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.

Post-COVID interstitial lung disease in symptomatic patients after COVID-19 disease

“…The exact prevalence of post-COVID disease is not yet known, and many studies have aimed to identify risk factors and predisposing factors. The international literature associates female sex , older age , obesity (Stockley et al 2021), invasive ventilatory support (Lerum et al 2021) and more severe COVID-19 disease with the disease, while steroid therapy is considered as a beneficial factor (Myall et al 2021). In contrast, in the present study, male sex is more prevalent in both groups, with no significant difference between the two groups.…”

“…Regarding respiratory function results, the currently available literature is consistent in describing a pattern of restrictive ventilatory dysfunction (reduced TLC, FVC, RV) and diffusion reduction (TLCO; KLCO) Lerum et al 2021;Sonnweber et al 2021;Guler et al 2021;Myall et al 2021;Stockley et al 2021). Several studies have highlighted the impairment in diffusion parameters, which may be related to the severity of COVID-19 disease Guler et al 2021), the presence of CT lesions (McGroder et al 2021), and the use of mechanical ventilation (Guler et al 2021).…”

An online breathing and wellbeing programme (ENO Breathe) for people with persistent symptoms following COVID-19: a parallel-group, single-blind, 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.…”

Measurement of breathing in patients with post-COVID-19 using structured light plethysmography (SLP)

“…► We know that patients who have had COVID- 19 can have abnormal lung function, and we wanted to examine whether there were abnormal breathing patterns in patients who had been in hospital and recovered from COVID-19, but after 3 months had persisting respiratory symptoms. We wanted to see whether patients treated on wards had different breathing abnormalities compared with those who had recovered from having more severe disease and had been intubated and mechanically ventilated for long periods in intensive therapy unit (ITU).…”

“…All patients had SLP measurements made as part of their physiological assessment with other techniques and devices with work and protocol published elsewhere. 19 SLP data from healthy subjects were recorded prior to the COVID-19 pandemic and retrieved retrospectively.…”