtained.

LOC is assessed from afar and those conscious but not exhibiting a normal level of alertness (A) are placed into a "code blue" level of triage (also designated level 2) and are recommended to be immediately taken to the ready areas if it is unoccupied. Those that are semiconscious react to externally to stimuli and can be placed as either verbally or visually responsive (V) or only responsive to painful stimuli (P). The pet should be continued to be carried by the owner back to the ready area without separation by the owner. Those that are unconscious (U) are placed into a "code red" level of triage (also designated level 1) and immediately taken to the ready area.

IMMEDIATE QUESTIONS WE ASK: It is recommended to ask owners of code red or blue pets, as the transfer to the ready area is done, if resuscitation can be stated. We commonly ask the question: "can CPR be stated if its necessary ranging from starting an IVand getting a patent airway (putting a breathing tube in) to giving breaths and emergency drugs or opening the chest to do heart compressions". A shortened version is "can we begin oxygen and start an line"? then if deemed necessary we comeback and ask quickly "can we start CPR?" or "can we do a tracehotomy?" or can we do immediate surgery to try and stop the bleeding?"

CRITERIA INDICATING CATEGORY 1 OR CODE RED PATIENTS: Given the economics and logistics involved in most small practices the following is a list of criteria that identify the patient that will need to be operated on an immediate or as near immediate basis to be life-saving in "category one" or "code red" and there is no time for transport to a referral center:

1. Airway obstruction that can not be managed conservatively with endotracheal tube placement and anti-edema therapy. An emergency tracheotomy will be required minimally. If intrathoracic tracheal obstruction is present that can not be relieved a rapid thoracotomy and intubation on the bronchial side of the obstruction will be required. Cardiac arrest is eminent. Open chest CPR will be required if arrest occurs.

2. Increasingly difficult breathing pattern and rising rate despite high-flow oxygen supplementation and a positive thoracentesis with continued blood or air being aspirated continuously via large bore catheter or chest-tube placement. A thoracotomy or parasternotomy will need to be accomplished, source of the air or blood found and controlled and positive-pressure ventilation and volume replacement continued postoperatively.

3. Increasingly difficult breathing pattern despite high-flow oxygen supplementation with a diaphragmatic hernia diagnosed by radiograph or ultrasound. Exploratory midline celiotomy and reduction or the hernia and repair will be required. Other support (respiratory, vascular) also will be required.

4. Cardiac arrest or near arrest with a history of trauma and either increasing respiratory difficulty or shock. This requires a rapid non-prep thoracotomy and aortic cross clamping and CPR. If spontaneous cardiac function is restored then definitive care of the pulmonary, vascular, or pleural space problem will be required.

5. Deepening shock in the face of continuing significant volume replacement. The source of hemorrhage will need to be controlled surgically. This generally means opening the thorax and/or abdomen, cross-clamping the aorta temporarily, finding the source of the hemorrhage, controlling it and then replenishing vascular volume rapidly. Occasionally other areas of hemorrhage are involved including the neck from penetrating trauma; thigh from a closed femoral fracture involving the femoral vessels, or open wounds that are bleeding extensively.

Triage categories can change rapidly. Emeregncy teams (ideally made up of at least 3 care-givers versed in resuscitation skills and performing in a coordinated effort) should realize the demand placed on frequent reassessments of each patient, especially in the first few hours following injury. All patients should be considered to have a serious life-threatening injury until proven otherwise. Those triaged initially as category 4 or code green, walking in the door without any obvious injury, can and have in my experience be placed into a code red status within minutes due to the rapid development of unresponsiveness due to exsanguination! THEREFORE IT IS HIGHLY RECOMMENDED THAT ALL patients with a history of recent trauma should be admitted to the hospital or sent to a facility where monitoring can be done at least for the next 12-24 hours and where strict confinement can be enforced. My motto is "his spleen is ruptured and continuing to bleed even though he looks like he is a lucky dog"

SAFETY

Safety of the hospital staff (doctors, nurses, and receptionists) during transport and initial evaluation of the emergency patient is very important. Usually the animals are painful and the placement of a muzzle is indicated until the extent of the injuries is known. If the patient has significant facial injuries, or is open-mouth breathing, it may be more appropriate to place a cage type muzzle instead of using gauze or a cloth muzzle which avoids holding the mouth closed. During transport the owner may have been

bitten and there may be human blood on the animal. To decrease the risk of transmission of infectious diseases such as hepatitis and HIV, it is strongly recommended that gloves should be worn by doctors and nurses during the initial examination of every trauma patient.

PRIMARY SURVEY - RESUSCITATION

Appropriate treatment of the trauma patient can be instituted only if the patient has been evaluated appropriately. From the time the pet is presented to the hospital to the time it is discharged primary surveys should be performed frequently. In the triage setting the survey should be quickly performed. It always is done the same. At other times it is performed in a slower paced setting. The survey examines breathing effort and respiratory pattern, abnormal body or limb posture, the presence of blood or other materials in or around the patient, and any other gross abnormalities. Level of consciousness as discussed before is assessed along with airway, breathing, and circulation effectiveness. If the animal is unconscious the head and neck should be extended to help provide a clear airway, assuming there are no concerns for a cervical spinal injury. The airway (nose, mouth, pharynx, and trachea) is checked for patency by looking, listening, and feeling. Appropriate precautions always should be taken when examining a patient’s oral cavity and oropharynx to ensure no one is bitten. Fingers should never be placed into the mouth of an agonal patient as this can lead to a serious injury.

The presence of increased respiratory effort, paradoxical chest wall movement, abdominal wall movement with respiration, nasal flare, open mouth, extended head and neck, abducted elbows, and cyanosis are all indicators of respiratory distress which require immediate treatment. Breathing is assessed by watching chest wall motion as well as listening to tracheal and lung sounds bilaterally. It is important to auscult lung sounds bilaterally since the animal may have a significant unilateral pneumothorax or hemothorax. Lung sounds always should be ausculted prior to listening to heart tones since the ear is much less discerning of softer sounds once it has adjusted to louder sounds. Circulation is assessed by checking mucous membrane color and capillary refill time, and ausculting for heart tones at the same time as central (femoral) pulses are palpated. Finally a very rapid assessment and palpation of the abdomen, flank, pelvis, spine and limbs is carried out.

If major abnormalities are noted then treatment is instituted immediately. For example, if the animal is not breathing it should be rapidly intubated and ventilated. Then the remainder of the primary survey is completed. During the primary survey, initial resuscitation of the patient is begun and external hemorrhage is controlled. Direct digital pressure placed on bleeding vessels or areas is the initial resuscitation measure taken and works in the majorityof cases. Hemorrhage control will not be discussed in this paper per se. It will be referred to in a subsequent paper presented at this conference).

In the severely traumatized patient it should be assumed that fractures are present until proven otherwise and ideally the patient should be restrained to prevent further injury. Restraint should be minimized if the patient is likely to injure itself further by struggling, if restraint will compromise the airway, breathing or circulation, or if restraint will cause the patient more pain. If there is concern that the patient may injure itself further if it is not restrained it may be appropriate to consider sedating the animal. Laterally recumbent patients or those with spinal injuries can be immobilized effectively by taping the animal to a board using duct tape. Tape is placed over bony prominences to avoid interfering with respiration. Tape can be placed over the rostral aspect of the patient at the level of the wing of the atlas, over the cranial thorax at the level of the scapula and caudally over the wing of the ilium. Backboards made from Plexiglas are useful because not only are they sturdy, but the animal can be visualized on all sides, and radiographs can be taken without having to remove the animal from the board.

VITAL SIGNS AND SECONDARY SURVEY

Once the primary survey is completed VS (vital signs) data is collected . This includes a thorough history taking session with the owner while staff are collecting VS data. This data includes HR., PR, PS (pulse strength) RR, R E (respiratory effort) (0-3 with 3 being the worst)), BP if possible , Jugular vein distension ability with occlusion, normal is distension visible and noted within 3 seconds, then with relation of pressure on the vein the relation time should be 3 seconds. Temperature by rectal should be avoided if there is any possibility of inducing a vagal nerve response. Cases on record have proven that vagal and sympathetic tone is heightened with respiratory compromised patients and vagal induced cardiac arrest have occurred in cases with hypoxemia, when the patient's rectal temperature was obtained. Information from individuals that had seen the accident will be very contributory to the mechanism of injury. A thorough physical exam should be performed starting again with the airway.. This should be done in the same manner in every patient to ensure no abnormalities are missed. A useful mnemonic as a guide for assessment of all important body systems is A CRASH PLAN.a

Visualization, palpation and auscultation are performed as required to assess these:A Airway It takes a 70 % obstruction = increased sounds. 100% = no sounds. C Cardiovascular Assess jugular vein distension time, amount, relaxation timeR Respiratory Examine respiratory pattern, rate, effort and auscult all lung fieldsA Abdomen Examine each quadrant UR,UL, LR,LL with umbilicus as centerS Spine Palpate spinous processes and assess sensation, movement, and reflexesH Head Palpate skull, check LOC, pupil light responses, eyes, ears, nose, throatP Pelvis Palpate pelvis, auscult coxofemora, ROM, do rectal, check genitalia L Limbs Palpate, check ROM each limb, check color, warmth, sensation of toes, A Arteries and Veins Palpate brachial and femoral arteries, color of toes, edemaN Nerves Assess sensation and movement of each limb, check skin and pads

A second set of vital signs should be taken and recorded after the secondary survey is completed. This includes respiratory rate and effort, heart rate and rhythm, pulse rate and strength, arterial blood pressure by doppler, and temperature.

RESUSCITATION

The goal during resuscitation of all major trauma patients is to improve and ideally normalize all physiologic parameters.while at the same time providing quality and titrated pain relief. Common initial resuscitative treatment with most major traumatized patients include the following:

Providing supplemental Oxygen

Oxygen (O2 ) should be provided to all seriously injured or ill patients from the time of admission to the ready area. The physiologic reason for this that a high percentage of major trauma patients have at least some lung ventilation-perfusion mismatching and oxygen supplemented helps prevent some of the dysoxia that would otherwise have occurred because of it. Oxygen can be administered by placing tubing from an O2 tank or anesthetic machine in front of the patient’s nose and mouth and running high flow rates (3 to 15 litres/min) of O2 via the tubing. Smaller patients can be placed in clear plastic bags. The O2 tubing is placed through a small hole in the front of the bag thus creating an O2 tent. The back end of the bag is left open and the examination can be completed with the patient in the bag. Supplemental flow-by O2 should be followed by delivery of O2 by non-re-breathing face mask, oxygen hood, CROWE oxygen collar, nasal, nasopharyngeal, nasotracheal, or transtracheal catheters or the use of either adult, pediatric or infant bilateral nasal cannula (nasal prongs). The latter can be placed quickly with only the need to place a section of tape on the device to form a nose-band then the apparatus is stapled to the patient's face and the placement.

Providing a clear airway

If airways sounds are heard but the patient is unconscious it is recommended that the patient be intubated. This will prevent aspiration of mucus, blood, or vomitus, and allow artificial ventilation to be performed if is indicated. The patient should be intubated in lateral or sternal recumbency as atraumatically as possible. Prior to intubation the patient is attempted to be ventilated with a bag-valve-mask (AMBU) with an oxygen reservoir. The tongue is extended, the mouth closed on it or an oral pharyngeal airway is placed first. Prior to delivering the breaths the esophagus is occluded digitally by pushing ventrally on the midline after the trachea is deviated to the right. After a few breaths are provided the tip of a curved MacIntosh laryngoscope blade is placed so that its tip is in the pre-epiglottis vallecula. The laryngoscope is used to minimize laryngeal stimulation which can cause a vagal arrest. Elevating the patient’s head to intubate may precipitate an arrest if the patient is hypotensive. Suction of the airway is performed as necessary to clear blood and secretions. This can be done using a Yankauer suction tip attached to an electric suction machine. A handheld suction unit (MityVac) also is effective for suctioning small volumes and is far less expensive (only costing $40-45.00). A clear endotracheal tube also can be used as a suction cannula. Clear polyvinyl chloride endotracheal tubes that have high volume and low pressure cuffs are ideal and are highly recommended.

If the unconscious patient cannot be intubated due to severe facial, laryngeal trauma, sublingual hematoma or other cause of obstruction an emergent tracheotomy should be performed immediately. An emergent tracheotomy is performed when the patient is dying due to the lack of a patent airway. The procedure, which is performed without clipping fur or performing a surgical prep takes less than 60 seconds. In the awake patient with severe upper airway compromise a tracheotomy can be performed under local anesthetic. An awake tracheotomy can also be used in the conscious or stuporous patient that requires positive pressure ventilation. In the hemodynamically unstable patient we will avoid the need for general anesthesia.

Awake Tracheotomy Procedure: I published this technique as follows: 1. Sit the patient on the edge of a table, providing blow-by oxygen as required2. Give the patient as sedative (IV acepromazine 0.1 - 1 mg PRN and IV butrophenol .5 -5

mg; these can be mixed in the same syringe; other neuroleptic combinations can also be given; a small amount of IV ketamine can be included as a third drug (0.1- 1 mg/kg)

3. A headlight is dawned after the surgical kit is opened on a Mayo pr other small stand and an endotracheal tube is selected (chose three with one larger and one smaller than what is believe to be the best based on tracheal palpation).

4. The head and neck are extended and the hair is clipped and a rapid prep of the skin accomplished. Chloroxynolol 3% is an ideal prep agent as it kills 99.9% of all pathogens within 30 seconds. Commercial products are available.

5. Place a local block in the midline midcervical region (1% lidocaine 2-8 ml) 6. Make a ventral midline incision in the mid cervical region over the trachea. 7. The sternohyoideus and thyroideus muscles are separated on the midline until the trachea

is visualized. A Gelpi or other self retaining retractor is inserted or an assistant uses hand-held retractors to provide continuous exposure to the trachea.

8. A transverse incision is made between 2 tracheal rings and the tracheostomy tube, commonly begun as an endotracheal tube is inserted. An endotracheal or tracheostomy tube is inserted, the cuff inflated and positive pressure ventilation immediately begun.

9. Two traction sutures are placed around the tracheal rings proximal and distal to the ostomy. The traction sutures are used to help guide the tube into the tracheal lumen when it is replaced following cleaning or if it becomes dislodged.

10. The tube is secured by tying IV administrative tubing to it and then tied behind the patient's neck.

11. A four-by-four gauze square is folded or cut to make a "pair of pants" dressing and this is used to cover the wound. This dressing is changed as required.

12. Suction of the tracheotomy tube is performed as needed, generally done every 8 hours as a minimum. The tracheotomy tube is changed a minimum of once per 24 hours.

The severed or severely injured trachea in the trauma patient: Rarely the trachea will be severed or separated by traction and a cervical incision or parasternal approach to the chest and trachea will be necessary on an emergent basis. This is done with a Mayo scissors. The injured trachea is diagnosed by noting poor lung inflation without any increase in resistance when the AMBU or rebreathing bag is squeezed and contents of these bags just "disappearing" After the approach is made and the tracheal injury is found an endotracheal tube is simply inserted and positive pressure ventilation begun. The injury will then be required to be repaired.

Assessing for Adequate Breathing and for Causes of Breathing Difficulties

The respiratory rate should be recorded and the breathing pattern should be closely observed. It is important to determine the cause of tachypnea which can be an indicator of either lung dysfunction, hypovolemia, or pain. Symmetry of chest movement and the presence of any abdominal component to the breathing pattern should be noted. Abnormalities may indicate rib fracture (s), flail chest, pneumothorax, hemothorax, pulmonary contusions or diaphragmatic hernia. The chest should be ausculted for the presence of breath sounds, areas of dullness, crackles or wheezes in at least 4 quadrants (upper and lower right and left sides). Chest percussion in at least 4 quadrants may help detect areas of dullness suggesting pulmonary contusions, hollow sounds indicating a pneumothorax, or a fluid line indicating a hemothorax.

Diagnostic thoracentesis: This should be performed bilaterally in any patient in which there is concern that the patient has a pneumothorax or a hemothorax. This should be done prior to taking chest radiographs since positioning the patient for radiographs may worsen respiration and may cause the animal to decompensate. Placement of a chest tube is indicated if negative pressure is never achieved during thoracentesis or thoracentesis is required more than twice within 2 to4 hours. Chest tubes should be placed under sedation and local anesthesia rather than general anesthesia unless control of the patient’s ventilation is required.

Arterial and venous blood gases: These can be done easily using a "bed-side blood gas analyzer". One type is the I-STAT. Only a few micro-liters of whole blood are needed for the analysis. Arterial blood gases are used to evaluate oxygenation and thus provide a means of assessing pulmonary function.

Oxymeter: If blood gases are not available O2 saturation often can be assessed using a pulse oximeter. Care should be taken to ensure a good pulse signal is being received by the monitor. If the site for placement of the oximeter probe is other than the tongue, shaving the site will improve contact. Pigmented skin should be avoided. Oxygen saturation should be maintained above 92 to 94 percent.

End-tidal Carbon Dioxide: Another monitor is also highly recommended to be used. This is an end-tidal CO2 monitor. It measures the amount of carbon-dioxide at the end of exhalation by means of an infra-red sensor. Normal values are 35-45 mmHg. Values higher than 50 indicate hypoventilation and hypercarbia. Values below 30 indicate hyperventilation or if the values suddenly decrease below 20 this represents a major decrease in CO2 presented to the lung , i.e., a great decrease in cardiac output. Thus the ETCO2 monitor can be very useful in the detection of hypo or hyperventilation and pre cardiovascular failure. The device can also help determine the effectiveness of resuscitation. Research indicates a resting ETCO2 of 12 or less is associated with a poor outcome.

Chest Radiograph: IF the patient can tolerate a DV radiograph of the chest this should be taken. If a lateral can also be taken this should also be done. However at no time should radiographs be done if the patient is stressed by the procedure. Trauma films - lateral films that involved the cervical through the pelvic area are recommended IF the patient can tolerate them without increasing respiratory effort. If a spinal injury is at all suspected these films should be done as soon as possible after "clearing" the ABC part of assessment and resuscitation.

Providing Positive Pressure Ventilatory Support - If required.

Many severely traumatized patients present with pulmonary injury that worsens rapidly during the early phase of resuscitation. Patients with severe pulmonary contusions or ventilatory failure due to muscle weakness from severe shock may not respond to supplemental O2. A decision should be made to intubated and artificially ventilate the patient if cyanosis or respiratory distress do not resolve with the provision of supplemental O2, or if respiratory effort is worsening despite provision of supplemental O2. If arterial blood gases are available positive pressure ventilation should be instituted if the arterial oxygen tension (PaO2) is less than 60 mm Hg with supplemental O2, or the arterial carbon dioxide tension (PaCO2) is greater than 45 to 55 mm Hg. If the clinician feels confident that a pulse oximeter sensor is providing accurate readings, and oxygen saturation is less than 90 to 92% on supplemental oxygen, and there is evidence of respiratory distress, artificial ventilation is indicated.Emergency medical pulmonary conditions such as cardiac or noncardiac edema and severe pneumonia may also be indications for immediate ventilatory support if oxygen supplementation does not provide significant decreases in ventilatory effort.

Anesthetic agents usually will be required in order to intubate the awake patient who is deemed to need positive pressure ventilatory support. Rapid control of the airway should be the goal since a prolonged induction may be fatal to the patient. Drugs should be chosen with care as these patients are usually hemodynamically unstable and many anesthetic agents depress cardiac function and cause hypotension. Blood pressure should be closely monitored during the administration of any anesthetic agent. Etomidate hydrochloride d ( 0.25 to 2 mg/kg IV) or ketamine hydrochloride e (5 to 10 mg/kg IV) and diazepam f (0.1 to 0.5 mg/kg IV) are ideal for rapid induction. Short acting thiobarbiturates (5 to 10 mg/kg IV) or propofol (3 to 6 mg/kg IV) also can be used. Thiobarbiturates and propofol can cause significant depression of cardiac function and hypotension and should be used with extreme caution; however, they do provide a rapid induction and are preferred over mask induction. They are the drugs of choice in head-injured patients. A combination of narcotics (oxymorphone hydrochloride h [0.05 to 0.1 mg/kg IV], or fentanyl citrate i [0.02 mg/kg IV; 30 to 60 mcg/kg/hr infusion]), in combination with diazepam f (0.2 to 0.5 mg/kg IV), and neuromuscular blockers (atracurium besylate [0.25 mg/kg IV; 0.1 mg/kg redose or 180 to 480 mcg/kg/hr infusion]), provides the safest means of maintaining trauma patients under anesthesia during positive pressure ventilatory support. All anesthetic drugs should be titrated to effect since patients in shock are much less tolerant of anesthetic agents than healthy animals and these doses are only intended as guidelines. In general it is recommended to start at 25 to 50 percent of the dose used in a healthy animal.

The priorities with positive pressure ventilation are to correct hypoxemia by maintaining PaO2 greater than 60 mm Hg and to maintain PaCO2 in the range of 35 to 45 mm Hg. Initially, positive pressure ventilation can be instituted using a manually operated resuscitation or AMBU bag; however, since most of these patients require multiple hours of ventilation therapy while the injured lung tissue heals, mechanical ventilation is preferred. Peak inspiratory pressures should be kept as low as possible (below 20 cm water) to avoid iatrogenic damage to injured lung tissue. The use of positive end expiratory pressure will help decrease inspiratory pressures in the pulmonary injured patient with a high ventilation-perfusion mismatch. Therefore, if peak inspiratory pressures above 20 cm water are required to maintain adequate O2 levels, positive end expiratory pressure should be instituted. Positive end expiratory pressure can be instituted when using an AMBU bag if the AMBU bag is fitted with a valve that regulates expiratory pressure. (Most newer models have one attached.) Positive end expiratory pressure ideally should remain below 10 cm water; however, it should be kept in mind that even 3 to 5 cm water may lower cardiac output by decreasing venous return to the heart. Therefore, it is very important to ensure adequate intravascular volume is maintained, and that BP and urine output are monitored closely. If cardiac contractility is depressed secondary to the trauma positive inotropes may be required. (see below).

Tidal volumes of approximately 10 to 15 ml/kg should be used and the ventilatory rate should be adjusted to maintain the PaCO2 in the desired range. The trauma patient has increased oxygen demands and PaO2 should ideally be maintained in a high normal range (80 to 100 mm Hg minimum). Oxygen toxicity may occur within 6 hours of breathing inspired concentrations of 100 percent O2 and levels should be reduced to below 60 percent as soon as it is feasible. However the inspired O2 concentration never should be reduced prematurely since hypoxia may be fatal.

The decision to provide artificial ventilatory support should not be undertaken lightly. These patients require intensive monitoring and 24 hour care. If a pneumothorax was present prior to starting ventilation therapy then unilateral or bilateral chest tubes will be required rapidly since positive pressure ventilation will worsen the air leak. Trauma patients on ventilators may develop pneumothoraces because the added pressure from the ventilation can rupture injured lung tissue. The lungs should be ausculted bilaterally at least hourly. Any decrease in airway sounds during auscultation of the thorax, any unexplained decrease in PaO2, or any increase in PaCO2, may be an indicator of a pneumothorax and thoracentesis should be performed. If blood gases are not available pulse oximetry and capnometry using an end-tidal CO2 monitor will help evaluate the effectiveness of ventilator therapy.

Accurate Assessment of Circulation

Auscultation and palpation: The heart is ausculted for the presence of murmurs and arrhythmias and the intensity of the heart sounds is noted. Dull sounds may indicate severe hypovolemia, pericardial effusion, pneumothorax, hemothorax, or diaphragmatic hernia. Pulses should be palpated centrally (femoral) and peripherally. The strength should be characterized and the presence of pulse deficits noted. Tachycardia (>140 in dogs and >220 in cats signify sympathetc amplification of rate and common causes in the emergency patient are pain, anxiety, hypovolemia or heart failure. In cats just the opposite commonly occurs with the heart failure; with pulses and heart rate being 140 to 170. Pulse strength that feels weaker than normal or "thready" signifies a narrow pulse pressure which is commonly caused by pain or hypovolemia. It can also be caused by pump failure. Jugular Distension Time and Amount; Jugular veins should be clipped and checked for distention since this can provide an estimate of central venous pressure (CVP). The presence of jugular distention in trauma patients in shock is most likely an indicator of increased intrathoracic pressure. In the previously healthy animal this may indicate a pneumothorax or pericardial tamponade. If the animal has underlying heart disease jugular distention can be associated with right heart failure. Jugular distention time and relaxation time also should be noted since they may provide an estimation of CVP. Normal JVD Time should be 3-4 seconds (that is the length of time in seconds from the time digital occlusion of the jugular vein is performed to the time the vein is fully distended. JV Relaxation Time normally is between 1 and 2 seconds. Greated than 2- 3 seconds indicates a delay in venous outflow in the cranial vena cava. This is common with heart failure, pericardial tamponade, tension pneumothorax, or heart base tumors. A jugular vein that remains flat and cannot be raised with digital pressure at the thoracic inlet is consistent with significantly decreased CVP and in most cases represents significant volume depletion (either relative or definitive).

Membrane color and refill time: Mucous membrane color and capillary refill time should be recorded. Normal color is pink. Red indicates vasodilation. Pale indicates vasoconstriction. There are many causes for each. In the emergency patient sepsis and endotoxemia should be thought of as the primary causes of the former and hypovolemia and pain as the principle causes in the later. Normal refill times are between 2-3 seconds. More rapid and more slow times are associated with hyperdynamic and hypodynamic causes respectively. These commonly include septic and endotoxemia in the former and hypovolemic shock and pain in the later.

Toe web temperature: Toe web temperature should be taken and compared with the rectal temperature. Toe web temperature is taken by placing a thermometer between a digital pad and the metacarpal/metatarsal pad. A difference of greater than seven degrees Fahrenheit is strongly suggestive of poor peripheral perfusion. Research by Kolata has revealed that a delta T greater than 7 degrees is associated with a decrease in cardiac output.below adequate perfusion of tissues. Clinical reseach has also shown that toe-temperature is a better indication of peripheral perfusion that capillary refill time.

Blood Pressure: Ideally arterial blood pressure (BP) should be measured during the secondary survey as one of the patient’s vital signs, since knowledge of the patient’s BP is very important during resuscitation. Baroreceptors are stimulated in hypotensive patients which causes the heart rate to rise.

Knowledge of the heart rate and the BP can help guide fluid resuscitation. (Table 2) There is a wide range of reported normal BP for dogs and cats. In the authors’ opinion patients who present in shock should be resuscitated to a systolic BP between 110 to 130 mm Hg and a diastolic BP between 60 to 80 mm Hg. IF NO EVIDENCE OF HEMORRHAGE IS PRESENT. Mean arterial pressure (MAP) should be maintained above 60 mm Hg to ensure renal perfusion in these cases. Mean arterial pressure can be calculated only if both systolic and diastolic BP are measured using the following formula:

MAP = diastolic BP + (systolic BP - diastolic BP)/ 3

Blood pressure can be recorded directly or indirectly. Direct BP measurement is the most accurate but requires placement of an arterial catheter which often is not practical in the emergency setting. Indirect BP measurements can be recorded using a Doppler ultrasonic flow detector, oscillometric device or a photodetector. Doppler flow detectors are preferred over oscillometric and photodetector devices since they also allow the clinician to assess flow to the periphery of the limb to which the ultrasonic flow probe is attached. Frequently irregular heart beats such as premature ventricular contractions can be detected using a Doppler ultrasonic flow detector.

Recent data suggests that diastolic BP can be consistently measured using a Doppler flow detector. (Devey) Digital palpation of femoral or peripheral arteries may not provide an adequate assessment of BP. The ability to detect pulses depends on the degree of vasoconstriction, pulse pressure (difference between systolic and diastolic BP), and skill of the clinician. During a recent study more experienced clinicians were able to determine femoral pulses down to a systolic BP as low as 30 mm Hg.

Clinical use of an indwelling 3 Fr 15 cm polyurethane catheter (Cook Veterinary Products) placed within the cranial tibial artery for the measurement of arterial pressure and the procurement of blood gases. The technique is not difficult in dogs greater than 20 kg in size. A small cutdown is first performed to allow visualization of the artery. A curved hemostat is then used to help elevate the vessel and then, using the Seldinger Wire technique, the catheter is inserted.

IF HEMORRHAGE IS SUSPECTED then the blood pressure accepted is 30 to 40 degrees below the cutoff provided for both systolic and diastolic. This is to provide an amount of hypotension that might be helpful in decreasing or arresting blood loss yet not so low as place renal or gastrointestinal cells in jeopardy.

Central Venous Pressure; Central venous pressure monitoring can be measured if . Ideally a jugular catheter should be placed, although a hindlimb catheter that extends into the abdominal vena cava may provide accurate measurements. (Machon) In medium and large dogs commercial catheters are not long enough to reach the abdominal vena cava. In this case a long feeding tube can be placed through a 16 or 14 gauge peripheral catheter. A 2 inch 14 gauge of 16 gauge over the needle catheter is inserted and the stylet is withdrawn. A 3 Fr or 5 Fr feeding tube respectively, is fed through the catheter to the premeasured distance. The catheter is withdrawn from the limb and the feeding tube is sutured in place and covered with a sterile dressing. The use of abdominal vena cava measurements has not been validated in trauma patients. Central venous pressure can be measured using an electronic transducer or a water manometer. It also can be estimated using an intravenous fluid bag attached to the central catheter The bag is simply lowered until the drips stop dripping in the chamber. The fluid line can also be disconnected and used as the "monometer".

Assuming no intrathoracic pathology, CVP is a reflection of preload or venous volume returning to the heart. Since adequate cardiac output depends in part on preload, CVP should be monitored as a guide to fluid therapy. Although normal CVP is reported to vary from between 0 and 10 cm of water, the goal during resuscitation should be to maintain the CVP between approximately 5 to 8 cm water provided active hemorrhage is not anticipated or known to be present. If active hemorrhage is of concern then CVP from 1-3 is aimed for. Measurements of CVP are affected by the pressure within the cavity in which the tip of the catheter is located. For example a pneumothorax will raise intrathoracic CVP, and increased intraabdominal pressure from bleeding may raise intraabdominal CVP.

Doppler detected blood flow: This is a mandatory monitoring parameter that must be observed throughout the assessment and resuscitation phase in each trauma patient if at all possible. In my opinion flow assessment is much more important than blood pressure assessment. It can be easily done by clipping the hair off the palmar arterial arch and then taping a 9 mm flow piezo-electric crystal probe to the foot in this location. The unit is turned on and arterial flow is assessed by auditory means; amount of flow during systole based on loudness, strength of the upstroke of each cardiac contraction based on sound during the early portion of systole, and heart rate. The doppler flow detector can also be used to interrogate the aorta in the unconscious pet by taping the probe to an esophageal stethoscope. Flow through the jugular vein can also be assessed by using the doppler unit. Throughout the admission and resuscitation phase blood flow is monitored. The sound of the blood flowing by the sensor provides a beat by beat monitoring tool that I have found second to none If the sound gets weaker this generally indicates less flow and therefore less perfusion. If the flow gets louder the opposite is assumed. Heart rate is also detected by listening to the doppler flows. It is an invaluable tool in monitoring during phases of care that are critical such as in the immediate admission period, during anesthesia, postoperatively in recovery, and anytime resuscitation is being accomplished.

Providing Cardiovascular Volume and Support as Required

Fluid Resuscitation

Since most trauma patients are suffering from a loss of effective circulating blood volume secondary to hemorrhage, fluid therapy forms the cornerstone of resuscitation for the patient in shock. Large bore peripheral or central catheters should be used for vascular access because these patients may require large volumes of fluid in a very short period of time. Fluid therapy consists of the use of both crystalloid (isotonic and hypertonic) solutions and colloid (biologic and synthetic) solutions. (Rudloff) In the patient with uncontrolled hemorrhage, fluid resuscitation may need to be restricted until the hemorrhage has been controlled. If the actively bleeding patient is aggressively resuscitated with fluids hemorrhage may worsen, and systolic BP should not exceed 90 to 100 mm Hg until the hemorrhage is controlled. This is a controversial form of resuscitation called hypotensive resuscitation which will be discussed in more detail in a subsequent article. Attempting to normalize BP before significant hemorrhage is controlled may lead to a worsening of the shock state, a coagulopathy from both loss of clotting factors and dilutional effects of the crystalloids, and increased post-resuscitation complications, especially tissue edema.

Crystalloids. These should be thought of as interstitial rehydrators not intravascular volume expanders. Sodium is the major electrolyte in crystalloid solutions and sodium concentrations in the different body compartments govern the distribution of crystalloid fluids. Within 1 hour approximately 75 to 80 percent of isotonic crystalloids administered will have redistributed to the interstitium or have been eliminated through the kidneys. (Griffe) As a result crystalloid solutions should not be administered slowly if the goal is improvement of intravascular volume. Hypertonic saline (HTS) administered as a 7.5 percent solution at a dose of 4 ml/kg body weight intravenously will cause rapid intravascular volume expansion; however, the effect is short-lived if HTS is not given with colloids because the sodium rapidly redistributes. Hypertonic saline has been reported to have a mild positive inotropic effect and to improve cerebral perfusion pressure by improving rheology. (Ducey, Velasco) Due to the extreme hypertonicity and high sodium concentration, HTS ideally should not be given to hypernatremic or severely dehydrated patients. HTS has also been shown to decrease adhesion molecule expression thus decreasing WBC margination and endothelial injury. Patients with head injury and lung injury have particularly benefited by the use of HTS or HTS mixed with a colloid to provide some sustained effect.

Synthetic colloids such as dextran 70 or hydroxyethyl starch. These are large molecular weight substances that exert a colloid osmotic pressure. As a result they improve intravascular volume which leads to improved blood pressure and perfusion. They also help in the prevention of endothelial, interstitial and intracellular edema. If the patient is actively hemorrhaging the colloids also will be lost from the vascular space. High molecular weight colloids should be used whenever possible to improve the duration of action. Synthetic colloids may contribute to bleeding tendencies which can be a concern

with trauma patients. This is more likely to occur with dextrans but may be seen with hetastarch at high doses (greater than 20 ml/kg). Coagulation abnormalities are likely due in part to dilutional effects, but dextrans also interfere with platelet action. (Griffel, Concannon) Although clinical bleeding is not reported to be a major problem with hetastarch, it has been the authors’ clinical experience that the administration of shock volumes of hydroxyethyl starch (20 ml/kg body weight) may be associated with increased capillary bleeding if surgery is required. The oxygen carrying colloid Oxyglobin has also been used as a volume expanding colloid and is recommended particularly when hemoglobin concentrations are low.

Whole blood transfusions may be indicated. It has been suggested that the hemoglobin (Hg) level should be at least 10 g/dl; however, in the healthy individual with an adequate intravascular volume, a Hb of 7 g/dl may be sufficient. (Carrico) In the severely injured patient the Hb levels may need to be higher than anticipated to help maintain an adequate delivery of O2 to the cells. Oxygen delivery (DO2) is calculated as the product of cardiac output (measured with the use of a Swan-Ganz pulmonary artery catheter) and the arterial O2 content. Therefore DO2 can be increased by increasing the Hb or increasing cardiac output. It is evident from the chart that even a Hb of 10 g/dl will be insufficient for delivery of adequate O2 to the cells if cardiac function is depressed. This may occur if the myocardium is contused, arrhythmias are present, or there is depressed cardiac contractility due to sepsis or concomitant systemic infection. Usually blood products are administered over several hours, however in the acutely hemorrhaging patient blood may need to be administered as quickly as the patient is losing it. The actual volumes of blood products required will depend on the amount of blood lost and the clinical status of the patient.

Plasma and Fresh Frozen Plasma. This is recommended in medical emergency patients that have hypoproteinemia or hypoalbuminemia. This is common in patients with parvovirus enteritis and in other disease processes of the intestine that have a protein loosing component such as bacterial inflammatory bowel disease. Other protein loosing processes such as peritonitis, glomerular nephritis, major burns or wounds are also disease processes that may indicate the need for plasma transfusions. Total solids or plasma protein below 4.0 grams per deciliter or albumin below 2.0 to 2.5 grams per deciliter would be laboratory indicators of the need for plasma. Fresh Frozen Plasma (FFP) which may be available commercially is indicated for patients with low clotting factors that are short lived especially factor seven. This may occur with many entities that are involved with plasma protein losses and causes of disseminated intravascular coagulation. FFP is also indicted in entities where antithrombin 3 is also low. This occurs in such protein loosing entities and burns, peritonitis, enteropathies, and nephropathies.

Autotransfusion. In situations where blood transfusions are not readily available the patient can be autotransfused with blood collected from the thoracic or abdominal cavities. If there is evidence of a ruptured intestinal tract, blood collected from the abdominal cavity should only be used as a last resort. The patient’s blood is collected as aseptically as possible and reinfused. (Crowe) Bubble formation should be avoided during the collection process to decrease lysis of erythrocytes. Blood collected for autotransfusion often does not clot and the need for anticoagulants is uncertain. (Symbas, Broadie) However, it is always safest to use an anticoagulant and give the blood through a 20 micron filter. In emergency situations the time required to mix the blood with an anticoagulant and administer through a small filter (which slows administration rates) may not be available, and the blood should be administered as soon as it is collected. Heparin should not be used as an anticoagulant. Disseminated intravascular coagulation (DIC) may result from autotransfusion due to the infusion of activated products of coagulation and fibrinolysis. (Carrico) Coagulation parameters should be monitored post autotransfusion and, if there is evidence of DIC, treatment should be instituted. Clotting factors should be replaced using fresh whole blood or fresh frozen plasma (FFP) (depending on the need for red blood cells and availability of blood products). Administration of low dose heparin n (50 u/kg body weight SC q8hr) which activates antithrombin, may be useful in the treatment of DIC.

Hypertonic Saline (6- 7.5%) without and with a synthetic colloid. Infusion 5 ml per kg of this per cent of saline will cause a flux of interstitial water into the vascular system rapidly. It also increases vagal activity and causes vasomotor tone enhancement and decreases endothelial adhesion molecule

activity. The vascular fluxes are short lived (lasting less than one hour) unless the hypertonic saline solution is infused with a colloid such as hetastarch or dextran. One ml of 23% solution (commercially available) that is mixed with approximately 4 ml of 6% hetastarch provides a solution that is slightly less than 6% hypertonic saline. This mixture is recommended to be used clinically for patients in shock that are not dehydrated or suspected of having an uncontrolled hemorrhage.

Guidelines for Fluid Administration

The volume and rate of fluid administration will depend on the patient’s hemodynamic parameters. In general, hemodynamic parameters should be returned to normal as fast as possible. If the patient is tachycardic and assessed to be hypovolemic, fluids should be given until the heart rate returns to close to normal (generally about 110-140 beats per minute). If the BP is low or not detectable, fluids should be administered as fast as possible to return BP to normal as soon as possible. There is a great deal of controversy surrounding the type of fluids to use. If the patient is in shock because of hemorrhage large volumes of crystalloids should be avoided since interstitial edema may result. Guidelines are offered below. If the patient is hypotensive or normotensive and tachycardic, a bolus of a crystalloid of 30 ml/kg is followed by reevaluation of the patient’s heart rate and BP. If the hemodynamic parameters improve and then deteriorate, or if they have not improved, a synthetic colloid is administered in slow intravenous boluses of 5 ml/kg up to 20 ml/kg and the crystalloid administration rate is decreased to 30 ml/kg/hr. If the patient stabilizes after the bolus of crystalloid then the crystalloids are continued at maintenance rates. If the patient has no detectable BP or if the BP is below 50 mm Hg systolic, synthetic colloids (20 ml/kg), or hypertonic saline (4 ml/kg) and a synthetic colloid (20 ml/kg) should be administered. If blood is available it can be substituted for the synthetic colloid. If the patient is thought to have a possible uncontrolled hemorrhage then all fluid administration is guided by the patient's blood pressure and hypotension is maintained slightly (until the bleeding is believed to be under control).

The packed cell volume and total plasma protein should be reevaluated after the first 30 to 60 minutes in any patient who is not responding to fluid resuscitation or any patient which has received more than 50 percent of its blood volume in fluids. If the packed cell volume is less than 20 percent or has dropped by more than 50 percent red blood cells are recommended. Since these patients also will be predisposed to a dilutional coagulopathy FFP should be concurrently administered. If fresh whole blood is available it is the blood product of choice in trauma patients.

If the patient appears to be adequately volume resuscitated based on CVP and BP is still lower than the target value a positive inotrope (dobutamine hydrochloride c 5-20 mcg/kg/min in the dog, 2-5 mcg/kg/min in the cat) should be considered. Positive inotropes should be given only if the patient is euvolemic. If the blood pressure does not respond, vasopressors may be indicated (dopamine ). Since vasopressors cause vasoconstriction which can decrease tissue perfusion and thus tissue oxygen delivery, they should be avoided unless absolutely necessary. The authors do not recommend giving vasopressors unless the BP remains below 80 mm Hg with fluid resuscitation and positive inotropes.

IMMOBILIZATION, MONITORING, TRAUMA FILMS, SECONDARY SURVEY, ETC.

Every major trauma patient should be immobilized to a board and trauma films taken to assess spinal and pelvic injury, diaphragm, thorax and abdomen. Tapping a patient to a clear plexiglass board is recommended using duct tape as it does not show up on radiographs. Lateral radiographs should include the skull to the tail and time taken to review them carefully. The taping also eliminates the patient from being able to move much which often decreases his pain and helps prevent clots from moving away from injured and bleeding tissues. If the patient is having difficulty with breathing this step is modified to position the patient in a position of comfort rather than lateral…breathing before circulation, circulation before spine concerns.

Electrocardiogram

A lead II electrocardiogram should be assessed for the presence of any arrhythmias since hypoxia and cardiac trauma frequently lead to ventricular premature contractions (VPC). Ventricular premature contractions should be treated if the patient is tachycardic, if the arrhythmia is interfering with perfusion (significant pulse deficits), if there are multifocal VPC’s, or if there is R-on-T phenomenon. Lidocaine or procainamide may be used.

Pulse Oximetry, Toe-Temperature, Venous Blood Gases, Whole BloodLactate, Urinary Output, End-Tidal CO2 , Chest and Trauma Radiographs, Quick-Look Ultrasound of the Chest and Abdomen, and Diagnostic Peritoneal Lavage; Clinical Chemistries and PCV/TS, urinalysis

All patients should be assessed with common sense and history and physical examination as the cornerstone of assessment and decision making. However there are other tools that can help in the emergency assessmernt. These include pulse oximetry, toe web -temperature, venous blood gases, whole blood lactate, urinary output, end-tidal CO2 , thoracic and trauma radiographs, quick-look ultrasound of the thorax and abdomen, and diagnostic peritoneal lavage; as well as common labAnalyses such as PCV, TS, glucose, electrolytes, ALT, ALK PHOS, amylase, BUN, creatinine, urinanalysis.

Basic laboratory tests such as hematocrit, total plasma protein, glucose, and blood urea nitrogen should be performed on every patient. These tests require minimal blood and usually can be run off the volume in the hub of the catheter stylet. If there is a concern that the patient is actively hemorrhaging internally the PCV should be monitored as frequently as every 15 to 30 minutes until it stabilizes. If there is no obvious evidence of active hemorrhage the PCV should be check in 2 to 4 hours.

Whenever possible laboratory tests including venous blood gases, electrolytes, serum chemistries, a complete blood count including platelet count with evaluation of a blood smear, and coagulation indices should be evaluated in seriously injured patients. Blood glucose and electrolyte levels should be kept in a normal range. Albumin should be kept greater than 2.0 g/dl. Venous blood gases can be used to evaluate metabolic and respiratory acidosis in the trauma patient. It is important to correct metabolic and respiratory causes of acidosis since a low pH can compromise myocardial performance, cause vasodilation, and interfere with the function of vital cellular enzyme systems. A high PaCO2 level (greater than 50 mm Hg) is consistent with ventilatory insufficiency. Ventilation should be reassessed and treated as discussed above.

Metabolic acidosis usually is a lactic acidosis associated with poor peripheral perfusion. Since this should be correctable with fluid therapy in almost all cases bicarbonate therapy rarely is indicated. There are no absolute guidelines for administration of bicarbonate in the treatment of metabolic acidosis in trauma patients. If the venous pH is less than 7.0 and the bicarbonate level is less than 12 mEq/L after initial fluid resuscitation, cautious bicarbonate therapy should be considered. BASE DEFICET OF 6 or GREATER = COMPROMIZED STATE THAT DEMANDS AGGRESSIVE ATTENTION. COULD ALSO MENTION WHOLE BLOOD LACTATES WITH HANDHELD UNIT (ACCUSPORT) . TRENDS ARE THE KEY

An activated clotting time (ACT) and a platelet estimate from a blood smear provide an early rapid assessment of coagulation indices. If the ACT is prolonged (greater than 120 seconds in a dog and 90 seconds in a cat) serious consideration should be given to administering FFP. It is the authors’ clinical impression that the ACT may prolong to 180 seconds in dogs with the use of hetastarch. If the ACT is prolonged beyond 180 seconds the authors recommend giving FFP. If the platelet numbers decrease by 50 percent or more after fluid resuscitation the authors recommend that an ACT and platelet estimate should be repeated in 4 to 8 hours. IT IS ALSO THE AUTHORS’ IMPRESSION THAT ACT IS FREQUENTLY PROLONGED IN THE SEVERELY BLUNTLY INJURED PATIENT as they have a traumatic inducted consumptive coagulopathy. It is important to consider FFP for AT3 and low dose heparin in cases with signif injury but in which no active bleeding as occurred for many hours post injury. This is to help prevent DVT, PE and other microembolic driven phenomena psot injury

ONGOING DECISION MAKING

If 24 hour observation and care is able to be provided this makes provides options many veterinarians do not have. If it is not available then it is recommended to error in the direction of being more aggressive rather than being more conservative. As an example; if a dogs is having a slight increase in ventilatory rate caused by a diaphragmatic hernia it is far better to operate early rather then to wait. The dog could decompensate in the middle of the night and be dead in the morning when the first technicians arrive for the day. Sad but real …there is no such thing as a stable compromised pet that has been seriously injured; there are no such thing as a stable acute diaphragmatic hernia patient. Surgical texts were written by people who have not had the experience on the front-lines in my opinion. Common sense should provide an insight as to what is best for the pet, sitting in a cage with an ever increasing "work of breathing". These cases need to be operated as soon as possible, preferably in the next 1-2 hours not the next morning when effort is even more labored and respiratory failure is now eminent.

In closing with this section I leave you some mottoes that have been helpful to me in guiding my decision making in the care of the seriously ill or major trauma patient:1. The pet and owner should be treated as a close family with kindness and compassion at all times.

Owners that are mad are not at you but at the situation.2. Assume a severe illness or injury with every emergency until proven otherwise. It is far better to

be aggressive in diagnostics than to miss a severe problem which only gets worse with the passage of time. A key to survival in trauma patients is effective recognition and treatment in time!

EMERGENCY PROCEDURES INVOLVING THE SEPTIC AND DIRTY ABDOMEN

Successful management of the septic abdomen requires diligence and perseverance. It requires early and accurate diagnosis, aggressive fluid and nutritional support, proper antibiotic coverage, timely and principle based surgery, and postoperative care as needed. The goals of surgery are to find and remove all pathological tissues that can be safely removed, correct conditions that can be corrected, remove all septic fluid and particulate matter through extensive irrigation, inserting a jejunostomy or other type of feeding tube, and providing open abdominal drainage. Clinicians should think of generalized peritonitis as a third degree burn within the abdomen, and just like burns a large amount of fluid and protein is lost. From clinical experience third space loss can be from 20% to100% of the patients blood volume per day. Aggressive fluid, electrolyte and plasma protein replacement is a key to patient survival and as important as surgery and antibiotics.

The causes of septic peritonitis commonly are associated with gastrointestinal bacterial contamination such that caused by bowel obstruction and necrosis, bowel rupture following ischemia, and puncture or perforation from foreign bodies or trauma. Other common causes are septic conditions involving the pancreas or the liver and biliary tract. Chemical irritation such as that associated with urine leakage into the peritoneal cavity from a ruptured urinary bladder can also lead to peritonitis. Bacteria initially are not associated with this form of septic peritonitis. As the inflammation continues however translocation of bacteria from the bowel occurs and proliferates and produces bacterial endotoxin and exotoxin that complicates the peritonitis further. Clinical signs are both local and systemic. Local signs are generalized and focal abdominal pain and vomiting. Systemic signs are associated with the production of inflammatory mediators leading to those associated with systemic inflammatory response syndrome (SIRS) and major organ dysfunction syndrome (MODS).

Diagnosis of abdominal sepsis:

The diagnosis of septic diffuse peritonitis primarily involves physical examination. Abdominal discomfort on palpation and vomiting are the most commonly observed clinical signs. Radiographs reveal a diffuse ground glass appearance. Ultrasound reveals free abdominal fluid. A sample of the fluid taken by centesis reveals many neutrophils and if the process involves bacteria they are often observed within the neutrophils. The more degenerative the neutrophils appear the more advanced the peritonitis generally is. Ultrasound is also helpful in the assessment of the major organs (liver, spleen, kidneys), urinary bladder, prostate and retroperitoneal space. Laboratory analysis of the blood generally reveals hemoconcentration, neutrophilia with a left shift, and mild elevations in BUN and creatinine, liver enzymes. In advanced cases degenerative neutrophilic shifts. Diagnostic peritoneal lavage can be very useful and should be used for assessing the peritoneal cavity in situations where abdominal radiographs, ultrasound or abdominal centesis are inconclusive. In cases where DPL results are equivocal such as the finding of WBC's present but not in high numbers (<2- 3,000 per cmm) it is recommended to repeat the lavage in a few hours to determine WBC number progression or changes in their cellular appearance. In cases where clinical signs or diagnostics are equivocal abdominal exploration or at least laparoscopy should be performed. In centers that have CT or MRI capabilities these modalities have been helpful in assessing the peritoneal cavity for septic conditions as well.

Treatment of abdominal sepsis:

Treatment entails preoperative supportive care, which involves volume restoration, initiation of intravenous high-level broad-spectrum antibiotics, correction of life-threatening electrolyte abnormalities, AND then surgery. It is highly recommended that both central venous pressure and direct or indirect blood pressure be monitored and that these be used to guide fluid support.

The goals of emergency surgical treatment are the following:1. Explore the abdomen and determine the cause of the peritonitis; inform owner if applicable. Use a

surgical headlight, Balfour retractors, lap pads and electrosurgery unit 2. Repair or stop the process that caused the peritonitis, e.g., resect the ruptured bowel section. The best to

use for intraabdominal work in the face of infection are non-absorbable polypropylene or polybutester or absorbable polydioxanone or similar material.

3. Perform serosal patching or omentally wrap sutured – repaired areas to prevent leakage.4. Debride and drain the abdomen of all septic material and fluid this includes retroperitoneum.5. Irrigate the abdominal cavity to wash all peritoneal surfaces with copious warm LRS or saline.6. Provide an access for nutritional support such as placement of a jejunostomy tube and an omental wrap around the area where the 3.5 –5 Fr soft polyethylene) tube exits the small intestine and then enters the abdominal wall. A pre-placed continuous suture is used to secure bowel wall to the abdominal wall where the jejunostomy tube exits. 7. Arrange for the maintenance of continued drainage and air access by leaving the abdomen open. The falciform ligament and unattached omentum are removed to prevent blockages.

The use of open abdominal drainage (OAD) in the management of the septic abdomen has improved survival significantly in our practice, as well as those of others. I have been performing OAD since 1982. The main explanations for this improvement in success are the following: 1. Allowing the abdomen to remain open ventrally prevents the retainment of septic exudate at the visceral-parietal peritoneal interfaces (common with simple tube drainage), i.e., more effective drainage is provided by this method versus others; 2. Keeping a large wound open into the abdomen allows air to either become actively or passively insufflated into the peritoneal cavity, which raises the redox potential (pO2 of 100 mmHg inside the abdomen with open

abdominal drainage versus pO2 of 20-40 mmHg within the peritoneal cavity when the abdomen is closed.

The common organisms that are associated with bacterial peritonitis are mostly microaerophilic or are completely anaerobic, e.g., E. coli and Clostridium perfringens, respectively. Allowing air to continue to bathe the peritoneal surfaces suppresses the growth of these organisms and the accumulation of toxic by-

products (exotoxins). Peritoneal macrophage function is also enhanced by the increased redox potential accompanying the open drainage technique.

Following thorough, copious irrigation with acetated Ringer's solution until the effluent is clear, the abdomen is dried as best as possible with suction and laparotomy pads. The caudal aspect of the incision is closed to avoid the difficulties encountered in dressing application between the rear limbs. A simple, continuous suture closure using monofilament polydioxanone, polypropylene or polybutester placed into the external rectus sheath is recommended. Then a, very loose, simple, continuous suture using the same monofilament material is placed into the external rectus sheath of the rest of the abdominal incision. A gap of at least 2 cm in the average-sized dog is left..

Several sterile absorbent pads (cotton, polyester) are then laid over the ventral abdominal incision line and circular cotton, stretchable gauze bandage is applied to hold the pads in place. An absorbent, disposable "diaper" or "blue pad" with a plastic outlining is then wrapped around the dressing to prevent "strike-through" of the abdominal pads from urine, etc., from the environment. Slippage of the dressing-blue pad combination is then prevented using some adhesive tape or elastic woven stretch tape. In male dogs, closed, chronic catheterization of the urinary bladder is usually performed as long as the abdomen is open to prevent urine "strike-through" from occurring.

The abdominal dressing is changed generally between 2 and 3 times per day. This depends on the amount of fluid and exudate draining. The patient is kept in sternal recumbency or standing, as much as possible to encourage drainage into the dressing through the use of gravity. The abdominal dressing under the blue pad is examined every 6-8 hours for "strike-through," i.e., the showing of drainage fluid in the dressing. When this occurs, the dressing is changed. For changing, the animal is placed in dorsal recumbency after the IV administration of a light dose sedative, if necessary, (oxymorphone, diazepam, and ketamine). Removal of the outer dressing and replacement of the absorbent pads using sterile technique is then performed. If the small intestine or omentum is adhered to the pads being removed, the operator wearing sterile gloves and using saline in a small sterile syringe gently teases these tissues off the pads. After removal of the old pads, inspection of the wound is done for evidence of necrosis. If it is observed, surgery is required for its removal. This is not a frequent occurrence, fortunately.

New inner pads are placed and the "trap door" or circumferential dressing is replaced and the sedation reversed if oxymorphone was used. The old dressings are weighed to calculate the amount of peritoneal exudate and fluid lost (1 gram = 1 ml). The amount of protein and electrolyte loss can be estimated from diagnostic laboratory determinations performed on a small sample of fluid aspirated from the abdomen at the time of abdominal dressing change. The same can also be examined microscopically to follow the cellular changes within the abdominal cavity.

Postoperative care of abdominal sepsis:

Postoperative care involves replacement of fluid, protein, and electrolytes that are lost from the peritoneal cavity. This is commonly done by use of a combination enteral, intravenous, or intraosseous routes. The former is preferred. Even animals occasionally vomiting, can be fed using a jejunostomy catheter (placed at the time of the exploratory laparotomy). Generally, fluid and electrolytes losses and maintenance requirements are met with lactated Ringer's solution with 20-40 mEq/L KCl added (for replacement) and half-strength lactated Ringer's solution and 2 1/2% dextrose and 20 mEq/L KCl added (for maintenance). Peritoneal albumin losses are usually replaced with plasma administration. Because anemia is common in patients that have septic peritonitis protein replacement may also be performed using whole blood in selected patients (those with PCV < 30%). The goal of protein replacement therapy is to achieve or maintain a plasma total protein level of 4g% or at least serum albumin level of 2.0-2.5%. Albumin levels below 1.5g% are associated with increased peritoneal fluid losses, lack of nutrient absorption in the small intestine and diarrhea, less tolerance to continued fluid and electrolyte losses, blood volume contraction, and an increased incidence of death due to sepsis. Plasma is most often required to replace the losses and amounts can be substantial, e.g., 5 ml to 20ml/kg per day. Other alternatives for plasma include human albumin (5% or 25%)

and colloids such as hetastarch or dextran. Commonly 1 ml/kg/hr is administered to maintain colloid oncotic pressure greater than 15 mm Hg. Occasionally paced RBC's, whole blood or Oxyglobin are required to maintain oxygen carrying capacity of the blood. Any patient with a hematocrit below 25-30% in my opinion is a candidate for red cell or synthetic hemoglobin replacement therapy.

Nutritional support provided by jejunostomy tube feeding (if serum albumin is greater than 1.5g%) and parenteral support using a 3.5% -5% amino acid solution. At least 75% of the patients treated (based on clinic experience), because of continued anorexia, gastroparesis and /or vomiting. If oral protein energy intake does not begin within 24-48 hours postoperatively and continue to improve following surgery, so that requirements are met within 4-5 days, nutritional support is required. The ability to fight the septic process is greatly decreased by the lack of adequate protein-energy intake. Metabolic energy and protein requirements increase up to 50% in these patients. Vitamin administration, including those generally not required in the non-stressed dog or cat, e.g., Vitamin C is also required.

It is important to encourage daily physical activity and movement for several reasons. Peritoneal drainage is facilitated by this activity. Physical movement also encourages deep breathing. In my experience, these patients are more prone to develop pneumonia and deep breathing and chest physiotherapy (percussion, postural drainage, nebulization), is indicated to prevent it or treat, if it is already present).

Antibiotic therapy is best guided by culture and sensitivity results. Prior to receiving the results it should be assumed that a mixed infection is present. Gram staining of the exudate can help confirm this. In this case the gram-negative anaerobes are treated with such antibiotics as metronidazol (Flagyl). Gram negative coliform aerobes with an aminoglycoside such as amikacin or tobramycin. The Gram positive anaerobes are best managed with penicillin-clindamycin like drugs. These drugs are all best given intravenously, at least initially, and are usually continued, as per C & S results, until at 2-3 weeks after all clinical signs of infection have dissipated. Another common combination we have found useful is Metronidazol at 7.5 mg.kg BID, Cephazolin 20 mg/kg TID, and Enrofloxacin 10mg/kg BID, all given intravenously.

Other supportive treatments to consider are: Supplemental and hyperbaric oxygen that activates plasmin on the endothelial surface, supports macrophage function, and decreases the rate of bacterial growth and endotoxin production; Use of heparin to prevent microthrombosis; Use of pentoxiflyn to decrease neutrophil adhesion and activation on the endothelial surface; Provide analgesics as needed for pain; Gastric decompression with trickel micro-enteral feeding initially followed by gradual increases in enteral nutrition until requirements are met.

The criteria for closing the abdomen we have used is when there is no further strike through of the abdominal dressing for approximately 18 to 24 hours. The animal at that time is taken back to the operating room and, under general anesthesia, the dressings are removed, culture taken and the loose, continuous sutures in the abdominal wall are pulled tight and tied. The subcutaneous tissues are then irrigated thoroughly. The skin and subcutaneous tissues are closed, preferably as one unit using an interrupted, vertical mattress, near near-far far, or cruciate pattern that closes the subcutaneous tissues without using buried sutures.

Prior to closure of the open abdomen the wound is inspected carefully. If necrosis of the edges of the abdominal wall are observed, the previously placed, loose, simple, continuous suture pattern will have to be removed, the edged debrided as necessary and then the abdomen closed using a new simple continuous suture pattern. Care should be taken to also include a sufficient bit of external abdominal fascia with each pass of the needle during closure. Upon inspection of the open abdomen, a "second look" exploration maybe indicated prior to closure.

If the drainage from the abdomen does not begin to decrease within 3-4 days, becomes worse in character (more prevalent, "fecal-like," biliary-like), a "second look" laparotomy is recommended. "Second look" laparotomies may also be elected on cases where the initial repair performed or tissue viability was believed tenuous. Second laparotomies are also generally done in cases with deep intra-abdominal abscesses and or

septic disease processes that may lead to deep abscess formation, e.g., suppurative necrotizing pancreatitis. In most of these cases, the placement of deep abdominal drains is also recommended. This is because in these relatively "closed areas" omentum, mesentery, and other nearby organs help form a pocket that cannot be "drained" well with open abdominal drainage alone. Deep localized abdominal drainage using silicone rubber multiple fenestrated gravity and suction drains keeps the "closed area" evacuated. Disease examples of where they have been used include suppurative pancreatitis, suppurative cholecystitis-cholangeohepatitis and areas of previously evacuated intraabdominal abscesses.

Hyperbaric oxygen therapy (HBOT) has been used in experimental animals with septic abdomens and has recently been shown to increase survival significantly without causing any complications. It is now being used routinely by veterinary centers that have them. Some human centers are also allowing pet animals to be treated in their facilities. Two one-hour treatments per day at 2 ATA are given beginning preoperatively and are continued for several days postoperatively. The treatments also help decompress and denitrogenate distended bowel loops which assists in the recovery of postoperative ileus and provides comfort. HBOT works as a adjunct with the antibiotics, suppressing growth of anaerobic and microaerophilic bacteria and enhancing macrophage function.

Recent research has also proved that providing 30 ml/kg warm saline enemas to remove fecal material from the colon is beneficial to laboratory animals suffering from experimentally induced abdominal sepsis. The reasons for this seems to be associated with decreases in bacteria and enterotoxins that otherwise may be translocated into the animal's circulation. Rats with experimentally induced pancreatitis have shown that daily saline enemas significantly decreased the incidence of pancreatic hemorrhage and necrosis and associated high morbidity and mortality. Therefore it is recommended to perform saline enemas very early in the management of septic abdomens.

Another recent treatment in gastrointestinal septic conditions that has been published is the use of supplemental oxygen (30%) given in the immediate postoperative period. A study in humans concerning the use of nasal oxygen catheter revealed s significant reduction in postoperative wound infections following a 3-hour supplemental oxygen course.

Closing remarks concerning assessment and treatment of abdominal sepsis:

In conclusion, the timely and aggressive attitude to the management of an acute abdomen with septic consequences has been reviewed. Time is a key factor and the diagnosis and management must be undertaken as early in the course of the resulting peritonitis if we are to have a good chance of success in the resolution of the sepsis. Preoperative care to required to insure good flows and pressures once anesthesia is induced. Anesthesia should involve a balance of a muscle blocker such as Atricurium (25 mg/kg.), a hypnotic agent such as halothane, isoflurance, or sevoflurane, an anxiolytic such as acepromazine (.01-0.1 mg/kg), and an analgesic such as oxymorphone (.03-.1 mg/kg) that will achieve patient comfort. Monitoring should involve blood pressure and doppler flow, temperature, respiratory effort and sound, ET CO2 , SpO2, CVP if possible, urine output and inputs of fluids, plasma, and blood products. Ventilation should be assisted throughout the surgery. Fluids require aggressive rates such as 10 ml/kg/hour. It is important to keep the patient's body temperature above 97 degrees also throughout the surgery. Once surgery is concluded, ending with irrigation, insertion of a feeding tube, and loosely lacing the abdomen closed (left open enough to let oxygen into the peritoneal cavity and allow septic fluid to drain out), the patient continues to be supported in the postoperative period. Postoperative care includes monitoring and providing nasal pharyngeal oxygen, fluids, antibiotics, plasma and blood as necessary, physical exercise, respiratory therapy, nasopharyngeal oxygen, etc. With continued diligent veterinary technician examinations, monitoring and support prognosis has improved dramatically in the last few years. Open abdominal drainage appears to continue to play a role in this success.