Defining a diaphragm-focused and patient-acceptable inspiratory muscle training (IMT) load in difficult to wean, mechanically ventilated patients: a protocol for a prospective, mixed methods study

Timothy O Jenkins; Mike I Polkey; David McWilliams; Cherry Kilbride; Vicky MacBean

doi:10.1136/bmjresp-2026-004168

Defining a diaphragm-focused and patient-acceptable inspiratory muscle training (IMT) load in difficult to wean, mechanically ventilated patients: a protocol for a prospective, mixed methods study

Timothy O Jenkins
, Mike I Polkey
, David McWilliams
, Cherry Kilbride
, Vicky MacBean

Centre for Healthcare and Community Transformation

Guy’s and St Thomas’ NHS Foundation Trust
Brunel University
Royal Brompton and Harefield Hospitals
University Hospitals Coventry and Warwickshire NHS Trust
Royal Free London NHS Foundation Trust

Research output: Contribution to journal › Article › peer-review

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Abstract

Introduction: Diaphragm dysfunction is associated with failure to wean from mechanical ventilation. Inspiratory muscle training (IMT) may help improve outcomes for difficult-to-wean patients, yet the optimal approach remains unknown. High load IMT causes a training effect on the extra-diaphragmatic inspiratory muscles, but does not improve weaning success, questioning the utility of frequently cited high intensity IMT loads. Additionally, patients may find IMT unpleasant and distressing due to dyspnoea experienced during IMT. The aim of this study is to define a diaphragm-focused IMT load which is acceptable to patients. Methods: This study is designed as a prospective, mixed methods study. Forty difficult to wean, tracheostomised patients on mechanical ventilation will perform IMT at 15, 30, 45 and 60% of their maximal inspiratory pressure (PImax) in a randomised order using a tapered flow resistive loading device (POWERBreathe KH2, POWERBreathe, UK). Electrical activity of the diaphragm will be measured using an oesophageal multipair catheter (NAVA, Getinge, Sweden); extra-diaphragmatic (parasternal, scalene and sternocleidomastoid) muscle activity will be measured using surface electromyography. Patient experience of each load will be explored by measuring perceived breathing difficulty and unpleasantness using 0–10 numeric rating scales, verbal or written communication techniques in line with the participants' communication ability, and/or bespoke communication boards co-designed with the study patient and public involvement (PPI) group. Quantitative and qualitative data will be integrated to inform a diaphragm-focused, patient-acceptable IMT load. Ethics and dissemination: Ethical approval was obtained from Wales Research Ethics Committee 4 (Reference 25/WA/0242) on 30 October 2025. Results from this study will be presented at scientific meetings and published in peer-reviewed journals. Trial registration number: NCT07256821.

Original language	English
Article number	e004168
Number of pages	7
Journal	BMJ Open Respiratory Research
Volume	13
Issue number	1
Early online date	24 Jun 2026
DOIs	https://doi.org/10.1136/bmjresp-2026-004168
Publication status	E-pub ahead of print - 24 Jun 2026

Bibliographical note

Publisher Copyright:
© Author(s) (or their employer(s)) 2026. Re-use permitted under CC BY. Published by BMJ Group. This is an open access article distributed in accordance with the Creative Commons Attribution 4.0 Unported (CC BY 4.0) license, which permits others to copy, redistribute, remix, transform and build upon this work for any purpose, provided the original work is properly cited, a link to the licence is given, and indication of whether changes were made. See: https://creativecommons.org/licenses/by/4.0/.

Funding

This study is funded by an NIHR Doctoral Clinical and Practitioner Academic Fellowship (DCAF), grant number NIHR305214, awarded to Timothy Jenkins to undertake a PhD. The study protocol underwent an independent peer review process before being awarded. The authors gratefully acknowledge all members of the study PPI group for their time, advice and sharing their experiences of ICU.

Funders	Funder number
National Institute for Health and Care Research	NIHR305214

Keywords

Respiratory Muscles
Exercise

Access to Document

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McWilliams2026VoRFinal published version, 617 KBLicence: CC BY

Cite this

Jenkins, T. O., Polkey, M. I., McWilliams, D., Kilbride, C., & MacBean, V. (2026). Defining a diaphragm-focused and patient-acceptable inspiratory muscle training (IMT) load in difficult to wean, mechanically ventilated patients: a protocol for a prospective, mixed methods study. BMJ Open Respiratory Research, 13(1), Article e004168. Advance online publication. https://doi.org/10.1136/bmjresp-2026-004168

Defining a diaphragm-focused and patient-acceptable inspiratory muscle training (IMT) load in difficult to wean, mechanically ventilated patients: a protocol for a prospective, mixed methods study. / Jenkins, Timothy O; Polkey, Mike I; McWilliams, David et al.
In: BMJ Open Respiratory Research, Vol. 13, No. 1, e004168, 24.06.2026.

Research output: Contribution to journal › Article › peer-review

Jenkins, TO, Polkey, MI, McWilliams, D, Kilbride, C & MacBean, V 2026, 'Defining a diaphragm-focused and patient-acceptable inspiratory muscle training (IMT) load in difficult to wean, mechanically ventilated patients: a protocol for a prospective, mixed methods study', BMJ Open Respiratory Research, vol. 13, no. 1, e004168. https://doi.org/10.1136/bmjresp-2026-004168

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Defining a diaphragm-focused and patient-acceptable inspiratory muscle training (IMT) load in difficult to wean, mechanically ventilated patients: a protocol for a prospective, mixed methods study

Abstract

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Keywords

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