Respiratory morbidity 6 to 12 months after mechanical ventilation for life-threatening respiratory syncytial virus infection

Background Respiratory morbidity in infants with life-threatening respiratory syncytial virus (RSV) infection necessitating invasive mechanical ventilation (MV) is underexplored. We therefore sought to characterize infant respiratory morbidity and pulmonary function six to 12 months after pediatric intensive care unit (PICU) discharge. Methods We invited 463 infants with RSV bronchiolitis necessitating MV (December 2011 - January 2023) for clinical assessments (structured interview, physical examination) and pulmonary function testing (PFT) using whole-body plethysmography and multiple breath washout (from 2016 onwards). Subjects were dichotomized by V'maxFRC Z score (normal versus abnormal). Results Data from 219/463 subjects (47.3%) were available for analysis (mean age at follow-up 50 standard deviation [ sd ] ±16 weeks and 40.3±14.2 weeks since PICU discharge. One-hundred-and-eighty (82.2%) subjects had parent-reported respiratory symptoms and sixty-eight (31.1%) used bronchodilator treatment as needed. For the whole cohort, mean FRCp z score was 1.0 ( sd ±1.5) and V'maxFRC z score −1.42 ( sd ±1.1) compared to reference data. Seventy-two (65%) subjects had lung clearance index values above the upper limit of normal. Twenty-four percent of patients who underwent both tests had abnormal results in both tests. V'maxFRC<−2 sd was found in 27.9% of subjects. Patient and clinical characteristics were equally distributed between subjects with and without abnormal lung function values (V'maxFRC<−2 sd or LCI above upper limit of normal). No risk factors for V'maxFRC<−2 sd were identified in logistic regression analysis. Conclusions Evidence of small airway dysfunction was found in almost one-third of subjects who have been ventilated for life-threatening RSV disease, although not always accompanied by respiratory symptoms.