Manual hyperinflation improves alveolar recruitment in difficult-to-wean patients

Study objectives: To investigate the effect of manual hyperinflation (MH) in patients with atelectasis associated with ventilation support. Design: Patients were randomized to either an experimental group or a control group. Setting: Pulmonary ICUs from two hospitals. Patients: Twenty-three patients with atelectasis associated with ventilation support. Interventions: The MH technique was at a rate of 8 to 13 breaths/min for a period of 20 min each session, three times per day for 5 days. The control group received their standard prescribed mechanical ventilation without supplemental MH. Sputum contents (wet/dry weight ratio, viscosity), respiratory system capacity (spontaneous tidal volume [VT], maximal inspiratory pressure, rapid shallow breathing index [f/VT], chest radiograph signs, and PaO₂/fraction of inspired oxygen [FIO₂]) were measured just prior to the MH at day 0 as baseline, and at day 3 and day 6 of the study. Measurements and results: There were significant improvements in scores over the 6-day study in the experimental group compared to the control group in spontaneous VT (p = 0.035) and chest radiograph signs (p = 0.040), and a trend toward improvement f/VT (p = 0.066) and PaO₂/FIO₂ (p = 0.061) after adjustment for covariates. Other outcome variables did not differ significantly between the experimental and control groups. Conclusions: MH performed on patients with atelectasis from ventilation support significantly improved alveolar recruitment.