Propofol decreases diaphragmatic contractility in dogs.

Abstract

Volatile anesthetics depress diaphragmatic muscle function; however, no data are available regarding the effect of propofol on diaphragmatic contractility. We therefore studied this effect in dogs. Pentobarbital-anesthetized animals were divided into three groups of 10 each. Group I received only maintenance fluid; Group II was infused with a subhypnotic dose of propofol (0.1-mg/kg initial dose plus 1.5-mg x kg(-1) x h(-1) maintenance dose); Group III was infused with an anesthetic dose of propofol (0.1-mg/kg initial dose plus 6.0-mg x kg(-1) x h(-1) maintenance dose). We assessed diaphragmatic contractility by transdiaphragmatic pressure (Pdi). With an infusion of propofol in Groups II and III, Pdi at low-frequency (20-Hz) stimulation decreased from the baseline values (P < 0.05), whereas Pdi at high-frequency (100-Hz) stimulation did not change. Compared with Group I, Pdi at 20-Hz stimulation decreased during propofol administration in Groups II and III (P < 0.05). The decrease in Pdi was more in Group III than in Group II (P < 0.05). We conclude that propofol is associated with a dose-related inhibitory effect on diaphragmatic contractility in dogs. Propofol is an effective IV anesthetic for the induction and maintenance of anesthesia. Subhypnotic and anesthetic doses of propofol decrease diaphragmatic contractility in dogs.