Maximal Respiratory Mouth Pressures Assessment in Stable Chronic Obstructive Pulmonary Disease Patients in a Tertiary Hospital in Southwest Nigeria

Objective: This study aimed to assess the respiratory muscle strength in stable chronic obstructive pulmonary disease (COPD) patients, via measuring maximal respiratory mouth pressures [maximal inspiratory pressure (PImax) and maximal expiratory pressure (PEmax)] to determine its association with disease severity and quality of life.Material and Methods: The study was a cross-sectional comparative study. A hundred and forty subjects (70 COPD patients and 70 controls) were recruited. Measurements of PImax, PEmax and spirometry were then performed. The health-related quality of life, severity of obstruction and dyspnea in the COPD patients were assessed using the COPD Assessment Test (CAT), post-bronchodilator Forced Expiratory Volume in 1 second (FEV 1) and the modified Medical Research Council (mMRC) dyspnea scale, respectively. Data was analyzed using Statistical Package for the Social Science (SPSS) version 25.0 (SPSS IL USA.).Results: The mean (±S.D.) PImax and PEmax of the COPD patients (31.78±14.40 cmH2O and 54.80±18.89 cmH2O, respectively) were significantly lower (p<0.001) than the controls (80.40±7.50 cmH2O and 95.44±12.52 cmH2O, respectively). Both the PImax and PEmax correlated positively with the FEV1 of the COPD patients (r=0.658 and 0.534, respectively, p<0.001). The PImax and PEmax decreased as the mMRC dyspnea grade worsened (p<0.001). There was a negative correlation between PImax; PEmax and the CAT score of the COPD patients (r=-0.704 and–0.583, respectively, p<0.001).Conclusion: There was significant respiratory muscle weakness in the COPD patients compared with the controls. The respiratory muscle weakness worsened as the airflow obstruction and dyspnea worsened. Respiratory muscle weakness may also add to the negative impact COPD has on the health status of COPD patients.