Long COVID – respiratory symptoms in non-hospitalised subjects – a cross-sectional study

Abstract

Background The aim of this study was to describe and analyse the variety of respiratory appearances in Long COVID subjects who were not hospitalised during the acute phase of the infection. Methods A consecutive series of 60 subjects participated 10.8 months (SD 4.5) after the acute phase of the infection. Respiratory function was tested concerning lung volumes, expiratory flow, muscle strength, physical capacity including concurrent oxygen saturation, chest expansion, lung sounds, pain and breathing pattern. Differences between those with or without positive test and duration of symptoms more or less than 6 months were analysed with T-test, Chi-square test and Fisher’s exact test. Results Decreased forced vital capacity was found in 6/60 (10%), and forced expiratory volume in 1 s and 7/60 (12%), low maximal inspiratory pressure in 38/58 (54%) and low maximal expiratory pressure in 10/58 (17%). Decreased physical capacity was registered in 36/52 (69%), and thoracic expansion in 26/46 (56%). Pathologic lung sounds had 15/58 (26%) and six patients desaturated during the test of physical capacity. A majority (36/58, 67%) presented pain in the ribcage. All but three patients (95%) showed a dysfunctional breathing pattern in sitting and standing. Only poor and fair correlations were found between age, duration and level of physical capacity compared to spirometry, respiratory muscle strength and thoracic expansion. Conclusion Abnormal breathing pattern and respiratory movements as well as pain, and reduced lung volumes, flow, respiratory muscle strength, physical capacity and thoracic expansion may be involved in Long COVID. The breathing symptoms should therefore be looked for in a wider picture beyond spirometry and oximetry.