Correlations of Diaphragm Thickness and Body Surface Area on Pulmonary Functions in Healthy Adults

The present study was undertaken to determine the correlation of diaphragm thickness and body surface area with pulmonary functions in healthy adults.

The various lung functions in humans are due the coordinated contraction and relaxation of different respiratory muscles. Pulmonary functions and strength of the respiratory muscles can get affected by the thickness of the diaphragm and body surface area (BSA). However, not many studies have been undertaken in healthy adult population.

Thirty nine healthy adult male students volunteered for the study. Diaphragm thickness, pulmonary function test & respiratory muscle strength was determined by non-invasive methods. Diaphragm thickness was measured by thoracic ultra-sonogram, pulmonary functions were measured by computerized spirometer. Respiratory muscle strength was estimated as Maximum mouth inspiratory pressure (MMIP) and Maximum mouth expiratory pressure (MMEP) by a calibrated pressure transducer attached to a student Physiograph. Correlation coefficient were obtained between pulmonary function parameters [tidal volume (VT), inspiratory reserve volume(IRV), expiratory reserve volume (ERV), vital capacity (VC), forced vital capacity (FVC), timed vital capacity (FEV₁), FEV₁/FVC%, peak expiratory flow rate (PEFR), Maximum mouth inspiratory pressure (MMIP) and Maximum mouth expiratory pressure (MMEP)] and diaphragm thickness & BSA.

MMIP showed significant correlation with diaphragm thickness, (r= 0.3401, P<0.05). Body surface area showed significant positive correlations with MMEP, IRV, VC, FVC, MVV, FEV₁.

This study proves that greater the diaphragm muscle thickness and higher the body surface area, better is the lung function.