Small airway disease in post-acute COVID-19 syndrome, a non-conventional approach in three years follow-up of a patient with long COVID: a case report

Post-COVID changes in lung function 6 months after veno-venous extracorporeal membrane oxygenation: a prospective observational clinical trial

Background

Severe coronavirus disease 2019 (COVID-19) may require veno-venous extracorporeal membrane oxygenation (V-V ECMO). While V-V ECMO is offered in severe lung injury to COVID-19, long-term respiratory follow-up in these patients is missing. Therefore, we aimed at providing comprehensive data on the long-term respiratory effects of COVID-19 requiring V-V ECMO support during the acute phase of infection.

Methods

In prospective observational cohort study design, patients with severe COVID-19 receiving invasive mechanical ventilation and V-V ECMO (COVID group, n = 9) and healthy matched controls (n = 9) were evaluated 6 months after hospital discharge. Respiratory system resistance at 5 and 19 Hz (R5, R19), and the area under the reactance curve (AX5) was evaluated using oscillometry characterizing total and central airway resistances, and tissue elasticity, respectively. R5 and R19 difference (R5-R19) reflecting small airway function was also calculated. Forced expired volume in seconds (FEV1), forced expiratory vital capacity (FVC), functional residual capacity (FRC), carbon monoxide diffusion capacity (DLCO) and transfer coefficient (KCO) were measured.

Results

The COVID group had a higher AX5 and R5-R19 than the healthy matched control group. However, there was no significant difference in terms of R5 or R19. The COVID group had a lower FEV1 and FVC on spirometry than the healthy matched control group. Further, the COVID group had a lower FRC on plethysmography than the healthy matched control group. Meanwhile, the COVID group had a lower DLCO than healthy matched control group. Nevertheless, its KCO was within the normal range.

Conclusion

Severe acute COVID-19 requiring V-V ECMO persistently impairs small airway function and reduces respiratory tissue elasticity, primarily attributed to lung restriction. These findings also suggest that even severe pulmonary pathologies of acute COVID-19 can manifest in a moderate but still persistent lung function impairment 6 months after hospital discharge.

Trial registration

NCT05812196.

Factors associated with small airway obstruction in COVID-19 survivors: A cross-sectional study among health-care providers

Coronavirus disease 2019 (COVID-19) has been identified for more than two years, yet studies assessing post-infection lung function are limited. Reports on lung function in COVID-19 patients indicate that patients have restrictive defects and small airway dysfunction that can persist and are not necessarily related to the severity of the disease. The aim of this study was to assess the incidence of small airway obstruction and its incidence-associated factors among COVID-19 survivors to better describe the long-term effects of COVID-19. A cross-sectional study was conducted among COVID-19 survivors who less than 50 years at Medan Adventist Hospital between 2020-2022. The data were collected through interview, direct assessment and respiratory examination. A total of 89 COVID-19 survivors were recruited of which the majority of them were female with a mean age of 32.6-year-old with the largest group was 19-30 years. The comorbidities found among the survivors were heart and thyroid disorders, with the most common symptom of post-COVID-19 was fatigue. Most of them had mild COVID-19. The mean forced mid-expiratory flow (FEF25-75%) was 96.3±20.22, with an incidence rate of small airway obstruction was 19.1%. Univariate and multivariate analyses indicated no significant association between age, gender, comorbidities, history of oxygenation during COVID-19 treatment, COVID-19 severity and the type of post COVID-19 syndrome symptoms with the incidence of small airway obstruction. In conclusion, among COVID-19 survivors who were less than 50 years old, those studied variables seems have less association with the incidence of small airway obstruction. Nevertheless, a further study with a bigger sample size is important to be conducted.