The effects of sodium nitroprusside-induced hypotension on splanchnic perfusion and hepatocellular integrity

The purpose of our study was to investigate the effects of sodium nitroprus side-induced hypotension on splanchnic perfusion and hepatocellular integri ty. Thirty patients undergoing radical prostatectomy were allocated randoml y to a sodium nitroprusside (SNP) or control group (control). Regional pCO( 2) was measured using gastric tonometry, and the regional to arterial diffe rence in partial pressure of CO3 and intramucosal pH were calculated. The c ytosolic liver enzyme ol-glutathione S-transferase and standard liver enzym e markers (alanine aminotransferase, aspartate aminotransferase, and gamma- glutamyltransferase) were also measured. Mean arterial pressure in the SNP group was 50 mm Hg for 97 min during surgery. A significant increase from b aseline in regional pCO(2) (from 40.0 +/- 4.2 mm Hg to 45.3 +/- 1.3 mm Hg) and regional to arterial difference in partial pressure of CO2 (from 4.1 +/ - 1.1 mm Hg to 9.7 +/- 1.4 mm Hg) was seen at 90 min after skin incision on ly in the SNP group. Intramucosal pH decreased significantly from 7.40 +/- 0.02 to 7.35 +/- 0.03 during the same period in this group. Tonometric vari ables returned to baseline values within 2 h postoperatively. alpha-Glutath ione S-transferase concentrations increased significantly in the SNP group from baseline to peak concentrations at the end of surgery (SNP: 9.93 +/- 4 .94 mu g/L; control: 5.85 +/- 1.86 mu g/L). A return to baseline values was seen 24 h postoperatively. No significant changes in standard liver enzyme markers were seen throughout the study period. It is concluded, that splan chnic perfusion was transiently impaired during controlled hypotension. Thi s is supported by significant changes in tonometric data. Increased serum l evels of alpha-glutathione S-transferase may indicate a disturbance in hepa tocellular integrity. Implications: We studied gastric mucosal tonometry an d the cytosolic liver enzyme alpha-glutathione S-transferase to evaluate th e effects of controlled hypotension induced by sodium nitroprusside on spla nchnic perfusion and hepatocellular integrity. Splanchnic perfusion decreas ed and alpha-glutathione S-transferase increased during and after a hypoten sive period, but returned to baseline values within the first postoperative day, indicating a transient impairment of splanchnic perfusion and hepatoc ellular integrity.