Comparative assessment of cough capacity in patients with neuromuscular disease: Spirometer versus portable peak flow meter.

INTRODUCTION

Cough impairment in neuromuscular diseases (NMD) increases pulmonary infection risk. Peak cough flow (PCF) is crucial for assessment, with spirometry (PCFs) as gold standard. Portable peak flow meters (PCFp) are practical, yet their comparability with spirometers in NMD remains debated. This study compared PCFs and PCFp in NMD patients with restrictive lung disease.

METHODS

A prospective, cross-sectional observational study included patients with NMD from a home mechanical ventilation unit. Inclusion criteria comprised a definitive diagnosis of NMD and the ability to perform forced expiratory maneuvers. PCF was measured using a calibrated spirometer (PCFs) and a portable peak flow meter (PCFp) in randomized order. The measurement protocol followed ATS/ERS 2019 standards. Agreement was evaluated using the Bland-Altman method and the Intraclass Correlation Coefficient (ICC). Data normality was assessed by the Shapiro-Wilk test. A p-value<0.05 was considered statistically significant.

RESULTS

Sixty-seven patients (62.1±14.9 years; 46.3% female) with various NMD where included. No significant difference was found between mean PCFs (314.5±98.5L/min) and PCFp (301.6±100.1L/min) (p=0.4535). The ICC was 0.92 (95% CI 0.88-0.95). The Bland-Altman analysis indicated a mean difference of 12.9L/min (limits of agreement ranged from -52.7L/min to 78.5L/min). A strong correlation was observed (r=0.949, p<0.001). Impaired cough capacity (35.8% of patients) was linked to older age and poorer function. No device differences were found within subgroups.

CONCLUSION

PCPp demonstrates an acceptable level of agreement with PCPs in NMD patients. PCPp is a reliable and accessible screening tool for home monitoring. However, the wide limits of agreement observed necessitate further studies involving larger, possibly specific, patient populations to definitively establish the full clinical interchangeability required for therapeutic decision-making.