Predicting maximum voluntary ventilation in normal healthy individuals using indirect inspiratory muscle strength measurements: a correlation study

Rohit Sontakke,Dhara Kothari,Mangesh Deore

doi:10.4236/health.2010.24043

Abstract

Maximum Voluntary Ventilation (MVV), one of the components of Pulmonary Function Testing (PFT), has multiple uses. Various factors including the inspiratory muscle strength (IMS) influence its magnitude. Our aim was to quantify the IMS indirectly using an economical and non invasive bedside assessment tool, determine its association with MVV and then develop a predictive equation for MVV. 41 healthy non-athletic physical therapy students participated in the study. IMS measurement was performed with a sphygmomanometer. Average of the three net deflections in sphygmomanometer following deepest possible breaths was taken as indirect measurement of IMS in mm of Hg. MVV was measured according to ATS guidelines using a spirometer. Results from the data analysis revealed a significant correlation between IMS and MVV(r = 0.83, p < 0.001) and the coefficient of determination = 0.68. So, we developed a regression equation: Y = 1.9669(X) + 49.838 with SEE: 13.02L/min and ANOVA for the equation was (F=68.9, p < 0.001). Hence, it can be concluded that a strong correlation between the indirect IMS and MVV was established and a predictive equation to estimate MVV was developed. This equation proved to have a high predictive value with a small error of estimation. This indicates that the value of the indirect IMS measurement obtained using the sphygmomanometer can be used to estimate MVV in normal healthy individuals without the use of a conventional spirometer.

Highlights

Evidence-based support for pulmonary rehabilitation in the management of patients with chronic respiratory dysfunction has grown tremendously, and this comprehensive intervention has clearly demonstrated to reduce dyspnea and health care costs, increase exercise performance, and improve health-related quality of life (HRQL) [1,2,3,4,5,6].One of the factors responsible for exercise limitations and reduced HRQL in patients with respiratory disorders is dyspnea [7,8]
The candidate was instructed to take the deepest possible breath starting from functional residual capacity (FRC) and hold it for 1 second until we noted the net deflection in manometer
The Pearson correlation coefficient (r) obtained was 0.83 (p

Summary

Introduction

Evidence-based support for pulmonary rehabilitation in the management of patients with chronic respiratory dysfunction has grown tremendously, and this comprehensive intervention has clearly demonstrated to reduce dyspnea and health care costs, increase exercise performance, and improve health-related quality of life (HRQL) [1,2,3,4,5,6].One of the factors responsible for exercise limitations and reduced HRQL in patients with respiratory disorders is dyspnea [7,8]. Weakness or mechanical inefficiency of the respiratory muscles results in a mismatch between central respiratory motor output and achieved ventilation. This mismatch can explain the dyspnea experienced by patients with neuromuscular diseases affecting the respiratory musculature [9] and in patients with respiratory muscle fatigue [10]. A meta-analysis of IMT in 17 clinical trials found limited support for its use in terms of improving pulmonary function, respiratory muscle strength and endurance, exercise capacity, and functional status in patients with COPD [14,15,16]. Inspiratory muscle training has been found to reduce dyspnea during exertion in patients with respiratory ailments and in normal healthy individu-

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