Timing of recovery of lung function after severe hypoxemic respiratory failure in children

Abstract

Objective: To describe the timing of recovery of lung function after severe acute hypoxemic respiratory failure (AHRF) in children.

Design: A serial observational follow-up study of clinical and lung function measurements up to 53 months after acute illness.

Setting: University pediatric intensive care unit in a national children's hospital.

Patients: Five critically ill children aged 5-14 years.

Interventions: None

Results: Clinical recovery: each patient required a 3-5 month convalescence before being able to attend full-time school because of lethargy and dyspnea. All patients developed wheeze 3-12 months after illness and four received long-term bronchodilator therapy. Lung function recovery: for both the forced vital capacity (FVC) and forced vital capacity in the first second (FEV1) four patients had abnormally low values, regaining only 60-70% of predicted values for their height and sex, and all of this improvement had occurred by 6-12 months after illness. Beyond this interval, patients remained on their same FVC and FEV1 centile. FEV1/FVC ratios were consistently within the normal range, indicating a predominantly restrictive defect. Changes in peak expiratory flow exhibited a time course of improvement similar to the other lung function tests.

Conclusion: In children, pulmonary recovery after severe AHRF may occur for 6-12 months. A 1-year follow-up could offer a rational single point for assessment of outcome and long-term counselling of child and parents.