Lung Function and Breathing Patterns in Hospitalised COVID-19 Survivors: a Review of Post-COVID-19 Clinics

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.

Impact of an online breathing and wellbeing programme (ENO Breathe) in people with persistent symptoms following COVID-19: a randomised controlled trial

“…The VAS results are in keeping with the qualitative findings regarding participant experience, which suggested improvements in breathlessness on exertion, rather than at rest or minimal exertion, and might relate to breathing pattern disorder, which appears prevalent post-COVID-19. 41 ENO Breathe includes a focus on breathing retraining, which might have been particularly helpful in individuals with breathing pattern disorder, and future research should assess whether formal assessment of the presence of this disorder should be used to guide referral into this kind of programme. The improvements observed could be influenced by the measures selected, the amount of time spent participating in the intervention, or heterogeneity of the participant group.…”