Serum lactate in liver resection with intermittent Pringle maneuver: the "square-root- shape.

Background: Serum lactate (sLac) concentration during liver resection with intermittent hepatic hilum clamping (i.e. Pringle maneuver, PM) was retrospectively investigated.

Methods: A total of 133 patients who underwent liver resection were enrolled. We analyzed the sLac peri-operatively. Correlations were searched between the PM and lactatemia and its variations (i.e. lactate clearance, cLac) and other factors which it might be related to. Lactatemia in triplicate intraoperatively was recorded, just after the awakening, and 1 and 2 h later. The cLac between two consecutive measurements [(sLac - sLac )/sLac ] was computed.

Results: A reliable dependence of sLac was found from the cumulative PM. More than 76 min of cumulative Pringle Time (cPT) exposed patients to a worse cLac at the end of the resection phase (P < 0.0001). We found cPT >76 min, global operation time >365 min and bleeding >225 ml to be predictors of hyperlactatemia (sLac >4 mmol/L). Normal liver resulted as a risk factor for hyperlactatemia and steatosis was not (P = 0.030 vs. P = 0.325). Finally, cLac showed a "square-root- shape, just like the mathematical operation sign.

Conclusions: Lactatemia during liver resection depends on the duration of PM, bleeding and the duration of the operation. Normal liver may expose the patient to the risk of hyperlactatemia.