RESUMEN
Storage of blood in acid-citrate-dextrose (ACD) solution gradually depletes red cell 2,3-diphosphoglycerate (DPG) and increases the affinity of hemoglobin for oxygen. We examined the effect of exchange transfusion of DPG-depleted blood on mesenteric blood flow and oxygen consumption in dogs subjected to endotoxin shock. Two groups of 6 dogs each were anesthetized and subjected to exchange transfusion with either fresh ACD blood or 21-day-old ACD blood prior to administration of Escherichia coli endotoxin (2 mg/kg). Mesenteric blood flow, arteriovenous oxygen content difference and systemic arterial blood pressure were monitored continuously before and for 60 min after endotoxin. Mesenteric blood flow was reduced from 250 +/- 21 ml/min before endotoxin to 114 +/- 15 ml/min at 5 min, 157 +/- 29 ml/min at 30 min, and 112 +/- 17 ml/min at 60 min after endotoxin in the dogs exchanged with fresh blood. Corresponding values for intestinal oxygen consumption were 10.4 +/- 1.0, 7.5 +/- 0.8, 8.4 +/- 1.0, and 6.8 +/- 0.7 ml/min. In dogs transfused with 21-day-old blood, pre-endotoxin blood flow was 208 +/- 2ml/min and declined to 115 +/- 12, 93 +/- 5, and 80 +/- 8 ml/min at 5, 30, and 60 min post-endotoxin. Corresponding values for intestinal oxygen consumption were 8.1 +/- 0.9, 6.6 +/- 0.7, 6.2 +/-0.5, and 5.5 +/- 0.7 ml/min. There was no significant difference (p greater than 0.1) in responses of blood flow or oxygen consumption to endotoxin shock between the two groups of dogs. These findings indicate that exchange transfusion with DPG-depleted blood does not impair oxygen extraction by the ischemic intestine.