Emergencies Involving Unconsciousness

Fortunately, unconsciousness is fairly uncommon in the dental office, even though syncope (simple fainting) is reported to be the most common medical emergency encountered in dental offices. By recognizing the early manifestations of presyncope, steps can be taken to prevent a person from falling. If unconsciousness does occur, the management is essentially the same regardless of the cause.

Many cases of unconsciousness can be avoided by reducing as much stress as possible. If a person does become unconscious, one should follow the basic guidelines, or call 911 if indicated; place the victim in the supine position; maintain the airway; administer oxygen if indicated; establish baseline vital signs; perform CPR if necessary; stay calm; and take the specific steps necessary for the condition.

Stress, physical or emotional, is the most common cause of unconsciousness, or vasodepressor syncope. Most often in the dental office the cause is psychogenic-of psychological origin, such as fear, anxiety, pain, and emotional upset. It is interesting to note that good news can have the same effect as bad news. Physical or nonpsychogenic causes also can cause syncope, especially in an individual classified as ASA III or IV, but these are not the usual causes for syncope in the dental office. Nonpsychogenic causes of syncope include being upright or in a standing position; hunger; exhaustion; and being in poor physical condition or in a hot, humid, crowded environment. Children seldom experience syncope, probably because children are less likely to curb their emotions. Older adults also seldom experience syncope.

The usual victim, upon entering the treatment room, sees a syringe that might be there for him, experiences fear and may not let anyone know he is afraid. Because of his fear, chemicals, primarily adrenaline, are released into his blood-stream to help his body adapt to the stress resulting from his fear. This chemical release causes a reaction called the flight-or-fight response. Since the person does not flee or fight, and suppresses the response, there is no anticipated muscular activity, and the large volume of blood that was directed to the muscle pools, does not return to the heart, and results in a drop in circulating blood, including blood going to the brain. The brain is most sensitive to a lack of oxygen, and in an effort to have enough blood to keep the brain functioning, reflex bradycardia develops with a resulting decrease in blood pressure. The blood pressure falls below the level necessary to maintain consciousness, cerebral ischemia occurs and he falls to the floor unconscious.

Fainting seems rather innocuous, not much of a medical emergency at all, but if cerebral ischemia is not corrected, permanent neurologic damage or death is possible. The early Romans, masters of torture and death, used crucifixion as one of their primary forms of killing and reserved it only for the worst criminals. Crucifixion is in fact death from forcibly maintained vasodepressor syncope.

Presyncope is the period of time when the body is being affected by inadequate cerebral circulation and the resulting lack of nutrition and oxygen. Early manifestations include a pale or ashen skin color with the skin possibly cool, and/or moist ("a cold sweat"). The victim might describe a feeling of warmth in the head and neck, lightheadedness, or dizziness; and may also feel nauseated, complain of numbness or tingling in the toes and fingers, and a variety of other related symptoms. Some people say they feel bad, or that everything is going dark just before losing consciousness. Fainting can occur without warning. Syncope is the period when the victim actually loses consciousness. Bradycardia, hypotension, and a weak, thready pulse is common. Unconsciousness results in muscular relaxation and the possibility of an obstructed or partially obstructed airway, due to a decrease in muscle tone that may cause the tongue to fall into the oropharynx. Another effect of this muscular relaxation may be fecal incontinence.

Postsyncope is a period that occurs as the victim returns to consciousness and the heart rate, pulse, and cerebral nutrition return to normal. During this time, the victim is more likely to reexperience syncope if raised from the supine position too quickly, or allowed to stand too soon after the episode. Any visually disturbing triggers such as a syringe or blood-soaked gauze should be removed from sight.

Prevention relies on using a thorough medical history to identify factors that may predispose a person to syncope, and on observing and evaluating a person to determine the anxiety level. Stress reduction methods should be used. Allowing or encouraging a person to verbalize fear is another useful step that can be taken. The clinician should also be aware of drugs being taken by a patient and their possible side effects. Fortunately treating patients while they are in the supine position prevents the development of cerebral anoxia with resultant syncope, and syncope during treatment is uncommon today. It is at other times, when the patient is upright, that syncope is most likely.

Syncope is generally self-correcting; once the person collapses, normal circulation returns. Inadequate cerebral circulation can be prevented or corrected if the person is placed in the supine position. So the first order of business, if an individual experiences presyncope or actually loses consciousness, is to position him or her in the supine position with the legs slightly elevated. Malamed suggests that, if able, the individual should also vigorously move the legs. Exceptions to the supine position rule include pregnant patients or those with respiratory difficulties and/or chest pain. A pregnant woman can be placed on her side with the legs slightly elevated to prevent further problems caused by the weight of the fetus on the vena cava. When respiratory difficulties or chest pain is present, the person should be positioned to allow ease of breathing, which is usually in a seated upright position. The second and most critical step is to maintain an open airway, making certain that the person is breathing well.

It could become necessary to perform rescue breathing and perhaps administer oxygen if indicated. However, oxygen should not be given to a person experiencing hyperventilation. The American Red Cross gives assurance that as long as a fainting victim recovers quickly, it is unnecessary to call EMS, but suggests that it be determined whether or not the episode is linked to a more serious condition.5 After recovery, it is good to forgo additional dental therapy for the rest of the day, since a second episode is possible. The clinician should determine what triggered the episode to prevent a reoccurrence in the future. Arrangements should be made for someone to drive the victim home. The old-fashioned remedy of asking a victim to place the head between the legs to keep from fainting is no longer advised. Bending to that extreme degree may further impede blood flow, cause even less blood to flow to the brain, and result in an even quicker loss of consciousness. Additionally, the person would be in a decidedly awkward position for airway maintenance should it become necessary.

If recovery from syncope takes longer than five minutes after positioning and/or if complete recovery does not occur in 15 to 20 minutes, another possible cause of unconsciousness should be considered and definitive management begun, including summoning EMS. One last caution when managing a simple case of syncope is for the practitioner to maintain composure, especially as the patient begins to regain consciousness. Introducing more stress could cause the victim to relapse back into unconsciousness.

Orthostatic hypotension (postural hypotension) is a disorder of the autonomic nervous system in which syncope occurs as a person abruptly assumes the upright position after being supine, or is in the standing or sitting position for an extended period of time. Malamed lists predisposing factors as:3

• certain drugs for which orthostatic hypotension is a side effect (some of these include anti-hypertensives, some classes of tranquilizers, some antidepressants, narcotics, and anti- parkinsonism drugs);
• a long period of lying in bed, especially if the individual has been confined to bed for a week or longer;
• a two-to three-hour dental appointment with the patient confined in the recumbent position, especially if psychosedative drugs have been administered;
• inadequate postural reflex even in a healthy young person if he or she is forced to stand for prolonged periods of time, especially if the knees are locked;
• the first trimester of pregnancy, when a woman may experience postural hypotension on arising, but she may not experience it at any other time during the day;
• late in the third trimester of pregnancy when supine hypotensive syndrome of pregnancy can occur if the patient is allowed to lie in the supine position for as little as three to seven minutes. The cause is reduced blood flow to the brain from the weight of the uterus compressing the inferior vena cava, hindering venous return from the legs;
• venous defects in the legs causing pooling of blood in the legs;
• post-recovery after sympathectomy, a surgical procedure to reduce high blood pressure and improve circulation to the legs;
• Addison's disease (chronic adrenocortical insufficiency);
• physical exhaustion;
• fatigue;
• starvation; and
• Shy-Drager syndrome (uncommon idiopathic orthostatic hypotension, usually causing severe disability or death within five-to-10 years of onset).

A victim of orthostatic hypotension experiences a rapid loss of consciousness when there is a rapid postural change from reclining to standing or sitting upright. There are generally few or no signs or symptoms of presyncope even for patients with chronic orthostatic hypotension.

Management of these patients is the same as for others unconscious patients, except that after the victim regains consciousness, postural changes from supine to upright should be made very slowly with two or three stops over several minutes. If at any time the patient feels dizzy or lightheaded, raising the chair should be stopped until the sensation has passed. Once again, the victim should be driven home by someone else, especially if there is no prior history of orthostatic hypotension, or if the condition was a result of drugs administered while undergoing dental treatment. A patient with chronic orthostatic hypotension, or with the condition as a result of prescribed medication, may be allowed to drive home if he has recovered sufficiently. Any patient who has no previous history of orthostatic hypotension should be referred for medical care unless the cause is readily apparent, like standing for a long period of time with the knees locked.

Acute adrenal insufficiency is less common but can also cause unconsciousness. Such a person is however, in the most immediate danger of dying. The adrenal gland produces aldosterone and cortisol hormones that allow the body to adapt to stress and are vital to survival. When there is a lack of these hormones, the body is less able to adapt to stressful situations, and this causes symptoms of adrenal insufficiency. Acute adrenal insufficiency can lead to death as result of peripheral vascular collapse (shock) and ventricular asystole (cardiac arrest).

The major predisposing factor in all cases of adrenal insufficiency is lack of glucocorticosteroid hormones. Insufficiency can result from sudden withdrawal of steroids from a patient who has primary adrenal insufficiency, or sudden withdrawal of steroids from a patient with normal adrenal cortices but with a secondary insufficiency. Administration of exogenous glucocorticosteroids is the most common cause of adrenal insufficiency. Little and Falace state that many patients taking steroids require supplemental steroids in the presence of illness, infection, surgery, or extreme stress. Susceptible patients should receive exogenous glucocorticosteroid coverage before, during and after stressful situations and care should be taken to reduce stress as much as possible. Little and Falace also advise that when treating patients with a history of steroid use, it is better to "overtreat" with additional steroids than to risk acute adrenal crisis because over short periods of time, increased amounts of steroids are safe.6 According to Malamed, a person who has taken exogenous glucocorticosteroid hormones may not recover normal adrenal function for nine months to two years, and a patient who falls under the Rule of Twos is the most susceptible.3

Clinical manifestations of acute adrenal insufficiency that should be considered very serious, especially in a susceptible individual include mental confusion, muscle weakness, intense pain in the abdomen, lower back and legs, signs of hypoglycemia, extreme fatigue, and episodes of syncope. A person with acute adrenal insufficiency may progress into coma and death, so immediate attention is critical.

Management of a conscious patient follows the basic guidelines for treatment of medical emergency with the addition of administering oxygen and glucocorticosteroid from the patient's emergency kit, if available, or from the office emergency kit, if it is included. Medical assistance should be summoned immediately and basic life support provided. Airway maintenance and oxygen are required in virtually all cases and transfer to the hospital is most likely necessary.