Clinical Outcomes of Routine Awake Prone Positioning in COVID-19 Patients: A Systematic Review and Meta-analysis of Randomized Controlled Trials.

Before coronavirus disease 2019 (COVID-19) emerged, proning had been demonstrated to improve oxygenation in those with acute hypoxic respiratory failure and be performed in non-intensive care settings. This benefit was further exemplified by the COVID-19 pandemic, leading to awake prone positioning (APP). We assessed the efficacy of routine APP versus standard care in preventing death and invasive mechanical ventilation (IMV) in non-intubated hypoxic COVID-19 patients. PubMed, Cochrane Library, Scopus, and medRxiv databases were used from January 1st, 2020, to January 15th, 2022, to identify randomized controlled trials (RCTs). Routine APP group were encouraged to be self-prone, whereas the standard care group received care according to local clinical practice and allowed APP crossover as rescue therapy. We included eight COVID-19 RCTs assessing 809 APP vs. 822 standard care patients. APP group had less IMV requirement (26.5% vs. 30.9%; OR - odds ratio 0.77; P=0.03) than the standard care group, with subgroup analysis showing greater benefit (32.5% vs. 39.1%; OR 0.75; P=0.02) for those mainly requiring oxygen support of non-invasive mechanical ventilation (NIMV) and high-flow nasal cannula (HFNC). The time to IMV initiation was similar (mean 8.3 vs. 10.0 days; P=0.66) for patients requiring NIMV and HFNC. Patients mainly receiving supplemental oxygen and non-rebreather masks had improved oxygenation parameters, although not statistically significant. Other outcomes involving all-cause hospital mortality, hospital and ICU (intensive care unit) length of stay, and adverse events were comparable. APP appeared to be an important modality for reducing IMV requirements, especially in those requiring NIMV and HFNC.

Comparison of clinical characteristics and outcomes of COVID-19 patients undergoing early versus late intubation from initial hospital admission: A systematic review and meta-analysis.

BACKGROUND: The true impact of intubation and mechanical ventilation in coronavirus disease 2019 (COVID-19) patients remains controversial. METHODS: We searched Pubmed, Cochrane Library, Embase, and Web of Science databases from inception to October 30th, 2021 for studies containing comparative data of COVID-19 patients undergoing early versus late intubation from initial hospital admission. Early intubation was defined as intubation within 48 h of hospital admission. The primary outcomes assessed were all-cause in-hospital mortality, renal replacement therapy (RRT), and invasive mechanical ventilation (IMV) duration. RESULTS: Four cohort studies with 498 COVID-19 patients were included between February to August 2020, in which 28.6% had early intubation, and 36.0% underwent late intubation. Although the pooled hospital mortality rate was 32.1%, no significant difference in mortality rate was observed (odds ratio [OR] 0.81; 95% confidence interval 0.32-2.00; P = 0.64) among those undergoing early and late intubation. IMV duration (mean 9.62 vs. 11.77 days; P = 0.25) and RRT requirement (18.3% vs. 14.6%; OR 1.19; P = 0.59) were similar regardless of intubation timing. While age, sex, diabetes, and body mass index were comparable, patients undergoing early intubation had higher sequential organ failure assessment (SOFA) scores (mean 7.00 vs. 5.17; P < 0.001). CONCLUSIONS: The timing of intubation from initial hospital admission did not significantly alter clinical outcomes during the early phase of the COVID-19 pandemic. Higher SOFA scores could explain early intubation. With the advancements in COVID-19 therapies, more research is required to determine optimal intubation time beyond the first wave of the pandemic.

Short Review of Liposteroid: A Novel Targeted Glucocorticoid Preparation for Treatment of Autoimmune and Inflammatory Diseases.

This paper briefly reviews the safety and efficacy of liposteroid in different inflammatory and non-inflammatory diseases. Corticosteroids (CS) are the first-line therapy in many inflammatory and autoimmune disorders. Although highly efficacious, long-term use of CS is limited due to the occurrence of significant side effects. Liposteroid, which is a liposomal formulation of dexamethasone palmitate, possess more potent anti-inflammatory and immunosuppressive properties compared to dexamethasone sodium phosphate. These two formulations have markedly different lipid solubility, resulting in different pharmacokinetic and pharmacodynamic properties. Liposteroid has been used with success in patients with rheumatoid arthritis, macrophage activation syndrome, and idiopathic pulmonary hemosiderosis. In addition, liposteroid has been used in some non-inflammatory diseases. Moreover, we conceive that liposteroid may have a beneficial effect in patients, who are critically ill due to COVID-19, and suffer from the macrophage activation syndrome.

Indications, Clinical Utility, and Safety of Bronchoscopy in COVID-19.

BACKGROUND: Bronchoscopy is an aerosol-generating procedure and routine use for patients with coronavirus disease 2019 (COVID-19) has been discouraged. The purpose of this review was to discuss the indications, clinical utility, and risks associated with bronchoscopy in patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pneumonia. METHODS: A literature search was performed by using appropriate key terms to identify all relevant articles from medical literature databases up to August 1, 2021. RESULTS: Twelve cohorts (9 retrospective and 3 prospective) reported the performance of 2,245 bronchoscopies in 1,345 patients with COVID-19. The majority of the subjects were male. Nearly two thirds of the bronchoscopies (62%) were performed for therapeutic indications; the rest (38%) were for diagnostic purposes. Bronchoalveolar lavage had an overall yield of 33.1% for SARS-CoV-2 in subjects with negative results of real-time polymerase chain reaction on nasopharyngeal specimens. The incidence of a secondary infection ranged from 9.3% to as high as 65%. Antibiotics were changed in a significant number of the subjects (14%-83%) based on the bronchoscopic findings. Bronchoscopy was well tolerated in most subjects except those who required noninvasive ventilation, in whom the intubation rate after the procedure was 60%. The rate of transmission of SARS-CoV-2 among health-care workers was minimum. CONCLUSIONS: Bronchoscopy in patients with COVID-19 results in a significant change in patient management. Transmission of SARS-CoV-2 seems to be low with consistent use of appropriate personal protective equipment by health-care workers. Therefore, bronchoscopic evaluation should be considered for all diagnostic and therapeutic indications in this patient population.

Successful use of endobronchial valve for persistent air leak in a patient with COVID-19 and bullous emphysema.

Patients with SARS-CoV-2 pneumonia can suffer from pneumothorax and persistent air leak (PAL). The pneumothorax occurs with or without pre-existing lung disease. PAL refers to air leak lasting more than 5-7 days and arises due to bronchopleural or alveolopleural fistula. The management of PAL can be challenging as a standard management guideline is lacking. Here we present the case of a 42-year-old smoker with COVID-19 who presented to the hospital with fever, cough, acute left-sided chest pain and shortness of breath. He suffered from a large left-sided pneumothorax requiring immediate chest tube drainage. Unfortunately, the air leak persisted for 13 days before one-way endobronchial valve (EBV) was used with complete resolution of the air leak. We also review the literature regarding other cases of EBV utilisation for PAL in patients with COVID-19.

Clinical Characteristics Between Survivors and Nonsurvivors of COVID-19 Patients Requiring Extracorporeal Membrane Oxygenation (ECMO) Support: A Systematic Review and Meta-Analysis.

Background: The use of extracorporeal membrane oxygenation (ECMO) in coronavirus disease 2019 (COVID-19) for refractory respiratory failure, severe cardiac dysfunction, and bridge to lung transplantation has been steadily increasing during the ongoing global pandemic. Objective: Our meta-analysis aims to compare the clinical characteristics between COVID-19 survivors and nonsurvivors requiring ECMO support. Methods: A systematic search of Pubmed, Cochrane, Embase, Scopus, and Web of Science databases was performed between December first, 2019, to June first, 2021. Studies with comparative data of COVID-19 ECMO patients were selected, in which clinical characteristics and complications were assessed. Results: Sixteen cohort studies involving 706 COVID-19 patients requiring ECMO support with pooled mortality rate of 40% were included. Younger age (mean 51 years vs 55 years; P < .001), fewer comorbidities (23% vs 31%; odds ratio [OR] 0.55; P = .02), and less renal replacement therapy (RRT) (21% vs 39%; OR 0.41; P = .007) and vasopressor (76% vs 92%; OR 0.35; P = .008) requirement were demonstrated in COVID-19 survivors requiring ECMO support than nonsurvivors. Survivors also had higher pre-ECMO pH (mean 7.33 vs 7.26; P < .001) than nonsurvivors. No difference was observed in gender, body mass index, duration of mechanical ventilation (MV) before ECMO support initiation, total ECMO support duration, and pre-ECMO parameters of PaO2/FiO2 ratio, tidal volume (mL/kg), positive end-expiratory pressure, and plateau pressure. The rate of bleeding complications was lower in survivors (32% vs 59%; OR 0.36; P = .001) than nonsurvivors, but no difference was observed in thromboembolism and secondary infections. Conclusions: We found advanced age, multiple comorbidities, lower pre-ECMO pH, greater RRT, and vasopressor requirements, and bleeding are predictors of death in COVID-19 patients requiring ECMO support. The duration of MV before ECMO support initiation and total ECMO support duration was similar among survivors and nonsurvivors. Our study results have important clinical implications when considering ECMO support in critically ill COVID-19 patients.

Comparing the clinical characteristics and outcomes of COVID-19-associate pulmonary aspergillosis (CAPA): a systematic review and meta-analysis.

PURPOSE: Invasive pulmonary aspergillosis has been increasingly recognized in COVID-19 patients, termed COVID-19-associate pulmonary aspergillosis (CAPA). Our meta-analysis aims to assess the clinical characteristics and outcomes of patients diagnosed with CAPA compared to those without CAPA. METHODS: We searched the Pubmed, Cochrane Library, SCOPUS, and Web of Science databases for studies published between January 1, 2020 and August 1, 2021, containing comparative data of patients diagnosed with CAPA and those without CAPA. RESULTS: Eight cohort studies involving 729 critically ill COVID-19 patients with comparative data were included. CAPA patients were older (mean age 66.58 vs. 59.25 years; P = 0.007) and had underlying chronic obstructive pulmonary disease (COPD) (13.7 vs. 6.1%; OR 2.75; P = 0.05). No differences in gender, body mass index (BMI), and comorbidities of diabetes and cancer were observed. CAPA patients were more likely to receive long-term corticosteroid treatment (15.0 vs. 5.3%; OR 3.53; P = 0.03). CAPA patients had greater severity of illness based on sequential organ failure assessment (SOFA) score with a higher all-cause in-hospital mortality rate (42.6 vs. 26.5%; OR 3.39; P < 0.001) and earlier ICU admission from illness onset (mean 11.00 vs. 12.00 days; P = 0.003). ICU length of stay (LOS), invasive mechanical ventilation (IMV) duration, the requirement of inotropic support and renal replacement therapy were comparable between the two groups. CONCLUSIONS: CAPA patients are typically older with underlying COPD and received long-term corticosteroid treatment. Furthermore, CAPA is associated with higher SOFA scores, mortality, and earlier onset of ICU admission from illness onset.

Bronchoscopy During Coronavirus Disease 2019 Pandemic: A Bronchoscopist's Perspective.

Bronchoscopy is a safe and commonly performed procedure for diagnostic as well as therapeutic indications. Bronchoscopy is also an aerosol-generating procedure, and due to the risk of severe acute respiratory syndrome coronavirus 2 transmission during the procedure, routine bronchoscopy has been discouraged by multiple professional societies, despite any solid evidence. There are only a few reports of bronchoscopy in patients with coronavirus disease 2019 in the literature. Bronchoscopy in this patient population plays a crucial role not only in the diagnosis of coronavirus disease 2019 but also in the identification of secondary bacterial or fungal infections and in directing appropriate antimicrobial therapy. Bronchoscopy with therapeutic interventions may be lifesaving. Based on the literature, the risk of coronavirus disease 2019 transmission appears to be low among bronchoscopists and other healthcare workers when appropriate personal protective equipment is used. Bronchoscopy in patients with coronavirus disease 2019 should be strongly considered when clinically indicated.

A systematic review and meta-analysis comparing the clinical characteristics and outcomes of COVID-19 and influenza patients on ECMO.

BACKGROUND: Extracorporeal membrane oxygenation (ECMO) is a valuable rescue therapy to treat refractory hypoxemia caused by influenza. The present meta-analysis aimed to compare the clinical characteristics and outcomes of ECMO between COVID-19 and influenza. METHODS: We searched the PubMed, Cochrane Library, SCOPUS, and Web of Science databases from inception to May 1, 2021. The included studies compared the clinical characteristics and outcomes of ECMO between adults with COVID-19 and those with influenza. RESULTS: The study included four retrospective cohorts involving a total of 129 patients with COVID-19 and 140 with influenza who were treated using ECMO. Clinical characteristics were similar between the COVID-19 and influenza groups, including body mass index (BMI), diabetes mellitus, hypertension, and immunocompromised status. A higher proportion of patients with COVID-19 on ECMO were male (75.9% vs. 62.9%; P = 0.04). There was no difference between the groups in terms of illness severity based on sequential organ failure assessment (SOFA) score or serum pH. Patients with COVID-19 had a longer mean duration of mechanical ventilation before ECMO (6.63 vs. 3.38 days; P < 0.01). The pooled mortality rate was 43.8%. The mean ECMO duration (14.13 vs. 12.55 days; P = 0.25) and mortality rate (42.6% vs. 45.0%; P = 0.99) were comparable between the groups. CONCLUSION: Clinical characteristics, ECMO duration, and mortality were comparable between patients with COVID-19 and those with influenza who required ECMO to treat refractory hypoxemia. The duration of mechanical ventilation before ECMO did not influence outcomes. Patients with COVID-19 benefit from ECMO salvage therapy similarly to those with influenza.

Pleural abnormalities in COVID-19: a narrative review.

OBJECTIVE: This narrative review aims to provide a detailed overview of pleural abnormalities in patients with coronavirus disease 19 or COVID-19. BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-Cov-2) is a novel beta coronavirus responsible for COVID-19. Although pulmonary parenchymal and vascular changes associated with COVID-19 are well established, pleural space abnormalities have not been the primary focus of investigations. METHODS: Narrative overview of the medical literature regarding pleural space abnormalities in COVID-19. The appropriate manuscripts were identified by searching electronic medical databases and by hand searching the bibliography of the identified papers. Pleural abnormalities on transverse and ultrasound imaging are discussed. The incidence, clinical features, pathophysiology, and fluid characteristics of pleural effusion are reviewed. Studies reporting pneumothorax and pneumomediastinum are examined to evaluate for pathogenesis and prognosis. A brief comparative analysis of pleural abnormalities among patients with COVID-19, severe acute respiratory syndrome (SARS), and Middle Eastern respiratory syndrome (MERS) has been provided. CONCLUSIONS: Radiologic pleural abnormalities are common in COVID-19, but the incidence of pleural effusion appears to be low. Pneumothorax is rare and does not independently predispose the patient to worse outcomes. SARS-CoV-2 infects the pleural space; however, whether the pleural fluid can propagate the infection is unclear.

Does COVID-19 pneumonia signify secondary organizing pneumonia?: A narrative review comparing the similarities between these two distinct entities.

Multiple observational studies have described the similarities between COVID-19 pneumonia and organizing pneumonia (OP). These two entities clinically manifest with mild and subacute respiratory symptoms, often with a delayed diagnosis due to the atypical ARDS and silent hypoxemia presentation. Radiological features are often indistinguishable between the two. With the increase in antemortem lung biopsies and autopsies being performed, more histopathological findings of OP and its variant, acute fibrinous and organizing pneumonia (AFOP), are being diagnosed. These entities are known complications of viral infections as a delayed immunological process, explaining the favorable response to corticosteroids. Clinicians should be vigilant to diagnose this under-recognized entity of secondary OP in people with COVID-19 when clinical deterioration occurs, especially with compatible radiologic findings and recent cessation of corticosteroids. Despite the proven benefits of corticosteroids in treating COVID-19, treatment approaches can be more effective as OP often requires higher doses and a more prolonged therapy duration for remission and preventing relapses. The purpose of our narrative review is to compare the similarities between COVID-19 pneumonia and OP, emphasizing the clinical, radiological, and histopathological features based on the evidence available in the literature.

Narrative review of the relationship between COVID-19 and PJP: does it represent coinfection or colonization?

BACKGROUND: Pneumocystis jirovecii (P. jirovecii) is increasingly identified on lower respiratory tract specimens of COVID-19 patients. Our narrative review aims to determine whether the diagnosis of pneumocystis jirovecii pneumonia (PJP) in COVID-19 patients represents coinfection or colonization based on the evidence available in the literature. We also discuss the decision to treat COVID-19 patients with coinfection by PJP. METHODS: A literature search was performed through the Pubmed and Web of Science databases from inception to March 10, 2021. RESULTS: We identified 12 COVID-19 patients suspected to have PJP coinfection. All patients were critically ill and required mechanical ventilation. Many were immunosuppressed from HIV or long-term corticosteroids and other immunosuppressive agents. In both the HIV and non-HIV groups, severe lymphocytopenia was encountered with absolute lymphocyte and CD4+T cell count less than 900 and 200 cells/mm, respectively. The time to PJP diagnosis from the initial presentation was 7.8 (range 2-21) days. Serum lactate dehydrogenase and beta-D-glucan were elevated in those coinfected with PJP. All patients were treated with anti-PJP therapy, predominantly sulfamethoxazole-trimethoprim with corticosteroids. The overall mortality rate was 41.6%, and comparable for both HIV and non-HIV groups. CONCLUSION: As the current evidence is restricted to case reports, the true incidence, risk factors, and prognosis of COVID-19 patients with PJP coinfections cannot be accurately determined. Comorbidities of poorly controlled HIV with lymphocytopenia and multiple immunosuppressive therapies are likely predisposing factors for PJP coinfection.

Pneumothorax in critically ill patients with COVID-19 infection: Incidence, clinical characteristics and outcomes in a case control multicenter study.

BACKGROUND: The clinical features and outcomes of mechanically ventilated patients with COVID-19 infection who develop a pneumothorax has not been rigorously described or compared to those who do not develop a pneumothorax. PURPOSE: To determine the incidence, clinical characteristics, and outcomes of critically ill patients with COVID-19 infection who developed pneumothorax. In addition, we compared the clinical characteristics and outcomes of mechanically ventilated patients who developed a pneumothorax with those who did not develop a pneumothorax. METHODS: This study was a multicenter retrospective analysis of all adult critically ill patients with COVID-19 infection who were admitted to intensive care units in 4 tertiary care centers in the United States. RESULTS: A total of 842 critically ill patients with COVID-19 infection were analyzed, out of which 594 (71%) were mechanically ventilated. The overall incidence of pneumothorax was 85/842 (10%), and 80/594 (13%) in those who were mechanically ventilated. As compared to mechanically ventilated patients in the non-pneumothorax group, mechanically ventilated patients in the pneumothorax group had worse respiratory parameters at the time of intubation (mean PaO2:FiO2 ratio 105 vs 150, P<0.001 and static respiratory system compliance: 30ml/cmH2O vs 39ml/cmH2O, P = 0.01) and significantly higher in-hospital mortality (63% vs 49%, P = 0.04). CONCLUSION: The overall incidence of pneumothorax in mechanically ventilated patients with COVID-19 infection was 13%. Mechanically ventilated patients with COVID-19 infection who developed pneumothorax had worse gas exchange and respiratory mechanics at the time of intubation and had a higher mortality compared to those who did not develop pneumothorax.

The incidence, clinical characteristics, and outcomes of pneumothorax in hospitalized COVID-19 patients: A systematic review.

BACKGROUND: Pneumothorax has been frequently described as a complication of COVID-19 infections. OBJECTIVE: In this systematic review, we describe the incidence, clinical characteristics, and outcomes of COVID-19-related pneumothorax. METHODS: Studies were identified through MEDLINE, Pubmed, and Google Scholar databases using keywords of "COVID-19," "SARS-CoV-2," "pneumothorax," "pneumomediastinum," and "barotrauma" from January 1st, 2020 to January 30th, 2021. RESULTS: Among the nine observational studies, the incidence of pneumothorax is low at 0.3% in hospitalized COVID-19 patients. However, the incidence of pneumothorax increases to 12.8-23.8% in those requiring invasive mechanical ventilation (IMV) with a high mortality rate up to 100%. COVID-19-related pneumothorax tends to be unilateral and right-sided. Age, pre-existing lung diseases, and active smoking status are not shown to be risk factors. The time to pneumothorax diagnosis is around 9.0-19.6 days from admission and 5.4 days after IMV initiation. COVID-19-related pneumothoraces are associated with prolonged hospitalization, increased likelihood of ICU admission and death, especially among the elderly. CONCLUSION: COVID-19-related pneumothorax likely signify greater disease severity. With the high variability of COVID-19-related pneumothorax incidence described, a well-designed study is required to better assess the significance of COVID-19-related pneumothorax.

State-of-the-art review of secondary pulmonary infections in patients with COVID-19 pneumonia.

BACKGROUND: The incidence of secondary pulmonary infections is not well described in hospitalized COVID-19 patients. Understanding the incidence of secondary pulmonary infections and the associated bacterial and fungal microorganisms identified can improve patient outcomes. OBJECTIVE: This narrative review aims to determine the incidence of secondary bacterial and fungal pulmonary infections in hospitalized COVID-19 patients, and describe the bacterial and fungal microorganisms identified. METHOD: We perform a literature search and select articles with confirmed diagnoses of secondary bacterial and fungal pulmonary infections that occur 48 h after admission, using respiratory tract cultures in hospitalized adult COVID-19 patients. We exclude articles involving co-infections defined as infections diagnosed at the time of admission by non-SARS-CoV-2 viruses, bacteria, and fungal microorganisms. RESULTS: The incidence of secondary pulmonary infections is low at 16% (4.8-42.8%) for bacterial infections and lower for fungal infections at 6.3% (0.9-33.3%) in hospitalized COVID-19 patients. Secondary pulmonary infections are predominantly seen in critically ill hospitalized COVID-19 patients. The most common bacterial microorganisms identified in the respiratory tract cultures are Pseudomonas aeruginosa, Klebsiella species, Staphylococcus aureus, Escherichia coli, and Stenotrophomonas maltophilia. Aspergillus fumigatus is the most common microorganism identified to cause secondary fungal pulmonary infections. Other rare opportunistic infection reported such as PJP is mostly confined to small case series and case reports. The overall time to diagnose secondary bacterial and fungal pulmonary infections is 10 days (2-21 days) from initial hospitalization and 9 days (4-18 days) after ICU admission. The use of antibiotics is high at 60-100% involving the studies included in our review. CONCLUSION: The widespread use of empirical antibiotics during the current pandemic may contribute to the development of multidrug-resistant microorganisms, and antimicrobial stewardship programs are required for minimizing and de-escalating antibiotics. Due to the variation in definition across most studies, a large, well-designed study is required to determine the incidence, risk factors, and outcomes of secondary pulmonary infections in hospitalized COVID-19 patients.

The incidence of pleural effusion in COVID-19 pneumonia: State-of-the-art review.

BACKGROUND: COVID-19-related pleural effusions are frequently described during the ongoing pandemic. OBJECTIVES: We described the incidence, characteristics, and outcomes of COVID-19-related pleural effusions based on the current evidence available in the literature. METHODS: We searched MEDLINE, Pubmed, and Google Scholar databases using keywords of "coronavirus disease 2019 (COVID-19)," "severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)," "pleural effusion," "pleural fluid," and "pleura" from January 1st, 2020 to January 31st, 2021. RESULTS: The incidence of pleural effusions was low at 7.3% among the 47 observational studies. Pleural effusions were commonly observed in critically ill patients and had Multisystem Inflammatory Syndrome (MIS). COVID-19-related pleural effusions were identified 5-7 days and 11 days, after hospital admission and onset of COVD-19 symptoms. The characteristic findings of pleural fluid were exudative, lymphocytic or neutrophilic-predominant pleural fluid with markedly elevated lactate dehydrogenase (LDH) levels and pleural fluid to serum LDH ratio. CONCLUSION: A well-designed study is required to assess the significance of COVID-19-related pleural effusions during this current pandemic.

Correlation of Respiratory Physiologic Parameters in Mechanically Ventilated Coronavirus Disease 2019 Patients.

Acute respiratory distress syndrome secondary to severe acute respiratory syndrome coronavirus-2 pneumonia or coronavirus disease 2019-related acute respiratory distress syndrome is the primary cause of mortality in coronavirus disease 2019. Some studies have described the concept of "high and low" elastance coronavirus disease 2019-related acute respiratory distress syndrome and proposed individualized management for the acute respiratory distress syndrome, deviating from low tidal volume ventilation. We report simultaneously measured respiratory parameters (static lung compliance, alveolar dead space ventilation, and shunt fraction) in 14 patients with advanced coronavirus disease 2019-related acute respiratory distress syndrome. The results were consistent with typical acute respiratory distress syndrome and did not support the concept of high-type coronavirus disease 2019-related acute respiratory distress syndrome and low-type coronavirus disease 2019-related acute respiratory distress syndrome.

The Significance of Subpleural Sparing in CT Chest: A State-of-the-Art Review.

The subpleural sparing pattern is a common finding on computed tomography (CT) of the lungs. It comprises of pulmonary opacities sparing the lung peripheries, typically 1cm and less from the pleural surface. This finding has a variety of causes, including idiopathic, inflammatory, infectious, inhalational, cardiac, traumatic, and bleeding disorders. Specific disorders that can cause subpleural sparing patterns include nonspecific interstitial pneumonia (NSIP), organizing pneumonia (OP), pulmonary alveolar proteinosis (PAP), diffuse alveolar hemorrhage (DAH), vaping-associated lung injury (VALI), cracked lung, pulmonary edema, pneumocystis jirovecii pneumonia (PJP), pulmonary contusion, and more recently, Coronavirus disease 2019 (COVID-19) pneumonia. Knowledge of the many etiologies of this pattern can be useful in preventing diagnostic errors. In addition, although the etiology of subpleural sparing pattern is frequently indistinguishable during an initial radiologic evaluation, the differences in location of opacities in the lungs, as well as the presence of additional radiologic findings, patient history, and clinical presentation, can often be useful to suggest the appropriate diagnosis. We did a comprehensive search on Pubmed and Google Scholar database using keywords of "subpleural sparing," "peripheral sparing," "sparing of peripheries," "CT chest," "chest imaging," and "pulmonary disease." This review aims to describe the primary differential diagnosis of subpleural sparing pattern seen on chest imaging with a strong emphasis on clinical and radiographic findings. We also discuss the pathogenesis and essential clues that are crucial to narrow the differential diagnosis.

Relationship Between Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) and the Etiology of Acute Kidney Injury (AKI).

Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Since it was first recognized in December 2019, it has resulted in the ongoing worldwide pandemic. Although acute hypoxic respiratory failure (AHRF) and acute respiratory distress syndrome (ARDS) are the main features of the disease, the involvement of other organs needs to be explored. There has been a growing concern regarding the association between acute kidney injury (AKI) and poor outcomes in SARS-CoV-2 patients. Based on current observational data, AKI is the 2nd most common cause of morbidity and mortality behind ARDS in SARS-CoV-2 patients. Angiotensin-converting enzyme 2 (ACE2) receptor has been shown to be the cornerstone of SARS-CoV-2 infection and possibly plays a significant role in the occurrence of renal injury. The pathogenesis of AKI is likely multifactorial that involves not only direct viral invasion but also dysregulated immune response in the form of cytokine storm, ischemia to kidneys, hypercoagulable state, and rhabdomyolysis, among others. We performed a literature search of the Pubmed and Google Scholar database from 1996 to 2020 using the following keywords: severe acute respiratory syndrome coronavirus 2, coronavirus disease 2019, angiotensin-converting enzyme 2 receptor, and acute kidney injury to find the most pertinent and highest-quality of evidence. Any cited references were reviewed to identify relevant literature. The purpose of this review is to discuss, explore, and summarize the relationship between AKI in SARS-CoV-2 patients, with a focus on its epidemiology, association with ACE2 receptors, and pathophysiology of AKI.