Pulmonary artery peak Doppler velocity as an estimator of systemic blood flow and predictor of intraventricular haemorrhage in preterm infants: a multicentre prognostic accuracy study.

Objectives: (1) To assess how main pulmonary artery peak Doppler velocity (MPAVpeak) correlates with right ventricular output (RVO) and superior vena cava flow (SVCf), (2) to assess the reproducibility of MPAVpeak and (3) to test the prognostic accuracy of MPAVpeak to predict high-grade intraventricular haemorrhage (IVH) or death at seventh day of life.

Design: Prospective cohort study.

Setting: Nine third-level neonatal units in Spain.

Patients: Preterm infants <33 weeks of gestational age who had standardised measurements of MPAVpeak, RVO and SVCf at 6, 12 and 24 hours of life.

Main outcome measures: High-grade IVH or death at seventh day of life.

Results: One hundred and ninety preterm infants with a median (IQR) gestational age and birth weight of 29.7 weeks (27.1-31.8) and 1152 g (892-1491), respectively, were included. High-grade IVH or death at seventh day of life occurred in 24 (12.6%). MPAVpeak was strongly correlated with RVO (Spearman rho 0.826-0.843). MPAVpeak discriminated well for low RVO (<120 mL/kg/min) at 6 (AUROC, area under the receiver operating characteristic curve=0.90), 12 (AUROC 0.94) and 24 hours (AUROC 0.86). Observer reproducibility was better for MPAVpeak (inter-observer limits of agreement ±8.4%) compared with RVO (±18.8%) and SVCf (±32.2%). The prognostic accuracy of MPAVpeak to predict high-grade IVH or death was good (AUROC >0.75) and non-inferior to RVO and SVCf (DeLong's test p>0.05).

Conclusions: MPAVpeak is an adequate marker of systemic blood flow with high reproducibility and acceptable prognostic accuracy in preterm infants below 33 weeks of gestational age during the first day of life.