ABSTRACT
Introduction: Lung functions impairment in covid-19 pneumoniasurvivors cause continued symptoms.Forced oscillation technique (FOT) and impulse oscillometry are valuable in serial monitoring and management of postcovid respiratory symptoms. We aimed to study changes in pulmonary mechanics over 1 year period in covid-19 survivors. Methods: Covid-19 survivors of mixed severity of 18-80 age group underwent serial measurements of FOT using Antlia Caltech © device: on the first follow-up post-discharge, second at 4 weeks after the first and third one-year post-diagnosis of Covid-19. Demographic details, pulse oximetry at rest and modified medical research council scale (mMRC) for dyspnea were recorded at each visit. Pre and post-bronchodilator resistance and reactance were analysed. Results: Out of 94 patientsenrolled,17 completed 1-year follow-up post-covid. 3 patients had moderate, 1 severe and 13 mild covid-19 disease.Age group of participant was 45-75 years (Mean= 58.1±2.2) consisting of 13 males and 4 females. 4 had diabetes and an equal number had hypertension. Rest were without any comorbidity. Small airway resistance R5-R20 was0.87±0.57, [0.25-2.03] (Mean±SD, Range. (n=17), p=0.047), 0.79±0.52, [0.01- 1.93] and 0.66±0.49, [-0.05 - 1.59] similarly reactance-X5 was -0.18±0.12, [-0.43-(-0.04)], -0.16±0.1, [-0.36 - 0.001] and -0.16±0.13, [-0.47-(-0.03)] at first visit, 4 weeks and after 1 year respectively. Results of post-bronchodilator change in small airways are depicted in Figure-1. Conclusion: We found statistically significant change towards improvement in small airway resistance R5-R20. Reactance at 5Hz-X5during monitoring period showed decremental change over a year. Some post-bronchodilator reversibility persisted at the end of 1 year.