Optimal cycles of hepatic ischemia and reperfusion for intermittent pedicle clamping during liver surgery
T. Horiuchi, R. Muraoka, T. Tabo, M. Uchinami, N. Kimura and N. Tanigawa
Second Department of Surgery, Fukui Medical School, Japan.
OBJECTIVES: To evaluate the intermittent clamping of hepatic vessels during
liver surgery and to determine the optimal duration of ischemia and
reperfusion. PARTICIPANTS: One hundred nine adult male Sprague-Dawley rats.
METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.
