#54354: Medical Emergencies in the Dental Setting

The most common emergency seen in the dental setting is vasovagal syncope [7]. This condition features a sudden and temporary loss of consciousness and can affect approximately 3% of men and 3.5% of women at some time in their lives [4]. There is a 6% incidence of syncope in patients who are older than 75 years of age [4]. Patients who have fainted maintain their pulse and their ability to breathe. However, because the nature of the loss of consciousness cannot be determined by visual means, the basics of airway patency, breathing, and circulation must be assessed to distinguish between syncope and a life-threatening condition such as a myocardial infarction.

The recovery from an episode of syncope is usually rapid, but the etiologies of this disorder can vary. Vasovagal syncope (or cardioneurogenic syncope) occurs when an acute decrease in blood pressure reduces the blood flow and subsequent oxygen perfusion to the brain. One source of this type of syncope is a condition called orthostatic hypotension. In patients with orthostatic hypotension, blood vessels in the legs do not constrict normally in the standing position, which results in pooling of blood in the legs and decreased blood flow to the brain. In a similar fashion, postural syncope (also referred to as postural hypotension) may occur when there is an abrupt change in a patient's position. This can occur after dental treatment when a patient has been in a supine position for an extended interval and abruptly changes to a standing position without allowing enough time for the cardiac output and blood pressure to properly equilibrate. Situational syncope is physiologically a variant of vasovagal syncope caused by the anxiety and stress that some patients experience during dental treatment.

Although patients recover quickly from an episode of syncope, all patients who faint in a dental office should be referred to their physician to determine the underlying cause and the appropriate treatment. Patients may emerge from syncope in a state of confusion and may experience emotional distress. Dental treatment should be terminated and not resumed until the cause of their syncope is determined and treated. Patients who have experienced previous episodes of syncope can usually determine the symptoms that occur just prior to their actual loss of consciousness. These may include sudden-onset dizziness, lightheadedness, weakness in the legs, and loss of peripheral vision ("tunnel vision"), among many others. If a patient can communicate these signs, the staff may be able to assist the patient to prevent a fall from a standing position and potential bodily injury.

After it is determined that the patient has maintained respiration and cardiac output and that cardiopulmonary resuscitation (CPR) is not necessary, the use of aromatic ammonia to facilitate the return to consciousness can be used. After regaining consciousness, the patient may be too distraught to drive, and arrangements should be made for transportation, preferably to a physician's office.

While syncope cannot be eliminated as a medical emergency, some practices can be instituted to minimize its occurrence. Patients who have experienced situational syncope during dental treatment may benefit from sedation for the duration of procedures. Repositioning a patient in gradual increments from a supine position to a sitting position after the completion of dental treatment can decrease the likelihood of postural syncope. It is important that patients be urged to remain seated until they feel stable and clear-headed.

Approximately 126.9 million adults in the United States have some form of cardiovascular disease, and almost one of every three deaths is attributed to this problem [6]. The American Heart Association indicates that 805,000 adults experience a myocardial infarction each year. In addition, more than 7 million adults in the United States have ever experienced a stroke [6]. With so many patients afflicted with various forms of cardiovascular disease, dental practices will invariably treat patients with diagnosed and undiagnosed cardiovascular conditions. Thus, it is critical that each dental practice can respond appropriately to a medical emergency that is of cardiovascular origin.

Seizures are a rare occurrence in the dental setting but can occur, and the characteristic convulsive movements of the limbs may endanger the patient. Epilepsy is a neurologic disease associated with recurrent, spontaneous seizure activity. However, seizures can occur in patients without a history of epilepsy for a variety of reasons, including brain tumors and withdrawal from alcohol, narcotics, or benzodiazepines.

The most serious manifestation of seizure activity is the tonic-clonic seizure (formerly grand mal seizure). These seizures, which are probably the best known, consist of two phases. The tonic phase features generalized muscle rigidity, dilation of the pupils, eyes that roll upward, and a loss of consciousness. The clonic phase includes uncoordinated movements of the limbs and head, often with the jaws tightly clenched. This clonic activity usually lasts less than two minutes, after which muscular relaxation and a return to consciousness occur.

The absence seizure was formerly referred to as a petit mal seizure. Absence seizures are rare in adulthood and almost always begin in children between 4 and 12 years of age [39]. This seizure is characterized by a brief period of altered consciousness, often described as a staring spell. The duration of the seizure is generally 5 to 30 seconds. The absence seizure may occur up to 100 times per day or only rarely [39]. The child is often described as having a blank stare that interrupts motor and mental activity, which begins and ends suddenly. The patient will have no loss of postural tone but may experience a mild increase or decrease in muscular tone. Occasionally, the child will exhibit minimal myoclonic movements around the eyelids or mouth. The patient may have automatisms associated with the seizure, including chewing or rapid blinking. During the seizure there is a loss of awareness [39]. There is usually no postictal period, and the individual may continue activities with full awareness after the seizure has subsided.

When patients do not enter the recovery phase and have repeated seizures, the condition is known as status epilepticus. This is a medical emergency, and EMS must be summoned as soon as possible, as patients can become hypoxic. If possible, supplemental oxygen should be administered.

Before any dental treatment is begun, the dentist should have a clear history of each patient's seizure activity and compliance with prescribed medications. Dental appointments should only proceed if a patient has been compliant with prescribed medications. Even when the precautions are followed, seizures can still occur. Many patients with a history of seizures have a prodromal phase or an aura prior to the tonic phase of seizure activity, allowing for some warning of the event. This provides an opportunity to remove any objects from the mouth that were placed for dental treatment to prevent aspiration or injury. This phase can also provide time to administer anticonvulsant medications. Attempting intramuscular injections or the placement of an intravenous line to administer anticonvulsant medications can be difficult and dangerous while the patient is seizing. Nothing, including a bite block or cotton rolls, should be placed in the mouth after the seizing activity has begun. The patient should remain in a supine position in the dental chair, and any dental instruments in the field of operation should be moved away to protect the patient from injury. Breathing is usually unaffected by seizure activity, but recording vital signs may not be possible. However, upon conclusion of the seizure, some patients will be unconscious and must have an evaluation of their airway, breathing, and circulation. Dental treatment should not be resumed but should be rescheduled to another time.

Because patients can emerge from seizures in a confused and exhausted state, they should not attempt to drive; transportation home may be provided by a responsible adult. If the seizure was a first-time occurrence for the patient, a referral to a physician is necessary in order to discover the underlying cause.

In the United States, approximately 11.3% of the population, or 37.3 million children and adults, have diabetes [17]. Type 1 diabetes, in which the body does not produce adequate amounts of insulin, accounts for about 5% of these cases and usually has an onset in childhood, adolescence, or young adulthood. These patients require insulin injections to manage the disease. The remaining 95% of patients have type 2 diabetes, caused by the body's impaired glucose metabolism. These patients usually develop diabetes at 40 years of age or older, and oral hypoglycemic medications with occasional supplementation with insulin are utilized by these patients [18,44]. Most dental practices will treat patients with diabetes and should be prepared for emergency situations that can develop before, during, or after dental treatment.

Dentists should discuss the type of diabetes, compliance with prescribed medications and dietary recommendations, problems with glycemic control, and acute and chronic complications of the disease with all patients with diabetes before dental treatment begins. Consulting a patient's physician before initiation of dental treatment can decrease the chance of a diabetic emergency. Diabetes-related emergencies in the dental setting usually involve hypoglycemia (low blood glucose) or, less frequently, hyperglycemia (elevated blood glucose).

According to the Centers for Disease Control and Prevention, 8% of adults and 5.5% of children are currently diagnosed with asthma [22]. This disease is the most common cause of respiratory distress among dental patients [23]. Asthma features the constriction of the bronchial and bronchiolar muscles and extensive secretion of viscous mucus in the respiratory tract, making breathing difficult to impossible. It is a chronic inflammatory respiratory disease characterized by recurrent episodes of dyspnea, coughing, and wheezing [24]. Asthma attacks occur when the bronchiolar tissue is hyper-responsive to a variety of stimuli, including cold air, smoke, medications (e.g., salicylates and nonsteroidal anti-inflammatory drugs [NSAIDs]), various chemicals, stress, allergens, exercise, and anxiety, among many others.

When a patient's medical history reveals asthma, it is important for the dental professional to determine the severity of the illness, the types of medication(s) prescribed, frequency and the severity of attacks, and known triggers that have stimulated asthma attacks in the past. If a patient is a persistent asthmatic with a high frequency of asthma attacks, his or her physician should be consulted before any treatment is begun, as the stress and anxiety that some patients associate with dental treatment can precipitate an attack.

Dental offices that treat patients with asthma should have short-acting inhalers, such as albuterol, available to rapidly reverse asthma symptoms in the event the patient does not bring one. Albuterol is a bronchodilator that acts by inducing the relaxation of constricted bronchiolar smooth muscles and inhibiting the release of substances from mast cells that cause bronchiolar constriction. Most inhalers are aerosol, although dry powder and nebulizer types are also available. If an asthma attack occurs during dental treatment, the procedure should be stopped, the patient placed in an upright position, and the albuterol inhaler should be used.

Intramuscular injections of 0.3–0.5 mg epinephrine in a 1:1,000 (1 mg/mL) concentration may be used if albuterol is not available. Epinephrine may be used every 20 minutes for two additional doses [5,45]. If necessary, supplemental oxygen and a second administration of the albuterol inhaler may be administered. A pulse oximeter can be used to determine oxygen saturation. Because members of the dental staff generally do not have the experience to discern the severity of an asthma attack, EMS should be summoned if the patient has not responded to the initial use of these medications.

If the anxiety and stress of dental procedures has been a stimulant for an asthma attack in the past, inhalation sedation with nitrous oxide may be helpful. However, nitrous oxide may cause irritation of the airway in sensitive patients. In these patients, nitrous oxide should only be used if it is approved by a physician. Moderate sedation can prove to be dangerous in patients with asthma because of the limited control of the airway. This method should only be used with physician approval and may need to be performed in a hospital environment. Narcotic analgesics should be avoided as they can stimulate histamine release, which can result in bronchospasm [25]. As a class, narcotics also cause respiratory depression.

An anaphylactic reaction represents the most serious degree of an allergic response. It is characterized by a set of symptoms that involves various organs and systems and occurs independently, simultaneously, or subsequently [30]. Initial symptoms often involve widespread hives and progress rapidly to bronchospasm, respiratory arrest, and ultimately, cardiac arrest. Whether the anaphylactic reaction is of immune or nonimmune origin, the stimulation of mast cells and circulating basophils release chemical mediators that begin the anaphylactic process.

The release of histamine and bradykinins causes vasodilation and edema, while the release of prostaglandin D2 and leukotrienes results in bronchoconstriction [31]. These biochemical events can cause a transfer of as much as 50% of intravascular fluids to extracellular spaces [32]. A steep decline in blood pressure and cardiovascular collapse can ensue. Immediate emergency treatment and contact of EMS is mandatory to save the patient's life.

While the patient is conscious, any dental materials in the patient's mouth should be removed to prevent their aspiration and further complication of the efforts to treat the patient. The patient should be placed in a supine position with the legs slightly elevated to facilitate blood flow to the brain. The basics of airway, breathing, and circulation should be constantly monitored.

According to the Australasian Society of Clinical Immunology and Allergy, epinephrine is the first line treatment of anaphylaxis and acts to reduce airway mucosal edema, induce bronchodilation, induce vasoconstriction, and increase strength of cardiac contraction.

(https://www.allergy.org.au/images/ASCIA_HP_Guidelines_Acute_Management_Anaphylaxis_2023.pdf Last Accessed: January 25, 2023)

Level of Evidence: Expert Opinion/Consensus Statement

Epinephrine remains the medication of choice to treat anaphylactic shock. Commercially prepared pre-loaded syringes of 0.3 mg of 1:1,000 epinephrine (usually referred to by their brand name, EpiPen) can be injected into the deltoid or vastus lateralis muscles or in the sublingual region. The highly vascular sublingual region can promote rapid absorption of the epinephrine. Subcutaneous administration of epinephrine does not provide as much bioavailability of epinephrine as the intramuscular or sublingual routes [5,45].

Once absorbed, epinephrine targets the alpha and beta receptors of the cardiovascular system, inducing vasoconstriction and increasing the systolic blood pressure. Epinephrine also acts as a bronchodilator and can relieve the respiratory distress associated with anaphylaxis. The dose of 0.3 mg epinephrine can be administered every 5 to 15 minutes until hypotension and respiratory distress are stabilized. An intramuscular injection of a histamine blocker such as diphenhydramine can also help by reducing the effects of the histamine release from the mast cells [5].

Positive pressure oxygen delivered through a mask can provide supplemental oxygen. Some patients will exhibit severe pharyngeal and laryngeal swelling and require intubation for the proper exchange of oxygen. All anaphylactic patients must be transferred to a hospital for further treatment and observation, as some patients have a biphasic response and begin to display symptoms of anaphylaxis even after seemingly effective treatment. Biphasic reactions have been reported to occur in 1% to 20% of anaphylaxis episodes, usually about eight hours after the first reaction, although they can occur up to 72 hours later [16]. After recovery from the anaphylaxis reaction, the patient should consult with his or her physician or allergist to identify which substance(s) caused the event and to prevent recurrence.

Local anesthetics provide a means by which restorative, surgical, and endodontic procedures can be completed in a comfortable fashion. Some estimates suggest that approximately 300 million cartridges of local anesthetics are used in the United States annually [34]. These injected medications have an outstanding record of safety, and allergies to local anesthetics are rare. Systemic complications that occur after the injection are also rare but do occur and can progress rapidly. However, the safety record of local anesthetics should not allow a sense of complacency to develop among clinicians regarding their use. Package inserts from the manufacturers contain warnings that those who administer local anesthetics should be prepared to diagnose and treat emergency situations such as dose-related toxicity and acute reactions that may occur after administration. The availability of oxygen and resuscitative equipment and the competence to use this equipment properly is also advised.

As discussed, the medical and dental history of each patient should be reviewed prior to the initiation of treatment and the administration of any medication. When the dental history reveals that a patient has had problems with local anesthetics before, a thorough investigation of the nature the problem, the local anesthetic used, and the required emergency treatment and outcome can provide important information. A consultation with dental clinicians involved in prior treatments and, if applicable, physicians involved in their emergency treatment may help to identify the etiology of the toxicity reaction so it can be avoided in subsequent appointments.

There is no substitute for appropriate staff training for medical emergencies. The occurrence of a medical emergency is not the time to assign specific roles for each staff member, check the emergency medicine kit for drugs that have expired, or make sure that the AED is working properly. The chaos and panic that can ensue among an unprepared dental staff can mean the difference between life and death.

Each staff member should be assigned a specific duty to assume during a medical emergency. Contingency plans should be made for the times when a staff member is absent. New staff members should be assigned their specific role when they join the practice. One person should be the designated leader responsible for directing other staff members and performing the initial assessment of airway, breathing, and circulation. It is important that this person has the demeanor to remain calm amid stressful circumstances. A second team member is responsible for bringing the emergency kit, the portable oxygen tank, and the AED to the patient. This staff member should be trained to assist with CPR. A third staff member is responsible for contacting EMS and providing information about the nature of the emergency situation and the patient's current vital signs. An estimated response time should be obtained [13,45]. Larger practices may have more than one such team, while practices that are just starting may have to divide the duties among just two or three staff members.

These roles should be practiced in medical emergency drills on a quarterly basis and should feature the various emergency situations to which the staff must respond. All staff members should be current with basic CPR training. Some states require a higher level of training, such as advanced cardiac life support, for practices that provide various levels of sedation for their patients.

Medications that are frequently used in medical emergencies have been highlighted in various sections of this course and can be purchased separately or as part of a medical emergency kit. Staff training for medical emergencies should highlight which medications are used for specific emergency situations, their route of administration, and the location of the emergency kit. A staff that is well-trained for medical emergencies during dental treatment can make the difference between the life and death of an afflicted patient.

Practices that routinely sedate patients with opioids or benzodiazepines should have antidotal drugs readily available to reverse the respiratory depression that can accompany the administration of these medications. Naloxone is an opioid antagonist that can reverse respiratory depression caused by this class of drugs, and flumazenil is capable of reversing the effects of benzodiazepine [14,15]. Flumazenil is given via an intravenous route, so clinicians who utilize it must be capable of establishing an intravenous line. Naloxone can be provided by intramuscular or intravenous means. Because many practices utilize sedation, especially for patients with a high level of anxiety about dental treatment, there should be a means to reverse respiratory depression due to excessive sedation.

The dental staff should have immediate access to medications and equipment used during dental emergencies. These supplies should be kept in a centrally located area, and their location should be known to all staff members. Several manufacturers supply the most commonly used emergency medications as a kit, and some will automatically ship new medications when those previously provided have expired. It remains prudent to have one staff member who periodically reviews the expiration dates of all emergency medications and orders replacements for those that have been used for an emergency situation. The indications and appropriate use for these medications should be communicated to all staff members.

The use of oxygen is common in many medical emergencies. A portable oxygen cylinder (E-size) with a nasal cannula or nasal hood should be present in each office. The oxygen cylinder(s) should be checked periodically for the appropriate volume of oxygen, as even a small leak can cause loss of the entire volume of oxygen. All staff members should know how to operate these oxygen cylinders. Some offices may have nitrous oxide and oxygen delivery systems for each operatory. However, the tubing for these systems is not long enough to reach a stricken person beyond the operatory itself. Therefore, even offices with these systems should have portable oxygen cylinders available. Replacement tanks should be ordered after a cylinder has been used for an emergency situation.

Monitoring vital signs is critical to any emergency situation, so each office should have a stethoscope and a sphygmomanometer to record blood pressure. Several automated devices that record vital signs are available and may be useful when patient movement, such as during a seizure, makes a manual blood pressure assessment difficult.

Some states require that each dental practice have an AED and that staff be trained in its proper use. These devices should be a part of every dental practice even if there is no requirement by law to do so. Most manufacturers can provide training for the entire staff via in-office presentations or training videos. AED training should be incorporated into practice emergency drills so each staff member can use this device in an emergency situation. Voice prompts guide the operator for proper assessment and use of the AED during a cardiac emergency. Because long intervals can pass between uses of this device, its batteries should be checked at regular intervals.