Optimal cycles of hepatic ischemia and reperfusion for intermittent pedicle clamping during liver surgery

To evaluate the intermittent clamping of hepatic vessels during liver surgery and to determine the optimal duration of ischemia and reperfusion.

One hundred nine adult male Sprague-Dawley rats.

Partial (70%) ischemia of the rat liver was induced by clamping of the left pedicle. To assess the influence of a single period of ischemia, the rats were divided into three groups for 15, 20, or 30 minutes of ischemia. To evaluate the influence of reperfusion duration, reperfusion following 15-minute ischemia was repeated 10 times in three groups for 5, 10, or 15 minutes of reperfusion duration. Hepatic tissue blood flow (HTBF) and hepatic beta-adenosine triphosphate (beta-ATP) levels were measured serially, and histopathological specimens were studied following single episodes of ischemia. In the reperfusion experiments, hepatic enzyme levels, survival rates, HTBF, beta-ATP, and histopathological findings were analyzed.

When the single period of ischemia was 15 minutes, HTBF and beta-ATP levels recovered after 1 hour of reperfusion. However, both HTBF and beta-ATP levels did not return to preischemic levels when the duration of the ischemia was 20 or 30 minutes. Levels of beta-ATP and HTBF were higher, with improvement in both the histopathological findings and the survival rate, when the duration of the repeated reperfusion periods was 15 minutes, compared with 5 or 10 minutes.

The maximum period of ischemia without irreversible damage was 15 minutes in rat liver. The damage was less severe when the duration of the repeated reperfusion periods was 15 minutes rather than 5 or 10 minutes.