The relationship between sildenafil dosing, exposure, and systemic hypotension in infants is incompletely understood.

The aim of this study was to characterise the relationship between predicted sildenafil exposure and hypotension in hospitalised infants.

We extracted information on sildenafil dosing and clinical characteristics from electronic health records of 348 neonatal ICUs from 1997 to 2013, and we predicted drug exposure using a population pharmacokinetic model.

We identified 232 infants receiving sildenafil at a median dose of 3.2 mg/kg/day (2.0, 6.0). The median steady-state area under the concentration–time curve over 24 hours (AUC24,SS) and maximum concentration of sildenafil (Cmax,SS,SIL) were 712 ng×hour/ml (401, 1561) and 129 ng/ml (69, 293), respectively. Systemic hypotension occurred in 9% of the cohort. In multivariable analysis, neither dosing nor exposure were associated with systemic hypotension: odds ratio=0.96 (95% confidence interval: 0.81, 1.14) for sildenafil dose; 0.87 (0.59, 1.28) for AUC24,SS; 1.19 (0.78, 1.82) for Cmax,SS,SIL.

We found no association between sildenafil dosing or exposure with systemic hypotension. Continued assessment of sildenafil’s safety profile in infants is warranted.

In very low birth weight infants, persistence of a patent ductus arteriosus results in morbidity and mortality. Therapies to close the ductus are effective, but clinical outcomes may depend on the accuracy of diagnosis and the timing of administration. The objective of the present study was to characterise the association between early echocardiography, therapy for patent ductus arteriosus, and outcomes in very low birth weight infants.

This retrospective cohort study used electronic health record data on inborn infants of gestational age ⩽28 weeks and birth weight <1500 g who were discharged after day of life 7 from 362 neonatal ICU from 1997 to 2013. The primary outcome was death between day of life 7 and discharge. Secondary outcomes included bronchopulmonary dysplasia, necrotising enterocolitis, and grade 3 or 4 intraventricular haemorrhage.

This study included a total of 48,551 infants with a median gestational age of 27 weeks (interquartile range 25, 28) and birth weight 870 g (706, 1050). Early echocardiography – that is, performed during days of life 2 to 6 – was performed in 15,971/48,551 (33%) infants, and patent ductus arteriosus was diagnosed in 31,712/48,551 (65%). The diagnosis was more common in infants who had undergone early echocardiography (14,549/15,971 [91%] versus 17,163/32,580 [53%], p<0.001). In multivariable analysis, early echocardiography was not associated with reduced mortality (odds ratio 0.97, 95% CI 0.89–1.05). Results were similar in the subset of infants who received therapy for patent ductus arteriosus (odds ratio 1.01, 95% CI 0.90–1.15).

Early echocardiography was associated with an increased diagnosis of patent ductus arteriosus, but not with decreased mortality.