Sedation During Dental Procedures
The following are the guidelines for sedation as per American Dental Association (ADA):
” MODERATE SEDATION – a drug-induced depression of consciousness during which patients respond purposefully to verbal commands, either alone or accompanied by light tactile stimulation. No interventions are required to maintain a patent airway, and spontaneous ventilation is adequate. Cardiovascular function is usually maintained.1 Note: In accord with this particular definition, the drugs and/or techniques used should carry a margin of safety wide enough to render unintended loss of consciousness unlikely. Repeated dosing of an agent before the effects of previous dosing can be fully appreciated may result in a greater alteration of the state of consciousness than is the intent of the dentist. Further, a patient whose only response is reflex withdrawal from a painful stimulus is not considered to be in a state of moderate sedation. The following definition applies to the administration of moderate or greater sedation: titration – administration of incremental doses of an intravenous or inhalation drug until a desired effect is reached. Knowledge of each drug’s time of onset, peak response and duration of action is essential to avoid over sedation. Although the concept of titration of a drug to effect is critical for patient safety, when the intent is moderate sedation one must know whether the previous dose has taken full effect before administering an additional drug increment.
DEEP SEDATION AND GENERAL ANESTHESIA deep sedation – a drug-induced depression of consciousness during which patients cannot be easily aroused but respond purposefully following repeated or painful stimulation. The ability to independently maintain ventilatory function may be impaired. Patients may require assistance in maintaining a patent airway, and spontaneous ventilation may be inadequate. Cardiovascular function is usually maintained.1 general anesthesia – a drug-induced loss of consciousness during which patients are not arousable, even by painful stimulation. The ability to independently maintain ventilatory function is often impaired. Patients often require assistance in maintaining a patent airway, and positive pressure ventilation may be required because of depressed spontaneous ventilation or druginduced depression of neuromuscular function. Cardiovascular function may be impaired. Because sedation and general anesthesia are a continuum, it is not always possible to predict how an individual patient will respond. Hence, practitioners intending to produce a given level of sedation should be able to diagnose and manage the physiologic consequences (rescue) for patients whose level of sedation becomes deeper than initially intended.1 For all levels of sedation, the qualified dentist must have the training, skills, drugs and equipment to identify and manage such an occurrence until either assistance arrives (emergency medical service) or the patient returns to the intended level of sedation without airway or cardiovascular complications.”
Considerable expertise is required to provide sedation to attain perfect goal. Since patients react differently to same amount of drug, monitoring respiratory and cardiovascular function assumes vital importance. The ADA does state to use capnography to monitor ventilation as outlined below for moderate and deep sedation.
Consciousness: Level of sedation (e.g., responsiveness to verbal command) must be continually assessed.
Oxygenation: Oxygen saturation must be evaluated by pulse oximetry continuously.
Ventilation: • The dentist must observe chest excursions continually. • The dentist must monitor ventilation and/or breathing by monitoring end-tidal CO2 unless precluded or invalidated by the nature of the patient, procedure or equipment. In addition, ventilation should be monitored by continual observation of qualitative signs, including auscultation of breath sounds with a precordial or pretracheal stethoscope.
Circulation: • The dentist must continually evaluate blood pressure and heart rate unless invalidated by the nature of the patient, procedure or equipment and this is noted in the time-oriented anesthesia record. • Continuous ECG monitoring of patients with significant cardiovascular disease should be considered.
Documentation: • Appropriate time-oriented anesthetic record must be maintained, including the names of all drugs, dosages and their administration times, including local anesthetics, dosages and monitored physiological parameters. • Pulse oximetry, heart rate, respiratory rate, blood pressure and level of consciousness must be recorded continually.”
“Ventilation: • Intubated patient: End-tidal CO2 must be continuously monitored and evaluated. • Non-intubated patient: End-tidal CO2 must be continually monitored and evaluated unless precluded or invalidated by the nature of the patient, procedure, or equipment. In addition, ventilation should be monitored and evaluated by continual observation of qualitative signs, including auscultation of breath sounds with a precordial or pretracheal stethoscope. • Respiration rate must be continually monitored and evaluated.”
Therefore, dental practioners must understand physics, physiology and interpretation of capnograms. The readers are encouraged to understand physiology and interpretations from the appropriate sections in this website.
A meta-analysis of sixteen studies concluded that adding capnography to standard monitoring of adults during moderate sedation may reduce the risk of developing hypoxemia, increase detection of adverse respiratory events, and is not associated with additional harms. They further concluded that these findings suggest routine use of capnography during moderate sedation has the potential to reduce adverse anesthetic outcomes in dental practice (Parker W, Estrich CG, At E, et al. Benefits and harms of capnography during procedures involving moderate sedation: A rapid review and meta-analysis. J Am Dent Assoc 2018 Jan;149(1):38-50.e2. doi: 10.1016/j.adaj.2017.08.030. PMID: 29304910)
The authors used rapid review methodology to identify relevant systematic reviews, which they updated through a systematic search by using the same search strategy as the identified reviews. The authors searched PubMed and Google Scholar and through the references of the identified systematic reviews, which yielded 2,892 studies. Inclusion criteria were that the article was available in English, was original research in adult humans who had undergone moderate procedural sedation, and involved comparing standard monitoring with the addition of capnography.
Sixteen studies were eligible, involving 3,866 adults undergoing procedural sedation. The authors used the Grading of Recommendations Assessment, Development and Evaluation approach to evaluate the evidence and rate it as being of moderate to low quality because of high risk of bias and heterogeneous effects for the outcomes of hypoxemia and adverse respiratory events. Capnographyhad higher sensitivity to detect adverse respiratory events than did standard monitoring alone (0.92; 95% confidence interval, 0.65 to 0.99) and may reduce the risk of developing hypoxemia by 31% (risk ratio, 0.69; 95% confidence interval, 0.57 to 0.82). Capnography did not affect the risk of developing serious adverse events, procedure time, sedation quality, or patient satisfaction.