EFFICACY OF RESPIRATORY MUSCLE STRENGTHENING TO FACILITATE WEANING FROM MECHANICAL VENTILATION AMONG PATIENTS IN INTENSIVE CARE UNIT: RANDOMIZED CONTROLLED TRIAL

S. Gupta¹, A. Bhise¹

¹Government Spine Institute, Civil Hospital Ahmedabad, Department of Physiotherapy, ICU Civil Hospital, Ahmedabad, India

Background: Whilst unarguably life-saving, for many mechanical ventilation has deleterious consequences for respiratory muscle function, which can result in ventilator- dependence. Within just 70 hours of intubation, invasive controlled mechanical ventilation results in diaphragmatic catabolism. Moreover, among the significant factors contributing to prolonged mechanical ventilation, one is decreased inspiratory muscle strength. This study aimed to test the effect of inspiratory muscle training in patients who have failed a spontaneous breathing trial in the intensive care unit on duration of mechanical ventilation and inspiratory muscle strength.

Purpose: This study aimed to answer the following questions:
1. Does respiratory muscle strengthening improve Maximal Inspiratory Pressure (MIP) and Rapid Shallow Breathing Index (RSBI)?
2. Is inspiratory muscle training effective in accelerating weaning from mechanical ventilation?

Methods: We recruited patients who have received invasive mechanical ventilation (MV) for at least seven days and have failed at least one breathing trial. Eligible patients who gave their informed consent were randomly allocated to the intervention or control group. The control group received conventional physiotherapy, which consisted of breathing exercises, bronchial hygiene, active exercises. The intervention group received conventional physiotherapy and respiratory muscle strengthening (RMS). The intensity of RMS was prescribed based on the Maximum Inspiratory Pressure (MIP), which was measured through the tracheostomy or endotracheal tube using a respiratory pressure meter and training was given using removable threshold device. The frequency of training was five sets of six breaths at 50% of MIP, performed twice a day, 7 days a week, with intensity increased progressively until the day of extubation. The MIP and Rapid and Shallow Breathing Index (RSBI) were measured at baseline and post-extubation. Also, total weaning days were recorded. The data were tested for normal distribution. Within-group and between-group analyses were performed using Wilcoxon matched-pairs signed rank test and Mann-Whitney U test in SPSS version 16.0. This study was approved by the local ethics committee.

Results: We screened 56 patients, of which 26 met criteria. Two patients drop out before completion, therefore, 24 patients were included in the analysis: Interventional (n₁=13) and Control (n₂=11). The mean ± standard deviation age were (n₁₌ 38±16.791) & (n₂= 40±14.17), mean duration of MV was (9.3±2.09) before inclusion. Both MIP and RSBI showed a significant improvement post treatment. MIP showed mean improvement of 4.92 cm H₂O with mean±SD=25.84±4.37 (p=0.016). RSBI showed mean improvement of 29.2 f/VT with mean±SD=71±19 (p=0.001). Mean duration of weaning was 17±5.26 days in the intervention and 21±7 days in the control group. But this change was not statistically significant (p=0.123).

Conclusions: Respiratory muscle training increases inspiratory muscle strength and improves ventilatory parameters useful for weaning decision-making, such as MIP and RSBI. Future studies should focus on the efficacy of inspiratory muscle training with larger samples, so practice across disciplines, including physiotherapy, respiratory therapy, nursing and intensive care medicine, can change towards the use of inspiratory muscle training.

Implications: The findings would be highly applicable to ICU staff who address the challenges of weaning failure.

Funding acknowledgements: Unfunded

Keywords:
Mechanical ventilator weaning
Invasive Mechanical Ventilators
Respiratory Muscle training

Topics:
Cardiorespiratory
Critical care
Cardiorespiratory

Did this work require ethics approval? Yes

Institution: Government Spine Institute

Committee: Institutional Sub-committee of Institutional Ethics Committee, Civil Hospital, Ahmedabad

Ethics number: GSIIESC/12/19