Fluid handling and blood flow patterns in neonatal respiratory distress syndrome versus transient tachypnea: a pilot study

BACKGROUND: Cardiovascular and renal adaptation in neonates with Respiratory Distress Syndrome (RDS) and Transient Tachypnea of the Newborn (TTN) may be different. METHODS: Neonates ≥32 weeks were diagnosed with RDS or TTN based on clinical, radiologic and lung sonographic criteria. Weight loss, feeding, urine output, and sodium levels were recorded for the first 3 days, and serial ultrasounds assessed central and organ Doppler blood flow. A linear mixed model was used to compare the two groups. RESULTS: Twenty-one neonates were included, 11 with TTN and 10 with RDS. Those with RDS showed less weight loss (− 2.8 +/− 2.7% versus − 5.6 +/− 3.4%), and less enteral feeds (79.2 vs 116 ml/kg/day) than those with TTN, despite similar fluid prescription. We found no difference in urine output, or serum sodium levels. Doppler parameters for any renal or central parameters were similar. However, Anterior Cerebral Artery maximum velocity was lower (p = 0.03), Superior Mesenteric Artery Resistance Index was higher in RDS, compared to TTN (p = 0.02). CONCLUSION: In cohort of moderately preterm to term neonates, those with RDS retained more fluid and were fed less on day 3 than those with TTN. While there were no renal or central blood flow differences, there were some cerebral and mesenteric perfusion differences which may account for different pathophysiology and management.