Hepatic blood flow and Cori cycle during hemorrhage in the pig

In hemorrhage, blood pressure and circulation are challenged and arterial lactate increases may be due to reductions in liver blood supply. In 12 pigs (weight 36±2 kg) hepatic blood flow was evaluated and arterial and hepatic venous blood were collected at steady state, and in response to reductions in total blood volume (2,8 ± 0,1 L) by 15%, 25% and 40%. In the prebleeding phase mean arterial pressure and heart rate were 103 ± 5 mmHg and 122 ± 8 b·min‐1 and during the blood loss they decreased and increased to 89 ± 6, 86 ± 6, 56 ± 6 mmHg and 140 ± 8, 160 ± 12, 179 ± 13 b·min‐1, respectively. Cardiac output as determined by thermodilution decreased from 5.6 ± 0.5 to 4.3 ± 0.5, 3.6 ± 0.3 and 2.3 ± 0.2 L·min‐1 and mixed venous O2 saturation from 76 ± 3 to 35 ± 9%. At moderate blood loss hepatic O2 saturation decreased from 61 ± 4 to 27 ± 3% and at a reduction in total blood volume by 40% it decreased further to 10 ± 2% with a lowest value of 1.4%. This corresponds to an equally marked reduction in hepatic blood flow. Arterial lactate measured in two pigs increased by about 2 mmol/L at each stage and lactate reached 6.2 mmol/L at 40% blood loss. In response to retransfusion of blood, mean arterial pressure, heart rate and cardiac output were re‐established but lactate remained elevated. Even a small blood loss with little change in cardiac output hepatic blood flow is markedly reduced and arterial lactate increases indicating that Cori cycle becomes impaired in progressive hemorrhage.