Anesth Prog 38:154-171 1991 Adult Sedation: Oral, Rectal, IM, IV Joseph A. Giovannitti, DMD,* and Larry D. Trapp, DDS, MSt *Division of Pain and Anxiety Control, Baylor College of Dentistry, Dallas, Texas; and tSection of Hospital Dentistry, UCLA, Los Angeles, California, and Department of Dental Anesthesiology, Loma Linda University, Loma Linda, California. onscious sedation is a pharmacologically induced the mortality rate for parenteral sedation to be approxi- state of relaxation in which the patient remains mately 1 in a million.3 Thus, with its proven benefit of conscious and cooperative throughout dental treatment. stress reduction and its relative safety, intravenous con- Apprehension, fear, and anxiety are either eliminated or scious sedation has a wide variety of uses. reduced to the point where a previously objectionable Aside from the obvious use in fearful or apprehensive procedure, such as dentistry, becomes acceptable. The patients, sedation may be indicated in medically compro- protective reflexes remain intact, cardiorespiratory pa- mised patients, children, gaggers, patients with a history rameters are stable, and the pain threshold may be ele- of problems with local anesthesia, and in those requiring vated. surgical or other prolonged dental procedures. An impor- Selection of the appropriate technique is based upon tant side benefit of conscious sedation is that it enables the patient's level of apprehension and should be individ- the dentist to perform a maximum amount of work in a ualized according to the sedative effect required, the need minimum amount of time. for amnesia, the need for an elevated pain threshold, and the duration of the dental procedure. Sedative medica- tions may be administered singly or in combination, de- pending on the individual patient and procedural require- BALANCING EFFICACY AND SAFETY ments. Single sedatives are useful in managing mild to moderate apprehension levels. Benzodiazepines with When drugs are administered to patients to produce con- specific anxiolytic properties, such as diazepam or mida- scious sedation, the observed effects are the culmination zolam, are the most widely used drugs for this technique. of a series of altered physiologic functions. In a true Not all patients however, will respond to a single drug sense, we produce pathophysiologic changes when we due to the many factors contributing to pharmacologic administer these agents, some of which are desirable, and variability. Multiple-drug techniques may result in less some of which are undesirable. Factors which determine variability in patient response; but with greater potential how a drug or drug combination will affect the various for drug-induced side-effects and drug interactions. functions of the human body include: the pre-existing Whenever conscious sedation is being considered for medical condition of the patient, the nature and duration use in a particular patient, the benefits of the sedation of the present illness, drug interactions, age, nutritional must be weighed against its inherent risks and the risks status, environmental factors, and genetically determined associated with the body's physiologic response to stress. factors that may render patients more susceptible or re- Catecholamine release during stress may lead to syn- sistant to the effects of a particular drug. In order to maxi- cope, agitation, excitement, tachycardia, hypertension, mize the desirable effects produced by these agents and and cardiac dysrhythmias. These physiologic and behav- minimize the undesirable effects, a clinician must accu- ioral changes are at best undesirable, and at worst major rately assess the patient's preanesthetic condition, be causes of medical emergencies. Dionne, and others1 thoroughly familiar with the pharmacodynamics of the have shown that benzodiazepines attenuate this stress drugs employed, and be properly trained to continuously response during oral surgery, thus validating the use of monitor the effects produced by these agents. In addition, sedation in dentistry. The safety of conscious sedation is the clinician should be properly trained to correct any exemplary. Ceravolo et a12 published an 11-year case significant pathophysiologic changes produced by the ad- study of 10,000 patients receiving IV sedation in which ministration of these drugs. The office team should be there were no major complications. Coplans estimates experienced and well-trained, and there should be suffi- cient backup resources in the event of an emergency. Without these basic precautions, inadvertent but signifi- Address correspondence to Dr. Larry D. Trapp, 25616 Narbonne cant changes in physiologic function may lead to injury or Avenue, #204, Lomita, CA 90717-2536. even death. © 1991 by the American Dental Society of Anesthesiology ISSN 0003-3006/91/$3.50 154 Anesth Prog 38:154-171 1991 Adult Sedation: Oral, Rectal, IM, IV 155 Care should be taken to avoid the pitfalls that may lead Table 1. Summary of Advantages and Disadvantages of to an adverse outcome. Without a doubt, the most com- Oral Premedications mon cause of anesthetic misadventures is an inadequate Advantages preoperative evaluation. This in turn may lead to clinical Simple and convenient to use. failure due to improper technique selection, overdosage, - Drugs readily available by prescription. or drug interaction. Exposing a medically compromised Drug reactions are generally less severe. patient to the risks of deep sedation or general anesthesia Oral route less objectionable than parenteral. Requires only minimal training. when conscious sedation will suffice places the patient at Duration of action may extend into posttreatment unnecessary risk. Conversely, using conscious sedation period. when general anesthesia is indicated may lead the practi- tioner to extend the technique beyond the limits of safe Disadvantages practice. This invariably leads to overdosage, airway ob- - Patient noncompliance. struction, and cardiorespiratory depression. Inadequate -Dosages are largely empirical. - Titration to clinical endpoint impossible. or improper monitoring also contributes directly to anes- -Erratic absorption makes response unpredictable. thetic morbidity and mortality. The mere presence of an -Level of sedation cannot be altered. electronic monitor does not guarantee the patient's -Not useful in extremely apprehensive patients. safety. Certain knowledge is required for proper interpre- -Duration of action may extend into posttreatment tation, and during conscious sedation no monitor should period. be a substitute for verbally and visually ascertaining the patient's level of consciousness, comfort, and coopera- tion. dosages used for premedication are largely empirical and are usually based upon body weight. Unfortunately, this ORAL PREMEDICATION also contributes to a variable response. The advantages and disadvantages of oral premedication are summarized Oral premedication is generally given first consideration in Table 1. in the management of the mildly apprehensive patient. Because of its ease of administration, convenience, and availability, oral premedication is a popular choice for Pharmacological Factors Influencing conscious sedation. The predoctoral dental curriculum Clinical Efficacy. offers the training necessary to master this technique, and Drug Absorption. The overall efficacy of oral pre- thus its use is widespread. The availability of a liquid dose medication is dependent upon the rate and completeness form makes oral premedication highly applicable to the of absorption from the gastrointestinal tract. Lipid-soluble pediatric dental patient. It is also a useful modality in drugs are more rapidly absorbed than nonlipid-soluble patients who are unwilling to accept alternate routes of drugs, and therefore have a more rapid rate of onset. The drug administration. Patients with mask-induced claustro- rate of absorption is also heavily influenced by the pH of phobia or those with an irrational fear of needles may find the gastric tissues. The absorption of most oral medica- the oral route less objectionable. tions occurs in the small intestine, where there is much The primary objective of oral premedication is to re- more mucosal surface area as compared to the stomach. duce anxiety while maintaining consciousness, comfort, Therefore, in order to expedite absorption the drug must and cooperation. This objective is usually met in the pass through the stomach and into the small intestine as mildly apprehensive patient. For the management of the rapidly as possible. The presence of food in the stomach moderately apprehensive patient, oral premedication can significantly delays gastric emptying time, and retards be effective when combined with either intramuscular or drug absorption. Similarly, increased levels of anxiety inhalational agents. However, it is not very effective in also delay gastric emptying. This may be one of the rea- extremely apprehensive patients unless intravenous tech- sons why the efficacy of oral premedication decreases as niques are also used. anxiety increases. Results with oral premedicants are not always predicta- Other factors that influence the systemic absorption of ble since patients may not always follow the prescribed oral medication are the dose form of the drug and inacti- instructions. Also, there is much variability in patient re- vation of the drug by the liver. The efficient absorption of sponse to oral medication. A full stomach will delay the one dose form over another has to do with the bioavaila-