Background and aims
Sustained inflations (SI) during postnatal stabilisation of preterm infants may promote alveolar recruitment and improve gas exchange. The aim was to investigate whether spontaneous breathing during SI influences alveolar recruitment and gas exchange.

Methods
For this post-hoc-analysis, respiratory function parameters of preterm infants enrolled into two trials in Graz and Edmonton were analysed. The initial respiratory management consisted of 1-3 SI using T-Piece-devices. Respiratory function monitoring was performed by Florian Monitor (Acutronic) or Respironics NM3 (Philips). Group differences of the first detected end-tidal CO2 (ETCO2), expiratory (VTe) and inspiratory tidal volumes (VTi) during and one minute after the initial SI in infants with and without spontaneous breathing during SI were evaluated.

Results
Twenty-seven preterm infants with mean gestational age of 28weeks (range 23-32) and birth weight of 1209±455g were included. Mean SI duration was 21.1±7.2sec, peak inspiratory pressure was 33.0±3.3cmH2O, and plateau pressure was 25.2±1.4cmH2O. 
In preterm infants with (n=17) and without (n=10) spontaneous breathing during SI, the median first ETCO2 detection was observed 6.2±9.1sec and 20.3±21.5sec after SI initiation (p=0.018), and the median time until the ETCO2 level firstly exceeded 20mmHg was 23.1±92.6sec and 111.0±163.2sec after SI initiation (p=0.023), respectively.
There were no significant differences between groups when either the cumulative VTi and VTe during SI, or the VTe at the end of SI, or the VTi and VTe in the first minute after SI were compared. 

Conclusion
Preterm infants who spontaneously breathe during SI have earlier ETCO2 compared to apnoeic infants suggesting improved alveolar recruitment and gas exchange.

RESPIRATORY FUNCTION MONITORING IN PRETERM INFANTS WITH SPONTANEOUS BREATHING OR APNOEA DURING SUSTAINED INFLATIONS AFTER BIRTH