Indomethacin-induced blood flow distribution in premature and full-term piglets.

Indomethacin (IND), widely used in premature infants to effect nonoperative closure of patent ductus arteriosus (PDA), has been implicated in gastrointestinal tract (GI) perforations and necrotizing enterocolitis (NEC). The vasoactive effects of IND could simultaneously affect regional blood flow distribution, specifically a decrease in intestinal blood flow. This study determined blood pressure (BP), heart rate (HR), cardiac output (CO), total peripheral resistance (TPR) and regional blood flows (mL/min/g) at baseline, 15, 60, and 120 minutes after intravenous infusion of IND (0.4 mg/kg) in three groups: preterm piglets delivered 7 to 10 days before term; 1- to 2-day-old piglets; and 7- to 14-day-old piglets. IND did not significantly affect hemodynamic parameters (BP, HR, CO, TPR) or regional blood flows to the heart, central nervous system, kidney or GI tract in the premature animals. In 1- to 2-day-old animals, a significant increase in BP and TPR occurred at 120 minutes, with significant decreases in blood flow to the GI tract in the esophagus, stomach, and rectosigmoid. In the 7- to 14-day group CO significantly decreased while TPR increased. Significant decreases in blood flow occurred throughout the GI tract, most pronounced in the small intestine and colon, essentially due to decreased mucosal blood flow. Our study indicates that indomethacin can cause selective GI tract mucosal ischemia, and that the effect is increased in the more developed animal. This effect on mucosal blood flow suggests the GI tract disturbances seen after IND administration are due to an ischemic injury to mucosa previously affected by ischemia-reperfusion injury from other stresses.