Inspiration for the Future: The Role of Inspiratory Muscle Training in Cystic Fibrosis

The therapeutic role of inspiratory muscle training in the management of asthma: a narrative review

Asthma is a disorder of the airways characterized by chronic airway inflammation, hyperresponsiveness, and variable recurring airway obstruction. Treatment options for asthma include pharmacological strategies, whereas nonpharmacological strategies are limited. Established pharmacological approaches to treating asthma may cause unwanted side effects and do not always afford adequate protection against asthma, possibly because of an individual's variable response to medications. A potential nonpharmacological intervention that is most available and cost effective is inspiratory muscle training (IMT), which is a technique targeted at increasing the strength and endurance of the diaphragm and accessory muscles of inspiration. Studies examining the impact of IMT on asthma have reported increases in inspiratory muscle strength and a reduction in the perception of dyspnea and medication use. However, because of the limited number of studies and discordant methods between studies more evidence is required to elucidate in individuals with asthma the efficacy of IMT on inspiratory muscle endurance, exercise capacity, asthma control, symptoms, and quality of life as well as in adolescents with differing severities of asthma. Large randomized controlled trials would be a significant step forward in clarifying the effectiveness of IMT in individuals with asthma. Although IMT may have favorable effects on inspiratory muscle strength, dyspnea, and medication use, the current evidence that IMT is an effective treatment for asthma is inconclusive.

The effect of inspiratory muscle training in PCD and CF patients: A pilot study

BACKGROUND

Effective work of breathing and bronchial hygiene requires synergy of inspiratory and expiratory muscles. Inspiratory muscle training (IMT) is a part of pulmonary rehabilitation in chronic obstructive pulmonary disease (COPD). There is some evidence of its efficacy in cystic fibrosis (CF) and, recently, in long COVID-19. We are not aware of studies on IMT in primary ciliary dyskinesia (PCD). Our aim was to assess the effect of IMT on respiratory muscle strength and pulmonary function in PCD and CF patients.

METHODS

A single center pilot study. Spirometry, lung clearance index (LCI), maximal inspiratory pressure (MIP), and maximal expiratory pressure (MEP) were measured at baseline (visit 1), after a month of IMT with ®POWERbreathe (visit 2), and at follow-up (visit 3).

RESULTS

The cohort included 27 patients (19 PCD, 8 CF); mean age 18.4 ± 9.8 years. After a month of IMT, there was a significant increase in MIP and MIP% (6.19-7.44, p = .015; and 81.85%-100.41%, p = .046, respectively), which was sustained at visit 3. Compliance ≥90% led to higher improvement in MIP. In sub-group analysis, improvement in MIP and MIP% remained significant for PCD patients (p = .026 and p = .049, respectively). No significant changes were found in spirometry, MEP or LCI.

CONCLUSIONS

IMT was well-tolerated and led to improved inspiratory muscle strength in PCD patients. The clinical implication of improved MIP should be further investigated. Larger, long-term studies are needed to evaluate long-term effects of IMT on pulmonary function, respiratory muscle strength, pulmonary exacerbations, and quality of life.

Does inspiratory muscle training provide additional benefits during pulmonary rehabilitation in people with interstitial lung disease? A randomized control trial

BACKGROUND

Interstitial lung disease (ILD) encompasses a diverse group of chronic lung conditions which is often characterized by inspiratory muscle weakness (IMW). Despite the potential importance of inspiratory muscle dysfunction in ILD, the effect of inspiratory muscle training (IMT) added to pulmonary rehabilitation (PR) in ILD largely remains unknown.

OBJECTIVE

The primary objective of the present study was to evaluate the benefits of IMT added to PR on inspiratory muscle strength and secondary objectives were to assess its effects on functional capacity, health-related quality of life (HRQoL), pulmonary function test (PFT) and dyspnea in ILD along with IMW.

METHODS

Fifty-one participants were randomly allocated into two groups; PR + IMT (n = 26) or PR alone (n = 25). The primary outcome [maximal inspiratory pressure (PI_max)] and secondary outcomes [6-min walk distance (6MWD), St. George's Respiratory Questionnaire (SGRQ), PFT and modified Medical Research Council dyspnea scale (mMRC)] were evaluated before and after the 8-weeks intervention. Independent t-test or Mann Whitney-U test was applied for between-group comparisons while for within-group comparison Wilcoxon's Sign Rank test or paired t test was performed.

RESULTS

At the end of 8 weeks exercise intervention inspiratory muscle strength (PI_max + 11.10 cm H₂O, p< .001), functional capacity (6MWD, + 47.90 m, p= .001), HRQoL (SGRQ-total - 4 points, p= .038) and dyspnea (mMRC dyspnea scale, -1.27, p< .001) improved significantly in PR+IMT group alone.

CONCLUSION

Inclusion of IMT to PR may have superior benefits as compared to PR alone in ILD accompanied with IMW.

Effects of Exercise on Nutritional Status in People with Cystic Fibrosis: A Systematic Review

BACKGROUND

Physical exercise is an important part of regular care for people with cystic fibrosis (CF). It is unknown whether such exercise has beneficial or detrimental effects on nutritional status (body composition). Thus, the objective of this review was to evaluate the effect of exercise on measures of nutritional status in children and adults with CF.

METHODS

Standardized reporting guidelines for systematic reviews were followed and the protocol was prospectively registered. Multiple databases were utilized (e.g., PubMed, Scopus, and CINHAL). Two reviewers independently reviewed titles/abstracts and then the full text for selected studies.

RESULTS

In total, 924 articles were originally identified; data were extracted from 4 eligible studies. These four studies included only children; pulmonary function ranged from severe to normal, and the majority of participants were at or below their recommended weight. Exercise training did not worsen nutritional status in any study; two studies that included resistance exercise reported an increase in fat-free mass. Three of the four studies also reported increased aerobic capacity and/or muscle strength.

CONCLUSIONS

Exercise training can produce positive physiologic changes in children with CF without impairing their nutritional status. In fact, resistance exercise can help improve body mass. Much less is known about how exercise may affect adults or those who are overweight.