Premature Infants Show Consistently Good Lung Compliance During Conventional Mechanical Ventilation

Introduction: Many extremely small preterm infants need to be intubated and mechanically ventilated during their intensive care stay. Animal studies indicate that lung compliance can deteriorate rapidly under conventional ventilation. This study investigated whether this presumed deterioration in compliance actually occurs in extremely small preterm infants.

Methods: Data from 56 conventionally ventilated preterm infants born from 2016 to 2022 at 25.22 weeks' gestation (±1.47) and 678.71 g (±138.14) birth weight were retrospectively analysed. This study investigated how dynamic compliance changed over the course of ventilation.

Results: The infants were conventionally ventilated from 7.25 days of life (±5.59) for 2.68 days (±2.35). Compliance at the beginning was 0.37 mL/cmH₂O/kg (±0.17), after 1 h 0.38 mL/cmH₂O/kg (±0.16), after 3 h 0.40 mL/cmH₂O/kg (±0.20), after 6 h 0.44 mL/cmH₂O/kg (±0.23), after 24 h 0.46 mL/cmH₂O/kg (±0.17) and after 48 h 0.43 mL/cmH₂O/kg (±0.13). The increase in compliance compared to baseline was statistically significant after 12 (p = 0.016) and 24 h (p = 0.042). Ventilation was performed with a PEEP of 7.51 cmH₂O (±1.16) and a peak pressure of 20.64 cmH₂O (±2.73). All received surfactant after birth and 21 (37.5%) also at the start of conventional ventilation.

Conclusion: During conventional ventilation in premature infants after administration of surfactant and with basically recruited lungs, no deterioration in compliance was observed either in the short or long term. The PEEP of almost 7.5 cmH₂O used may have contributed to the fact that the deterioration described in the animal model did not occur in the preterm infants.