ENDOTOXIN AND TRANSIENT HYPOXIA CAUSE SEVERE ACIDOSIS IN THE PIGLET

Purpose: Both hypoxia and gram-negative sepsis are thought to play a r ole in the development of necrotizing enterocolitis (NEC). Endotoxin, a lipopolysaccharide (LPS), is a potent mediator of gram-negative seps is. The author investigated the effect of LPS and hypoxia on arterial and mesenteric venous blood gas values in a piglet model. Methods: 16 piglets (mean age, 9 days; mean weight, 3.2 kg) were anesthetized and mechanically ventilated. Catheters were placed in the aorta and the su perior mesenteric vein (SMV). After a 30-minute stabilization period, piglets were randomly assigned to four experimental groups: normoxic v entilation (FIO2, 0.21), normoxic ventilation and LPS infusion (200 mu g/kg, intravenously), hypoxic ventilation (FIO2, 0.10 for 20 minutes) , or hypoxic ventilation and LPS infusion. All subjects were then moni tored for an additional 30 minutes (recovery period). Multiple, paired blood gas samples were obtained from the aorta and SMV during the sta bilization, experimental, and recovery periods. Results: Piglets subje cted to both hypoxia and LPS experienced a much more severe acidosis i n both the aorta (pH, 7.10 +/- 0.08) and SMV (pH, 7.03 +/- 0.09) than piglets subjected to either hypoxia or LPS alone (P <.05). In addition , LPS lowered the arterial oxygen saturation in piglets exposed to acu te, transient hypoxia (36 +/- 4% v 59 +/- 12%, P<.05). Conclusion: Thi s study suggests that the combination of transient hypoxia and gram-ne gative sepsis may act synergistically to produce both a severe acidosi s and decreased tissue oxygenation. Copyright (C) 1997 by W.B. Saunder s Company.