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Inspiratory Muscle Training for Patients With Chronic Obstructive Pulmonary Disease: A Practical Guide for Clinicians

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Abstract

Hill K, Cecins NM, Eastwood PR, Jenkins SC. Inspiratory muscle training for patients with chronic obstructive pulmonary disease: a practical guide for clinicians.

Reduced inspiratory muscle strength is common in people with chronic obstructive pulmonary disease (COPD) and is associated with dyspnea and decreased exercise capacity. Most studies of inspiratory muscle training (IMT) in COPD have demonstrated increased inspiratory muscle strength. Many have also shown improvements in dyspnea and exercise capacity. However, a persisting challenge when translating and applying the findings of these studies in clinical practice is the disparity in training loads, modalities, and outcomes measures used in the different studies. This commentary summarizes our clinical and research experience with a threshold IMT device with the aim of providing clinicians interested in prescribing IMT in this population with practical recommendations regarding patient selection, assessment, and implementation of training. We propose using an interval-based high-intensity threshold IMT program for people who are unable to participate fully in whole-body exercise training because of comorbidities such as severe musculoskeletal problems. Initial training loads equivalent to at least 30% of a person's maximum inspiratory pressure (PImax) are required for all people undertaking IMT. Supervision, which includes monitoring of oxygen saturation throughout the first training session, is recommended, and patients are warned to expect transient delayed-onset muscle soreness, a consequence of muscle adaptation to an unaccustomed activity. We recommend training be undertaken 3 times a week for 8 weeks, with loads progressively increased as symptoms permit. It is prudent to exclude people at risk of pneumothorax or spontaneous rib fracture. Evaluation of IMT should include measures of PImax, dyspnea, health-related quality of life, and exercise capacity.

Section snippets

Patient Selection

Pulmonary rehabilitation that includes supervised whole-body exercise training has achieved strong evidence for reducing dyspnea, improving HRQOL, and increasing exercise capacity.17 Several studies have investigated whether the addition of IMT to a program of whole-body exercise training offers benefits above those seen after whole-body exercise training in isolation.18 The results, when combined in meta-analyses, have demonstrated additional gains in inspiratory muscle strength and endurance

Evidence for High-Intensity Interval-Based IMT

As with other skeletal muscles, improvements in strength are likely to be dose-dependent.25 Constant load training protocols limit the load that can be achieved by people with COPD because of the rapid development of intolerable symptoms that necessitate resting.26 As with interval-based whole-body exercise training, the application of an interval-based approach to IMT can optimize the load able to be tolerated by allowing regular rest periods and subsequent relief of symptoms.15, 16 This, in

Patient Assessment

Assessment prior to IMT requires measurements of inspiratory muscle function in addition to outcome measures such as dyspnea, exercise capacity, and HRQOL. In clinical practice, the PImax is often measured in respiratory medicine laboratories.27 Small hand-held devices are also commercially available for this purpose.28

The measurement of PImax involves the generation of a maximum inspiratory effort, sustained for more than 1 second, against an occluded airway.27 Practice attempts are required

Modality Selection

We recommend the use of a threshold loading device to train the inspiratory muscles.16 The device is composed of a mouthpiece attached to a small plastic cylinder that contains a spring-loaded poppet value. The valve opens to permit inspiratory flow only once the person has generated adequate negative intrathoracic pressure to condense the spring.34 Although normocapnic hyperpnea and resistive loading devices have been described as training modalities, both have limitations that reduce their

Reassessment

Reassessment of all outcome measures is performed 8 weeks after the initiation of training. At this time, IMT is ceased if little improvement has occurred in dyspnea, exercise capacity, or HRQOL despite an increase in PImax.

Maintenance

Training-related gains are lost within 12 months if regular IMT is ceased.41 In order to optimize the maintenance of benefits, we encourage the completion of at least 2 IMT sessions each week at the load achieved during the final session of the 8-week program. The role of IMT during an acute exacerbation of COPD is unknown; therefore, we cease both training and maintenance programs during these clinical events. As with whole-body exercise training, the training load used during IMT will need to

Conclusions

This report describes a practical approach to the initiation and progression of an IMT program for people with stable COPD. We advocate the use of a threshold loading device and a high-intensity interval-based training program. Our recommendations are based on current evidence and our clinical practice in this area.

References (41)

  • D.E. O'Donnell et al.

    Dynamic hyperinflation and exercise intolerance in chronic obstructive pulmonary disease

    Am J Respir Crit Care Med

    (2001)
  • T. Similowski et al.

    Contractile properties of the human diaphragm during chronic hyperinflation

    N Engl J Med

    (1991)
  • A.L. Hamilton et al.

    Muscle strength, symptom intensity, and exercise capacity in patients with cardiorespiratory disorders

    Am J Respir Crit Care Med

    (1995)
  • R. Gosselink et al.

    Peripheral muscle weakness contributes to exercise limitation in COPD

    Am J Respir Crit Care Med

    (1996)
  • F. Lotters et al.

    Effects of controlled inspiratory muscle training in patients with COPD: a meta-analysis

    Eur Respir J

    (2002)
  • K. O'Brien et al.

    Inspiratory muscle training compared with other rehabilitation interventions in chronic obstructive pulmonary disease: a systematic review update

    J Cardiopulm Rehabil Prev

    (2008)
  • J.P.T. Higgins et al.

    Cochrane handbook for systematic reviews of interventions 4.2.6 [updated September 2006]: The Cochrane Library

    (2006)
  • E. Crisafulli et al.

    Role of comorbidities in a cohort of patients with COPD undergoing pulmonary rehabilitation

    Thorax

    (2008)
  • J.L. Larson et al.

    Cycle ergometer and inspiratory muscle training in chronic obstructive pulmonary disease

    Am J Respir Crit Care Med

    (1999)
  • A. Ramirez-Sarmiento et al.

    Inspiratory muscle training in patients with chronic obstructive pulmonary disease: structural adaptation and physiologic outcomes

    Am J Respir Crit Care Med

    (2002)
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      Owing to the use of a mouthpiece in the independently breathing population, patients also need to be able to maintain an adequate lip seal, and thus patients with bulbar dysfunction (e.g. due to stroke) or severe burns around the lips and mouth would not be appropriate for IMT (unless there is a tracheostomy in situ). Consistent with other guidelines, IMT in independently breathing patients is also not recommended for patients with high risk of pneumothorax or spontaneous rib fractures or within 12 months of lung surgery because of the high intrathoracic pressures generated during training.16 In the independently breathing patient, the same commercially available IMT device described previously can be used; however, in this case, the mouthpiece and nose clip are essential (unless the patient is breathing through a tracheostomy).

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    Supported by a National Health and Medical Research Council Senior Research Fellowship (grant no. 513704).

    No commercial party having a direct financial interest in the results of the research supporting this article has or will confer a benefit on the authors or on any organization with which the authors are associated.

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