The desat-max in 2-chair test appears to be a worthwhile parameter to identify sickness: An appraisal

Background & objectives The 2-chair test (2CT) has recently been proposed as a cardiopulmonary reserve-specific assessment of post-exercise recovery response. The objective of this study was to find out the most appropriate parameter of 2CT to categorically differentiate between 'normal' and symptomatic diseased population. Methods In a prospective manner, we recruited a random cohort of symptomatic patients attending our outpatient department (OPD) with different respiratory diseases. We also selected another cohort of 'normal' persons from the willing attendants of the patients who had no symptoms and revealed no abnormality on chest X-ray and spirometry. Persons belonging to both groups were requested to mark their 'sickness' on a scale of 0 to 10 ('0' meaning none and '10' meaning maximum possible) under the PPSS (patient-perceived sickness score) and were subjected to perform 2CT. All the test variables related to pulse rate and peripheral capillary oxygen saturation (SpO2) changes were noted for both groups. The 'symptomatic' and 'normal' persons were compared based on the 2CT variables to find the well-performing discriminatory parameter. Results The comparison of 2CT variables of 419 patients and 30 'normal' controls revealed that the PR change max, maximum SpO2, minimum-SpO2, and desat-max can significantly differentiate between the two. However, the desat-max correlated to the PPSS best. The VIP plot, primary component analysis, and pattern-hunter representation further substantiated this. Interpretation & conclusions The desat-max appears to be a sensitive parameter to differentiate the normal from the symptomatic diseased population. Further research in this area is warranted.