Reliability and validity of real time chest expansion (RTCEX) device to measure chest expansion with visual feedback

Abstract

Chest expansion is used to assess the effect of treatment for patient with respiratory disease. Chest expansion is measured at two levels i.e. axillary level and xiphoid process. The values represent the circumference magnitude of thoracic cage from maximum inhalation to maximum exhalation which is measured by inch tape. Chest expansion values were calculated by the difference between the inspiratory and expiratory measurement. Tape measurement of the chest expansion is generally performed during exercise in research or clinic, but it shows only temporary numerical value, which is difficult for the examiner to interpret. To rule out these hurdles, a Real Time Chest Expansion (RTCEX) device with visual feedback was developed to show the clear cut data of chest expansion values. The purpose of the study was to find the reliability and validity of RTCEX device to measure chest expansion with visual feedback. Sample of 45 subjects between the age group 20-40 years, both male and female were included in the study. The study was conducted in Dr.D.Y.Patil College of Physiotherapy. As the RTCEX device was aimed to find out the chest expansion values of the individual, the validity of the device had to be established. The chest expansion values were reevaluated by inch tape method. To establish the reliability of the RTCEX device, inter-rater and intra-rater reliability of the device was performed. There was an excellent Intra and Inter rater reliability of the device with Intra class correlation coefficient of 0.968 and 0.951 respectively. The mean chest expansion difference between the inch tape and device method is 0.7 which is clinically not significant which indicates a good validity of the chest expansion device over the inch tape method. The Real Time Chest Expansion (RTCEX) device was considered as a reliable and valid method of measuring chest expansion. This novel device with visual feedback will encourage the patient to do chest expansion more effectively.