Which ICU patients benefit most from inspiratory muscle training? Retrospective analysis of a randomized trial

ABSTRACT

Background: Inspiratory muscle training (IMT) increases inspiratory muscle strength and improves quality of life in intensive care unit (ICU) patients who have been invasively mechanically ventilated for ≥7 days. The purpose of this study was to identify which patients benefit most from IMT following weaning from mechanical ventilation.

Methods: Secondary analysis of a randomized trial of supervised daily IMT in 70 patients (mean age 59 years) in a 31-bed ICU was carried out. Changes in inspiratory muscle strength (maximum inspiratory pressure, MIP) between enrolment and 2 weeks (ΔMIP) were analyzed to compare the IMT group (71% male) and the control group (58% male). Linear regression models explored which factors at baseline were associated with ΔMIP.

Results: Thirty-four participants were allocated to the IMT group where baseline MIP was associated with an increase in ΔMIP, significantly different from the control group (p = 0.025). The highest ΔMIP was associated with baseline MIP ≥ 28 cmH₂O. In the IMT group, higher baseline quality of life (EQ5D) scores were associated with positive ΔMIP, significantly different from the control group (p = 0.029), with largest ΔMIP for those with EQ5D ≥ 40.

Conclusions: Physiotherapists should target ICU patients with moderate inspiratory muscle weakness (MIP ≥28 cmH₂O) and moderate to high quality of life (EQ5D>40) within 48 h of ventilatory weaning as ideal candidates for IMT following prolonged mechanical ventilation.

KEYWORDS:

• Physiotherapy techniques
• breathing exercises
• critical care
• intensive care

Acknowledgments

The authors wish to gratefully acknowledge the Canberra Hospital Private Practice and Auxiliary Research Funds for making this research possible, as well as the staff of the Acute Support Physiotherapy Department for their assistance with the intervention.

Conflict of interest

The authors state that there is no conflict of interest.

Ethics approval

This study was approved by the Australian Capital Territory Health Human Research Ethics Committee (ETH.10.10.370) and the University of Queensland Medical Research Ethics Committee (2010001488).

Prior presentation

Australia New Zealand Intensive Care Society Scientific Meeting, Gold Coast, Australia, October 2017.

Additional information

Funding

We gratefully acknowledge the Canberra Hospital Private Practice Fund and the Canberra Hospital Auxiliary Research Fund.