Optical aggregometry versus the PFA-100TM:: experimental studies in pigs treated with propofol

An experimental study of platelet aggregation was performed in 22 male Landrace x Large-White crossbred pigs treated with propofol at different doses, to compare the results of optical aggregometry with those of the PFA-100(TM) (Dade Int., Miami, FL, USA), a new platelet function analyzer. Platelet aggregation was analyzed in basal blood samples by both methods, after which the pigs were divided into three groups: G1, anaesthetic induction with propofol (2 mg/kg intravenously (i.v.)); G2, anaesthetic induction with propofol (2 mg/kg i.v.), followed by a second dose of 1.5 mg/kg; and G3, anaesthetic induction with propofol (2 mg/kg i.v.), followed by 1 h of continuous i.v. infusion at 13 mg/kg/h. Four minutes after propofol injection, blood samples were again taken from each group and studied by both methods. In groups G2 and G3, both methods showed reduced platelet aggregation, while in group G1 neither evidenced an anti-aggregating effect of propofol. Under our experimental conditions: (1) the propofol effect on platelet aggregation depends on the plasma concentration; (2) the results obtained with the two methods are comparable; (3) PFA-100(TM) may provide an alternative to optical aggregometry for detecting the effects of anaesthetic agents ex vivo.