Coagulation, blood loss and platelet activation during isoflurane or sevoflurane anesthesia

Abstract

INTRODUCTION: Sevoflurane has been shown to inhibit platelet aggregation1,2. This study investigates whether sevoflurane causes different coagulation changes, blood loss and platelet activation compared to isoflurane. METHODS: With IRB approval, patients undergoing elective joint arthroplasty were recruited. Patients discontinued their NSAID and no LMWH were used. They were allocated randomly to receive either sevoflurane (Group S) or isoflurane (Group I) anesthesia. Opioids and femoral blocks were employed at the discretion of the anesthesiologists. Intravenous fluids were prescribed using a strict protocol and red cell transfused if hemoglobin dropped below 8g/dL. All operations were performed by the surgeon authors (WMT & KYC) using a standardized technique. Blood is collected for complete blood count, prothrombin time, activated partial thromboplastin time, thrombelastography (TEG®) and plasma soluble CD40 ligand (sCD40L) concentration before induction and in PACU. Intraoperative and postoperative blood loss was recorded. Native TEG® measurement was performed using the TEG® 5000 (Haemoscope Corp, IL, USA). sCD40L was measured using platelet poor plasma (PPP) with a commercial ELISA kit (R&D Systems, MN, USA). PPP was prepared by centrifugation of EDTA blood at 10,000g, 4 oC for 10 minutes. RESULTS: 20 patients were recruited in each group (M/F = 4/16 and 6/14; age = 65±15 and 64±12, Group S and I). There was no difference in all TEG® or other coagulation parameters between the groups (table1), nor in blood loss, fluid requirement or change in Hb (table2).[table1][table2]No patient required transfusion. However patients in Group S had significantly lower plasma sCD40L concentrations at end of surgery.[figure1]Conclusion Sevoflurane reduces platelet activation without impairing coagulation or increasing blood loss compared to isoflurane. REFERENCES: 1. Anesthesiology 1996;85:1447. 2. Can J Anaesth 1997;44:1157.