Pulmonary hypertension during respiratory syncytial virus bronchiolitis: a risk factor for severity of illness.

Background: Respiratory syncytial virus infection is the most frequent cause of acute lower respiratory tract disease in infants. A few reports have suggested that pulmonary hypertension is associated with increased severity of respiratory syncytial virus infection. We sought to determine the association between the pulmonary hypertension detected by echocardiography during respiratory syncytial virus bronchiolitis and clinical outcomes.
Methods: We retrospectively reviewed 154 children admitted with respiratory syncytial virus bronchiolitis who had an echocardiography performed during the admission. The association between pulmonary hypertension and clinical outcomes including mortality, intensive care unit (ICU) admission, prolonged ICU stay (>10 days), tracheal intubation, and need of high frequency oscillator ventilation was evaluated.
Results: Echocardiography detected pulmonary hypertension in 29 patients (18.7%). Pulmonary hypertension was observed more frequently in patients with congenital heart disease (CHD) (n = 11/33, 33%), chronic lung disease of infancy (n = 12/25, 48%), prematurity (<37 weeks gestational age, n = 17/59, 29%), and Down syndrome (n = 4/10, 40%). The presence of pulmonary hypertension was associated with morbidity (p < 0.001) and mortality (p = 0.02). However, in patients without these risk factors (n = 68), pulmonary hypertension was detected in five patients who presented with shock or poor perfusion. Chronic lung disease was associated with pulmonary hypertension (OR = 5.9, 95% CI 2.2-16.3, p = 0.0005). Multivariate logistic analysis demonstrated that pulmonary hypertension is associated with ICU admission (OR = 6.4, 95% CI 2.2-18.8, p = 0.0007), intubation (OR = 4.7, 95% CI 1.8-12.3, p = 0.002), high frequency oscillator ventilation (OR = 8.4, 95% CI 2.95-23.98, p < 0.0001), and prolonged ICU stay (OR = 4.9, 95% CI 2.0-11.7, p = 0.0004).
Conclusions: Pulmonary hypertension detected by echocardiography during respiratory syncytial virus infection was associated with increased morbidity and mortality. Chronic lung disease was associated with pulmonary hypertension detected during respiratory syncytial virus bronchiolitis. Routine echocardiography is not warranted for previously healthy, haemodynamically stable patients with respiratory syncytial virus bronchiolitis.