Relationship of resuscitation, respiratory function monitoring data and outcomes in preterm infants

Intraventricular haemorrhage (IVH) and broncho-pulmonary dysplasia (BPD) are major complications of premature birth. Studies from infants receiving neonatal intensive care have demonstrated that hypocarbia is associated with the development of IVH and BPD. Hypocarbia can result from excessive mechanical ventilation. 

In this retrospective study, the authors tested the hypotheses that prematurely born infants who developed an IVH or BPD would have high expiratory tidal volumes (V_TE) (V_TE > 6 ml/kg) and/or low-end tidal carbon dioxide (ETCO2) levels (ETCO2 levels < 4.5 kPa) as recorded by respiratory function monitoring or hyperoxia (oxygen saturation (SaO2) > 95%) during resuscitation in the delivery room. 

During resuscitation, a respiratory function monitor was set to display tidal volume, flow, inflation pressures and ETCO2 levels. For analysis, there were in total 150 recordings available, but 56 had to be excluded due to artefacts in tidal volumes of ETCO2 traces and 24 excluded due to large leak. There were 31 548 inflations assessed from recordings of the remaining 70 infants.  

The infants who developed IVH (31 infants) received more inflations during the resuscitation in the delivery room resulting in high tidal volume (>6 mls/kg) or a low ETCO2 (<4.5 Kpa). 

In their discussion, the authors point out that the wide range of tidal volumes and ETCO2 levels suggest that the clinical team were not routinely using the displayed information to guide the level of support. Many pediatric trainees are unaware of the size of a ”normal” tidal volume. 

Conclusion

In conclusion, infants who developed IVHs were resuscitated with significantly more inflations resulting in large tidal volumes and low ETCO2 levels after correcting for differences in gestational age and birth weight than those who did not develop IVH.