Abstract
Background
Inspiratory muscle training improves respiratory muscle function and may improve weaning
outcomes in patients with weaning difficulties. Compared to the commonly used pressure
threshold loading, tapered flow resistive loading better accommodates pressure–volume
relationships of the respiratory muscles, which might help to facilitate application
of external loads and optimise training responses.
Objective
The objective of this study was to compare acute breathing pattern responses and perceived
symptoms during an inspiratory muscle training session performed against identical
external loading provided as pressure threshold loading or as tapered flow resistive
loading. We hypothesised that for a given loading, tapered flow resistive loading
would allow larger volume expansion and higher inspiratory flow responses and consequently
higher external work of breathing and power than pressure threshold loading and that
subsequently patients perceived fewer symptoms during tapered flow resistive loading
than during pressure threshold loading.
Methods
In this exploratory study, 21 patients (maximal inspiratory pressure: 35 ± 14 cmH2O and vital capacity:0.85 L±0.37 L) performed two training sessions against external
loads equalling 42 ± 15% of maximal inspiratory pressure provided either as pressure
threshold loading or as tapered flow resistive loading. During these training sessions,
breath-by-breath data of breathing parameters were collected, and patients rated their
perceived breathing effort, dyspnoea, and unpleasantness.
Results
Compared to pressure threshold loading, tapered flow resistive loading allowed significantly
larger volume expansion (0.53 ± 0.28 L versus 0.41 ± 0.20 L, p < 0.01) and inspiratory
flow responses (0.43 ± 0.20 L/s versus 0.33 ± 0.16 L/s, p = 0.01). Tapered flow resistive
loading was perceived as less unpleasant (3.1 ± 1.9 versus 3.8 ± 2.4, p = 0.048).
No significant differences in breathing effort, dyspnoea, work of breathing, and power
were observed.
Conclusions
For a given loading, inspiratory muscle training with tapered flow resistive loading
allowed larger volume expansion and higher inspiratory flow responses than pressure
threshold loading, which led patients to perceive tapered flow resistive loading as
less unpleasant. This might help us to facilitate early implementation of inspiratory
muscle training in patients with weaning difficulties.
Clinical trial registration number
Clinicaltrials.gov identifier: NCT03240263
Keywords
To read this article in full you will need to make a payment
Purchase one-time access:
Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online accessOne-time access price info
- For academic or personal research use, select 'Academic and Personal'
- For corporate R&D use, select 'Corporate R&D Professionals'
Subscribe:
Subscribe to Australian Critical CareAlready a print subscriber? Claim online access
Already an online subscriber? Sign in
Register: Create an account
Institutional Access: Sign in to ScienceDirect
References
- Inspiratory muscle rehabilitation in critically ill adults. A systematic review and meta-analysis.Ann Am Thorac Soc. 2018; 15 (Epub 2018/03/28. PubMed PMID: 29584447): 735-744https://doi.org/10.1513/AnnalsATS.201712-961OC
- Inspiratory muscle training facilitates weaning from mechanical ventilation among patients in the intensive care unit: a systematic review.J Physiother. 2015; 61 (Epub 2015/06/21. PubMed PMID: 26092389): 125-134https://doi.org/10.1016/j.jphys.2015.05.016
- Can inspiratory muscle training improve weaning outcomes in difficult to wean patients? A protocol for a randomised controlled trial (IMweanT study).BMJ Open. 2018; 8e021091https://doi.org/10.1136/bmjopen-2017-021091
- Inspiratory muscle training with an electronic resistive loading device improves prolonged weaning outcomes in a randomized controlled trial.Crit Care Med. 2021; 49 (Epub 2020/12/18. PubMed PMID: 33332819): 589-597https://doi.org/10.1097/ccm.0000000000004787
- Training specificity of inspiratory muscle training methods: a randomized trial.Front Physiol. 2020; 11 (Epub 2020/12/22. PubMed PMID: 33343384; PubMed Central PMCID: PMC7744620)576595https://doi.org/10.3389/fphys.2020.576595
- The pressure-volume diagram of the thorax and lung.Am J Physiol. 1946; 146 (Epub 1946/01/01. PubMed PMID: 20982947): 161-178https://doi.org/10.1152/ajplegacy.1946.146.2.161
- Efficacy of a novel method for inspiratory muscle training in people with chronic obstructive pulmonary disease.Phys Ther. 2015; 95 (Epub 2015/04/11. PubMed PMID: 25858974): 1264-1273https://doi.org/10.2522/ptj.20140245
- Lung volume specificity of inspiratory muscle training.J Appl Physiol. 1994; 77 (1985) (Epub 1994/08/01. PubMed PMID: 8002529): 789-794https://doi.org/10.1152/jappl.1994.77.2.789
- Pressure-flow specificity of inspiratory muscle training.J Appl Physiol. 1994; 77 (1985) (Epub 1994/08/01. PubMed PMID: 8002530): 795-801https://doi.org/10.1152/jappl.1994.77.2.795
- Specificity and reversibility of inspiratory muscle training.Med Sci Sports Exerc. 2003; 35 (PubMed PMID: 12569211): 237-244https://doi.org/10.1249/01.MSS.0000048642.58419.1E
- Inspiratory muscle adaptations following pressure or flow training in humans.Eur J Appl Physiol. 1999; 79: 467-471https://doi.org/10.1007/s004210050538
- Measurement validity of an electronic inspiratory loading device during a loaded breathing task in patients with COPD.Respir Med. 2013; 107 (Epub 2013/02/21. PubMed PMID: 23421970): 633-635https://doi.org/10.1016/j.rmed.2013.01.020
- Measurement validity of an electronic training device to assess breathing characteristics during inspiratory muscle training in patients with weaning difficulties.PLoS One. 2021; 16 (Epub 2021/08/27. PubMed PMID: 34437582)e0255431https://doi.org/10.1371/journal.pone.0255431
- Epidemiology of weaning outcome according to a new definition. The WIND study.Am J Respir Crit Care Med. 2017; 195 (Epub 2016/09/15. PubMed PMID: 27626706): 772-783https://doi.org/10.1164/rccm.201602-0320OC
- Psychophysical bases of perceived exertion.Med Sci Sports Exerc. 1982; 14 (Epub 1982/01/01. PubMed PMID: 7154893): 377-381
- Reference values for lung function tests. II. Maximal respiratory pressures and voluntary ventilation.Braz J Med Biol Res = Revista brasileira de pesquisas medicas e biologicas. 1999; 32 (Epub 1999/07/21. PubMed PMID: 10412550): 719-727https://doi.org/10.1590/s0100-879x1999000600007
- Lung volumes and forced ventilatory flows.Eur Respir J. 1993; 6: 5-40https://doi.org/10.1183/09041950.005s1693
- Specificity of training adaptation: time for a rethink?.J Physiol. 2008; 586 (Epub 2008/01/03. PubMed PMID: 18167367; PubMed Central PMCID: PMC2375570): 1-2https://doi.org/10.1113/jphysiol.2007.147397
- Randomised controlled trial of adjunctive inspiratory muscle training for patients with COPD.Thorax. 2018; 73 (Epub 2018/06/20. PubMed PMID: 29914940): 942-950https://doi.org/10.1136/thoraxjnl-2017-211417
Article info
Publication history
Published online: August 27, 2022
Accepted:
July 17,
2022
Received in revised form:
June 22,
2022
Received:
April 15,
2022
Publication stage
In Press Corrected ProofFootnotes
☆This research project was supported by Research Foundation Flanders, Belgium (FWO, https://www.fwo.be/en/): grant number G053721N.
Identification
Copyright
© 2022 Australian College of Critical Care Nurses Ltd. Published by Elsevier Ltd. All rights reserved.
