8/12/2019 Anes Local http://slidepdf.com/reader/full/anes-local 1/24 Bonagua, Joachim Anne Clare G. DMD2E Anesthesiology Lec March 7, 2014 Local anesthetics are frequently administered in dentistry and thus can be expected to be a major source of drug-related complications in the dental office. Additionally, the dentist will more often be confronted with the treatment of risk patients; thus, the incidence of side effects can be expected to rise. Complications of Local Anesthesia Anesthetic toxicity (overdose) While rare in adults, young children are more likely to experience toxic reactions because of their lower weight. Most adverse drug reactions occur within 5-10 minutes of injection. Overdose of local anesthetics are caused by high blood levels of anesthetic as a result of an inadvertent intravascular injection or repeated injections. Local anesthetic overdose results in excitation followed by depression of the central nervous system and to a lesser extent of the cardiovascular system. Early subjective symptoms of the central nervous system include dizziness, anxiety and confusion and may be followed by diplopia, tinnitus, drowsiness and circumoral numbness or tingling. Objective signs include muscle twitching, tremors, talkativeness, slowed speech and shivering followed by overt seizure activity. Unconsciousness and respiratory arrest may occur. The initial cardiovascular system response to local anesthetic toxicity is an increase in heart rate and blood pressure. As blood plasma levels of the anesthetic increase, vasodilatation occurs followed by depression of the myocardium with subsequent fall in blood pressure. Bradycardia and cardiac arrest may follow. Local anesthetic toxicity is preventable by following proper injection technique, i.e., aspiration during slow injection. Clinicians should be knowledgeable of maximum dosages based on weight. If lidocaine topical anesthetic is used it should factored into the total administered dose as it can infiltrate into the vascular system. After injection the patient should be observed for any possible toxic response as early recognition and intervention are the keys to a successful outcome.
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
8/12/2019 Anes Local
http://slidepdf.com/reader/full/anes-local 1/24
Bonagua, Joachim Anne Clare G. DMD2E
Anesthesiology Lec March 7, 2014
Local anesthetics are frequently administered in dentistry and thus can be
expected to be a major source of drug-related complications in the dental office.
Additionally, the dentist will more often be confronted with the treatment of risk
patients; thus, the incidence of side effects can be expected to rise.
Complications of Local Anesthesia
Anesthetic toxicity (overdose)
While rare in adults, young children are more likely to experience toxic reactions
because of their lower weight. Most adverse drug reactions occur within 5-10minutes of injection. Overdose of local anesthetics are caused by high blood
levels of anesthetic as a result of an inadvertent intravascular injection or
repeated injections. Local anesthetic overdose results in excitation followed by
depression of the central nervous system and to a lesser extent of the
cardiovascular system.
Early subjective symptoms of the central nervous system include dizziness,
anxiety and confusion and may be followed by diplopia, tinnitus, drowsiness and
circumoral numbness or tingling. Objective signs include muscle twitching,
tremors, talkativeness, slowed speech and shivering followed by overt seizureactivity. Unconsciousness and respiratory arrest may occur.
The initial cardiovascular system response to local anesthetic toxicity is an
increase in heart rate and blood pressure. As blood plasma levels of the
anesthetic increase, vasodilatation occurs followed by depression of the
myocardium with subsequent fall in blood pressure. Bradycardia and cardiac
arrest may follow.
Local anesthetic toxicity is preventable by following proper injection technique,
i.e., aspiration during slow injection. Clinicians should be knowledgeable of
maximum dosages based on weight. If lidocaine topical anesthetic is used it
should factored into the total administered dose as it can infiltrate into the
vascular system. After injection the patient should be observed for any possible
toxic response as early recognition and intervention are the keys to a successful
outcome.
8/12/2019 Anes Local
http://slidepdf.com/reader/full/anes-local 2/24
While generally safe, local anesthetic agents can be toxic if used in excessive
doses or administered improperly. Even when administered properly, patients
may still experience unintended reactions to local anesthetics.
Excessive doses may be unintentionally administered in several ways.
Repetitive (small) doses of local anesthetic to achieve an adequate level of
anesthesia may lead to eventual administration of toxic doses.
Injection of anesthesia in a confined space may result in excessive fluid
pressure that may damage nerves.
Doses intended for epidural or intra-support-tissue administration may be
accidentally delivered as intravascular injection, resulting in accelerated
systematic absorption.
The toxic effects of local anesthetics can be classified by localized and systemiceffects.
Toxicity:
Localized
A cause of local toxicity is allergic reaction to para-aminobenzoic acid (PABA).
These reactions range from urticaria to anaphylaxis.
PABA is a metabolic product of the degradation of Ester class of local
anesthetics, such as procaine (Novocaine), benzocaine, and, to a lesser degree,amide class anesthetics such as lidocaine, and prilocaine. It is also a metabolic
by-product of pramod methylparaben, a preservative in multi-dose vials of
lidocaine. When allergic response to injected anesthetics does occur, it is most
likely due to the ester class local anesthetics. The amide class of local
anesthetics is far less likely to produce allergic reaction. Use of topical
anesthetics for relief of eye pain can result in severe corneal damage.
Systemic
Systemic toxicity of local anesthetics can be described by the direct effects onthe immune system, blood (hematologic), central nervous system,
and cardiovascular system.
Immune system
As noted previously, allergic reaction to metabolic break-down of anesthetic
agents and preservatives (PABA) can cause anaphylaxis.
There is now one published case report of successful treatment of
refractory cardiac arrestin bupropion and lamotrigine overdose using lipid
emulsion.
Although lipid rescue mechanism of action is not completely understood it may
be that the added lipid in the blood stream acts as a sink, allowing for theremoval of lipophilic toxins from affected tissues. This theory is compatible with
two studies on lipid rescue for clomipramine toxicity in rabbits and with a clinical
report on the use of lipid rescue in veterinary medicine to treat a puppy with
moxidectin toxicosis.
Allergic reactions
Allergic reactions are sensitivities to substances called allergens that come intocontact with the skin, nose, eyes, respiratory tract, and gastrointestinal tract.
They can be breathed into the lungs, swallowed, or injected.
Although allergic reactions to injectable amide local anesthetics are rare,
patients may exhibit a reaction to the bisulfite preservative added to anesthetics
containing epinephrine. Patients with a sulfa allergy should not receive
articaine. Patients may also exhibit allergic reactions to benzocaine topical
anesthetics. Allergies can manifest in a variety of ways including urticaria,
dermatitis, angioedema, fever, photosensitivity and anaphylaxis.
Considerations
Allergic reactions are common. The immune response that causes an allergic
reaction is similar to the response that causes hay fever. Most reactions happen
soon after contact with an allergen.
Many allergic reactions are mild, while others can be severe and life-threatening.
They can be confined to a small area of the body, or they may affect the entire
body. The most severe form is called anaphylaxis or anaphylactic shock. Allergic
reactions occur more often in people who have a family history of allergies.
Although first-time exposure may only produce a mild reaction, repeated
exposures may lead to more serious reactions. Once a person has had an
exposure or an allergic reaction (is sensitized), even a very limited exposure to
a very small amount of allergen can trigger a severe reaction.
Most severe allergic reactions occur within seconds or minutes after exposure to
the allergen. However, some reactions can occur after several hours,
particularly if the allergen causes a reaction after it has been eaten. In very rare
cases, reactions develop after 24 hours.
Anaphylaxis is a sudden and severe allergic reaction that occurs within minutes
of exposure. Immediate medical attention is needed for this condition. Without
treatment, anaphylaxis can get worse very quickly and lead to death within 15
minutes.
DO NOT
Do NOT assume that any allergy shots the person has already received
will provide complete protection.
Do NOT place a pillow under the person's head if he or she is having
trouble breathing. This can block the airways.
Do NOT give the person anything by mouth if the person is having trouble
breathing.
Paresthesia
Paresthesia is a sensation of tingling, tickling, prickling, pricking, or burning of aperson's skin with no apparent long-term physical effect. The manifestation of a
paresthesia may be transient or chronic.
The most familiar kind of paresthesia is the sensation known as "pins and
needles" or of a limb "falling asleep". A less well-known but still fairly common
paresthesia is formication.
Paresthesia or "persistent anesthesia" is a transient or potentially permanent
condition of extended numbness after administration of local anesthesia and the
injected anesthetic has terminated.
Potential causes include trauma induced to the nerve sheath during
administration of the injection, hemorrhage about the sheath, type of anesthetic
used, or administration of anesthetic potentially contaminated with alcohol or
Paresthesia is the persistence of anesthetic symptoms beyond the expected
duration. It can be caused by trauma to the nerve by the needle during
injection. It can also be caused by hemorrhage in and around the
nerve. Reports of paresthesia are more common with articaine and prilocaine
and thus nerve block should be avoided in children with these local
anesthetics. The tongue and lips are the most common areas affected. Most
cases resolve in 8 weeks without treatment.
TREATMENT
Medications offered can include the immunosuppressant prednisone,
intravenous gamma globulin (IVIG), anticonvulsants such
asgabapentin or Gabitril and antiviral medication, among others, according to
the underlying cause.
In addition to treatment of the underlying disorder, palliative care can include
the use of topical numbing creams, such as lidocaine or prilocaine. Care must
be taken to apply only the necessary amount, as excess can contribute to the
condition. Otherwise, these products offer extremely effective, but short-lasting,
relief from the condition.
Paresthesia caused by shingles is treated with appropriate antiviral medication.
Postoperative soft tissue injury
Accidental biting or chewing of the lip, tongue or cheek is a problem seen in
very young pediatric mentally or physically disabled patients. Soft tissue
anesthesia lasts longer than pulpal anesthesia and may be present for up 4
hours after local anesthesia administration. The most common area of trauma
is the lower lip and to a lesser extent the tongue, followed by the upper lip.
Infection
Infection, especially a needle track infection, which manifests itself pretty late,
can occur. To prevent infection it is recommend that needles not be reused in apatient's mouth. Fresh needles should always be used, and the area to be
penetrated should be cleaned prior to insertion of the needle.
Facial nerve paralysis may occur temporarily with a nerve block. Again, reassure
the patient that the condition will disappear as the anesthetic agent is
metabolized.
Complications resulting from a maxillary nerve block are rare, but may include:
- regional sixth nerve block, results in temporary teplopia for the patient
- hematoma (rare)
- retrobulbar block (rare)
- optic nerve block, which can result in temporary blindness (rare)
Important complications of local anaesthesia
Pain
Bleeding and haematoma formation
Nerve injury due to direct injury
Infection Ischaemic necrosis
Several preventive measures can be followed:
Select a local anesthetic with a duration of action that is appropriate for thelength of the planned procedure.
Advise the patient and accompanying adult about the possibility of injury if thepatient bites, sucks or chews on the lips, tongue and cheek. They shoulddelay eating and avoid hot drinks until the effects of the anesthesia are totally
dissipated.
Reinforce the warning with patient stickers and by placing a cotton roll in themucobuccal fold if anesthesia symptoms persist.
The management of soft tissue trauma involves reassuring the patient andparent (it's okay if the tissue turns white), allowing up to a week for the injuryto heal, and lubricating the area with petroleum jelly or antibiotic ointment toprevent drying, cracking and pain.
COMPLICATIONS ATTRIBUTED TO NEEDLE INSERTION
SYNCOPE
Fainting, "blacking out," or syncope is the temporary loss of consciousness
followed by the return to full wakefulness. This loss of consciousness may be
accompanied by loss of muscle tone that can result in falling or slumping over.
To better understand why fainting can occur; it is helpful to explain why
somebody is awake.
8/12/2019 Anes Local
http://slidepdf.com/reader/full/anes-local 8/24
The brain has multiple parts, including two hemispheres, the cerebellum, and
the brain stem. The brain requires blood flow to provide oxygen
andglucose (sugar) to its cells to sustain life. For the body to be awake, an area
known as the reticular activating system located in the brain stem needs to be
turned on, and at least one brain hemisphere needs to be functioning. For
fainting or syncope to occur, either the reticular activating system needs to lose
its blood supply, or both hemispheres of the brain need to be deprived of blood,
oxygen, or glucose. If blood sugar levels are normal blood flow must be briefly
disrupted to the whole brain or to the reticular activating system.
Fainting is not caused by head trauma, since loss of consciousness after ahead
injury is considered a concussion. However, fainting can cause injury if the
person falls and hurts themselves, or if the faint occurs while participating in an
activity like driving a car.
Fainting is differentiated from seizure, during which patients may also lose
consciousness.
CAUSES
Decreased blood flow to the brain can occur because 1) the heart fails to pump
the blood; 2) the blood vessels don't have enough tone to maintain blood
pressure to deliver the blood to the brain; 3) there is not enough blood or fluidwithin the blood vessels; or 4) a combination of reasons one, two, or three
above.
SIGNS AND SYMPTOMS
With fainting (syncope), the patient is unaware that they have passed out and
fallen to the ground. It is only afterward that they understand what has
happened.
There may be symptoms or signs before the syncopal episode, which may
include:
The person may feel lightheaded, nauseated, sweaty, or weak. There may
be a feeling of dizziness or vertigo(with the room spinning), vision may
Hyperesthesia is an increased sensitivity to the stimuli. It could be elevated
sensation of touch, hearing, smell or vision for instance. Increased touch
sensitivity is called tactile sensitivity or tactile defensiveness while auditory
sensitivity is the name given to increased sound sensation.
Causes
Excessive consumption of caffeine can temporarily induce this condition in
humans, due to excessive stimulaton of the spinal cord, as well as the cortex
and medulla in the central nervous system. However, this is far from the only
cause, and usually wears off after 3-5 hours.
In some cases, an outside stimulus is not involved and it is triggered by
overstimulation of the area of the brain involved in sensation, in which case the
hyperesthesia should resolve within a few hours. Whenever hyperesthesia
occurs, it is advised that the patient may lie in a cool, quiet, dark place to
resolve the condition. In some, aerobic breathing exercises and physiotherapy is
beneficial.
Chronicity
But when hyperesthesia manifests as chronic, a neurologist is consulted who
may prescribe medications such as analgesics to dull sensation, anti-seizure
medications, and also anti-anxiety drugs.
Tactile hyperesthesia
Tactile sensitivity could occur in ADHD, fragile X syndrome and autism.
According to a large study conducted at Hebrew University, 69 percent of boys
with ADHD also had tactile hyperesthesia. It may be present as a symptom in
neurologic disorders such as herpes family viral infections, peripheral
8/12/2019 Anes Local
http://slidepdf.com/reader/full/anes-local 18/24
neuropathy and radiculopathies. When the respective neurologic disorder is
treated, hyperesthesia is simultaneously treated. Tactile sensitivity in children is
treated by therapy under the guidance of a trained occupational therapist. In
the process the child is guided through structured but fun-filled activities thatchallenge the child’s sensation, according to the Sensory Processing Disorder
Foundation.
Treatment
Treatment is based on underlying cause of the symptom. If the symptom is
treated, hyperesthesia in other words could also be treated. For example,
hyperesthesia, which occurs in vitamin B12 deficiency, is treated by prescribing
vitamin B12 supplements.
Hematoma
A hematoma is a collection of blood outside of a blood vessel.
Symptoms of hematomas depend upon their location and whether
adjacent structures are affected by the inflammation and swelling
associated with the bleeding.
Treatment of a hematoma depends upon which organ or body tissue is
affected.
Superficial hematomas of the skin and soft tissue, such as muscle, may be
treated with rest, ice, compression, and elevation (RICE). Heat may also
be considered.
8/12/2019 Anes Local
http://slidepdf.com/reader/full/anes-local 19/24
What is a hematoma?
By definition, a hematoma is a collection of blood outside of a blood vessel. It
occurs because the wall of a blood vessel wall, artery, vein or capillary, has
been damaged and blood has leaked into tissues where it does not belong. The
hematoma may be tiny, with just a dot of blood or it can be large and cause
significant swelling.
The blood vessels in the body are under constant repair. Minor injuries occur
routinely and the body is usually able to repair the damaged vessel wall by
activating the blood clotting cascade and forming fibrin patches. Sometimes the
repair fails if the damage is extensive and the large defect allows for continued
bleeding. As well, if there is great pressure within the blood vessel, for example
a major artery, the blood will continue to leak through the damaged wall and
the hematoma will expand.
Blood that escapes from within a blood vessel is very irritating to the
surrounding tissue and may cause symptoms of inflammation including pain,
swelling, and redness. Symptoms of a hematoma depend upon their location,
their size, and whether they cause associated swelling or edema.
What are the types of hematomas?
Hematomas are often described based upon their location.
The most dangerous hematomas are those that occur inside the skull. Because
the skull is an enclosed box, anything that takes up space increases pressure
within that box and potentially impairs the ability of the brain to function.
8/12/2019 Anes Local
http://slidepdf.com/reader/full/anes-local 20/24
Epidural hematomas
These occur because of trauma, often to the temple, where the middle
meningeal artery is located. Bleeding accumulates in the epidural space, outsidethe “dura” which is the lining of the brain. Because of the way the dura is
attached to the skull, small hematomas can cause significant pressure and brain
injury.
Subdural hematomas
These may also occur because of trauma but the injury is usually to the veins in
the brain. This causes a slower leak of blood, which enters the “subdural” space
below the dura. The space below the dura has much more room for blood to
accumulate before brain function suffers. As people age, they lose some brain
tissue and the subdural space is relatively larger. Bleeding into the subdural
space may be very slow, gradually stop, and not cause acute symptoms. These
“chronic” subdural hematomas are often found incidentally on computerized
tomography (CT) scans as part of a patient evaluation for confusion or because
another traumatic incident occurred. However, subdural hematomas may belarge, cause associated brain swelling, and may be lethal.
Intracerebral hematomas
These occur within the brain tissue itself. Intracerebral (intra= within +
cerebrum=brain) hematomas may be due to bleeding from uncontrolled high
blood pressure, an aneurysm leak or rupture, trauma,tumor, or stroke.
Scalp hematomas
These occur on the outside of the skull and often can be felt as a bump on the
head. Because the injury is to the skin and muscle layers outside of the skull,
Bruises and contusions of the skin (ecchymosis) are terms that describe
subcutaneous hematomas. These occur due to trauma or injuries to the
superficial blood vessels under the skin. Individuals who take anticoagulant
medication are more prone to subcutaneous hematomas.
Intra-abdominal hematomas and hemorrhage may be due to a variety of
injuries or illnesses. Regardless of how the blood gets into the abdomen, the
clinical finding is peritonitis (irritation of the lining of the abdomen). Hematomas
may occur in solid organs such as the liver, spleen, or kidney. They may occur
within the walls of the bowel, including the small intestine (duodenum, jejunum,
and ileum) or the large intestine (colon). Hematomas may also form within the
lining of the abdomen called the peritoneum or behind the peritoneum in the
retroperitoneal space (retro=behind).
Passing clots or hematomas
It is a common complaint when women menstruate. Blood can accumulate in
the vagina as part of the normal menses and instead of flowing out immediately,
it may form small blood clots. Passing blood clots after delivering a baby is alsorelatively common. However, vaginal bleeding and passing blood clots or
hematomas while pregnant is not normal and should be a sign to seek
immediate medical attention.
Hematomas may occur anywhere in the body. Regardless of how a hematoma is
described or where it is located, it remains a collection of clotted blood outside