In vivo and in vitro effects of different anaesthetics on platelet function.

Different effects of thiopental, propofol and sevoflurane on platelets have been reported. Patients undergoing thyroid surgery were anaesthetized with thiopental-fentanyl-sevoflurane (n = 11) or propofol-fentanyl-sevoflurane (n = 9). Platelet aggregation and thromboxane A2 generation were studied at baseline, and at the end of anaesthesia induction and surgery. Dose-response experiments were also performed in vitro with single agents. Thiopental-fentanyl-sevoflurane significantly reduced collagen-induced aggregation by the end of induction, while ADP-induced aggregation and thromboxane generation were unaffected. Propofol-fentanyl-sevoflurane had no effect on platelets. Thiopental dose-dependently inhibited platelets in vitro, while fentanyl or propofol did not. In conclusion, thiopental reduces platelet function both ex vivo and in vitro and propofol might be considered haemostatically safer.