Faint in the supine position. Selective review of the literature and a case report.

A case of faint occurred in a patient undergoing periodontal surgery with intravenous conscious-sedation in the horizontal position. The faint occurred 3 hours and 40 minutes into the procedure, immediately following the extraction of a maxillary molar that could not be salvaged due to excessive bone loss. Since the patient was judged to be adequately sedated by both the operator and the anesthetist, the faint could not be attributed to anxiety. Recent evidence suggests that somatosensory stimulation of the trigeminal nerve may produce a reflex parasympathetic discharge that could account for some syncopal episodes observed during dental procedures.