Key Takeaway
IMT significantly increased maximal inspiratory pressure (MIP +11.35 cmH2O) and improved FVC in adults with spinal cord injuries, though effects on quality of life were inconsistent.
Summary
This systematic review and meta-analysis investigated the effects of inspiratory muscle training (IMT) on inspiratory muscle strength, lung function, and quality of life in adults with spinal cord injuries (SCI). Spinal cord injuries often impair respiratory muscle function depending on the level of injury, making respiratory complications a leading cause of morbidity and mortality in this population.
The authors searched multiple databases and included 11 studies involving adults with SCI who underwent IMT programs. The primary outcome was maximal inspiratory pressure (MIP), with secondary outcomes including forced vital capacity (FVC), forced expiratory volume in one second (FEV1), and quality of life measures.
The meta-analysis found that IMT produced a statistically significant improvement in MIP, indicating meaningful gains in inspiratory muscle strength. FVC also improved significantly, suggesting enhanced lung volume capacity. However, effects on FEV1 and quality of life measures were less consistent across studies. The findings support IMT as a beneficial rehabilitation tool for improving respiratory muscle strength and lung function in SCI patients, though more high-quality trials are needed to establish optimal protocols.
Methods
Systematic review and meta-analysis of 11 studies involving adults with spinal cord injuries. Databases searched included PubMed, CINAHL, Embase, and Cochrane Library. IMT interventions used threshold loading devices at varying intensities. Outcomes assessed included MIP, FVC, FEV1, and quality of life. Risk of bias assessed using established quality assessment tools.
Key Results
IMT significantly improved MIP (MD = +11.35 cmH2O, 95% CI: 4.86-17.84, p < 0.001) compared to controls. FVC showed significant improvement favoring IMT. FEV1 improvements were not statistically significant across pooled analyses. Quality of life outcomes were reported in few studies with inconsistent results. Benefits were observed across different injury levels, though higher-level injuries (cervical) tended to show larger absolute gains.
Limitations
Small number of included studies (11) with generally small sample sizes. Heterogeneity in SCI level, completeness of injury, time since injury, and IMT protocols. Several studies had methodological limitations including inadequate blinding and high attrition rates. Limited quality of life data prevented robust meta-analysis of this outcome. Lack of long-term follow-up data in most studies.