Modulating effects of propofol on metabolic and cardiopulmonary responses to stressful intensive care unit procedures

Objective: Patients in the intensive care unit (ICU) undergo acute increases in metabolic and cardiopulmonary demands in response to routine care interventions, such as chest physical therapy. This study examined whether the short-acting drug, propofol, could blunt the responses to chest physical therapy. Design: Prospective, randomized, crossover (placebo vs. drug) study. Setting: University hospital surgical ICU. Patients: Postoperative ICU patients being ventilated in the synchronized intermittent mandatory ventilation mode. Interventions: Two groups of 16 patients were studied. Each patient received two successive sessions of chest physical therapy. In random fashion, one was preceded by the administration of placebo and the other by an intravenous bolus of propofol (0.75 mg/kg in one group and 0.35 mg/kg in the other group). Each session was preceded and followed by a period of rest. Measurements and Main Results: The increases in oxygen uptake, CO2 elimination, oxygen delivery, heart rate, and systolic blood pressure associated with chest physical therapy were attenuated with the low dose and suppressed with the high dose of propofol. The Paco(2) concentration was slightly increased during both placebo and drug administration. Conclusions: Propofol, in the doses administered in this study, significantly reduced the hemodynamic and metabolic stresses caused by chest physical therapy.