Page 68 - Physiological based CPAP for preterm infants at birth Tessa Martherus

Chapter 3
Abstract Background
Preterm infants are commonly supported with 4-8 cmH2O continuous positive airway pressures (CPAP), although higher CPAP levels may improve functional residual capacity (FRC).
Methods
Preterm rabbits delivered at 29/32 days (~26-28 weeks human) gestation received 0, 5, 8, 12, 15 cmH2O of CPAP or variable CPAP of 15 to 5 or 15 to 8 cmH2O (decreasing ~2 cmH2O/min) for up to 10 min after birth.
Results
FRC was lower in the 0 (6.8 (1.0-11.2) mL/kg) and 5 (10.1 (1.1-16.8) mL/kg) compared to the 15 (18.8 (10.9-22.4) mL/kg) cmH2O groups (p=0.003). Fewer kittens achieved FRC >15 mL/kg in the 0 (20%), compared to 8 (36%), 12 (60%) and 15 (73%) cmH2O groups (p=0.008). While breathing rates were not different (p=0.096), apnoea tended to occur more often with CPAP <8 cmH2O (p=0.185). CPAP belly and lung bulging rates were similar whereas pneumothoraces were rare. Lowering CPAP from 15 to 5, but not 15 to 8 cmH2O, decreased FRC and breathing rates.
Conclusion
In all, 15 cmH2O of CPAP improved lung aeration and reduced apnoea, but did not increase the risk of lung over-expansion, pneumothorax or CPAP belly immediately after birth. FRC and breathing rates were maintained when CPAP was decreased to 8 cmH2O.
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