Hemodynamic Effects of Infusions of the Emulsion Formulation of Propofol during Nitrous Oxide Anesthesia in Humans

The hemodynamic response to anesthesia with the aqueous emulsion formulation of propofol was studied in healthy patients (ASA I or II), aged 39–57 yr, premedicated with morphine, 0.15 mg/kg. Anesthesia was induced in all patients with propofol, 2 mg/kg. Subsequently, patients were randomly assigned to two groups and maintained by a continuous intravenous infusion (group 1 received 54 μg·kg−1·min−1, group 2 received 108 μg·kg−1·min−1) to supplement 67% nitrous oxide. Three minutes after induction, systolic arterial pressure (SAP) decreased 28% (P < 0.01) and was associated with decreased (−12%) cardiac output (Q70) and decreased (−15%) systemic vascular resistance (SVR). The hemodynamic response to tracheal intubation was not obtunded, but peak values of arterial pressures and heart rate did not exceed those recorded awake. Thirty minutes elapsed before repeating measurements prior to the first surgical incision. In group 1, SAP and Q70 decreased to 65% and 68% of awake values and in group 2 to 55% and 74% (P < 0.05). Mild ventilatory depression persisted for the duration of spontaneous ventilation and was not reduced by the stimulus of surgery, which caused no significant hemodynamic responses in either group. Decreasing arterial Pco2 to the awake value by controlled ventilation increased SVR (P < 0.05), but the associated increased SAP and decreased Q70 did not reach statistical significance. No patient reported awareness. The infusion of the emulsion formulation of propofol was associated with satisfactory anesthesia and recovery and with hemodynamic effects similar to those recorded with other intravenous anesthetics.