Lactate levels in open interstitial thermal ablation for liver tumors

Intraoperative radio frequency interstitial thermal ablation (RITA) may result in a reduction of the functional hepatic reserve. To assess this further, we evaluated perioperative lactate levels as a measure of hepatic dysfunction. Sixteen patients scheduled for open RITA (O-RITA) were enrolled in the study. Arterial lactate levels (mmol/L) were measured prior to tumor needle insertion (T0), after O-RITA completion (T1), after wound closure (T2) and 24 hrs after surgery (T3). Correlation between hemodynamic parameters including MAP, and CVP, at T0, T1, T2, T3 and the perioperative rate of lactate production were also analyzed. Total bilirubin, transaminases and international normalized ratio for prothrombin activity (INR) were measured preoperatively and postoperative at day 1, 2, 3 and 7. Data are expressed as mean +/- SD and analyzed with ANOVA. Additionally, the Duncan post hoc test was used for multiple comparisons of the differences in mean values. A p-value <0.05 was considered significant. Lactate levels did not increase significantly at time points specified above (P = NS). Similarly, hemodynamic parameters analyzed did not show any significant change at the different time points (P = NS). Total bilirubin and INR did not demonstrate statistically significant changes at the aforementioned time points. Serum transaminases peaked during the immediate postoperative period and normalized to preoperative values by one-week post surgery. These results demonstrate that O-RITA does not induce hyperlactatemia and does not reduce the functional residual liver parenchyma.