Effects of esmolol- and sodium nitroprusside-induced controlled hypotension on hepatocellular integrity in patients undergoing endonasal sinus surgery

Background: Controlled hypotension (CH) is an established method to reduce intraoperative bleeding. The aim of the study was to investigate the influence of CH induced by sodium nitroprusside (SN) or esmolol on hepatocellular integrity. Methods: Prospective, randomized, controlled study. 45 patients scheduled for elective endonasal sinus surgery were allocated to one of the following three groups: 1. SN-group (n = 15): CH induced by SN. 2. Esmolol-group: CH induced by esmolol. In both groups mean arterial pressure was kept between 50-55 mmHg. 3. Control group (n = 15): no hypotension was performed (MAP > 70 mmHg). The cytosolic liver enzyme alpha-glutathione S-transferase (alpha-GST) and standard liver enzymes (alanine aminotransferase, aspartate aminotransferase, gamma-glutamyltransferase) were measured at the following timepoints: preoperative (TO), at the end of surgery (T1), 2 h (T2), 24 h (T3) and 48 h (T4) postoperatively. Results: alpha-GST concentrations were significantly higher in patients receiving CH (SN: 5,9 +/- 3,4; Esmolol: 6,5 +/- 2,8 mug/L) in comparison with controls (2,5 +/- 1,4 mug/L) at T1. Already at T2 there were no significant differences between the three groups. Standard liver enzymes showed a similar course in all groups. Conclusion: The small but significant increase of alpha-GST in both hypotension groups suggests that hypotension induces a mild damage of hepatocellular integrity.