Outcomes of acute respiratory distress syndrome in COVID-19 patients compared to the general population: a systematic review and meta-analysis

Alveolar Organoids in Lung Disease Modeling

Lung organoids display a tissue-specific functional phenomenon and mimic the features of the original organ. They can reflect the properties of the cells, such as morphology, polarity, proliferation rate, gene expression, and genomic profile. Alveolar type 2 (AT2) cells have a stem cell potential in the adult lung. They produce and secrete pulmonary surfactant and proliferate to restore the epithelium after damage. Therefore, AT2 cells are used to generate alveolar organoids and can recapitulate distal lung structures. Also, AT2 cells in human-induced pluripotent stem cell (iPSC)-derived alveolospheres express surfactant proteins and other factors, indicating their application as suitable models for studying cell-cell interactions. Recently, they have been utilized to define mechanisms of disease development, such as COVID-19, lung cancer, idiopathic pulmonary fibrosis, and chronic obstructive pulmonary disease. In this review, we show lung organoid applications in various pulmonary diseases, drug screening, and personalized medicine. In addition, stem cell-based therapeutics and approaches relevant to lung repair were highlighted. We also described the signaling pathways and epigenetic regulation of lung regeneration. It is critical to identify novel regulators of alveolar organoid generations to promote lung repair in pulmonary diseases.

A Matched Survival Analysis of Lung Transplant Recipients With Coronavirus Disease 2019-Related Respiratory Failure

BACKGROUND

Lung transplantation is an acceptable and potentially life-saving treatment option for coronavirus disease 2019 (COVID-19)-induced acute respiratory distress syndrome and pulmonary fibrosis. This study was conducted to determine whether recipients of lung transplantation (LT) for COVID-19-related lung disease have comparable outcomes to other recipients with a similar level of lung dysfunction.

METHODS

The Organ Procurement and Transplant Network database was queried for adult LT candidates between 2006 and 2021. Recipients with COVID-19-related respiratory failure were matched 1:2 using a nearest-neighbor algorithm. Kaplan-Meier methods with log-rank tests were used to compare long-term survival. A proportional hazards model was used to calculate risk of death.

RESULTS

A total of 37,333 LT candidates from all causes were compared with 334 candidates from COVID-19-related respiratory failure. COVID-19 recipients were more likely to be younger (50 vs 57 years, P < .001), male (79% vs 60%, P < .001), require extracorporeal membrane oxygenation (56.3% vs 4.0%, P < .001), and have worse lung function (lung allocation score, 82.4 vs 47.8; P < .001) at transplantation. Subsequently, 227 COVID-19 recipients were matched with 454 controls. Patients who received a transplant for COVID-19 had similar rates of mechanical ventilation, extracorporeal membrane oxygenation, postoperative complications, and functional status at discharge compared with controls. There was no difference in overall survival or risk of death from COVID-19 (hazard ratio, 0.82; 95% CI, 0.45-1.53; P = .54).

CONCLUSIONS

Six-month survival for recipients of LT for COVID-19-related respiratory failure was comparable to that of other LT recipients.

Impact of the Angiotensin-Converting Enzyme (ACE) Inhibitors on the Course of the Acute Respiratory Distress Syndrome (ARDS) Developed During COVID-19 and Other Severe Respiratory Infections Under Hyperferritinemia Conditions: A Cohort Study

Background

Angiotensin-converting enzyme 2 (ACE2) is not only the entry route of SARS-CoV-2 infection but also triggers a major mechanism of COVID-19 aggravation by promoting a hyperinflammatory state, leading to lung injury, hematological and immunological dysregulation. The impact of ACE2 inhibitors on the course of COVID-19 is still unclear. The effect of ACE2 inhibitors on the course of acute respiratory distress syndrome (ARDS) during COVID-19 and other severe respiratory infections in conditions of hyperferritinemia (HF) was investigated.

Methods

A cohort study of critically ill patients with COVID-19 and other respiratory diseases (widespread infection, pneumonia) who underwent treatment in The Critical Care Unit of the First University Clinic (Tbilisi, Georgia) during the 2020-2021 years was conducted. The impact of the ACE2 inhibitors on the course of the ARDS developed during COVID-19 and other severe respiratory infections in conditions of different severity of HF was evaluated.

Results

In COVID-19-infected (I) and uninfected (II) patients with ARDS, ACE2 inhibitors reduce the levels of Ang II, C reactive protein (CRP) and D-dimer (I: from 1508.07  ±  26.68 to 48.51  ±  24.35, from 233.92  ±  13.02 to 198.12  ±  11.88, from 7.88  ±  0.47 to 6.28  ±  0.43; II: from 1000.14  ±  149.49 to 46.23  ±  88.21, 226.48  ±  13.81 to 183.52  ±  17.32, from 6.39  ±  0.58 to 5.48  ±  0.69) at moderate HF and Ang II, CRP levels (I: from 1845.89  ±  89.37 to 49.64  ±  51.05, from 209.28  ±  14.41 to 175.37  ±  9.84; II: from 1753.29  ±  65.95 to 49.76  ±  55.74, 287.10  ±  20.50 to 214.71  ±  17.32) at severe HF, reduce interleukin-6 (IL-6) expression at moderate HF (I: from 1977.23  ±  354.66 to 899.36  ±  323.76) and cause reduction of pCO2 index at severe HF (I: from 69.80  ±  3.22 to 60.44  ±  2.20) in COVID-19-infected patients.

Conclusion

Study results show that the ACE2 inhibitors play an important role in the regulation of inflammatory processes in both COVID-19-infected and uninfected patients with ARDS. ACE2 inhibitors decrease immunological disorders, inflammation, and lung alveoli dysfunction, especially in COVID-19-infected patients.

Same but Different? Comparing the Epidemiology, Treatments and Outcomes of COVID-19 and Non-COVID-19 ARDS Cases in Germany Using a Sample of Claims Data from 2021 and 2019

BACKGROUND

Acute respiratory distress syndrome (ARDS) is a severe lung condition that can be caused by a variety of underlying illnesses. Due to SARS-CoV-2, the number of cases with ARDS has increased worldwide, making it essential to compare this form of acute respiratory failure with classical causes of ARDS. While there have been several studies investigating the differences between COVID-19 and non-COVID-19 ARDS in early stages of the pandemic, little is known about the differences in later phases, especially in Germany.

AIM

The aim of this study is to characterize and compare the comorbidities, treatments, adverse events, and outcomes of COVID-19-associated ARDS and non-COVID-19 ARDS using a representative sample of German health claims data from the years 2019 and 2021.

METHODS

We compare percentages and median values of the quantities of interest from the COVID-19 and non-COVID-19 ARDS group, with p-values calculated after conducting Pearson's chi-squared test or the Wilcoxon rank sum test. We also run logistic regressions to access the effect of comorbidities on mortality for COVID-19 ARDS and non-COVID-19 ARDS.

RESULTS

Despite many similarities, we find that that there are some remarkable differences between COVID-19 and non-COVID-19 ARDS cases in Germany. Most importantly, COVID-19 ARDS cases display fewer comorbidities and adverse events, and are more often treated with non-invasive ventilation and nasal high-flow therapy.

CONCLUSIONS

This study highlights the importance of comprehending the contrasting epidemiological features and clinical outcomes of COVID-19 and non-COVID-19 ARDS. This understanding can aid in clinical decision making and guide future research initiatives aimed at enhancing the management of patients afflicted with this severe condition.

Mortality in patients with COVID-19 versus non-COVID-19- related acute respiratory distress syndrome: A single center retrospective observational cohort study

The pathophysiology of coronavirus disease-2019 (COVID-19)-related acute respiratory distress syndrome (ARDS) varies from other pneumonia-related ARDS. We evaluated whether the mortality rates differed for COVID-19 and non-COVID-19-related ARDS in the Asian population in 2021. This single center retrospective observational cohort study included patients with COVID-19 and non-COVID-19-related ARDS that required invasive mechanical ventilation. The primary outcome was all-cause in-hospital mortality. The secondary outcomes included hospital length of stay, ICU length of stay, duration of mechanical ventilation, and ventilator-free days (VFDs) during the first 28 days. A 1:1 propensity score matching was performed to correct potential confounders by age, obesity or not, and ARDS severity. One-hundred-and-sixty-four patients fulfilled the inclusion criteria. After 1:1 propensity score matching, there were 50 patients in each group. The all-cause in-hospital mortality of all patients was 38 (38%), and no significant differences were found between COVID-19 and non-COVID-19-related ARDS (17 [34%) vs. 21 [42%], p = 0.410). Both groups had length of stay (30.0 [20.0-46.0] vs. 27.0 [13.0-45.0] days, p = 0.312), ICU length of stay (19.0 [13.0-35.0] vs. 16.0 [10.0-32.0] days, p = 0.249), length of mechanical ventilation (19.0 [10.0-36.0] vs. 14.0 [9.0-29.0] days, p = 0.488), and ventilator-free days during the first 28 days (5.5 [0.0-17.0] vs. 0.0 [0.0-14.0] days, p = 0.320). Immunocompromised status (Hazard ratio: 3.63; 95% CI: 1.51-8.74, p = 0.004) and progress to severe ARDS (Hazard ratio: 2.92; 95% CI: 1.18-7.22, p = 0.020) were significant in-hospital mortality-related confounders. There were no significant difference in mortality among both groups. Immunocompromised status and progression to severe ARDS are two possible risk factors for patients with ARDS; COVID-19 is not a mortality-related risk exposure.

Recovery from Covid-19 critical illness: A secondary analysis of the ISARIC4C CCP-UK cohort study and the RECOVER trial

Background

We aimed to compare the prevalence and severity of fatigue in survivors of Covid-19 versus non-Covid-19 critical illness, and to explore potential associations between baseline characteristics and worse recovery.

Methods

We conducted a secondary analysis of two prospectively collected datasets. The population included was 92 patients who received invasive mechanical ventilation (IMV) with Covid-19, and 240 patients who received IMV with non-Covid-19 illness before the pandemic. Follow-up data were collected post-hospital discharge using self-reported questionnaires. The main outcome measures were self-reported fatigue severity and the prevalence of severe fatigue (severity >7/10) 3 and 12-months post-hospital discharge.

Results

Covid-19 IMV-patients were significantly younger with less prior comorbidity, and more males, than pre-pandemic IMV-patients. At 3-months, the prevalence (38.9% [7/18] vs. 27.1% [51/188]) and severity (median 5.5/10 vs 5.0/10) of fatigue were similar between the Covid-19 and pre-pandemic populations, respectively. At 6-months, the prevalence (10.3% [3/29] vs. 32.5% [54/166]) and severity (median 2.0/10 vs. 5.7/10) of fatigue were less in the Covid-19 cohort. In the total sample of IMV-patients included (i.e. all Covid-19 and pre-pandemic patients), having Covid-19 was significantly associated with less severe fatigue (severity <7/10) after adjusting for age, sex and prior comorbidity (adjusted OR 0.35 (95%CI 0.15-0.76, p=0.01).

Conclusion

Fatigue may be less severe after Covid-19 than after other critical illness.

Unfavorable Outcome and Long-Term Sequelae in Cases with Severe COVID-19

Emerging evidence shows that individuals with COVID-19 who survive the acute phase of illness may experience lingering symptoms in the following months. There is no clear indication as to whether these symptoms persist for a short time before resolving or if they persist for a long time. In this review, we will describe the symptoms that persist over time and possible predictors in the acute phase that indicate long-term persistence. Based on the literature available to date, fatigue/weakness, dyspnea, arthromyalgia, depression, anxiety, memory loss, slowing down, difficulty concentrating and insomnia are the most commonly reported persistent long-term symptoms. The extent and persistence of these in long-term follow-up is not clear as there are still no quality studies available. The evidence available today indicates that female subjects and those with a more severe initial disease are more likely to suffer permanent sequelae one year after the acute phase. To understand these complications, and to experiment with interventions and treatments for those at greater risk, we must first understand the physio-pathological mechanisms that sustain them.

Quality of Life in COVID-Related ARDS Patients One Year after Intensive Care Discharge (Odissea Study): A Multicenter Observational Study

BACKGROUND

Investigating the health-related quality of life (HRQoL) after intensive care unit (ICU) discharge is necessary to identify possible modifiable risk factors. The primary aim of this study was to investigate the HRQoL in COVID-19 critically ill patients one year after ICU discharge.

METHODS

In this multicenter prospective observational study, COVID-19 patients admitted to nine ICUs from 1 March 2020 to 28 February 2021 in Italy were enrolled. One year after ICU discharge, patients were required to fill in short-form health survey 36 (SF-36) and impact of event-revised (IES-R) questionnaire. A multivariate linear or logistic regression analysis to search for factors associated with a lower HRQoL and post-traumatic stress disorded (PTSD) were carried out, respectively.

RESULTS

Among 1003 patients screened, 343 (median age 63 years [57-70]) were enrolled. Mechanical ventilation lasted for a median of 10 days [2-20]. Physical functioning (PF 85 [60-95]), physical role (PR 75 [0-100]), emotional role (RE 100 [33-100]), bodily pain (BP 77.5 [45-100]), social functioning (SF 75 [50-100]), general health (GH 55 [35-72]), vitality (VT 55 [40-70]), mental health (MH 68 [52-84]) and health change (HC 50 [25-75]) describe the SF-36 items. A median physical component summary (PCS) and mental component summary (MCS) scores were 45.9 (36.5-53.5) and 51.7 (48.8-54.3), respectively, considering 50 as the normal value of the healthy general population. In all, 109 patients (31.8%) tested positive for post-traumatic stress disorder, also reporting a significantly worse HRQoL in all SF-36 domains. The female gender, history of cardiovascular disease, liver disease and length of hospital stay negatively affected the HRQoL. Weight at follow-up was a risk factor for PTSD (OR 1.02, p = 0.03).

CONCLUSIONS

The HRQoL in COVID-19 ARDS (C-ARDS) patients was reduced regarding the PCS, while the median MCS value was slightly above normal. Some risk factors for a lower HRQoL have been identified, the presence of PTSD is one of them. Further research is warranted to better identify the possible factors affecting the HRQoL in C-ARDS.

Brain-Lung Crosstalk: Management of Concomitant Severe Acute Brain Injury and Acute Respiratory Distress Syndrome

Purpose of Review

To summarize pathophysiology, key conflicts, and therapeutic approaches in managing concomitant severe acute brain injury (SABI) and acute respiratory distress syndrome (ARDS).

Recent Findings

ARDS is common in SABI and independently associated with worse outcomes in all SABI subtypes. Most landmark ARDS trials excluded patients with SABI, and evidence to guide decisions is limited in this population. Potential areas of conflict in the management of patients with both SABI and ARDS are (1) risk of intracranial pressure (ICP) elevation with high levels of positive end-expiratory pressure (PEEP), permissive hypercapnia due to lung protective ventilation (LPV), or prone ventilation; (2) balancing a conservative fluid management strategy with ensuring adequate cerebral perfusion, particularly in patients with symptomatic vasospasm or impaired cerebrovascular blood flow; and (3) uncertainty about the benefit and harm of corticosteroids in this population, with a mortality benefit in ARDS, increased mortality shown in TBI, and conflicting data in other SABI subtypes. Also, the widely adapted partial pressure of oxygen (P_aO₂) target of > 55 mmHg for ARDS may exacerbate secondary brain injury, and recent guidelines recommend higher goals of 80–120 mmHg in SABI. Distinct pathophysiology and trajectories among different SABI subtypes need to be considered.

Summary

The management of SABI with ARDS is highly complex, and conventional ARDS management strategies may result in increased ICP and decreased cerebral perfusion. A crucial aspect of concurrent management is to recognize the risk of secondary brain injury in the individual patient, monitor with vigilance, and adjust management during critical time windows. The care of these patients requires meticulous attention to oxygenation and ventilation, hemodynamics, temperature management, and the neurological exam. LPV and prone ventilation should be utilized, and supplemented with invasive ICP monitoring if there is concern for cerebral edema and increased ICP. PEEP titration should be deliberate, involving measures of hemodynamic, pulmonary, and brain physiology. Serial volume status assessments should be performed in SABI and ARDS, and fluid management should be individualized based on measures of brain perfusion, the neurological exam, and cardiopulmonary status. More research is needed to define risks and benefits in corticosteroids in this population.

Clinical Characteristics and Outcomes of Patients With COVID-19-Associated Acute Respiratory Distress Syndrome Who Underwent Lung Transplant

Importance

Lung transplantation is a potentially lifesaving treatment for patients who are critically ill due to COVID-19-associated acute respiratory distress syndrome (ARDS), but there is limited information about the long-term outcome.

Objective

To report the clinical characteristics and outcomes of patients who had COVID-19-associated ARDS and underwent a lung transplant at a single US hospital.

Design, Setting, and Participants

Retrospective case series of 102 consecutive patients who underwent a lung transplant at Northwestern University Medical Center in Chicago, Illinois, between January 21, 2020, and September 30, 2021, including 30 patients who had COVID-19-associated ARDS. The date of final follow-up was November 15, 2021.

Exposures

Lung transplant.

Main Outcomes and Measures

Demographic, clinical, laboratory, and treatment data were collected and analyzed. Outcomes of lung transplant, including postoperative complications, intensive care unit and hospital length of stay, and survival, were recorded.

Results

Among the 102 lung transplant recipients, 30 patients (median age, 53 years [range, 27 to 62]; 13 women [43%]) had COVID-19-associated ARDS and 72 patients (median age, 62 years [range, 22 to 74]; 32 women [44%]) had chronic end-stage lung disease without COVID-19. For lung transplant recipients with COVID-19 compared with those without COVID-19, the median lung allocation scores were 85.8 vs 46.7, the median time on the lung transplant waitlist was 11.5 vs 15 days, and preoperative venovenous extracorporeal membrane oxygenation (ECMO) was used in 56.7% vs 1.4%, respectively. During transplant, patients who had COVID-19-associated ARDS received transfusion of a median of 6.5 units of packed red blood cells vs 0 in those without COVID-19, 96.7% vs 62.5% underwent intraoperative venoarterial ECMO, and the median operative time was 8.5 vs 7.4 hours, respectively. Postoperatively, the rates of primary graft dysfunction (grades 1 to 3) within 72 hours were 70% in the COVID-19 cohort vs 20.8% in those without COVID-19, the median time receiving invasive mechanical ventilation was 6.5 vs 2.0 days, the median duration of intensive care unit stay was 18 vs 9 days, the median post-lung transplant hospitalization duration was 28.5 vs 16 days, and 13.3% vs 5.5% required permanent hemodialysis, respectively. None of the lung transplant recipients who had COVID-19-associated ARDS demonstrated antibody-mediated rejection compared with 12.5% in those without COVID-19. At follow-up, all 30 lung transplant recipients who had COVID-19-associated ARDS were alive (median follow-up, 351 days [IQR, 176-555] after transplant) vs 60 patients (83%) who were alive in the non-COVID-19 cohort (median follow-up, 488 days [IQR, 368-570] after lung transplant).

Conclusions and Relevance

In this single-center case series of 102 consecutive patients who underwent a lung transplant between January 21, 2020, and September 30, 2021, survival was 100% in the 30 patients who had COVID-19-associated ARDS as of November 15, 2021.

COVID-19 pneumonia imaging follow-up: when and how? A proposition from ESTI and ESR

Abstract

This document from the European Society of Thoracic Imaging (ESTI) and the European Society of Radiology (ESR) discusses the role of imaging in the long-term follow-up of COVID-19 patients, to define which patients may benefit from imaging, and what imaging modalities and protocols should be used. Insights into imaging features encountered on computed tomography (CT) scans and potential pitfalls are discussed and possible areas for future review and research are also included.

Key Points

• Post-COVID-19 pneumonia changes are mainly consistent with prior organizing pneumonia and are likely to disappear within 12 months of recovery from the acute infection in the majority of patients.

• At present, with the longest series of follow-up examinations reported not exceeding 12 months, the development of persistent or progressive fibrosis in at least some individuals cannot yet be excluded.

• Residual ground glass opacification may be associated with persisting bronchial dilatation and distortion, and might be termed “fibrotic-like changes” probably consistent with prior organizing pneumonia.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00330-021-08317-7.