Surfactant (S) replacement therapy for hyaline membrane disease (HMD) has been implicated in increased shunting across the patent ductus arteriosus(PDA) secondary to drop in PAP. However this is controversial based on limited human studies. Also effects of synthetic versus natural surfactants on PAP is unkown

Thirty-four paired Doppler echocardiographic studies (DE) were performed on twenty-nine ventilated infants with HMD pre and 1 hour post S as part of a blinded randomized multicentre trial of Exosurf vs BLES in premature infants with established HMD with a/A ratio < 0.22. Pulsed Doppler velocity profile was obtained across the PDA and digitized to obtain mean velocity across PDA. Mean pressure gradient across PDA was calculated using the modified Benouli's equation ΔP = 4 V2 (where ΔP = pressure gradient mm Hg, V = mean velocity m/sec). Simultaneous arterial blood pressure (SAP) was obtained from an indwelling arterial line. PAP was calculated by subtracting ΔP from SAP. No ventilatory changes were made between the paired studies. Arterial blood gases were collected simultaneously. Results are shown as mean±SD of PAP to SAP pressure ratio.

Conclusion: There were no significant changes in PAP/SAP after either surfactant. However there is a trend towards a fall in PAP following BLES administration. Table

Table 1 No caption available.
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