Effects of halothane and enflurane on prostanoid concentrations in operation patients

Prostanoid formation may be stimulated by different events associated with anaesthesia and operation, such as positive pressure ventilation and tissue trauma. We investigated the effects of halothane and enflurane on plasma and serum prostanoid concentrations in 19 patients scheduled for minor operations. In 9 abdominal surgery patients, thromboxane B₂ concentrations were followed up to the fifth postoperative day. Prostanoid determinations were carried out with RIA. In general, the changes in prostanoid concentrations in patients anaesthetised with halothane or enflurane were similar. During spontaneous breathing there was a decrease in plasma PGE₂ and TxB₂ concentrations. During intermittent positive pressure ventilation and operation, PGE₂ and TxB₂ concentrations rose but 6-keto-PGF_1α did not. After operation, TxB₂ concentrations remained elevated but the other prostanoids returned to preoperative values. TxB₂ concentrations decreased to the preoperative level on the first postoperative day. The elevated TxB₂ concentrations during and after surgery can be regarded, in some patients, as a potential risk factor for cardiovascular and thromboembolic complications.