The effect of aminophylline on gastrointestinal blood flow and oxygen metabolism in the conscious newborn lamb

Aminophylline, widely used in the neonatal period, has been reported to be associated with necrotizing enterocolitis. We hypothesized that aminophylline might alter gastrointestinal blood flow and oxygen delivery. The effects of this drug on gastrointestinal (GI) blood flow and oxygen delivery, consumption, and extraction were examined using the radioactive microsphere method in ten chronically catheterized, unanesthetized lambs aged 5-12 days. While cardiac output and systemic oxygen consumption did not change, we found statistically significant increases (p < 0.05) in small intestinal blood flow as a function of lamb weight and as a percentage of cardiac output. Splanchnic oxygen consumption also increased significantly. The oxygen reserve available to the GI tract can be compromised by aminophylline at levels similar to those used in the human neonate for treatment of apnea.