Alterations in respiratory status: early signs of severe necrotizing enterocolitis

Necrotizing enterocolitis (NEC) presents with well-recognized signs of intestinal inflammation such as bilious vomiting, bloody stool, abdominal distension, and tenderness. The authors observed otherwise unexplained changes in the respiratory status requiring increased respiratory support during the 24 hours before direct evidence of the intestinal disorder in patients with severe NEC.

To study this observation the authors collected data on 10 consecutive patients in whom NEC required an operation.

Eight of these patients were recovering from respiratory distress syndrome (RDS). During the 24 hours before any direct sign of intestinal dysfunction seven of these eight had a respiratory prodrome needing increased respiratory support. Two patients required intubation and mechanical ventilation. Five needed increased supplemental oxygen. This prodrome included decreased oxygenation in seven, increased respiratory rate in five, and increased PCO2 in five, preceded by hypocarbia in three.

These changes in the respiratory condition revisit the concept of high output respiratory failure. This term was introduced to describe the respiratory failure in adult patients who suffer acute intestinal illness. Increased metabolic demand from the intestinal illness was thought to stress the ability of the patient to delivery oxygen and remove carbon dioxide. The ability of the respiratory system to meet the increased demands is limited by the intestinal dysfunction itself (abdominal pain and distension). In our patients recovering from RDS the pulmonary reserve is inherently limited. Because they are carefully monitored, it is easy to retrieve evidence of respiratory changes that precede the direct signs of intestinal disease. In the earliest stages of intestinal illness before the direct signs of intestinal dysfunction, these patients often manifest unexplained signs of respiratory compensation and decompensation and require increased respiratory support. Regardless of the pathophysiology, these alterations in respiratory status represent an early warning sign of NEC.