An alteration in the level of consciousness of a patient may result from a large variety of medical problems, The altered state can range from lightheadedness to a complete loss of consciousness. Without attempting to
Manifestations of Patient Preparing to Vomit
include all possible causes of altered consciousness, a discussion is presented of commonly occurring conditions that may lead to an acutely altered state of consciousness while patients are undergoing oral surgical procedures.
Vasovagal syncope. The most common cause of a . transient loss of consciousness in the dental office is vasovagal syncope. This generally occurs because of a series of cardiovascular events triggered by the emotional stress brought on by the anticipation of or delivery of dental
care. The initial event in a vasovagal syncopal episode Is the stress-induced release of increased amounts of catecholamines that cause a decrease in peripheral vascular resistance, tachycardia, and sweating. The patient maycomplain of feeling generalized warmth, nausea, and pal-arterial blood pressure appears, with a corresponding decrease in cerebral blood flow. The patient may then complain of feeling dizzy or weak. Compensatory mechanisms attempt to maintain adequate blood pressure, but they soon fade, leading to vagally mediated bradycardia. Once the blood pressure drops below levels necessary to sustain consciousness, syncope.occurs (Fig. 2-9).
If cerebral ischemia is sufficiently severe, the patient may also develop seizure activity. The syncopal episode and any accompanying seizure usually ends rapidly once. the patient assumes or is placed in a horizontal position with the feet elevated (Fig, 2-1(0). Once consciousness is
regained, the patient may have pallor, nausea, and fatigue for several minutes.
Prevention of vasovagal syncopal reactions involves proper patient preparation. The extremely anxious patient should be treated by using an anxiety reduction protocol and, if necessary, given pretreatment. anxiolytic drugs. Oral surgical care should be provided while the patient is
in a semi supine or fully supine position. Any signs of an impending syncopal episode should be quickly treated by placing the patient in a fully supine position or a position in which the legs are elevated above the level of the heart and by placing a cool moist towel on the forehead. If the
patient is hypoventilatiog and is slow to recover consciousness, a respiratory stimulant such as aromatic ammonia may be useful. If the return of consciousness is delayed for more than a minute, an alternative cause for depressed consciousness other than vasovagal syncope
should be sought. After early recovery from the syncopal episode, the patient should be allowed to recover in the office and then be discharged with an escort. Future office
visits by the patient will require preoperative sedation, additional anxlety reducing’measures or both.
Orthostatic hvpotension. Another common cause of a transient altered state of consciousness in the dental setting is orthostatic (or postural) hypotension. This problem occurs because of pooling of blood in the
periphery that is not remobilized quickly enough to prevent cerebral ischemia when a patient rapidly assumes an uprighr posture. The patient will therefore feel light headed or become syncopal. Patients with orthostatic hypotensioh who remain conscious will usually complain of palpitations and generalized weakness, Most individuals who are not hypovolemic or have orthostatic hypotension resulting from the pharmacologic effects of drugs such as antihypertensive agents will quickly recover by reassuming the reclined position. Once symptoms disappear the patient can generally sit up (although this should be done slowly) and sit on the edge of the chair for a few moments before standing. Blood pressure can be taken in each position and allowed to return to normal before a more upright posture is assumed (Box 2-11).
In the ambulatory population this is usually encountered in patients receiving the following medications: drugs that produce intravascular depletion, such as diuretics; drugs that produce peripheral vasodilation,
such as most nondiuretic antihypertensives, narcotics, and many, psychiatric drugs; and drugs that prevent the heart rate from increasing reflexly, such as beta-sympathetic antagonist medications (e.g ropranolol). Patients with a predisposition to postural hypotension
can usually be managed by allowing a much longer period to attain a standing position (l.e., by stop- allow reflex cardiovascular compensation to occur). If the patient was sedated by using long-acting- narcotics, an
antagonist such as naloxone may be necessary .Patients with severe problems with postural hypotension as a result of drug therapy should be referred to their physician for possible alteration of their drug regimen.
Seizure. Idiopathic seizure disorders are exhibited in, many ways, ranging from grandmas seizures, with their frightening display of clonic contortions of the trunk and extremities, to petite mal seizures that may occur with
only episodic ab scenes stare). Although rare, some seizure disorders, such as those secondary to in jury induced brain damage or damage from ethanol abuse, have a known cause. Usually the patient will have had the seizure disorder previously diagnosed ana will be receiving antiseizure medications, such as phenytoin (Dilantin), phenobarbital, or valproic acid. Therefore the dentist should discover through the medical interview the degree of seizure control present to decide if oral surgery
can be safely performed. The patient should be asked
Management of Orthostatic Hypotension
to describe what witnesses have said occurs just before, during, and after the patient’s seizures. It is helpful to disover any factors that seem to precipitate the seizure, the patient’s compliance with antiseizure drugs, and the recent frequency of seizure episodes. Patients with seizure
disorders who appear to have good control of their disease, that is, infrequent episodes that are brief in duration and are not easily precipitated by anxiety, are usually able to safely undergo oral surgery in the ambulatory setting. (See Chapter 1 for recommendations.)
The occurrence of a seizure while a patient is undergoing care in the dental office, although usually creating great concern among the office staff, is rarely an emergency that calls for actions other than simply protecting
the patient from self-injury. However, management of the patient during and after a seizure varies, based on the type of seizure that occurs. The patient’s ability to exchange air must be monitored by close observation. If
it appears that the airway is obstructed, measures to reopen it must be taken, for example, by placing the head in moderate extension (chin pulled away from the chest) and moving the mandible away from the pharynx. If the patient vomits or seems to be having problems keeping secretions out of the airway, the patient’s head must be positioned to the side to allow obstructing materials to drain out of the mouth. If possible, high-volume suction should be used to evacuate materials from the pharynx. Brief periods of apnea may occur, which require no treatment other than ensuring a patent airway. However, apnea for more than 30 seconds demands that BLStechniques be initiated. Although frequently described as
being important, the placement of objects between the. teeth in an attempt to prevent tongue biting is hazardous and therefore usually unwarranted.
Continuous or repeated seizures without periods ofrecovery between them are known as status epilepticus. This problem warrants notification of outside emergency assistance because it is the most common type of seizure disorder to cause mortality. Therapy includes instituting measures already described for self-limiting seizures; in addition, administration of a benzodiazepine is indicated. Injectable water-insoluble benzodiazepines such as diazepam must be given IV to allow predi tability of results, which may be difficult in the seizing patient if venous access is not already available. Injectable watersoluble benzodiazepines such as midazolam provide a better alternative, because 1M injection will give a more
rapid response. However, the doctor administering benzodiazepines
for a seizure must be prepared to provide BLS, because patients may experience a period of apnea after receiving a large rapid dose of benzodiazepines.
After seizures have ceased, most patients will be left either somnolent or unconscious. Vital signs should be monitored carefully during this time, and the patient . should not be allowed to leave the office until fully alert
and in the company of an escort. The patient’s primary care physician should be notified to decide if medical evaluation is necessary and if or when ambulatory dental care is advisable-in the future (Fig. 2-11).
Tremors, palpitations, and anxiety usually precede seizures caused by ethanol withdrawal. Therefore the appearance’of these signs in a patient should warrfthe clinician the patient’s condition is instituted. Control is usually obtained by the use of benzodiazepines, which are used’
until the uintoward effects of abstinence from ethanol cease. Seizures that occur in ethanol-abusing patients are treated in a similar manner to other seizures.
Local anesthetic toxicity. Local. anesthetics, when properly used, are a safe and effective means of providing pain control when performing dentoalveolar surgery. However, as with all medications, toxicity reactions occur if the local anesthetic is given in an amount or in a manner
that produces an excessive serum concentration.
Prevention of a toxicity reaction to local anesthetics generally involves several factors. First, the dose to be used should be the least amount of local anesthetic necessary to produce the intensity and duration of pain control required to successfully complete the planned surgical procedure. The patient’s age, lean body mass, liver function, and history of problems with local anesthetics must be considered when choosing the dose of local anesthesia. The second factor to consider in preventing a local anesthetic
overdose reaction is the manner of. drug administration. The dentist should give the required dose slowly, avoiding intravascular injection, and use vasoconstrictors to slow the entry of local anesthetics into the blood. It
should be remembered that topical use of local anesthetics in wounds or on mucosal surfaces allows rapid entry of local anesthetics into the systemic circulation. The choice of local anesthetic agents is the third important factor to consider in attempting to lessen the risk of a toxicity reaction.
Local anesthetics vary in their lipid solubility, vasodilatory properties, protein binding, and inherent toxicity. Therefore the dentist must be knowledgeable about the various local anesthetics available to allow C!.
rational derision to be made when choosing which drug to administer and in what amounts (Table 2-4).
The clinical manifestations of a local anesthetic overdose vary, depending on the severity of the overdose, how rapidly it occurs, and the duration of the excessive serum concentrations. Signs of a mild toxicity reaction
. may be limited to increased patient confusion, talkativeness, anxiety, and slurring of speech. As the severity of the overdose increases, the patient may display stuttering speech, nystagmus, and generalized tremors. Symptoms such as headache, dizziness, blurred vision, and drowsiness may also occur. The most serious manifestations of local anesthetic toxicity are the appearance of generalized tonic-clonic seizure .activity and cardiac depression leading to cardiac arrest (Table 2-5).
Mild local anesthetic overdose reactions are managed by monitorlng- vital signs, instructing the patient to hyperventilate moderately with or witbol adwinistering oxygen, and gaining venous access. If signs of anesthetic toxicity do not rapidly disappear, a slow IV..2.5–to 5-mg
dose of diazepam should be given. Medical assistance should also be summoned if signs of toxidty do not rapidly resolve or progressively worsen.
If convulsions occur, patients should be protected from hurting themselves. Basic life-support measures are instituted as needed and venous access gained, if possible, for administration of anticonvulsants. Medical assistance should- be obtained. If venous. access· is available,
Suggested Maximum Dose of Local Anesthetics
·Maximum doses are those tor normal healthy.individuals.
“Maximum dose of epinephrine is O.2.mg per appointment.
Manifestations and Management of Local Anesthetic Toxicity
Manifestations of Acute Hypoglycemia
diazepam should be slowly titrated until the sejzure activity stops (5 to 25 mg is the usual effective range). Vital signs should be checked frequently.
Diabetes mellitus. Diabetes .mellitus is a metabolic disease in’ which the patient’s long-term prognosis appears dependent on keeping serum glucose levels close to normal. An untreated insulin-dependent diabetic constantly
runs the risk of developing ketoacidosis-and its,attendant alteration of consciousness, requiring emergency treatment. Although a compliant insulin-taking diabetic may suffer long-term problems because of relatively
high serum glucose levels, the more common emergency situation they encounter is hypoglycemia resulting a mismatch of insulin dose and serum glucose. Severe hypoglycemia i$ the emergency situation dentists
are most likely to face when providing oral surgery for adiabetic patient .
Sfrum glucoseco~centration in-the diabetic patient represents a balance between administered insulin, glucose placed into the serum from various sources, and glucose use. The two primary sources of glucose are dietary
and gluconeogenesis from’ adipose tissue, muscle, and glycogen stores. Physical. activity is the principal means by which serum glucose is lowered. Therefore serum glucose levels can fall because of any or all of the following:
. 1., Increasing administered insulin
2. Decreasing dietary caloric intake
3. Increasing metabolic use of glucose (e.g., exercise,
infection, emotional stress)
Problems with hypoglycemia during dental care usually arise because the patient has acutely decreased caloric intake, an infection, or an increased metabolic rate caused by marked anxiety. If the patient has not compensated for this diminution of available glucose by decreasing the
usual dose of insulin” hypoglycemia results. Although patients taking oral hypoglycemics can also have problems with hypoglycemia, their swings in serum glucose levels are usually less pronounced than those of insulindependent patients with diabetes, so they are much less
likely to quickly become severely hypoglycemic.
Many patients with diabetes are well Informed about their disease and are capable of diagnosing their own hypoglycemia before it becomes severe. The patient may feel hunger, nausea, or lightheadedness or may develop a ,
headache. The dentist may notice th» patient becominglethargic, with decreased spontaneity of conversation and ability to concentrate: As hypoglycemia worsens, the patient may becoine diaphoretic or have tachycardia, piloerection, or increased anxiety and exhibit unusual
behavior, The patient may soon become stuporous or lose consciousness (TabTe2-6).
avoided through measures designed to keep serum glucose levels on the high.side of normal or even ‘temporarily above normal. During the health history interview, the dentist should get a clear idea of the degree of control of the patient’s diabetes. If patients do not, regularly check
their own urine or serum glucose, their physician should be contacted to determine whether routine dental cate can be performed safely. Before any planned procedures, measures discussed In Chapter 1 ‘concerning the diabetic patient should be taken.
If a diabetic patient indicates a feeling of low blood sugar or if signs or symptoms of hypoglycemia. appear, the procedure being performed should be stopped and the patient allowed to consume a high-caloric carbohydrate, such as a few packets of sugar, a glass of fruit juice, or other
sugar-contalntng beverages. If the patient fails to rapidly improve, becomes unconscious, or is otherwise unable to take a glucose source by mouth, venous access should be gained and an ampule (SOmL) of 50% glucose (dextrose) in water should be administered IV over 2 to 3 minutes. If ” venous access cannot be established, 1mg of glucagon can be given 1M. If SQ%glucose and glucagon are unavailable, a O.S-mL dose of 1:1000 epinephrine can be administered . SC and repeated every 15 minutes as needed (Fig. 2-12).
A patient who seems to have recovered from a hypoglycemic episode should remain in the office for at least 1 hour, and further symptoms ‘should be treated with oral glucose sources. The patient should be escorted home with instructions on how to avoid a hypoglycemic episode during the next dental appointr.ient. Thyroid dysfunction. Hyperthyroidism and hypothyroidism are slowly developing disorders that can produce
an altered state of consciousness but rarely cause emergencies. The most common circumstance in which an ambulatory, relatively healthy-appearing’ patient develops an emergency from thyroid dysfunction is when a thyroid storm (crisis) occurs.
Thyroid storm is sudderi, severe exacerbation of hyperthyroidism that mayor may not have been previously .Thyroid storm is sudderi, severe exacerbation of hyperthyr diagnosed. If can be precipitated by infection, surgery, trauma, pregnancy, or any other physiologic or emotional
stress. Patients predisposed to thyroid crisis frequently have signs of hyperthyroidism, such as tremor, tachycardia, weight loss, hypertension, irritability, intolerance to heat, and exophthalmos; they may have eyen received therapy for the thyroid disorder.
Patients with known, hyperthyroidism should have their primary care physician consulted before any oral surgical procedur.e. A determination of the adequacy of control of excessive thyroid hormone production should be obtained from the patient’s physician, and, if necessary,
the patient should receive antithyroid drugs and iodide treatment preoperatively. If clearance for ambulatory surgery is given, the patient should be managed as shown in the outline in Chapter 1.
The first sign of a developing thyroid storm is an ‘elevation of temperature and heart rate. Most of the usual signs and symptoms of untreated hyperthyroidism occur in an exaggerated form” The patient becomes irritable, delirious, or even ‘comatose. Hypotension, vomitirig, and
diarrhea also occur.
Treatment of thyrotoxic crisis begins with terminatiori of any procedure and notification of those outside the office able to give emergency assistance. Venous access should be attained, crystalloid solution started at a moderate rate, and the patient kept as calm as possible. Attempts may be taken to cool the patient until he or she can be transported to a hospital, where antithyroid and sympathetic .blocklng drugs can be administered safely Box 2-12).
Adrenal insufficiency. Primary adrenocortical insufficiency (Addison’s disease) or other medical conditions in which the adrenal cortex has been destroyed are rare. However, adrenal insufficiency secondary to exogenous corticosteroid administration is relatively common because of the multitude of clinical conditions for which therapeutic corticosteroids are given, Patients with adrenal insufficiency are frequently not informed concerning their potential need for supplemental medication, and those with secondary adrenal ‘insufficiency may fail to inform the’ dentist that they are taking corticosteroids. This is not a problem, provided the patient is not physiologically or emotionally stressed.
However, should the patient be stressed, adrenal suppression that results from exogenous corticosteroids may prevent the normal telease of increased amounts of endogenous glucocorticoids needed to help the body
meet the elevated metabolic demands. Patients at risk for acute adrenal insufficiency as a result of adrenal suppression are generally those who take at least 20 mg of cortisol (or its equivalent) daily for at least 2 weeks any time
Manifestations of Acute Management of Thyroid Storm
Hyperpyrexia (i.e., fever)
Nervousness and agitation
Nausea and vomiting
Partial or complete loss of consciousness
Terminate all dental treatment
Have someone summon medical assistance
Monitor all vital signs
Initiate BlS if necessary _ _
Start IVline with drip’ of crystalloid solution (150 ml/hr)
-Transport patient to emergency care facility
BLS, Basic Life Support; JII, intravenous.
Equivalency of Commonly Used Glucocorticosteroids
during the year preceding the planned major oral surgical procedure (Table 2-7). However, in most straightforward oral surgical procedures done under local anesthesia or nitrous oxide-and local anesthesia, administration.of supplemental corticosteroids is unnecessary, When significant adrenal suppression is suspected, the steps discussed
in Chapter 1 should be followed.
Early clinical manifestations of acute adrenal insufficiency crisis include mental confusion, nausea, fatigue, and muscle weakness. As the condition worsens, the patient develops more severe mental confusion; pain in
the back, abdomen, and legs; vomiting; and hypotension. Without treatment the patient will eventually begin to drift in and out of consciousness, with coma harkening the preterminal stage (Box 2-13) .
Management of an adrenal crisis begins by stopping all dental treatment and taking vital signs. If the patient is found to be hypotensive, they must be immediately placed in a head-down, legs elevated position. Medical
assistance should be summoned. Oxygen should be administered and venous access gained. A 100-mg dose of hydrocortisone sodium succinate should be given IV (or 1M, if necessary). IV fluids are rapidly administered until hypotension improves. Vital signs should be measured
frequently while therapeutic measures are being taken. Should the patient lose consciousness, the need for initiation of basic life-support measures should be evaluated (Box 2-14).
Cerebrovascular compromise. Alterations in cerebral blood flow can be compromised in three prindpal ways: (1) -embolization of particulate matter from a distant site, (2) formation of a thrombus in a cerebral vessel; or (3) rupture of a vessel. Material that embolizes to the brain comes most frequently from thrombi in the left side of the heart, from the carotid artery, or from bacterial vegetations on infected heart surfaces. Cerebrovascular thrombi generally form in areas of atherosclerotic
changes. Finally, vascular rupture can occur because of rare congenital defects in the vessel, that is, berry aneurysms.