Target-controlled versus manually-controlled infusion of propofol for direct laryngoscopy and bronchoscopy

Few studies have compared the clinical profile of target-controlled infusions of propofol with that of manually-controlled infusions. Fifty-four ASA physical status I or Il patients scheduled for an elective otorhinolaryngology endoscopy performed under general anesthesia with spontaneous ventilation were enrolled in this prospective randomized studs, to compare the clinical outcome of such administrations. Before induction, all patients received a single alfentanil bolus dose (10 mug/kg). Propofol administration was adapted to maintain absence of movement, hemodynamic stability, and efficient spontaneous ventilation. When compared with the Manually-Controlled Infusion group, in the Target-C on trolled Infusion group there were fewer movements at insertion of the laryngoscope (14.8% vs. 44.4), improved hemodynamic stability (largest variations of mean arterial blood pressure <10% of control values, versus 20%), fewer episodes of apnea, and less respiratory acidosis after endoscopy (pH = 7.37 +/- 0.05 and Paco(2) = 50 +/- 7 mm Hg versus pH = 7.28 +/- 0.06 and Paco(2) = 58 +/- 9 mm Hg); the recovery was also shorter (time to opening eyes or verbal response, 4.6 +/- 2.0 min and 6.8 +/- 2.5 min versus 10.8 +/- 7.3 min and 15.7 +/- 7.1 min). Propofol consumption was comparable in the two groups. Targeting the effect-site concentration improved the time course of the propofol drug effect during direct laryngoscopy performed during spontaneous ventilation when compared with manual infusion.