PLATELET ACTIVATION IN MAJOR SURGICAL STRESS - INFLUENCE OF COMBINED EPIDURAL AND GENERAL-ANESTHESIA

Platelets are activated in surgery releasing vasoactive substances suc h as serotonin and thromboxane. Platelets become temporarily hypoaggre gable during surgery followed by a postoperative hyperaggregability. L ocal anaesthetics are known to inhibit platelet function but earlier r eports are conflicting. In order to study the impact of the combined u se of general and regional anaesthesia on platelet function during maj or surgery 16 otherwise healthy patients were randomised to either gen eral anaesthesia (GA) (n=8) or GA combined with epidural anaesthesia ( GA+EPI) (n=8) for elective upper abdominal surgery. Cyclic 3'5'-adenos ine monophosphate, plasma glucose, plasma cortisol and the rate pressu re product (RPP) were markers of the stress response. ADP-induced plat elet aggregation and the release products beta-thromboglobulin, seroto nin and thromboxane 2 were measured in plasma before and during as wel l as for 3 days after surgery. A marked stress response was noted in b oth groups and epidural anaesthesia (EPI) only reduced the rate pressu re product (RPP). Platelet aggregation was reduced during surgery, a l ittle more so in the GA+EPI group. Postoperatively both groups showed significant hyperaggregability. The release products were not signific antly influenced by regional anaesthesia. In conclusion epidural as co mbined with general anaesthesia affects platelet responses to major ab dominal surgery only to a minor extent, although it may attenuate the haemodynamic response.