Gastric emptying in post-thoracotomy patients receiving a thoracic fentanyl-bupivacaine epidural infusion

Abstract

Background and objective: The effect of anaesthesia and surgery on gastric emptying is not constant, and this has not been previously studied in patients undergoing thoracotomy for lung resection with a bupivacaine-fentanyl epidural infusion for analgesia. There are important implications in this group of patients with regards to the recommencement of important oral medication as well as the risks of aspiration of gastric contents. The study examined gastric emptying in these patients until the second postoperative day.

Methods: In a prospective repeated measures study, the effect of fentanyl-bupivacaine epidural analgesia at the mid-thoracic level on gastric emptying was assessed in 11 patients undergoing thoracotomy for lung resection. Gastric emptying was measured using a paracetamol absorption technique. Patients acted as their preoperative controls and were assessed 4 h postoperatively and on the second postoperative day.

Results: The mean (SEM) maximum plasma paracetamol concentration was 204.6 (20.4) μmol L⁻¹ before operation, 61 (9.5) μmol L⁻¹ 4 h postoperatively and 114.3 (22.6) μmol L^−l on the second postoperative day. Mean (SEM) paracetamol absorption at 120 min was 15 638 (1441) μmol min L^−l preoperatively, 5731 (821) μmol min L^−l4 h postoperatively and 9325 (1759) μmol min L^−l on the second postoperative day. Postoperative values were significantly (P < 0.005) less than the preoperative values.

Conclusions: After thoracotomy, gastric emptying was delayed until at least the second postoperative day in patients receiving mid-thoracic fentanyl-bupivacaine epidural analgesia.