Pre-Anesthetic Checkup

PRE-ANESTHETIC CHECKUP

Presenter: Dr. Rashmit Shrestha

1st year RESIDENT Moderator: Prof. Dr. Md Aslam

ANESTHESIAAnesthesia (from Greek an “without” aesthesis “sensation”)The components of the anesthetic state include • unconsciousness• loss of memory• lack of pain• immobility and attenuation of autonomic

responses to noxious stimulation.

PREOPERATIVE EVALUATION

• Defined as the process of clinical assessment that precedes the delivery of anesthesia for surgery and for non surgical procedures.

• It consists of the consideration of information of multiple sources that may include the patient’s interview, medical records, physical examination

and findings from medical tests and evaluations.

GOALS

• To ensure that the patient is in the best(optimal) condition.

• Patients with unstable symptoms should be postponed for optimization prior to elective surgery.

• Anesthetic drugs and techniques have profound effects on human physiology. Hence, focused review of all major organ system should be done prior to elective surgery.

OBJECTIVES

• Doctor patient relationship.

• Patient data.

• Anesthetic plan

• Patient consent

STEPS OF PREOPERATIVE VISIT

1. Problem identification

2. Risk assessment

3. Preoperative preparation

4. Plan of anesthetic technique.

Clinical Examinations

• Phase 1: History taking-– Gathering of information,

• Phase 2: Physical examination-– Objective findings,

• Phase 3: Explanation-– Information giving & decision making,

7

Phase 1: History taking• Demographic details,• Presenting complaint (PC),• History of presenting complaint (HPC),• Past medical history (PMH),• Previous anesthetic history-any h/o difficult intubation,any h/o allergy at

that time• Drug history (DH),• Family history (FH),• Social history (SH),• Systemic enquiry (SE),

8

Demographic details

• Date & time of examination,• Patient’s name, DOB, Age, weight & address,• Source of referral,• Doctor’s name,• Source of history: patient, relative, care taker

9

Physical examination:

• General exam:– Blood pressures, Pulse, Respiration, Temp

(clinical asses),– Jaundice, pallor, cyanosis , clubbing & edema,

hydration status.– Weight (kg),

Continue..

Systemic examination: Cardiac & Vascular examination, Pulmonary examination,

Special examination: Airway assessment, Peripheral venous access, Spinal examination,

Airway

• Incidence of difficult intubation reported to range between 0.13 – 5.9%

• It can be predicted and expert anaesthsiologist is called for the case.

• Evaluation is the first step in management of difficult intubation.

AIRWAY CLASSIFICATION SYSTEM

MALLAMPATI SCORECLASS DIRECT VISULAISATION OF

AIRWAY1 Full view of Soft Palate, fauces,

uvula, tonsillar pillars2 Soft palate, fauces ,upper

portion of uvula3 Soft palate ,uvular base

4 Hard palate only.

LARYNGOSCOPIC VIEWCormack lehaneCLASS LARYNGOSCOPIC VIEW

1 Entire glottic

2 Posterior commisure

3 Tip of epiglottis

4 No glottic structure.

Airway evaluation

• Mentothyroid distance : normal 6 cm.• Mentosternal distance : normal 15 cm• Mentohyoid distance : normal 3 FB• Neck movement: flexion and extension of

neck, history of radiation• Nasal cavity

Thyromental distance

Difficult intubation

• Mouth opening less than 3 cm.• Limitation of neck movement• Micrognatia• Macroglossia• Protusion of teeth• Short neck• Morbid obesity

Airway Examination

Normal – Opens mouth normally (Adults: greater than 2 finger widths or 3 cm)– – Able to visualize at least part of the uvula and tonsillar pillars with

mouth wide open & tongue out (patient sitting)– – Normal chin length (Adults: length of chin is greater than 2 finger

widths or 3 cm)

– Normal neck flexion and extension without pain / paresthesias

Airway Examination

Abnormal – Small or recessed chin – Inability to open mouth normally – Inability to visualize at least part of uvula

or tonsils with mouth open & tongue out –High arched palate –Tonsillar hypertrophy –Neck has limited range of motion – Low set ears – Signficant obesity of the face/neck

Airway assessment: predictive testsSensitivity = 50-60%

• Mallampati modified test:Visibility of pharyngeal structures.• Patil test:Thyro-mental distance <6.5cm• Mandibular protrusion:Class C : inability to protrude lower incisors beyond the upper.• Wilson test.• Radiological assessment of the mandible and cervical spine.

WILSON RISK TEST

medical status mortalityASA I normal healthy patient without organic, biochemical,

or psychiatric disease0.06-0.08%

ASA II mild systemic disease with no significant impact on daily activity e.g. mild diabetes, controlled hypertension, obesity .

Unlikely to have an impact0.27-0.4%

ASA III severe systemic disease that limits activity e.g. angina, COPD, prior myocardial infarction

Probable impact 1.8-4.3%

ASA IV an incapacitating disease that is a constant threat to life e.g. CHF, unstable angina, renal failure ,acute MI, respiratory failure requiring mechanical ventilation

Major impact 7.8-23%

ASA V moribund patient not expected to survive 24 hours e.g. ruptured aneurysm

9.4-51%

ASA VI brain-dead patient whose organs are being harvested

ASA Physical Status Classification System

For emergent operations, you have to add the letter ‘E’ after the classification.

Cardiovascular system

• Pulse: rate, rhythm, character and volume,

• Blood pressure (BP),

• Jugular venous pulse (JVP): height and character,

• Ankle edema: presence or absence,Dr Resham B Rana, MD 26

Continue

• Inspection: – any scar, abnormal vessels, lumps, chest shape, apex beat-

position,–

• Palpation (localize technique): – confirm apex beat, character, presence of thrills &

peripheral pulses on both sides,

• Percussion (technique): – precordium- size of heart,

• Auscultation (technique): – heart sounds, murmur,

H/O TO REVIEW OF THE ORGAN SYSTEM

CVS Symptoms of the following problems sought

in all patients.Ischaemic heart diseaseHTNHeart failureConduction defect and arrythmiaPeripheral vascular disease

Patient with h/o of MI are greater risk of perioperative reinfarction, the incidence of which is related to the time interval between surgery and infarct.

The presence of unstable angina has been associated with a high perioperative risk of MI.

The presence of active congestive heart failure has been associated with an increased incidence of perioperative cardiac morbidity.

REVISED CARDIAC RISK INDEX(UNDERGOING ELECTIVE MAJOR NON CARDIAC PROCEDURES)

1. High risk type of surgery2. History of ischaemic heart disease3. History of congestive heart failure4. History of cerebrovascular disease5. Preoperative treatment with insulin6. Preoperative serum creatinine>2mg/dl

Rates of major complications with 0,1,2 or 3 of these factors are 0.5,1.3,4 and 9% respctively.

The American heart association /American College of cardiology task force on perioperative evaluation of cardiiac patient undergoing noncardiac surgery has definded three risk groups-1 Major2 Intermediate3 MinorThey indicate that recent MI(<30 days)places patients in the group of highest risk,after that period ,a prior MI places the patient in the group at intermediate risk.

CLINICAL PREDICTORS OF INCREASED PERIOPERATIVE CVS RISK(MI,CHF,DEATH)

• MAJOR

Unstable coronary sydromesRecent MI with evidence of important ischaemic risk by clinical symptoms or noninvasive study.Unstable or severe anginaDecompensated congestive heart failureSignificant arrythmiasHigh grade AV blockSymptomatic ventricular aarythmias in the presence of underlying heart disease.Supraventricular arrythmias with uncontrolled ventricular rate.Severe valvular disease.

• INTERMEDIATE

Mild angina pectorisPrior MI by history or pathological Q wave Compensated or prior CHF.Diabetes mellitus.

• MINOR

Advanced ageAbnormal ECG (Left ventriculay hypertrophy,LBBB,ST-T abnormalities)Rhythm other than sinus(e.g- AF)Low functional capacity (e.g- inability to climb one flight of stairs )History of strokeUncontrolled systemic HTN

Clinical Predictors of Increased Perioperative Cardiovascular Risk

• Functional Capacity– Metabolic equivalents– 1 MET – Can you take care of yourself? Eat, dress,

use the toilet? Walk a block or two on level ground 2-3 MPH

– 4 METs – Do light work around the house like dusting or washing the dishes? Climb a flight of stairs?

– >10 METs – Participate in strenuous sports like swimming, singles tennis, football?

Clinical Predictors of Increased Perioperative Cardiovascular Risk

• Functional Capacity– Perioperative cardiac and long-term risks are

elevated in patients unable to obtain 4-MET demand

– www.1000takes.com

HYPERTENSON Untreated and poorly controlled HTN may lead

to exaggerated cardiovascular responses during anesthesia.

Both HTN and hypotension can be precipitated,which increase the incidence of both mycardial and cereberal ischaemia.

BLOOD PRESSURE

CATEGORY SBP(MM HG) DBP(MM HG)

Optimal <120 and <80

Normal <130 and <85

High Normal 130-139 or 85-89

Hypertension

Stage 1 140-159 or 90-99

Stage 2 160-179 or 100-109

Stage 3 ≥180 or ≥110

There is controversy regarding a trigger to delay or cancel a surgical procedure in a patient with untreated or inadequately treated hypertension.

It is less clear in patients with blood pressure above 180/100 mm hg ,although no absolute evidence exists that postponing surgery will reduce risk.

In the absence of end organ changes,such as renal insufficency left ventricular hypertrophy with strain,the benfits of optimizing BP must be weighed against the risk of delaying surgery.

• Aggressive treatment of BP is associated wih increased reduction in long term risk,although the effect diminishes in all but in diabetic patient diastolic pressure is reduced to 90mmhg.

• Patient with BP of >180 mm hg systolic or 110 hg diastolic are prone to develope perioperative MI, venticular dysarrythmias, and lability in BP.

CORONARY ARTERY DISEASEFor those patients without overt symptoms or history the probability of CAD varies with the type and number of atherosclerotic risk factor present.

Pheripheral arterial disease has been associated with CAD in multiple studies.

There is a high incidence of both silent MI and myocardial ischaemia in diabetics.

CARDIAC RISK STRATIFICATION FOR NONCARDIAC SURGICAL PROCEDURES IN PATIENTS WITH KNOWN

CORONARY ARTERY DISEASE

• HIGHReported cardiac risk often> 5%1. Emergency major operations,particularly in the

elderly2. Aortic and major vascular3. Peripheral vascular4. Anticipated proloned surgical procedures

associated with large fluid shifts and/or blood loss.

• INTERMEDIATEReported cardiac risk gnerally <5%1. Carotid endarterectomy2. Head and neck3. Intraperitoneal and intrathoracic4. Orthopedic5. prostate

• LOWReported cardiac risk generally < 1%1. Endoscopic procedures2. Superficial procedures3. Cataract Surgery4. Breast Ambulatory procedures

• Coronary Angiography

• Evidence of adverse outcome from non-invasive test• Angina unresponsive to therapy• Unstable angina, especially with intermediate or high

risk surgery• Equivocal noninvasive test in high clinical risk patient

undergoing high risk surgery

Pulmonary DiseasePulmonary complications occurs more frequently than cardiac complications (5-10% incidence )Perioperative complications includes: 1. Aspiration2. Atelectasis 3. Pnuemonia 4. Bronchitis5. Bronchospasm 6. Hypoxemia7. AE COPD8. Respiratiory Failure requiring Mechanical Ventilation

Pre-operative Investigations• General: 1- Complete Blood Count and Hemoglobin

Concentration 2- Clotting screen 3- Liver function. 4- ECG 5- Echocardiogram Abnormal ECG, ischemic heart….

6- Chest x-ray 7- Blood sugar level 8-Electrolytes, Blood Urea Nitrogen/ Creatinine

Preparation For Anesthesia

• Continuing Current Medications/ Treatment of Coexisting Diseases

It is the RESPONSIBILITY of the anesthesiologist to instruct patients regarding which medications to take and which to hold preoperatively.

Instruct Patients to take the medications with small sips of water, even if fasting!

Medications to be Continued on the day of Surgery1. Antihypertensives except ACE Is and ARBs2. Cardiac medications e.g ᵦ- blockers, digoxin3. Antidepressants, anxiolytics and other psychiatric medications4.Thyroid medications5.Birth control pills, eye drops, heartburn or reflux medications, narcotics, anticonvulsants, asthma medications, Steroids, Statins,

AspirinConsider selectively continuing aspirin in patients where the risk of cardiac events is felt to exceed the risk of major bleeding.if reversal of platelet inhibition is necessary,

stop aspirin at least 3 days before surgery.Do not discontinue aspirin if patients who

have drug eluting coronary stents until they have completed 12 months of dual anti platelet therapy.

Thienopyridines (Clopidogrel and Ticlopidine)• Patients having Cataract Surgery – Do not need

to stop.• If reversal of platelet inhibition is necessary,

then clopidogrel must be stopped 7 days before surgery (Ticlopidine – 14 days)

• Do not discontinue Thienopyridines in Pt. who have drug eluting stents before 1 year.

Medications to be discontinued

• Topical medications e.g creams and ointments• Oral hypoglycemic agents ( on the day of Sx)• Diuretics (on the day of Sx except Thiazide)• Sildenafil ( Viagra) of similar drugs –

discontinue 24 hrs before Sx.• NSAIDS – discontinue 48 hrs before Sx.• Warfarin ( Coumadin) discontinue 4 days

before Sx

NPO guidelinesSubstance Maximum Hours of Fasting

Solid 8

Formula 6

Cow’s Milk 6

Citrus Juice 6

Breast milk 4

Clear liquids 2

Pharmacological Agents to Reduce the risk of Pulmonary Aspiration

• Histamine – 2 Receptor Antagonist : block the ability of histamine to induce secretion of gastric fluid with high hydrogen concentrations e.g. Cimetidine, Ranitidine, Famotidine

• Antacids – neutralize the acid in gastric contents• Proton pump inhibitors: supress gastric acid

secretion by binding proton pump of the parietal cell

• Gastrokinetic Agents : Metoclopramide- Dopamine antagonist.

Psychological Preparation

• Preoperative visit and interview with the patient and family members,

• The anesthesiologist should explain anticipated events and the proposed anesthetic management in an effort to reduce anxiety and diminish apprehension.

Pharmacological preparation

• To relief anxiety and production of sedation• Prophylaxis against allergic reactions e.g. to

latex• Prevention of Autonomic reflexes mediated

through the vagus nerve.• Prevention of nausea and vomiting.

Benzodiazepines

• Produces anxiolysis, amnesia and sedations e.g. Diazepam, Midazolam, Lorazepam

Diphenhydramine : histamine-1 receptor antagonist, blocks the peripheral effects of histamine, it has sedative, anticholinergic and antiemetic activity.Anticholinergics : (Atropine, glycopyrolate, scopolamine)

1. Antisialogogue effect2.sedation and amnesia3. Vagolytic effect

Antibiotic Prophylaxis• Cephalosporins are the most popular antibiotics

because they cover skin microbes,• For intestinal Sx, anaerobic and Gram negative

coverage is needed.• Antibiotics must be administered within 1 hr

prior to incision except : Vancomycin should be given 2hr prior to incision when tourniquet is used, the antibiotics should

be adminstered prior to its inflation.

Summary of the Patient Preparation

• The anesthesiologist who takes the time to adequately prepare the patient medically and psychologically for anesthesia and surgery will find that their job of caring for the patient intraoperative becomes easier, and they are more likely to have a positive outcome as well as a satisfied patient.

Thank You

References

• 1. CLINICAL ANESTEHESIOLOGY, Morgan & Mikail’s, 5TH Edition, Page № 295-307

• 2. Clinical Anesthesia, Paul G. Barash, Seventh Edition, Page № 583- 609

• 3.http://www.medscape.com/viewarticle/819629_2

• 4. Miller’s Anesthesia 8th edition.