Impact of Inspiratory Muscle Training and Positive Expiratory Pressure on Lung Function and Extubation Success of ICU Patients: a Randomized Controlled Trial.

Introduction: Preparing patients for extubation from mechanical ventilation (MV) necessitates focused respiratory muscle strengthening. This study aimed to evaluate the effect of threshold inspiratory muscle training (IMT) and positive expiratory pressure (PEP) exercises on outcomes of patients who underwent MV in intensive care unit (ICU).

Methods: This randomized controlled trial was conducted in 2023 at the ICUs of Imam Reza Hospital, Mashhad, Iran. Participants were allocated to either intervention or control group (each comprising 35 patients) through block randomization. The intervention group received standard daily chest physiotherapy as well as targeted inspiratory and expiratory muscle strengthening exercises using the threshold IMT/PEP device, administered twice daily over one week. The control group received standard daily chest physiotherapy alone. Finally, the outcomes (lung compliance, duration of intubation, extubation success rate, and diaphragmatic metrics) of the two groups were compared.

Results: 70 patients with the mean age of 56.10 ± 14.15 (range: 28.00-85.00) years were randomly divided into two groups (50% male). Significant improvements were observed in the intervention group regarding pulmonary compliance values (35.62 ± 4.43 vs. 30.85 ± 6.93; p= 0.001), peak expiratory flow (PEF) (55.20 ± 10.23 vs. 47.80 ± 11.26; p = 0.002), and maximum inspiratory pressure (MIP) (33.40 ± 4.25 vs. 30.08 ± 6.08; p = 0.01) compared to the control group. Diaphragm inspiratory thickness (0.29 ± 0.03 vs. 0.26 ± 0.04; p = 0.001), diaphragm expiratory thickness (0.22 ± 0.03 vs. 0.20 ± 0.04; p = 0.006) and motion (1.61 ± .29 vs. 1.48 ± .21; p = 0.04) also exhibited significant differences between the two groups. Extubation success rate was higher in the intervention group (68.60% vs. 40%; p = 0.01). The duration of mechanical ventilation was 15.14±7.07 days in the intervention group and 17.34±7.87 days in the control group (p = 0.20). The mean extubation time was 7.00 ± 1.88 days for the intervention group and 9.00 ± 2.00 days for the control (p < 0.001).

Conclusion: Threshold IMT/PEP device exercises effectively enhance respiratory muscle strength, diaphragm thickness, and reduce ventilator dependency. These findings support their potential for inclusion in rehabilitation programs for ICU patients.