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Three Part Question

Does[inspiratory muscle training] facilitate [weaning from mechanical ventilation] in [patients who are struggling to wean in the ICU]?

Clinical Scenario

A 68 year old patient, mechanically ventilated in the ICU has failed at multiple attempts at conventional weaning to a state of ventilator liberation, becoming dyspneic and desaturating. You wonder if there is a treatment adjunct you could use to increase her respiratory strength prior to further weaning attempts.

Search Strategy

AMED, EMBASE, CINAHL and Medline using Athens were reviewed.
Reference lists of appropriate papers also cross referenced and reviewed.
{Inspiratory muscle training} AND {strengthening OR weaning OR optimising OR facilitating OR liberation} AND mechanical ventilation
Limited to studies written in English, in adults and published between 2011 and 2021.

Search Outcome

255 papers were returned; 232 were irrelevant to the clinical scenario and question; 23 were reviewed; 4 were found to be either prospective studies or guidelines.
10 studies were included in the review.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Tonella, R; Ratti L; Delazari B; Junior C, Silva P, Herran A; Faez D; Saad I; Figueiredo L; Moreno R 2017 Brazil	21 patients trache ventilated patients 10 Electronic Inspiratory Muscle training (EIMT) – powerbreathe, manual setting 3 x 10 breaths, 1 min break between sets Twice daily Resistive load of 30% initial MIP Daily increase of 10% resistance 11 Intermittent nebulisation programme (INP) – t-piece for progressively increasing duration until 48 hrs autonomy	Prospective RCT	Maximal Inspiratory Pressure (MIP)	MIP increased in both groups - Significant in EIMT (p<0.017)	Small sample size
			RSBI	No difference in RSBI between groups
			Duration of Mechanical Ventilation (MV)	No difference in duration of MV 21.8 +/- 9.8 days INP to 14.5 +/- 10 days EIMT (p<0.082)
			Total weaning time	Total weaning time shorter in EIMT (p<0.0192) 9.4 +/- 6.47 days INP to 3.5 +/- 1.6 days EIMT
Condessa R; Brauner L; Saul A; Baptista M; Silva A; Vieira S 2013 Brazil	92 patients 45 IMT Respironics IMT device 40% MIP 5 x 10 breaths Twice daily, 7 days a week; 47 usual care only. 77 patients completed (38 experimental, 39 control).	Randomised controlled trial	Duration of weaning from MV	Weaning period was 8 hrs shorter in the IMT group (not significant)	Study did not reach its calculated sample size – large loss to follow up. Small sample size to show significant results Short training time Heterogeneity within patient group
			Inspiratory and expiratory muscle strength	MIP increased in IMT group by 7cmH20 and decreased in control group by 3cm H20 (significant) MEP increased in IMT group and decreased in the control group (significant)
			Tidal volume	Tidal volume increased in IMT group and decreased in control group (significant)
			RSBI	RSBI reduced (improved) more in the IMT group than control group (not significant)
Martin A; Smith B; Davenport P; Harman E; Gonzalez – Rothi R; Baz M; Layon A; Banner M; Caruso L; De 2011 United States of America	69 patients; 35 Respironics IMT device 5 Days (M-F) a week Highest threshold patient could manage 4 x 6-10 breaths, 2 mins rest with MV between sets Threshold progressed daily as tolerated 34 SHAM using resistive inspiratory muscle training device at lowest setting, with additional holes drilled into it. 4 x 6 – 10 breaths 5 days a week 2 minutes rest on MV between sets All undertook breathing trials – ATC, CPAP or reducing PS. No rehabilitation activities during breathing trials until could tolerate 6 hrs	Randomised Controlled Trial	MIP	MIP increased in IMT group (44.4 +/- 18.4 to 54.1 +/- 17.8 cmH20 (p<0.0001). Sham not significant	Single blinding only (patients) Small sample size Mostly surgical patients – unclear if the results can be generalised to all patients
			Weaning	Weaning success: 25 of IMST group weaned (71%) compared to 16 (47%) of SHAM group (p<0.039)
Elkins M and Dentice R 2015 Australia	10 studies, 394 patients who received IMT. The control intervention was SHAM or no IMT.	Systematic Review	Maximal Inspiratory Pressure (MIP)	Training significantly improved MIP, RSBI and weaning success.	Assessor blinding only present in 2 studies Concealed allocation and intention to treat analysis not used in most studies. Included studies used different training methods and background ventilation modes. Usual care differences between studies may impact the effect of IMT. The included studies are from across the globe, where weaning and sedation strategies may vary.
			Duration of mechanical ventilation	No significant difference to weaning duration, duration of mechanical ventilation, reintubation rate, tracheostomy rate.
			Length Of Stay ICU and hospital	Improvements to length of stay in ICU and length of stay in hospital
			Adverse events	There were no adverse events recorded.
Moodie L; Reeve J; Elkins M 2011 Australia	150 participants across 3 studies; 2 studies: IMT pressure threshold device 1 study adjustment of the sensitivity of pressure trigger on the ventilator Aimed at 20% MIP to highest pressure tolerated 5-30minutes 5-7 days a week	Systematic Review	Maximal Inspiratory Pressure (MIP)	Significant improvement in MIP when using IMT	Recognises MIP difficult to reliably measure in ventilated patients Improvement in MIP but MIP remains significantly lower than average Variety of conditions leading to mechanical ventilation Different modes of IMT used between studies Differences in timings of initiation of IMT may have effected results – 1 study started IMT at 24hrs of ventilation, whilst another implemented IMT after a mean of 45 days. Background ventilation modes varied between included studies which may have impacted results.
			Weaning success (spontaneous breathing off ventilation for at least 48hrs)	Not significant but favoured the experimental groups.
			Weaning duration (IMT implementation to discontinuation of MV)	Not significant but favoured the experimental groups
Bissett B; Leditschke A; Green M 2012 Australia	10 tracheostomised, ICU patients who had previously failed to wean. 3 -6 x 6 breaths at a training threshold of RPE OF 6-8/10. If RPE was lower than 6, training pressure was increased by 2-4cmH20 195 IMT sessions	Case series	Weaning success	2 patients died from factors unrelated to IMT, 8 successfully weaned, were decannulated and discharged from ICU.	Case series, small sample size Focused on safety of implementation rather than effect of training. Impact of physiotherapist/ patient relationship on confidence of unassisted breathing may impact results.
			Number of adverse events in response to IMT	No adverse events recorded in response to IMT
			Physiological response to IMT	Training pressures significantly increased by mean 18cmH20
da Silva Guimarães B, Cordeiro de Souza L, Cordeiro H, Regis T, Leite C, Puga F, Alvim S, Lugon J. 2021 Brazil	110 patients (9 drop outs) 48 intervention(IMT) 53 control group (traditional T-piece protocol) Electronic Inspiratory Muscle training (EIMT) – powerbreathe, manual setting 3x 10 breaths, repeated x2, 2-3 min break between sets Resistive load of 40% initial MIP Progressively escalated until the target load was reached – last x5 breaths of each subset run under target load.	Randomised Controlled Trial	Maximal Inspiratory Pressure	Substantial increase in MIP with IMT (70.5 [51.0–82.5] vs –48.0cm H2O [36.0–72.0cm H2O]; p = 0.003)	Small sample size and single-centre site Used out-dated definition of successful weaning Lack of blinding due to nature of study High losses to follow up (9 in total) Traditional care not usually using T-piece
			Weaning success at 60days	Outcomes at the 60th day of ICU were significantly better in the intervention group regarding both survival (71.1% vs 48.9%; p = 0.030) and weaning success (74.8% vs 44.5%; p = 0.001)
Ahmed M 2018 Egypt	30 patients 15 Patients IMT 15 Patients control (usual care) Training was conducted through tuning the ventilator sensitivity based on the patients’ maximal inspiratory pressure (MIP) The IMT group started with initial load of 30% of their MIP and increased up to 40% as tolerated. 5mins x2 sessions per day, 7 days per week for duration of MV weaning.	Prospective, randomized clinical study	Change in Maximal Inspiratory Pressure	Mean MIP pre-weaning in both groups was 16 cm H2O. Significant difference in the final mean MIP between the IMT group (23.27 cm H2O) and the control group (17.40 cm H2O).	Small sample size Patients only in acute/ acute on chronic RF- limiting comparability across the wider ICU population. Exclusion of patients with tracheostomies- loss of patients with prolonged weaning.
			Weaning duration	There is also significant shortening in the weaning time in the experimental group and less frequent likelihood of reintubation
Sandoval Morenoa L, Casas Quirogab I, Wilches Lunac E, García A 2019 Columbia	126 Patients mechanically ventilated for 48hrs or more Control group: Conventional respiratory management in ICU Experimental group: RMT program with the Threshold IMT respiratory muscle trainer every day, twice a day. Three series of 6---10 repetitions, with two minutes of rest between series. The initial training load was adjusted considering 50% of the maxi-mum inspiratory pressure (Pimax)	A randomized, controlled, double-blind parallel-group clinical trial	Weaning from mechanical ventilation	Nil significance in duration of weaning time between groups.	Short RMT period as patients were already weaning Absence of diaphragm dysfunction and extubated early. Needs to include patients with difficult/ prolonged weaning
			Maximal inspiratory pressure	Statistically significant increase in MIP within each group, however not between each group.
Bissett B, Leditschke A, Neeman T, Boots R, Paratz J 2016 Australia	Patient group: patients 48 hours following successful weaning. 70 participants Intervention:IMT x1/day, 5 days a wk for 2 weeks (34 participants) Control: usual care (36 participants)	Randomised Controlled Trial	Maximal Inspiratory Pressure	Greater improvements in inspiratory pressure (training: 17%, control: 6%, mean difference: 11%, p=0.02).	Small study Does the HRQoL result mean anything? It is measuring an improvement in QoL whilst still an inpatient.
			Fatigue resistance index (FRI)	No statistically significant differences in FRI (0.03 vs 0.02, p=0.81),
			Health related quality of life	Improvement in quality of life was greater in the training group (14% vs 2%, mean difference 12%, p=0.03)

Comment(s)

All papers reported a significant increase in maximal inspiratory pressure (MIP) when using IMT. Weaning time was found to be shorter in groups using IMT, with a greater weaning success rate. No studies reported significant adverse events attributed to IMT.

Clinical Bottom Line

The inclusion of IMT appears to be beneficial in increasing respiratory muscle strength, which in turn facilitates quicker and more successful rates of weaning from mechanical ventilation. The use of IMT is shown to be safe for use in the ICU setting.

References

1. Tonella, R; Ratti L; Delazari B; Junior C, Silva P, Herran A; Faez D; Saad I; Figueiredo L; Moreno R; Dragosvac; Falcao A. Inspiratory muscle training in the intensive care unit: a new perspective Journal of Clinical Medical Research 2017; 9 (11): 929 - 934
2. Condessa R; Brauner L; Saul A; Baptista M; Silva A; Vieira S Inspiratory muscle training did not accelerate weaning from mechanical ventilation but did improve tidal volume and maximal inspiratory pressures: a randomised trial Journal of physiotherapy. 2013 ; 59: 101 – 107
3. Martin A; Smith B; Davenport P; Harman E; Gonzalez – Rothi R; Baz M; Layon A; Banner M; Caruso L; Deoghare H; Huang T; Gabrielli A Inspiratory muscle strength training improves weaning outcome in failure to wean patients: a randomized trial Critical Care 2011 (15)
4. Elkins M and Dentice R Inspiratory muscle training facilitates weaning from mechanical ventilation among patients in the intensive care unit: a systematic review Journal of Physiotherapy 2015
5. Moodie L; Reeve J; Elkins M Inspiratory muscle training increases inspiratory muscle strength in patients weaning from mechanical ventilation: a systematic review Journal of physiotherapy. 2011. (57); 213-221
6. Bissett B; Leditschke A; Green M Specific inspiratory muscle training is safe in selected patients who are ventilator-dependent: A case series. Intensive and Critical Care Nursing 2012. 28: 98-104
7. da Silva Guimarães B, Cordeiro de Souza L, Cordeiro H, Regis T, Leite C, Puga F, Alvim S, Lugon J. Inspiratory Muscle Training With an Electronic Resistive Loading Device Improves Prolonged Weaning Outcomes in a Randomized Controlled Trial Critical Care Medicine 2021 Apr 1;49(4):589-597.
8. Ahmed M Effect of inspiratory muscle training on weaning from mechanical ventilation in acute respiratory failure Egypt Journal of Bronchology 2018 12:461–466
9. Sandoval Morenoa L, Casas Quirogab I, Wilches Lunac E, García A Efficacy of respiratory muscle training in weaning of mechanical ventilation in patients with mechanical ventilation for 48 hours or more: A Randomized Controlled Clinical Trial Medicina Intensiva 2019; 43 (2); 79-89
10. Bissett B, Leditschke A, Neeman T, Boots R, Paratz J Inspiratory muscle training to enhance recovery from mechanical ventilation: a randomised trial. Thorax 2016;71:812-819