Alterations in plasma oxidative stress markers after laparoscopic operations of the upper and lower abdomen.

The patient's position during laparoscopic surgery can have a clinically relevant effect on lower limb and splanchnic circulation; this factor has not yet been investigated with respect to oxidative stress markers. In order to assess this effect, a prospective clinical trial was designed wherein 2 groups of patients were studied. In group A, 15 patients underwent upper abdominal nonhepatobiliary operations (13 modified Nissen fundoplications and 2 Taylor vagotomies) in the head-up position. In group B, 15 patients underwent lower abdominal operations (10 laparoscopic colectomies and 5 inguinal hernia repairs) in the head-down position. The pneumoperitoneum was maintained at 14 mm Hg in all cases. Plasma concentrations of thiobarbituric-acid reactive substances (TBARS), a marker of lipid peroxidation, plasma total antioxidant status (TAS), and serum uric acid concentrations were measured preoperatively, 5 minutes after deflation of the pneumoperitoneum, and 24 hours postoperatively. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) serum activities were measured preoperatively and 24 hours postoperatively. In group A, there was a significant increase in TBARS levels (p<0.005) immediately after deflation of the pneumoperitoneum and a significant decrease in TAS and uric acid levels (p<0.005) in the first postoperative day. There was also a significant postoperative elevation in both ALT and AST activities (p<0.001). In group B, no significant increase was found in postoperative TBARS or transaminase levels. TAS and uric acid levels decreased significantly in the first postoperative day (p<0.05) and (p<0.005, respectively). In conclusion, these results show that a combination of pneumoperitoneum and the head-up position causes significant increase in lipid peroxidation, decrease in plasma TAS, and increase in transaminases. The mechanism responsible for these events could be the low-flow ischemia-reperfusion syndrome induced by the pneumoperitoneum and aggravated by the head-up position.