CHAPTER 14 Pharmacologic Management of Patient Behavior
To perform the highest quality dental care for the pediatric patient, the practitioner may need to use pharmacologic means to obtain a quiescent, cooperative patient. Techniques that use drugs to induce a cooperative yet conscious state in an otherwise anxious or uncooperative child are most commonly referred to as techniques of sedation. Levels of sedation are defined as follows (American Academy of Pediatric Dentistry [AAPD] guidelines):
The goals of sedation for the pediatric patient are (1) to guard the patient’s safety and welfare, (2) to minimize physical discomfort and pain; (3) to control anxiety, minimize psychological trauma, and maximize the potential for amnesia; (4) to control behavior or movement so as to allow the safe completion of the procedure; and (5) to return the patient to a physiologic state in which safe discharge, as determined by recognized criteria, is possible. In-office sedation techniques used by pediatric dentists produce a minimally depressed state or level of consciousness in which the patient retains the ability to maintain a patent airway independently and continuously, and is able to respond appropriately to physical stimulation or verbal commands. This means that the patient can in some way purposefully acknowledge a request to move or open the eyes, or react to an uncomfortable applied stimulus. All reflexes are essentially intact. If the patient is incapable of response by virtue of being very young or severely disabled, one should exercise care not to depress the patient to a point where such a determination is difficult to make. The techniques and drugs used to produce this state should possess a margin of safety of ample width to preclude unintended loss of consciousness.
In contrast to this awake state, deep sedation and general anesthesia are defined as conditions of the patient characterized by an incomplete, partial, or total loss of protective reflexes. In addition, there may be a partial or complete loss of the ability to independently and continuously maintain a patent airway. Cardiovascular function may also be impaired. Under these circumstances, the patient is noninteractive and does not respond purposefully to physical stimulation or verbal command.
Occasionally the sedated patient will drift into normal sleep. When this occurs, it becomes the practitioner’s responsibility to be assured that what is being observed is a normal sleep state by frequently arousing the patient. This may be frustrating, because the objective is to produce a patient who is totally cooperative and the sleeping patient is just that.
Often, deep sedation and general anesthesia are differentiated; however, for the purposes of describing what is required to manage the patient in this condition in terms of training, monitoring, facilities, and personnel, the two conditions are treated as a single physiologic state of the patient. The requirements for management of the unconscious patient are much more stringent and address a greater concern for the safety of the patient.
A caution for the practitioner should be to avoid thinking of the patient’s state in terms of the techniques employed rather than the level of consciousness. Historically, many sedation techniques have been defined by the route of administration. It is not the technique of administration but the drugs or agents employed that produce the effect observed in the patient. For example, one can produce an unconscious or fully anesthetized patient using the oral route. The concept of rescue is essential to safe sedation. Practitioners of sedation must have the skills to rescue the patient from a deeper level than that intended for the procedure (AAPD guidelines).
When a regimen of sedation for the pediatric patient is prepared, it is important to consider the differences between the adult patient and one in the pediatric age group. The sedation of children is different from the sedation of adults. Differences in size, weight, and age as a measure of maturation of systems are obvious. Less obvious, but equally important, are the differences in basal metabolic rate between the adult and pediatric patient. Basal metabolic activity is greater in children, which ultimately affects not only drug response but also important physiologic parameters as well. Because oxygen demand is greater but the alveolar system is less mature, the respiratory rate is far higher in children than in adults (Table 14-1). This is an important consideration when drugs that depress the respiratory system are administered.
Airway management requires different consideration in the pediatric patient because of anatomic variations. The narrow nasal passages and glottis, combined with hypertrophic tonsils and adenoids, enlarged tongue, and greater secretions, produce a much greater risk of airway obstruction. The airway of all patients should be examined before sedation (Fig. 14-1). Patients with tonsillar tissue that occupies more than 50% of the pharyngeal space are at increased risk for respiratory obstruction, and alternative treatment options should be considered.3 Children demonstrate a reduced tolerance to respiratory obstruction. Thus sudden apnea is a greater concern in the pediatric age group. Because the thorax is smaller, with less expansion capability, children have less functional reserve. Consequently they are more prone to rapid desaturation on obstruction or respiratory depression. For this reason children with sleep apnea are not good candidates for sedation.
Figure 14-1 Standardized system for evaluation of tonsillar size. Classification of tonsil size should be completed for all patients before sedation. Patients classified as +3 or greater (having more than 50% of the pharyngeal area occupied by tonsils) are at increased risk for developing airway obstruction.
(From Brodsky L. Modern assessment of tonsils and adenoids. Pediatr Clin North Am 1989;36:1551-1569; and Cote CJ, et al. A practice of Anesthesia for Infants and Children. Philadelphia, WB Saunders, 1993:313-314.)
Cardiovascular parameters are different for children. The heart rate is faster and blood pressure is lower than in the adult. Children are more susceptible to bradycardia, decreased cardiac output, and hypotension. Unlike in the adult population, heart rate is the primary determinate of blood pressure in children. Compensatory mechanisms to maintain adequate blood pressure when the heart rate is depressed are not as well developed in children. Thus a decrease in heart rate leads to a corresponding decrease in blood pressure and tissue oxygenation. This concept must be well appreciated when giving drugs that depress the heart rate in the pediatric age population.
The effect and duration of action of drugs is much more variable in children. For agents that are more lipophilic, retention may be prolonged, especially in children who are obese. For some patients, drug metabolism may be increased. Because of better peripheral perfusion in children, the onset of intramuscularly administered drugs may be more rapid.
The anatomic and physiologic differences between children at different age levels and adults lead one to the conclusion that dosage is not simply an application of a formula for derivation of a percentage of the adult dosage of any agent. Drug dosages for children should be carefully individualized for each patient following established guidelines.
Because sedation embodies a group of techniques designed to alter patient behavior, the practitioner should have a rationale for making the choice as to which patients will most likely benefit from their use. The indiscriminate application of these techniques to all patients must be avoided. Several behavioral or anxietyassessment profiles have been developed that can be of great help to the practitioner as the various techniques are introduced into a practice.4,5 As one gains experience, this decision becomes more one of clinical judgment and intuition as to which approach produces the most successful results for specific types of patients for that individual practitioner. No one technique or agent, or combination of agents, should be expected to be successful every time. There are also degrees of success, and total immobilization and near unconsciousness of a patient should not necessarily be equated with the most successful sedation. One should choose the agent and technique that best fits the patient type as well as the nature of what needs to be accomplished.
A thorough medical history is required to determine whether a patient is suitable for sedative procedures. This, along with a recent physical examination, constitute a risk assessment or physiologic status evaluation. This health evaluation should be used to place the patient in one of the categories set forth by the American Society of Anesthesiologists (www.asahq.org/clinical/physicalstatus.htm) and should be documented in the record (Box 14-1).
|Class I||A normal healthy patient|
|Class II||A patient with mild systemic disease (e.g., controlled reactive airway disease)|
|Class III||A patient with severe systemic disease (e.g., a child who is actively wheezing)|
|Class IV||A patient with severe systemic disease (e.g., a child with status asthmaticus)|
|Class V||A moribund patient who is not expected to survive without operation (e.g., a patient with severe cardiomyopathy requiring heart transplantation)|
Patients who are in ASA I are frequently considered appropriate candidates for minimal, moderate, or deep sedation. Some children assigned to ASA class II or III may actually benefit from this approach, but this must be determined in consultation with the child’s physician. Generally, patients categorized into classes III and IV, children with special needs, and those with anatomic airway abnormalities or extreme tonsillar hypertrophy are better managed in a hospital setting. (AAPD guidelines).
The parent or legal guardian must be agreeable to the use of sedation for the child. These individuals are entitled to receive complete information regarding the reasonably foreseeable risks and the benefits associated with the particular technique and agents being used, as well as any alternative methods available. Therefore the explanation should be in clear, concise terms that are familiar to them (Fig. 14-2). The consent form can be on or part of a sedation record with space provided for the signatures of all parties.
Information in written form should be reviewed with the person caring for the child and given to this person along with the notice of the scheduled appointment (Fig. 14-3). This information should include a 24-hour contact number for the practitioner.
The reasons for these recommendations are twofold. First, emesis during or immediately after a sedative procedure is a potential complication that can result in aspiration of stomach contents leading to laryngospasm or severe airway obstruction. Aspiration may even present difficulties later in the form of aspiration pneumonia. At the very least, it creates an unfavorable disruption of the office routine. Second, because most sedative agents are administered by the oral route, drug uptake is maximized when the stomach is empty.
The parent or guardian should also be advised that he or she will be expected to remain in the area of the office during the sedation appointment. With regard to transportation, the instructions should request that a second person accompany the parent so that the person caring for the child may be free to attend to the child’s needs during the trip home.
The caregiver should be advised that, on arriving home, the child may sleep for several hours and may be drowsy and irritable for up to 24 hours after the sedation. It is important to stress the need for frequent observation if the child is sleeping, to ensure an open airway. Activity should be restricted to quieter pursuits and be closely supervised for the remainder of the day.
Following treatment, the child should first be offered clear liquids and may advance to solid foods as tolerated. Once solids are tolerated, there are no dietary restrictions other than those imposed as a result of the dental procedure performed. Nausea and vomiting may occur, especially when narcotics have been used, which may thus prolong the delay before beginning solid food intake. In this event, special attention should be paid to the fluid intake to ensure adequate hydration.
Knowledge on the part of the parent of what to expect is the most reliable way to ensure a calm, comfortable, and uncomplicated postsedation period. Therefore these instructions and recommendations should be in written form and should be reviewed again with the person responsible for the patient and given to this person at the time of discharge from the office (Fig. 14-4).
Meticulous and accurate documentation of the sedation experience is imperative. In the event of an adverse reaction, the best insurance is an accurate, clear, continuous, documented account of what occurred before, during, and after the encounter.
Preprocedural records should document (1) proper adherence to food and liquid intake restrictions; (2) the preoperative health evaluation, including the patient’s health history and a complete physical assessment along with the patient’s current weight, age, and baseline vital signs; (3) name and address of the physician who usually cares for the child; (4) a note as to why the particular method of management was chosen; (5) the presence of informed consent; and (6) the delivery of instructions to the caregiver.
Intraoperatively the appropriate vital signs should be recorded as they are assessed (Table 14-2). Timed notations regarding the patient’s appearance should be included. The type of drug, the dose given, and the route, site, and time of administration should be clearly indicated. If a prescription is used, either a copy of the prescription or a note as to what was prescribed should also be a part of the permanent record.
After completion of treatment, the patient should be continuously observed in an appropriately equipped recovery area. The patient should remain under direct observation until respiratory and cardiovascular stability have been ensured. The patient should not be discharged until the presedation level of consciousness or a level as close as possible for that child has been achieved (Box 14-2). At the time of discharge, the condition of the patient should be noted.
Box 14-2 Discharge Criteria
A variety of methods are available for producing sedation or alteration of mood in the pediatric patient. These systemic procedures are based on the thoughtful use of various drugs that produce sedation as one of their principal effects, as well as the use of differing routes of administration. Sedative drugs may be administered by inhalation or by oral, rectal, submucosal, intramuscular, or intravenous routes. The use of combinations of drugs and specific selection of routes of administration to maximize effect and increase safety, as well as maximize patient acceptability, are common. Inhalation of a nitrous oxide–oxygen mixture is often coupled with administration of an agent by any of the other routes.
Prescription medications intended to accomplish procedural sedation must not be administered without the benefit of direct supervision by trained personnel. It is no longer acceptable to administer any sedative drug outside of the treatment facility (e.g., given at home by the parent or caregiver). Administration of sedating medications at home poses an unacceptable risk, particularly for infants and preschool-aged children traveling in car-safety seats. (AAPD guidelines).
The primary goal of these techniques is to produce a quiescent patient to ensure the best quality of care. Another goal might be to accomplish a more complex or lengthy treatment plan in a shorter period by lengthening appointment times and thereby reducing the number of repeat visits required. Children presenting with a dental injury or acute pain may require sedation for completion of treatment as well as postoperative analgesia. In fact, the reduction in anxiety may reduce the amount of analgesia required. Sedation may also allow for more comfortable and acceptable treatment for physically impaired or cognitively disabled patients. Often these patients may benefit from parenteral sedation. Although the presence of a compromising medical condition is generally a contraindication to sedation, some patients in this category may in fact benefit from its use.6 This would, of course, include patients for whom stress reduction would reduce the likelihood of complications. These children should be managed in close cooperation with the physicians who regularly cares for them.
Nitrous oxide is a slightly sweet-smelling, colorless, inert gas. It is compressed in cylinders as a liquid that vaporizes on release. This is an endothermic reaction that pulls heat from the cylinder and environment; consequently the cylinder becomes cool or even cold when in use. The gas is nonflammable but will support combustion.
Nitrous oxide is slightly heavier than air, with a specific gravity of 1.53, and has a blood to gas partition coefficient of 0.47. Because of its low solubility in blood, it has a very rapid onset and recovery time. Nitrous oxide will become saturated in blood within 3 to 5 minutes following administration and is physically dissolved in the serum fraction of the blood. There is no biotransformation, and the gas is rapidly excreted by the lungs when the concentration gradient is reversed. Very small amounts may be found in excreted body fluids and intestinal gas.
A phenomenon termed diffusion hypoxia may occur as the sedation is reversed at the termination of the procedure. The nitrous oxide escapes into the alveoli with such rapidity that the oxygen present becomes diluted; thus the oxygen–carbon dioxide exchange is disrupted and a period of hypoxia is created. However, this phenomenon is reported not to occur in healthy pediatric patients.7 Nonetheless, to minimize this effect, the patient should be oxygenated for 3 to 5 minutes after a sedation procedure, if for no other reason than to allow for proper nasal hood evacuation of the exhaled gas.
Nitrous oxide produces nonspecific central nervous system (CNS) depression. Although it is classed with inhalational general anesthetics, it produces limited analgesia, and thus surgical anesthesia is unlikely unless concentrations producing anoxia are reached. Nitrous oxide is the weakest of all inhalation agents, with a minimum alveolar concentration of 105. The minimum alveolar concentration of an inhalation agent is a measure of its potency. It is the concentration required to produce immobility in 50% of patients. At concentrations between 30% and 50%, nitrous oxide will produce a relaxed, somnolent patient who may appear dissociated and easily susceptible to suggestion. Amnesia may occur in some patients, but there is little alteration of learning or memory. At concentrations greater than 60%, patients may experience discoordination, ataxia, giddiness, and increased sleepiness. The concentration of nitrous oxide should not routinely exceed 50%. One of the advantages of nitrous oxide is that it can easily be titrated up for stimulating procedures (e.g., injections) and titrated down during easier periods of the procedure (e.g., restorations).
Nitrous oxide reduces hypoxic-driven ventilation and has minimal effect on the hypercapnic respiratory drive. When used as a single agent, nitrous oxide will not cause hypoxemia. It should be avoided, however, in patients who rely significantly on hypoxia-driven ventilation, in whom exposure to high levels of oxygen can result in respiratory depression. When combined with other agents that depress respiration, nitrous oxide decreases the body’s normal response to low oxygen tension. These effects are usually negligible, however, because of the high concentration of oxygen administered with the combination. Nitrous oxide slightly increases the respiratory minute volume. As the patient becomes more relaxed from the effects of nitrous oxide, the respiratory rate may decrease slightly. The gas is nonirritating to the respiratory tract and can be given to patients with asthma without fear of bronchospasm. Problems can arise, however, from the added respiratory effects when it is given in combination with narcotics or other CNS depressants.
Cardiac output is decreased and peripheral vascular resistance is increased when nitrous oxide is used. This is generally of insignificant degree and is a consideration only in patients with severe cardiac disease. The respiratory and cardiac effects may be secondary to the high concentration of oxygen administered in conjunction with nitrous oxide.