Electrical Impedance Plethysmography Technique in Estimating Pulmonary Function Status

An attempt has been made to study the appropriateness of electrical impedance plethysmography (EIP) in detecting pulmonary health status. A feasibility study was conducted on normal, obstructive and restrictive subjects aged between 20 and 60 years. Quantitative assessment of pulmonary function was made by way of both EIP and pulmonary function tests (PFT). Amongst the various EIP parameters, a statistically significant difference was observed for the respiratory band power, between normal (129.7) and obstructive (35.8) subjects, indicating that this EIP variable can be used to distinguish between the two pulmonary function states. A significant positive correlation was observed between a spirometry parameter, peak expiratory flow rate (PEFR), and an EIP parameter, respiratory amplitude (r = 0.372, p < 0.05), thereby indicating that EIP information by way of respiratory amplitude is comparable to that provided by PEFR. Hence, both respiratory amplitude and respiratory band power were seen to provide useful information on pulmonary health status.