Evaluation by thoracic impedance cardiography of diazepam, placebo, and two drug combinations for intravenous sedation of dental outpatients

The cardiovascular and respiratory effects of three common intravenous premedicants were examined noninvasively in a population of 20 dental outpatients scheduled for surgical removal of third-molars. Two third molars from one side of the mouth were removed at each appointment. Group 1 received a diazepam titration (mean dose = 25.6 mgs) at one appointment and placebo at the other appointment. Group 2 received a combination of diazepam (12.5 mg), fentanyl (0.1 mg), and methohexital (mean dose = 18.0 mg) at one appointment and the combination of diazepam (15.0 mg) and methohexital (mean dose = 27.0 mg) at the other appointment. Noninvasive measurement of cardiac output revealed little change during intravenous drug administration, but a significant increase was seen in all groups following local anesthesia and during surgery. Heart rate was elevated and stroke volume decreased during administration of the two-drug combinations. Oxygen saturation was greatly decreased following the combination of diazepam, fentanyl, and methohexital. These findings indicate that the combination of diazepam, fentanyl, and methohexital results in decreased oxygen saturation, a transient decrease in stroke volume, and an elevated heart rate when used as an intravenous premedicant for dental outpatients.