CHAPTER 54 Drugs for Medical Emergencies
Every dentist can expect to be involved in the diagnosis and treatment of medical emergencies during the course of clinical practice. These emergencies may be directly related to dental therapy, or they may simply occur by chance in the dental environment. In studies surveying the incidence and type of medical emergencies in dental practice, 95.6% of the respondents reported such emergencies. Although most of the reported emergencies were minor (e.g., 53% were syncopal episodes), life-threatening or major emergencies were also described.14,33 Many medical emergencies occur during the administration of local anesthesia and during painful procedures such as extractions and pulp extirpation.35 The potential need for acute medical intervention during dental treatment may be increased for practitioners treating a high percentage of elderly patients, patients with special needs, or medically compromised patients, and practitioners using minimal, moderate, or deep sedation and general anesthesia.
It has been postulated that the incidence of medical emergencies in dentistry as a whole is increasing.34 This increase may be attributed to the following factors:
Many chronic medical conditions, such as asthma, congestive heart failure, coronary artery disease, and cerebrovascular disease, may become acute medical emergencies when exacerbated by the stress of the dental appointment. Stress, anxiety, fear, and phobia may cause other minor stress-related emergencies, such as syncopal episodes and hyperventilation syndrome. A thorough preoperative evaluation, meticulous detail to achieving profound local anesthesia in a safe manner, consideration of nonpharmacologic stress reduction protocols, and the use of pharmacologic sedative techniques to minimize pain, fear, and anxiety help reduce this risk.
Preoperative evaluation includes the use of a medical history questionnaire, oral history, review of systems, physical examination, vital signs, and appropriate laboratory tests and consultations. This evaluation should determine the risk/benefit ratio of the contemplated procedure, what drugs should be used or avoided, the potential for a medical emergency, and the type of monitoring best suited for the particular patient.
Although almost any medical emergency can occur during the course of dental treatment—which means that dental personnel must be prepared to provide effective basic life support (BLS) and seek emergency medical services in a timely manner—dentists must be able to diagnose and treat common medical problems (e.g., syncope or hyperventilation syndrome) definitively and respond effectively to certain less common (or even rare) but potentially life-threatening emergencies, especially emergencies that may arise as a result of dental treatment (e.g., anaphylactic reaction to an administered drug).9 These emergencies are listed in Box 54-1.
Many factors determine the degree of preparedness for medical emergencies needed in a specific dental practice, but all dental offices must be ready at some minimal level.30 The use of local anesthesia is an indication for the dentist to be prepared to handle medical emergencies, as evidenced by the following language in product literature approved by the U.S. Food and Drug Administration: “Dental practitioners who employ local anesthetic agents should be well versed in diagnosis and management of emergencies that may arise from their use. Resuscitative equipment, oxygen and other emergency drugs should be immediately available for immediate use.”6 An overall emergency preparedness plan, as outlined in Box 54-2, is essential for every dental practice. Implicit in Box 54-2 is the necessity to develop a team approach in preparing for and responding to medical emergencies in the dental office, with each staff member (receptionist, dental auxiliary, dental hygienist, and dentist) responsible for a specific role.
Preparedness must be individually tailored according to the type of patient treated (e.g., young, healthy patients in an orthodontic practice versus medically compromised patients in a periodontal practice), location (an urban setting where emergency help is close at hand versus a rural location where there may be a significant delay until help arrives), and training (whether the dentist and staff are capable of performing advanced emergency procedures and protocols). Although a comprehensive guide to the pathophysiologic characteristics, prevention, diagnosis, and management of specific medical emergencies is beyond the scope of this chapter, several sources for this purpose are listed in the general references. In practices where sedation or general anesthesia is administered, advanced emergency training and equipment are required and often promulgated by state dental practice acts.
Although many medical emergencies may be properly treated without the use of drugs, every dental office must contain an emergency kit with drugs appropriate to the training of the individual dentist, the patient being treated, and the type of procedures being performed.2,18 No drug can take the place of a properly trained health professional and support staff in diagnosing and treating emergencies. Nevertheless, the design and purchase of an appropriate emergency kit often play an integral role in dictating the course and outcome of emergency treatment.
Besides determining which drugs should be included in an emergency kit, the dentist must understand that he or she must maintain the knowledge base to use them. In the midst of a medical emergency, with the patient by definition in an acutely abnormal or even critical situation, there is no time to begin reading labels, leafing through emergency texts, or administering drugs as suggested by a brochure in the emergency kit. In addition, there is a significant difference between the theoretic knowledge of how to treat an emergency and being able to put such cognitive skills to practical use. Constant review and training keeps the dental team sharp. Regular continuing education in medical emergencies, review of new advances in pharmacology, certification and recertification in BLS and advanced cardiac life support (ACLS), and emergency drills are the best methods to prepare for emergencies.
Many states mandate certification in BLS for dental licensure, and in offices that use deep sedation/general anesthesia, training in ACLS is a standard of care. Without prompt attention to the ABCDs (airway, breathing, circulation, defibrillation) of cardiopulmonary resuscitation (CPR), drugs are of little value. The advent of automatic external defibrillators has made early defibrillation an integral part of the BLS “chain of survival” for the treatment of cardiac arrest. Since January 1998, health care provider CPR courses conducted by the American Heart Association include a mandated module on automatic external defibrillator application and use.7 Some states have begun to mandate the presence of an automatic external defibrillator in general dental offices.
The role of drugs and the type of intervention that should be attempted by a dentist during a medical emergency are controversial issues. If any consequence of dental treatment is foreseeable and results in harm, liability may be imposed.41 Emergency drugs are generally powerful, rapidly acting compounds. The correct approach to the use of drugs in any medical emergency should be essentially supportive and conservative. In a review covering the use over a 2-year period of 8500 emergency drug systems purchased by dentists, a 0.75% incidence of use was reported.47
Emergency kits either can be organized by the individual practitioner or can be purchased commercially. Many dentists are uncomfortable choosing and purchasing individual drugs for their emergency kits, and the purchase of a high-quality, commercially available emergency drug kit modified for dentistry can provide consistent drug availability (i.e., periodic drug updating) in an organized fashion.
There is a general tendency to overequip basic dental emergency kits with drugs that are beyond the needs and expertise of many general dentists. The drugs placed in an office emergency kit should include only drugs familiar to the dentist. Only one agent should be included for each particular need. The fewer drugs in an emergency kit, the easier it is to know their proper use, especially during an emergency.37 Many authors, state boards of dental registration, commercial vendors, and professional groups have suggested the composition of dental medical emergency kits.32 The composition of these kits varies greatly and depends on the training and philosophy of emergency care of the creator, whether the kit is dental specific, and whether sedation or anesthesia is used. The definitive pharmacologic features of these drugs are discussed in other chapters.
All dentists must keep certain drugs readily available in the office in fresh supply for immediate administration (Table 54-1). Dentists must know reflexively when, how, and in what doses to give these specific agents for acutely life-threatening situations.
|Oxygen||For use in all medical emergencies in which hypoxemia may be present||Steel cylinders (green); E tanks, 690 L|
|Epinephrine||Acute allergic reactions, acute asthma (not responding to adrenergic inhaler)||Ampules, 1 mg; vials, 1 and 30 mg; syringes, 0.3 and 1 mg|
|Nitroglycerin||Angina pectoris, acute myocardial infarction||Tablets (sublingual), 0.15, 0.3, 0.4, and 0.6 mg; spray, 0.4 mg/actuation|
|Albuterol||For bronchodilation||Aerosol, 90 µg/actuation|
|Glucose||Hypoglycemic episode||Various oral/transmucosal preparations (orange juice, cake icing, cola)|
|Aspirin||For reducing platelet aggregation||Chewable aspirin, 81-325 mg|
Data compiled from Curriculum guidelines for management of medical emergencies in dental education, J Dent Educ 54:337-338, 1990; Fast TB, Martin MD, Ellis TM: Emergency preparedness: a survey of dental practitioners, J Am Dent Assoc 112:449-501, 1986; Lipp M, Kubota Y, Malamed SF, et al: Management of an emergency: to be prepared for the unwanted event, Anesth Pain Control Dent 2:90-102, 1992; Malamed SF: Medical emergencies in the dental office, ed 5, St Louis, 2000, Mosby; Malamed SF: Drugs for medical emergencies in the dental office. In Ciancio SG, editor: ADA guide to dental therapeutics, ed 3, Chicago, 2003, ADA Publishing; Moore PA: Review of medical emergencies in dentistry: staff training and prevention, part 1, Gen Dent 36:14-17, 1988; Phero JC: Maintaining preparedness for the life-threatening office medical emergency, Dent Econ 81:47-50, 1991; Stewart D: Emergency resuscitation kits, SAAD Digest 6:223-231, 1987.
Oxygen is a primary, if not the primary, emergency drug indicated in any medical emergency in which hypoxemia may be present. These emergencies include, but are not limited, to acute disturbances involving the cardiovascular system, respiratory system, and the CNS. In a hypoxemic patient, breathing enriched oxygen elevates the arterial oxygen tension, which improves oxygenation of peripheral tissues. Because of the steepness of the oxyhemoglobin dissociation curve, a modest increase in oxygen tension can significantly alter hemoglobin saturation in a hypoxemic individual. Hypoxemia leads to anaerobic metabolism and metabolic acidosis, which often adversely affect the efficacy of emergency pharmacologic interventions.
Oxygen can be delivered to a spontaneously breathing patient by full facemask, nasal cannula, or nasal hood. Dental offices also must have the capacity to deliver oxygen via positive-pressure ventilation. Controlled ventilation may be accomplished with the use of a bag-valve-mask device (consisting of a mask, self-inflating bag, and nonrebreathing valve) or with a manually triggered oxygen-powered breathing device (consisting of a mask connected by a valve activated by a lever and high-pressure tubing to the oxygen supply). Each method of providing positive-pressure ventilation requires practice for effective use. Providing a seal around the nose and mouth while ventilating the patient can be difficult with the bag-valve-mask device. The oxygen-powered device is easier to use, but care must be taken not to inflate the stomach. Both techniques are preferred, however, over mouth-to-mouth, mouth-to-nose, or mouth-to-mask techniques.3 Airway adjuncts such as oropharyngeal and nasopharyngeal airways, endotracheal equipment, laryngeal mask airways, and the means of establishing an emergency airway by cricothyrotomy and transtracheal ventilation can be useful or even lifesaving in the hands of a trained and experienced health professional. Without appropriate training, however, their use may prove deleterious in an acute emergency.
Although oxygen toxicity may occur after prolonged therapy with high concentrations of oxygen, it is not an issue during clinical resuscitation. This statement is true even for the rare patient whose respiratory drive depends on hypoxemia because of chronically elevated carbon dioxide concentrations. If clinically indicated, oxygen should never be withheld during any medical emergency.8 Inspired oxygen concentrations depend on the delivery system used (Box 54-3).
|DELIVERY SYSTEM||INSPIRED OXYGEN CONCENTRATION (%)|