Intestinal blood flow and oxygen consumption: responses to hemorrhage in the developing piglet.

Age-related differences in the intestinal hemodynamic and oxygenation responses to arterial hemorrhage were studied in anesthetized and ventilated 1-d, 3-d, 1-wk, and 2-wk-old piglets. Steady-state values of superior mesenteric blood flow, venous pressure, and arteriovenous oxygen difference were obtained before and after 5 and 10 mL/kg arterial hemorrhage. With 5 mL/kg hemorrhage, intestinal blood flow fell significantly below baseline values, but oxygen extraction increased to maintain oxygen uptake at control levels in all age groups. In contrast to 2-wk-old piglets, the intestine of 1-d, 3-d, and 1-wk-old animals could not compensate for the greater reduction in blood flow produced by 10 mL/kg hemorrhage, resulting in a significant reduction in oxygen uptake. Thus, the intestine of developing piglets up to 1 wk of age appears to be at greater risk for tissue hypoxia induced by arterial hemorrhage than that of older animals.