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

Abstract

Intraventricular haemorrhage (IVH) and bronchopulmonary dysplasia (BPD) are major complications of premature birth. We tested the hypotheses that prematurely born infants who developed an IVH or BPD would have high expiratory tidal volumes (V) (V > 6 ml/kg) and/or low-end tidal carbon dioxide (ETCO) levels (ETCO levels < 4.5 kPa) as recorded by respiratory function monitoring or hyperoxia (oxygen saturation (SaO) > 95%) during resuscitation in the delivery suite. Seventy infants, median gestational age 27 weeks (range 23-33), were assessed; 31 developed an IVH and 43 developed BPD. Analysis was undertaken of 31,548 inflations. The duration of resuscitation did not differ significantly between the groups. Those who developed an IVH compared to those who did not had a greater number of inflations with a high V and a low ETCO, which remained significant after correcting for differences in gestational age and birth weight between groups (p = 0.019). Differences between infants who did and did not develop BPD were not significant after correcting for differences in gestational age and birth weight. There were no significant differences in the duration of hyperoxia between the groups.Conclusions: Avoidance of high tidal volumes and hypocarbia in the delivery suite might reduce IVH development. What is known • Hypocarbia on the neonatal unit is associated with the development of intraventricular haemorrhage (IVH) and bronchopulmonary dysplasia (BPD). What is new • Infants who developed an IVH compared to those who did not had significantly more inflations with high expiratory tidal volumes and low ETCOs.

End-tidal carbon dioxide levels during resuscitation and carbon dioxide levels in the immediate neonatal period and intraventricular haemorrhage

“…We reviewed the records of infants born at less than or equal to 33 weeks of gestational age who required resuscitation in the delivery suite between March 2010 and March 2014. A certain part of their data was reported in a previous paper [3]. Ethical approval was given by the Outer London Ethics Committee for the data collection.…”

“…Furthermore, fluctuations of pCO 2 can adversely affect cerebral oxygenation and perfusion and the electrical activity of the brain [6]; such fluctuation is predictive of adverse neurodevelopmental outcomes [7]. We have demonstrated that not only high EtCO 2 levels during resuscitation in the delivery suite were associated with IVH development but also inflations resulting in larger tidal volumes and lower EtCO 2 levels [3]. Those findings were subsequently confirmed by Mian and colleagues who found that tidal volumes in excess of 6 ml/kg were associated with cerebral damage in the neonatal period [8].…”

“…The resuscitation protocol, together with the monitoring methodology, has previously been described [3]. The clinicians attending the resuscitations had all been trained in newborn life support and had received the Resuscitation Council (UK) Newborn Life Support provider certificate.…”

“…The resuscitation recordings were analysed to determine the duration of resuscitation, the number of inflations, the inflation pressure, the positive end expiratory pressure (PEEP), inflation time (Ti), mean airway pressure (MAP), expiratory tidal volume (V TE ) of each inflation and the breath-by-breath minute ventilation. The highest EtCO 2 was recorded as were the number of inflations with tidal volumes more than 6 mls/kg (high tidal volumes) or end-tidal CO 2 levels of less than 4.5 kPa (low EtCO 2 levels) and the number of inflations with both high tidal volumes and low EtCO 2 levels as previously described [3]. The degree of fluctuation of EtCO 2 (delta EtCO 2 ) during resuscitation was determined by calculating the difference between the highest and lowest EtCO 2 value during resuscitation in delivery suite.…”

“…Several studies of preterm infants have demonstrated that abnormal levels of carbon dioxide (CO 2 ) within the first few days post-delivery are associated with the development of IVH [1,2]. We recently reported that preterm infants who developed an IVH had higher endtidal CO 2 (EtCO 2 ) levels in the delivery suite during resuscitation [3]. It has not, however, been determined whether abnormal EtCO 2 levels during resuscitation of preterm infants translate into abnormal CO 2 levels over the subsequent 72 h after birth, and hence, whether it is a prolonged rather than an early insult which results in the development of IVH.…”