Does epidural anaesthesia reduce the incidence of postoperative oxygen desaturation episodes in patients undergoing open abdominal aortic aneurysm repair?

BACKGROUND

Postoperative desaturation can lead to severe hypoxaemia and even tissue hypoxia, followed by cardiological and neurological complications. Opioid usage is the one of the most important risk factors of postoperative desaturation and hypoxemia. Epidural anaesthesia is recommended for vascular surgery for many reasons; the reduction or elimination of opioid doses is one reason. The aims of the study were to evaluate the incidence of desaturation episodes in patients after surgical procedures with abdominal aortic clamping, to determine whether the episodes in question lead to clinical symptoms of hypoxia and to determine whether epidural anaesthesia decreases the incidence of desaturation episodes.

METHODS

After abdominal aortic repair, 58 patients who did not have any respiratory disease, were classified as ASA II-III, and were aged from 46 to 80 years were observed in the ICU during spontaneous breathing with oxygen supplementation. Non-invasive O₂ saturation measurements were taken continuously, and all desaturation incidents (defined as O₂ saturation ≤ 93% for 4 min) were noted. Patients were divided into two equal groups: A - epidural blockade used after the operation for pain relief and B - intravenous opioids administered during the postoperative period. We evaluated and compared the desaturation frequency during the postoperative period.

RESULTS

Desaturation was observed among 26 (89%) patients in group A and 27 (93%) patients in group B. There were no statistical differences among the groups (P = 1.0). Severe hypoxemia (O₂ saturation ≤ 84%) was observed among 7 (24.1%) patients in group A and 10 patients in group B (34.5%) (P = 0.38). Clinical symptoms of hypoxia were similar in both groups (P = 1.0).

CONCLUSIONS

Epidural anaesthesia did not protect against postoperative desaturation. Though oxygen therapy was used, desaturation was observed in approximately 90% of patients.