Emergency Medication in the Dental Setting: Current Approaches
Despite their rarity, dental practices need to be prepared for emergent events.
In a dental practice, the prospect of a medical emergency is a daily reality and a practical conundrum. Practice is the key to successful outcomes, but because emergent events are rare in dentistry, so is the practitioner’s experience in responding to them. As a result, many dentists harbor doubts about their emergency skills.1-3 Armed with basic equipment and certain medications—as well as training at regular intervals that includes staff members—the dental office can ready itself for the most likely emergencies. Such preparation satisfies not only regulatory requirements, but also the implicit ethical and clinical obligations inherent in all patient care.
The focus of this article is competent use of the fewest drugs needed to address the widest spectrum of emergent events. However, it begins with an overview of emergency preparedness. State requirements vary not only in regard to medication and equipment but also in basic life support (BLS) and advanced cardiac life support (ACLS) training. A small minority of states mandates the availability of automatic electronic defibrillators (AEDs); yet all of these areas are critical to the enactment of effective emergency response.4 While it is not feasible for any setting to try to prepare for every conceivable emergency, viewing emergency preparedness as a progression of appropriate actions—rather than a single intervention—can be helpful in planning for many eventualities. Simplicity is also important. It is far better to understand and be able to quickly administer a few effective drugs than to stock a large number of outdated and unfamiliar medications.
The aging of the population—carrying increasingly complex medical needs and drug combinations into a trend toward longer procedures—may well change the profile of an emergency in tomorrow’s dental setting. Today, however, studies show that syncope is the most frequent emergency, with percentages ranging from 50% to 60%.5 In the United States and Canada, the category of mild allergy follows as the next most common event at 8%.6 Other incidents—at rare rates of occurrence—include more severe allergic reactions, angina pectoris/myocardial infarction, cardiac arrest, postural hypotension, seizures, bronchospasm, and diabetic emergencies.7 (It should be noted that this research covers reported events in the dental setting; the majority are believed to go unreported.)
Vasovagal syncope—the most common type of fainting in or out of the dental office—is produced by a lack of blood to the brain. The patient usually loses consciousness for only a few minutes. Reasons have been identified as stress, anxiety, sudden or unexpected pain, the sight of blood or needles, and other situations inducing fear. Syncope typically does not require medication for treatment, although patients should be referred to their medical physicians to determine whether an underlying condition has precipitated the event.
As stated, cardiac arrest is among the least likely sources of dental emergency. However, it also poses the greatest potential for fatality or long-term consequence. It is worth noting that among those at highest risk for cardiac arrest—based simply on age, gender, risk factors, and hours spent in the office—are dentists themselves. Over 350,000 cases of cardiac arrest occur each year in the United States. Cardiac arrest presents in these rhythms: asystole, pulseless electrical activity (PEA), pulseless ventricular tachycardia (pulseless VT) or ventricular fibrillation (VF). VT and VF are the rhythms considered especially responsive to treatment. As approximately 90% of cardiac arrests are attributable to VF or pulseless VT, dentists should be familiar with the recommended emergency response.
Defibrillation should generally begin as quickly as possible. (The survival rate of those receiving shocks within the first 1 minute is approximately 90%.) Cardiopulmonary resuscitation (CPR) should be delivered until the defibrillator is attached and the rhythm analyzed. Until recently, it was advised that CPR always precede defibrillation, but a new study raises questions about the effectiveness of this delay.8
The importance of defibrillation and chest compressions in combination is not in dispute,4 but evidence linking drugs and survival rates from the hospital following cardiac arrest is much less clear. When shock treatment with a defibrillator fails to restore normal heart rhythm during ventricular fibrillation, however, standard practice continues to include the administration of certain medications, although chest compressions should not be interrupted by drug delivery.
Three types of drugs apply to the management of cardiac arrest: vasopressors, anti-arrhythmics, and the class including atropine.
Vasopressor drugs treat hypotension resulting from cardiogenic, circulatory, septic, and hemorrhagic shock. Chest compressions generally produce less than 25% of normal cardiac output. Poor blood pressure results from the lack of resistance to blood flow. Vasopressors are used during cardiac arrest primarily to increase coronary and cerebral perfusion pressures. The most common and most studied vasopressor drugs are epinephrine 1:10,000 and vasopressin.
Epinephrine has been used in the treatment of cardiac arrest for over 100 years. Epinephrine 1:10,000—administered via intravenous or intraosseous means—has longstanding success in restoring perfusion and stimulating cardiac activity in the aystolic. (After defibrillation, 1 mg epinephrine is delivered every 3 to 5 minutes. In the nonshockable rhythms—asystole and PEA—epinephrine is administered first.) Epinephrine continues to be recommended in the treatment of cardiac arrest, as some studies document a link to short-term survival.9,10 Unfortunately, epinephrine carries a grave limitation—an association with lost neurofunction, including irreparable brain damage. This consequence has prompted extensive research into a replacement drug, much of it directed toward vasopressin.
Vasopressin—provided in 40 units every 10 to 12 minutes—has gained increasing popularity as an alternative or an adjunct to epinephrine. This drug increases peripheral vascular resistance (vasoconstriction) and thus raises arterial blood pressure. The action represents an important compensatory mechanism for restoring blood pressure. But unlike epinephrine, vasopressin has little or no impact on organs or central circulation. Laboratory studies on animals have linked vasopressin with chest compressions to improved cerebral oxygen delivery11 and the probability of better neurologic outcome12 when compared to epinephrine. Still other research has associated the combination of epinephrine and vasopressin during CPR with increased mean arterial blood pressure.13
Guidelines of the American Heart Association (2010) say that either vasopressin or epinephrine may be used in the treatment of cardiac arrest, or the drugs can be alternated. Clearly more studies will augment knowledge and guide protocols regarding either the combination of vasopressin and epinephrine or the superiority of one over the other. Dentists should consider the literature and the nature of their practices and patients when evaluating and choosing between these medications and keep either one or the other on hand, again, for simplicity’s sake.
Anti-arrhythmic drugs are used to restore normal cardiac rhythm and conduction. For those patients in cardiac arrest secondary to VF who do not respond to defibrillation, the American Heart Association’s first-line choice is amiodarone, with an initial dose of 300 mg, which can be followed by one dose of 150 mg. In the absence of amiodarone, lidocaine may be used. A case can be made that lidocaine is the preferable agent in the dental setting.
Amiodarone is a potent agent with a complex profile. In some studies, amiodarone was shown to be superior to both placebo and lidocaine in improving survival to hospital admission for patients with out-of-hospital refractory VF/pulseless VT; however, these patients did not survive discharge from the hospital.14,15
The research concerning amiodarone is by no means conclusive. Amiodarone is significantly more expensive, possesses a longer half-life (measured in weeks rather than hours), and carries potentially life-threatening toxic side effects. Amiodarone is also difficult to administer and to manage. For these reasons, lidocaine can be viewed as a safer and more versatile option. The initial recommended dose is 100 mg every 3 to 5 minutes, with a maximum of 3 mg/kg.
In any event, either amiodarone or lidocaine should be used—never both. The combination of two anti-arrhythmic medications could actually produce a pro-arrhythmic effect.
Arguments cannot be made for the use of any anti-arrhythmic drugs for patients in asymptomatic tachycardia in the dental setting. The American Heart Association advises that in the case of asymptomatic patients—heart rate fast, blood pressure good; heart rate slow, blood pressure good—the correct approach is monitoring prior to sending the patient forward for further evaluation and treatment.
Available evidence suggests that the routine use of atropine during PEA or asystole is unlikely to be beneficial. For that reason, atropine is no longer recommended for routine use and was removed by the American Heart Association in 2010 from the ACLS Cardiac Arrest Algorithm. However, atropine is still advised for patients with symptomatic bradycardia. When the heart rate is slow and blood pressure is low—secondary to a vasovagal reaction that does not resolve spontaneously—atropine can be used as a vagalytic. (Oxygen is always administered in the event the bradycardia is secondary to hypoxemia.) Atropine is usually administered intravenously in doses of 0.5 mg every 5 minutes to a maximum dose of 3 mg. Atropine can also be given at 0.5 mg in a sublingual wash.
Acute Coronary Syndrome
Aspirin is an essential drug for the management of acute coronary syndrome or heart attack (myocardial infarction [MI]). Aspirin is well established as an effective antiplatelet drug used to limit expansion of the blood clot—and limit formation of further clots—in the coronary artery during MI. The standard of care for patients believed to be experiencing MI is between 162 and 325 mg aspirin.
Along with aspirin, nitroglycerin is a mainstay in treating acute coronary syndrome and angina, particularly for its vasodilatory effects following chest pain.
Like epinephrine, nitroglycerin presents issues with regard to packaging, resulting in costly convenience without any difference in quality or therapeutic effect. The most appropriate forms of nitroglycerin for the dental setting are the sublingual tablet or sublingual spray. The usual dosage is 0.4 mg per tablet or puff.
Two contraindications exist for nitroglycerin. One is the presence of hypotension (systolic pressure less than 90). The other is patient use of such potent vasodilators as Viagra, Cialis, or Levitra. The combination of nitroglycerin and these erectile-dysfunction drugs could lead to hypotension and/or unconsciousness.
Anaphylactic Response, Allergy, Bronchial Spasm
As mentioned, other types of emergency occurring within a dental setting include allergy, asthma, bronchial spasm, and anaphylactic response, which is the most serious type of allergic reaction. Initial symptoms may quickly progress to respiratory and even cardiac arrest. Epinephrine remains the drug of choice to treat anaphylactic shock and acute bronchial spasms.
Epinephrine offers a variety of delivery options. One especially expensive version is the pen, in excess of $100 per use. The pen also limits the practitioner to a single method in an emergency, via intramuscular injection. Individual doses of epinephrine can be created for delivery via tuberculin syringe. These single-dose vials offer greater flexibility and also provide the recommended 0.3 mg dose at a significantly lower cost than the pens.
Patients who are experiencing hypersensitivity or some allergic reaction—if recognized early enough—often respond well to 50 mg of diphenhydramine alone. Epinephrine 0.3 mg 1:1000 may still be necessary in incidences of hypersensitivity or allergy, but this administration would nonetheless be followed by diphenhydramine as part of pre-hospital stabilization. Injectable diphenhydramine—available through intravenous or intraosseous means—should always be available in the dental setting.
Albuterol sulfate—packaged as an inhaler—is the most common bronchodilator found in the dental office and a sound choice for the patient who is short of breath secondary to bronchial spasm. It is important to note that when this represents the patient’s first experience with this event, the education process can be challenging. The patient must in this stressful circumstance be taught to coordinate inhalation with the depression of a button. In addition, the process at best may still leave 90% of the drug dose ineffectively on the tongue.
This efficacy problem is eliminated in the hospital through the nebulizer machine. However, a more practical alternative in the dental setting is the spacer; the spacer holds the drug in a void in the device, so even when short breaths are taken, the patient receives the benefit of the drug. In rare cases, patients become so short of breath, they fail to receive the drug’s benefit despite the presence of spacers. These cases may necessitate epinephrine 0.3 mg 1:1000 but still include the delivery of albuterol once the ventilation effort has been improved.
The number of Americans with diabetes is estimated to total 25.8 million adults and children, or 8.3% of the population. Another 79 million are classified as prediabetic.16 Diabetes-related emergencies in the dental setting usually involve hypoglycemia (low blood glucose) or, less frequently, hyperglycemia (elevated blood glucose). Hypoglycemia is a frequent source of visits to the nation’s emergency departments.17
The options for glucose delivery are IV, injection, rectal, or oral. Disadvantages to the intravenous method—composed of 50% glucose—is the necessity for a secure IV line. Unpleasant soft-tissue damage will likely result if the line is not secure. A better option, then, in the dental setting is glucose paste. This can be purchased in a medical supply house or even a grocery store—in the form of cake frosting. Glucose paste or cake frosting can also be administered rectally to patients who are unconscious.
Fewer Decisions Mean A Greater Prospect of Success
While every emergency plan must involve some degree of individual choice, tailored detail, and team commitment, the medications discussed in this article were highlighted because they address the vast majority of the emergencies likely to occur in the course of dental practice. To reiterate, simplicity is vital. Ultimately, the more elements involved, the more complicated the response, the more decisions that will need to be made, the longer it will take to deliver treatment, and the greater the likelihood the intervention will fail.
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14. Kudenchuk PJ, Cobb LA, Copass MK. Amiodarone for resuscitation after out-of-hospital cardiac arrest due to ventricular fibrillation. N Engl J Med. 1999;341(12):871-878.
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16. American Diabetes Association. 2011 National Diabetes Fact Sheet. January 26, 2011. Available at: http://www.diabetes.org/diabetes-basics/diabetes-statistics/. Accessed February 27, 2012.
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About the Author
Life Support Services
Ann Arbor, Michigan