Persistent inspiratory muscle weakness among extubated patients after prolonged intubation is frequent and can be predicted early by maximal inspiratory pressure measured 12 days after its initial diagnosis: a prospective observational study

Critical Care volume 29, Article number: 477 (2025) Published: 07 November 2025

Background

Prolonged mechanical ventilation (MV) frequently results in inspiratory and peripheral muscle weakness, impairing recovery. These conditions can be identified at the bedside using respectively Maximal Inspiratory Pressure (MIP) measurement and Medical Research Council (MRC) score. This study investigated the evolution over the acute-care hospital stay of MIP and MRC score in patients with documented post-extubation inspiratory muscle weakness (IMW), defined as MIP ≤ 30 cmH2O, and looked for the factors associated with persistent IMW at the end of the acute care hospital stay.

Method

This exploratory prospective observational study was conducted across five Swiss hospitals. Patients in the Intensive Care Unit (ICU) who were extubated after ≥ 7 days of MV, with IMW diagnosed within 48 h post planned extubation, were included. Patients’ characteristics and ICU-related factors were recorded throughout the acute care stay as were MIP and MRC score. ICU-acquired weakness (ICU-AW) recorded in the medical file, ICU readmission, reintubation, and hospital mortality were also documented. Descriptive statistics and linear interpolation for missing MIP data were applied, and associations with persistent IMW (MIP ≤ 30 cmH2O) at study completion were explored using univariable logistic regression. The optimal timepoint for predicting persistent IMW using MIP was identified using a random forest model.

Results

Sixty-nine patients (48 men, 21 women) completed the study. At study completion, persistent IMW was observed in 30 patients (43%), with a median MIP of 22 [13–24] cmH2O. MIP was of 44 [36–64] in patients without persistent IMW. Persistent IMW was positively associated in univariable logistic regression with female sex, duration of catecholamine use until inclusion, MIP at day 12, MRC score at day 12 and changes in MIP from inclusion to day 12. The presence of respiratory comorbidities was negatively associated with persistent IMW.

Conclusion

Persistent IMW following prolonged MV is frequent throughout the acute care stay and until acute care hospital discharge. The MIP measured at day 12 after inclusion, as well as its change from inclusion to day 12, were strongly associated with persistent IMW.