Quantifying pulmonary hypertension in ventilated infants with bronchiolitis: A pilot study

Objective: To determine whether previously well infants ventilated for bronchiolitis have sufficiently elevated pulmonary artery pressures (PAP) to warrant a trial of inhaled nitric oxide (iNO) therapy. Methods: Consecutive infants mechanically ventilated for bronchiolitis were offered Doppler echocardiography between 24 and 72 h after intubation. Patients were divided into those with normal PAP, mild, moderate or severe pulmonary hypertension. Patients with at least moderate pulmonary hypertension (systolic PAP > 30 mmHg and > 50% of systemic systolic arterial pressure) were offered a 60 min trial of iNO therapy at a concentration of 20 ppm and repeat echocardiography. Results: Six infants (four preterm, two term) were studied at a mean corrected age of 13 weeks (4, 24). Respiratory syncytial virus was confirmed on immunofluorescence of nasal secretions in five of six subjects (84%). Echocardiography was performed (mean, 5.5 days) (95%CI3.8-7.3) after the onset of symptoms. All patients had structurally normal hearts. Four patients had mild pulmonary artery hypertension and two had normal pulmonary artery pressures. None of the patients qualified for iNO therapy. The mean (range) duration of intubation was 14 days (9-19) and the duration of hospitalization was 28 days (14-42). All patients recovered. Conclusion: Significant pulmonary hypertension should not be presumed in previously well preterm and term infants ventilated for bronchiolitis.