Respiratory Research (Sep 2021)

Lung function and breathing patterns in hospitalised COVID-19 survivors: a review of post-COVID-19 Clinics

  • James A. Stockley,
  • Eyas A. Alhuthail,
  • Andrew M. Coney,
  • Dhruv Parekh,
  • Tarekegn Geberhiwot,
  • Nandan Gautum,
  • Shyam C. Madathil,
  • Brendan G. Cooper

DOI
https://doi.org/10.1186/s12931-021-01834-5
Journal volume & issue
Vol. 22, no. 1
pp. 1 – 12

Abstract

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Abstract Introduction There is relatively little published on the effects of COVID-19 on respiratory physiology, particularly breathing patterns. We sought to determine if there were lasting detrimental effect following hospital discharge and if these related to the severity of COVID-19. Methods We reviewed lung function and breathing patterns in COVID-19 survivors > 3 months after discharge, comparing patients who had been admitted to the intensive therapy unit (ITU) (n = 47) to those who just received ward treatments (n = 45). Lung function included spirometry and gas transfer and breathing patterns were measured with structured light plethysmography. Continuous data were compared with an independent t-test or Mann Whitney-U test (depending on distribution) and nominal data were compared using a Fisher’s exact test (for 2 categories in 2 groups) or a chi-squared test (for > 2 categories in 2 groups). A p-value of < 0.05 was taken to be statistically significant. Results We found evidence of pulmonary restriction (reduced vital capacity and/or alveolar volume) in 65.4% of all patients. 36.1% of all patients has a reduced transfer factor (TLCO) but the majority of these (78.1%) had a preserved/increased transfer coefficient (KCO), suggesting an extrapulmonary cause. There were no major differences between ITU and ward lung function, although KCO alone was higher in the ITU patients (p = 0.03). This could be explained partly by obesity, respiratory muscle fatigue, localised microvascular changes, or haemosiderosis from lung damage. Abnormal breathing patterns were observed in 18.8% of subjects, although no consistent pattern of breathing pattern abnormalities was evident. Conclusions An “extrapulmonary restrictive” like pattern appears to be a common phenomenon in previously admitted COVID-19 survivors. Whilst the cause of this is not clear, the effects seem to be similar on patients whether or not they received mechanical ventilation or had ward based respiratory support/supplemental oxygen.

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