Tolerance of the liver to intermittent Pringle maneuver in hepatectomy for liver tumors

Abstract

Background: Hepatectomy can be performed with a low mortality rate, but massive hemorrhage during the operation remains a potentially lethal problem. The Pringle maneuver is traditionally used during hepatectomy to reduce blood loss, but the effect on the metabolic function of hepatocytes is potentially harmful. Although our randomized study showed that an intermittent Pringle maneuver is safe and effective during hepatectomy, the upper limit of the duration of the Pringle maneuver is not known. Hypothesis: The liver can tolerate intermittent Pringle maneuver if the duration is not excessive. Design: From July 20, 1995, to November 25, 1997, 112 patients underwent hepatectomy for liver tumors. The data of 50 patients who had hepatectomy without the Pringle maneuver were compared with those of 62 patients who had a liver transection using a Pringle maneuver for 20 minutes and a 5-minute clamp-free interval. The data were collected prospectively. Main Outcome Measures: The surface area of liver transection was measured, and blood loss during liver transection per centimeter square of transection area was calculated. Routine liver biochemical tests, arterial ketone body ratio (AKBR), and plasma cytokine-interleukin (IL) 1α, 1β, 2, and 6, and tumor necrosis factor α-levels were measured before and after the operation. The morbidity and hospital mortality rates were also compared among the patients with different ischemic durations and those without an intermittent Pringle maneuver. Setting: Tertiary referral center. Results: The cutoff point of accumulated ischemic time that induced substantial liver damage, as shown by the postoperative recovery rate of the AKBR, was found to be 120 minutes. Compared with the control group, the patients whose accumulated ischemic time was shorter than 120 minutes had less blood loss related to transection area (10 mL/cm2 vs 22 mL/cm2; P < .001), less blood transfused (0 L vs 0.6 L; P = .004), a shorter transection time related to transection area (2.0 min/cm2 vs 2.8 min/cm2; P = .002), a significantly higher AKBR in the first 2 hours after liver transection, an equal recovery rate of the AKBR, and a comparable increase of the plasma level of IL-6 postoperatively. For the patients whose accumulated ischemic time was longer than 120 minutes, blood loss from the transection area was less than for the control group (14 mL/cm2 vs 22 mL/cm2; P < .05), but the transection time related to the transection area and the blood transfusion volume did not differ from those of the control group. Furthermore, they had a significantly lower recovery rate of the AKBR and higher plasma levels of IL-6 postoperatively than the control group. Conclusion: The upper limit of tolerance of the liver to intermittent Pringle maneuver is 120 minutes.