Effect of abdominal weight training with and without cough machine assistance on lung function in the patients with prolonged mechanical ventilation: a randomized trial

PURPOSE: The patients with prolonged mechanical ventilation (PMV) have the risk of ineffective coughing and infection due to diaphragm weakness. This study aimed to explore the effect of abdominal weight training (AWT) intervention with/without cough machine (CM) assistance on lung function, respiratory muscle strength and cough ability in these patients. METHODS: Forty patients with PMV were randomly assigned to three groups: AWT group (n = 12), AWT + CM group (n = 14) and control group (n = 14). Change of maximum inspiratory pressure (MIP), Maximum expiratory pressure (MEP) and peak cough flow (PCF) between 1 day before and 2 weeks after the intervention were compared among these three groups. RESULTS: MIP before and after intervention in AWT group (30.50 ± 11.73 vs. 36.00 ± 10.79; p < 0.05) and AWT + CM group (29.8 ± 12.14 vs. 36.14 ± 10.42; p < 0.05) compared with control group (28.43 ± 9.74 vs 26.71 ± 10.77; p > 0.05) was significantly improved. MEP before and after intervention in AWT group (30.58 ± 15.19 vs. 41.50 ± 18.33; p < 0.05) and AWT + CM group (27.29 ± 12.76 vs 42.43 ± 16.96; p < 0.05) compared with control group (28.86 ± 10.25 vs. 29.57 ± 14.21; p > 0.05) was significantly improved. PCF before and after intervention in AWT group in AWT group (105.83 ± 16.21 vs. 114.17 ± 15.20; p < 0.05) and AWT + CM group (108.57 ± 18.85 vs. 131.79 ± 38.96; p < 0.05) compared to control group (108.57 ± 19.96 vs. 109.86 ± 17.44; p > 0.05) showed significant improvements. AWT + CM group had significantly greater improvements than control group in MIP and peak cough flow than control group (13.71 ± 11.28 vs 19.64 ± 29.90, p < 0.05). CONCLUSION: AWT can significantly improve lung function, respiratory muscle strength, and cough ability in the PMV patients. AWT + CM can further improve their expiratory muscle strength and cough ability. Trial registration ClinicalTrials.gov registry (registration number: NCT0529538 retrospectively registered on March 3, 2022).