Prevention and Management of Medical Emergencies

Continuing Education

In dental school, clinicians are trained in ways to assess patient risk and manage medical emergencies. However, because of the rarity of these problems, practitioners should seek continuing education in this area, not only to refresh their knowledge but also to learn new concepts concerning medical evaluation and management of emergencies. An important feature of continuing education is to maintain certification in basic life support (BLS), including the use of automated external defibrillator units ( Box 2.3 ). Some recommend that continuing education in medical emergency management be obtained annually, with a BLS skills update and review obtained biannually. Dentists who deliver parenteral sedatives other than nitrous oxide are wise to obtain certification in advanced cardiac life support and to have the drugs and equipment necessary for advanced cardiac life support available.

Office Staff Training

The dentist must ensure that all office personnel are trained to assist in the recognition and management of emergencies. This should include reinforcement by regular emergency drills in the office and by annual BLS skills renewal by all staff members. The office staff should be preassigned specific responsibilities so that in the event of an emergency, each person knows what will be expected of him or her.

Access to Help

The ease of access to other health care providers varies from office to office. Preidentifying individuals with training that would make them useful during a medical emergency is helpful. If the dental practice is located near other professional offices, prior arrangements should be made to obtain assistance in the event of an emergency. Not all physicians are well versed in the management of emergencies, and dentists must be selective in the physicians they contact for help during an emergency. Oral-maxillofacial surgeons are a good resource, as are most general surgeons, internists, and anesthesiologists. Ambulances carrying emergency medical technicians are useful to the dentist facing an emergency situation, and communities provide easy telephone access (911) to a rapid-response emergency medical service team. Finally, it is important to identify a nearby hospital or freestanding emergency care facility with well-trained emergency care experts.

Once the dentist has established who can be of assistance in the event of an emergency, the appropriate telephone numbers should be kept readily available. Easily identified lists can be placed on each telephone, or telephone numbers can be entered into the memory of an automatic-dial telephone and/or added to cellphone contacts. The numbers should be called periodically to test their accuracy.

Emergency Supplies and Equipment

The final means of preparing for emergencies is by ensuring that appropriate emergency drugs, supplies, and equipment are available in the office. One basic piece of equipment is the dental chair that should facilitate placing the patient in the supine position or, even better, in the head-down, feet-raised position. In addition, it should be possible to lower the chair close to the floor to allow BLS to be performed properly, or standing stools should be kept readily available. Operatories should be large enough to allow a patient to be placed on the floor for BLS performance and should provide enough room for the dentist and others to deliver emergency care. If the operatory is too small to allow the patient to be placed on the floor, specially designed boards that are available can be placed under the patient's thorax to allow effective BLS administration in the dental chair.

Frequently, equipment used for respiratory assistance and the administration of injectable drugs is needed during office emergencies. Equipment for respiratory assistance includes oral and nasal airways, large suction tips, connector tubing that allows the use of high-volume suction, and resuscitation bags (e.g., air mask bag unit [AMBU bags]) with clear facemasks. Laryngoscopes and endotracheal tubes for tracheal intubation may be helpful to dentists trained in their proper use or for others called into the office to assist during an emergency.

Useful drug administration equipment includes syringes and needles, tourniquets, intravenous (IV) solutions, indwelling catheters, and IV tubing ( Table 2.1 ). Emergency kits containing a variety of drugs are commercially available ( Fig. 2.1 ). If dentists have made arrangements for help from nearby professionals, they may also want to include drugs in their kits that the assisting individuals suggest may be helpful. The drugs and any equipment in the kit must be clearly labeled and checked frequently for completeness and to ensure that no drugs have passed their expiration date. Labeling should include not only the drug name but also situations in which the drug is most commonly used. A list of drugs that should be in a dental office emergency kit is provided in Table 2.2 .

One emergency item that must be available in dental offices is oxygen. Many dentists use oxygen supplied in a portable tank. The dentist should be properly trained to be capable of delivering the oxygen under positive pressure to the patient. Establishing a system to check periodically that a sufficient supply of oxygen is always available is important. Dentists who use a central oxygen system also need to have portable oxygen available for use outside of the operatory, such as in the waiting room or during transport to an emergency facility.

Hypersensitivity Reactions

Several of the drugs administered to patients undergoing oral surgery can act as antigenic stimuli, triggering allergic reactions. Of the four basic types of hypersensitivity reactions, only type 1 (immediate hypersensitivity) can cause an acute, life-threatening condition. Type 1 allergic reactions are mediated primarily by immunoglobulin E antibodies. As with all allergies, initiation of a type 1 response requires exposure to an antigen previously encountered by the immune system. Reexposure to the antigen triggers a cascade of events that are then exhibited locally, systemically, or both in varying degrees of severity mainly in response to significant mast cell degranulation and the widespread release of histamine. Table 2.3 details the manifestations of type 1 hypersensitivity reactions and their management.

The least severe manifestation of type 1 hypersensitivity is dermatologic. Skin or mucosal reactions include localized areas of pruritus, erythema, urticaria (wheals consisting of slightly elevated areas of epithelial tissue that are erythematous and indurated), and angioedema (large areas of swollen tissue generally with little erythema or induration). Although skin and mucosal reactions are not in themselves dangerous, they may be the first indication of more serious allergic manifestations that will soon follow. Skin lesions usually take anywhere from minutes to hours to appear; however, those appearing and progressing rapidly after administration of an antigenic drug are the most menacing and concerning for progression to the more life-threatening clinical presentations.

Allergic reactions affecting the respiratory tract are more serious and require more aggressive intervention. The involvement of small airways occurs with wheezing, as constriction of bronchial smooth muscle (bronchospasm) and airway mucosal inflammation occurs. The patient will complain of dyspnea and may eventually become cyanotic. The patient may be using accessory muscles to assist in breathing. Involvement of the larger airways usually first occurs at the narrowest portion of those air passages—the vocal cords in the larynx. Angioedema of the vocal cords causes partial or total airway obstruction. The patient is usually unable to speak and produces high-pitched crowing sounds (stridor) as air passes through constricted cords. As the edema worsens, total upper airway obstruction may eventually occur, presenting an immediate threat to life.

Generalized anaphylaxis is the most dramatic hypersensitivity reaction, usually occurring within seconds or minutes after the parenteral administration of the antigenic medication; a more delayed onset occurs after oral or topical drug administration. Many signs and symptoms of anaphylaxis exists, but the most important with respect to early management are those resulting from cardiovascular and respiratory tract disturbances.

An anaphylactic reaction typically begins with a patient complaining of malaise or a feeling of impending doom. Skin manifestations soon appear, including flushing, urticaria, and pruritus on the face and trunk. Nausea and vomiting, abdominal cramping, and urinary incontinence may occur. Symptoms of respiratory compromise soon follow, accompanied with dyspnea and wheezing. Cyanosis of nail beds and mucosa appear next if air exchange becomes insufficient. Finally, total upper airway obstruction occurs, which causes the patient quickly to become unconscious. Disordered cardiovascular function initially occurs with tachycardia and palpitations. Blood pressure tends to fall because of decreasing cardiac output secondary to peripheral vasodilation, and cardiac dysrhythmias appear. Cardiac output eventually may be compromised to a degree sufficient to cause loss of consciousness and cardiac arrest. Despite the potentially severe cardiovascular disturbances, the usual cause of death in patients having an anaphylactic reaction is laryngeal obstruction caused by vocal cord edema.

As with any potential emergency condition, prevention is the best strategy. During the initial interview and subsequent recall visits, patients should be questioned about their history of drug allergies. In addition, dentists should ask patients specifically about medications they intend to use during the planned oral surgical care. If a patient claims to have an allergy to a particular drug, the clinician should question the patient further about the way in which the allergic reaction has exhibited and what was necessary to manage the problem. Many patients will claim an allergy to local anesthetics; however, before subjecting patients to alternative forms of anesthesia, the clinician should try to ensure that an allergy to the local anesthetic does indeed exist. Many patients have been told they had an allergic reaction when, in fact, they experienced a vasovagal hypotensive episode or mild palpitations secondary to epinephrine sensitivity. If an allergy is truly possible, the patient may require referral to a physician who can perform hypersensitivity testing. After it is determined that a patient does have a drug allergy, the information should be displayed prominently on the patient's record in a way to alert care providers but still protect patient confidentiality.

Management of allergic reactions depends on the severity of the signs and symptoms. The initial response to any sign of untoward reaction to a drug being given parenterally should be to cease its administration. If the allergic reaction is confined to the skin or mucosa, IV or intramuscular (IM) antihistamine should be administered. Diphenhydramine hydrochloride 50 mg or chlorpheniramine maleate 10 mg are commonly used antihistamines. *

* All doses given in this chapter are those recommended for an average adult. Doses will vary for children, for older adults, and for those with debilitating diseases. The clinician should consult a drug reference book for additional information.

The antihistamine is then continued in an oral form (diphenhydramine [Benadryl] 50 mg or chlorpheniramine [Chlor-Trimeton] 8 mg) every 6 to 8 hours for 24 to 48 hours to ensure that the drug has been eliminated from the body. Immediate, severe urticarial reactions warrant immediate parenteral (IV or IM) administration of a corticosteroid containing solution such as 100 mg of hydrocortisone, 8 mg of dexamethasone, or 125 mg of methylprednisolone, followed by an antihistamine. The patient's vital signs should be monitored frequently for 1 hour; if the patient is stable, he or she should be referred to a physician or an emergency care facility for further evaluation.

If a patient begins to show signs of lower respiratory tract involvement (i.e., wheezing during an allergic reaction), several actions should be initiated. Outside emergency assistance should be summoned immediately. The patient should be placed in a semi-reclined position, and nasal oxygen should be begun. If the patient is dyspneic but stable cardiovascularly, two puffs of albuterol may be administered followed by two more doses if improvement is noted. If the patient is showing significant respiratory distress, the clinician should not hesitate to administer epinephrine by IM injection of 0.3 mL of a 1 : 1000 solution or with an aerosol inhaler (e.g., Medihaler-Epi, each inhalation of which delivers 0.3 mg). Epinephrine is short acting; if symptoms recur or continue, the dose can be repeated within 5 minutes. Antihistamines, such as diphenhydramine or chlorpheniramine, as well as corticosteroids, are then given. The patient should be immediately transferred to the nearest emergency facility for further management.

If a patient shows signs of laryngeal obstruction (i.e., stridor), epinephrine (0.3 mL of 1 : 1000 solution given IM) should be given as quickly as possible, and oxygen should be administered. If a patient loses consciousness and attempts made to ventilate the patient's lungs fail, an emergency cricothyrotomy or intubation may be required to bypass the laryngeal obstruction. *

* Cricothyrotomy is the surgical creation of an opening into the cricothyroid membrane just below the thyroid cartilage to create a path for ventilation that bypasses the vocal chords.

A description of the technique of cricothyrotomy or tracheotomy is beyond the scope of this book, but these techniques may be lifesaving in an anaphylactic reaction. It should be noted that the true emergency airway is the cricothyrotomy because the tracheostomy procedure must be done in a controlled well-lit environment (such as an operating room) to ensure the preservation of vital structures. Once an airway is reestablished, an antihistamine and further doses of epinephrine should be given. Vital signs should be monitored, and steps necessary to maintain the patient should be taken until emergency assistance is available.

Patients who show signs of cardiovascular system compromise should be closely monitored for the appearance of hypotension and bradycardia, which may necessitate initiation of BLS if cardiac output falls below the level necessary to maintain viability or if cardiac arrest occurs (see Box 2.3 ).

Chest Discomfort

The appearance of chest discomfort in the perioperative period in a patient who may have ischemic heart disease calls for rapid identification of the cause so that appropriate measures can be taken ( Box 2.4 ). Discomfort from cardiac ischemia is frequently described as a squeezing sensation, with a feeling of heaviness on the chest ( Box 2.5 ). Discomfort usually begins in a retrosternal location, radiating to the left shoulder and arm. Patients with documented heart disease who have had such discomfort in the past will usually be able to confirm that the discomfort is their angina. For patients who are unable to remember such a sensation in the past or who have been assured by their physician that such discomfort does not represent heart disease, further information is useful before assuming a cardiac origin of the symptom. The patient should be asked to describe the exact location of the discomfort and any radiation, how the discomfort is changing with time, and if postural position affects the discomfort. Pain resulting from gastric reflux into the esophagus because of chair position should improve when the patient sits up and is given an antacid. Discomfort caused by costochondritis or pulmonary conditions should vary with respirations or be stimulated by manual pressure on the thorax. The only other common condition that can occur with chest discomfort is anxiety, which may be difficult to differentiate from cardiogenic problems without the use of monitoring devices not commonly present in the dental office.

If chest discomfort is suspected to be caused by myocardial ischemia, or if that possibility cannot be ruled out, measures should be instituted that decrease myocardial work and increase myocardial oxygen supply. All dental care must be stopped, even if the surgery is only partially finished. The patient should be reassured that everything is under control while vital signs are being obtained, oxygen administration is started, and nitroglycerin is administered sublingually or by oral spray. The nitroglycerin dose should be 0.4 mg dissolved sublingually and repeated (if necessary) every 5 minutes for up to a maximum of three doses as long as systolic blood pressure is at least 90 mm Hg. If vital signs remain normal, the chest discomfort is relieved, and the amount of nitroglycerin that was required to relieve the discomfort was not more than normally necessary for that patient, the patient should be discharged with plans for future surgery to be done in an oral-maxillofacial surgery office or in a hospital after conferring with the patient's physician ( Fig. 2.2 ).

Some circumstances do require transport to an emergency facility. If the pulse is irregular, rapid, or weak, or if the blood pressure is found to be below baseline, outside emergency help should be summoned while the patient is placed in an almost supine position with the legs raised, and then oxygen and nitroglycerin therapy are started. Venous access should be initiated and a slow 5% dextrose in normal saline IV drip should be begun, if possible, for use by emergency personnel. Another serious situation requiring transfer to a hospital is a case in which the patient's discomfort is not relieved after 20 minutes of appropriate therapy. In this case, it should be presumed that a myocardial infarction is in progress. Such a patient is especially prone to the appearance of serious cardiac dysrhythmias or cardiac arrest; therefore vital signs should be monitored frequently, and BLS should be instituted, if indicated. Aspirin may be administered in the case of a suspected myocardial infarction, 325 mg chewed and swallowed, to aid in decreasing thrombus progression by its antiplatelet effects. Morphine sulfate (4 to 6 mg) may be administered IM or subcutaneously to help relieve the discomfort and reduce anxiety. Morphine also provides a beneficial effect for patients who are developing pulmonary edema; however, care should be taken to avoid significant hypotension (see Fig. 2.2 ). Transfer to a hospital should be expedited because therapy may be initiated in the form of thrombolytic agents, an angioplasty, stenting procedure, or coronary artery bypass grafting, which may be able to preserve some or all of the ischemic myocardium.