NEONATAL SOCIETY ABSTRACTS
A randomized trial comparing the effects of Volume Guided Ventilation and Synchronised Intermittent Positive Pressure Ventilation on the cerebral and mesenteric circulation following surfactant administration
Presented at the Neonatal Society 2007 Summer Meeting (programme).
Sinha AK, Kempley ST
Royal London Hospital, Barts and the London NHS Trust, London, UK
Background: Natural surfactant administration in infants on conventional pressure limited timecycled ventilation results in a rapid decrease in anterior cerebral artery (ACA) velocit (1). The mechanism of this change is unclear, but it may be related to rapid improvement in lung compliance following natural surfactant administration. A volume-guided ventilation modality on the Draeger Babylog 8000+ ventilator can limit the volume of gas delivered during rapid changes in lung compliance.
Aim: To examine the haemodynamic effects of exogenous porcine surfactant (Curosurf, Dose 200mg/kg), administration using conventional pressure-limited time-cycled ventilation (SIPPV) with administration using volume-guided ventilation (VG).
Methods: Babies ventilated for RDS were randomized to receive SIPPV or VG during surfactant administration after informed written parental consent. Doppler measurements from the ascending portion of the anterior cerebral artery (ACA) and proximal part of superior mesentric artery (SMA) were obtained by standard method (2). Blood flow velocity was derived from the time-averaged mean of the peak velocity envelope averaged over at least 6 cardiac cycles. Measurements were obtained prior to surfactant administration and for one hour afterwards. ANOVA was used for statistical analysis.
Results: Gestation, birthweight, baseline arterial CO2 and mean BP were similar in the 2 groups (Table 1). There was no significant difference in ACA and SMA velocity between the 2 groups. Babies on SIPPV showed a reduction in ACA blood flow velocity at 1 and 5 minutes after surfactant administration. ANOVA showed a significant time effect on ACA blood flow velocity in the SIPPV group but not in the VG group.
Conclusion: Volume guided ventilation may attenuate some of the cerebral circulatory changes seen after surfactant administration. This warrants further investigation to establish its clinical relevance.
1. Cowan F. Arch Dis Child 1991; 66: 1105-9 2. Murdoch E. Acta Paediatrica 1998; 87: 411-5