Following on from my recent post about PEEP levels and PDA shunts, this new article from Perth. The authors prospectively enrolled very immature infants (< 28 weeks) before a planned early extubation and did echocardiograms before and after. The mean airway pressure before extubation was 7 and the mean CPAP pressure afterward was 5. (Wagh D, Gill A: Is extubation associated with changes in ductal and pulmonary blood flow in extremely preterm neonates? Journal of Paediatrics and Child Health 2013, 49(12):1052-1056).
The authors did the study as they had a run of pulmonary hemorrhages in tiny babies after extubation, and they were wondering if it was the extubation that did it. We have seen a similar intermittent clustering of cases of PH, and have wondered the same thing. We have even sometimes delayed extubation because we were worried about the possibility, not so much because we thought that extubation might increase the risks, but dealing with a serious hemorrhage in an extubated baby is really problematic. Trying to intubate when there is blood flowing through the cords in a 600g baby is not simple!
In the 20 babies that they studied there was no change in the PDA diameter, left pulmonary artery flow or the PDA flow between 5 minutes before and 20 minutes after extubation, even in the 3 babies that went on to develop PH (admittedly 2 of the 3 were several days after extubation).
I don’t know if this complication is getting more frequent everywhere, but it is another reason I think for reconsidering prophylactic indomethacin which seem to reduce severe PH, at least in a secondary analysis from the TIPP trial.