The inhibitory effect of propofol on platelet aggregation remains unclear, and studies on the subject disagree. Furthermore, although propofol infusions are widely used for general anesthesia and as sedatives for patients in intensive care units, little information is available on its concentration- and time-related effects on platelet aggregation. Here, the authors investigated the in vitro effect of propofol, at concentrations required for sedation and general anesthesia, on platelet aggregation after 1, 2, or 3 h. Blood from healthy volunteers (n = 9) was incubated at propofol plasma concentrations of 0, 2, 4, and 10 μg/mL in a water bath at 37°C. Platelet aggregation was measured using a platelet function analyzer (PFA-100) after 1, 2, or 3 h of incubation. Times to occlude collagen/epinephrine (CEPI) or collagen/adenosine 5'-diphosphate (CADP)-coated membranes (closure times, CTs) were measured. The CEPI and CADP CTs of non-incubated blood were 125.6 ± 19.5 s and 93.0 ± 12.2 s, respectively, and no significant difference in CEPI CTs was observed at propofol plasma concentrations of 0, 2, 4, and 10 μg/mL after incubation for 1, 2, or 3 h. CADP CTs were comparable at propofol concentrations of 0, 2, 4, and 10 μg/mL at each incubation time. These findings suggest that propofol at concentrations required for sedation and general anesthesia has no inhibitory effect on platelet aggregation after 3 h of incubation.

Objectives: To investigate the efficacy of pretreatment with cisatracurium for prevention of pain associated with propofol injection, and compare its efficacy with that of lidocaine. Methods: Patients undergoing general anaesthesia were randomized to receive normal saline (control group), lidocaine (0.5 mg/kg), 0.03 mg/kg cisatracurium or 0.15 mg/kg cisatracurium. All drugs were administered into the largest dorsal vein of the hand with venous occlusion for 30 s, followed by propofol (0.5 mg/kg). Pain was evaluated using a four-point scale.Results: The incidence and severity of pain was significantly lower in the lidocaine and 0.15 mg/kg cisatracurium groups than the control and 0.03 mg/kg cisatracurium groups (n ¼ 50/group). There was no significant difference between the lidocaine and 0.15 mg/kg cisatracurium groups in the incidence and severity of pain. Conclusions: 0.15 mg/kg cisatracurium effectively decreases the incidence and severity of pain induced by propofol injection without any significant complications.