Background: The interest of studying colloid osmotic pressure (COP) in neonates is based on a possible relation between low COP and severity of neonatal respiratory distress.
Population and methods: Because this relation has not been accurately established, COP was prospectively measured at birth in 84 infants: 35 with respiratory distress syndrome treated with mechanical ventilation (group RD+: GA = 34.5 +/- 3.5 weeks; BW = 2,190 +/- 830 g); 49 free of severe respiratory disease (group RD-: GA = 37.5 +/- 2.5 weeks; BW = 2,720 +/- 655 g).
Results: On day one after birth COP was significantly lower in the RD+ group (15.0 +/- 2.2 mmHg) as compared with that in the RD- group (17.9 +/- 2.5 mmHg), and was negatively correlated with mean oxygenation index (OI) on day one, with the highest OI over the first five days of life, and with total duration of oxygen support (P < 0.05). COP was significantly reduced in the neonates with systemic hypotension on day one (P < 0.05).
Conclusions: These results confirm a correlation between COP at birth and incidence and severity of neonatal respiratory distress. The relationship between low COP and systemic hypotension suggests an important role of COP in the ability of maintaining volemia. This study stresses the strong relationship between water homeostasis and neonatal respiratory distress. Nevertheless, it does not allow to conclude that modifying COP is necessary to improve neonatal respiratory disease.