Dyspnea: The vanished warning symptom of COVID-19 pneumonia

Derivation and external validation of a nomogram predicting the occurrence of severe illness among hospitalized coronavirus disease 2019 patients: a 2020 Chinese multicenter retrospective study

Background

The worldwide pandemic of coronavirus disease 2019 (COVID-19) has still been an overwhelming public health challenge, and it is vital to identify determinants early to forecast the risk of severity using indicators easily available at admission. The current multicenter retrospective study aimed to derive and validate a user-friendly and effective nomogram to address this issue.

Methods

A training cohort consisting of 437 confirmed COVID-19 cases from three hospitals in Hubei province (Tongji Hospital affiliated with Huazhong University of Science and Technology, Wuhan Third Hospital of Wuhan University and Wuhan Jinyintan Hospital in Hubei province) was retrospectively analyzed to construct a predicting model, and another cohort of 161 hospitalized patients from Public Health Clinical Center of Shanghai was selected as an external validation cohort from January 1, 2020 to March 8, 2020. Determinants of developing into severe COVID-19 were probed using univariate regression together with a multivariate stepwise regression model. The risk of progression to severe COVID-19 was forecasted using the derived nomogram. The performances of the nomogram regarding the discrimination and calibration were assessed in the cohort of training as well as the cohort of external validation, respectively.

Results

A total of 144 (32.95%) and 54 (33.54%) patients, respectively, in cohorts of training and validation progressed to severe COVID-19 during hospitalization. Multivariable analyses showed determinants of severity consisted of hypertension, shortness of breath, platelet count, alanine aminotransferase (ALT), potassium, cardiac troponin I (cTnI), myohemoglobin, procalcitonin (PCT) and intervals from onset to diagnosis. The nomogram had good discrimination with concordance indices being 0.887 (95% CI: 0.854-0.919) and 0.850 (95% CI: 0.815-0.885) in internal and external validation, respectively. Calibration curves exhibited excellent concordance between the predictions by nomogram and actual observations in two cohorts.

Conclusions

We have established and validated an early predicting nomogram model, which can contribute to determine COVID-19 cases at risk of progression to severe illness.

Are there differences in the relationship between respiratory rate and oxygen saturation between patients with COVID-19 and those without COVID-19? Insights from a cohort-based correlational study

BACKGROUND

Physicians have observed patients with COVID-19 without respiratory distress despite marked hypoxaemia and extensive radiographic abnormalities, a controversial phenomenon called 'silent hypoxaemia'. We aimed to compare the relationship between RR and peripheral oxygen saturation (SpO2) in patients with COVID-19 versus patients without COVID-19 when breathing air on admission.

METHODS

We conducted a retrospective multicentre ED cohort correlational study.We used the Spanish Investigators on Emergency Situations TeAm network cohort of patients with COVID-19 admitted to 61 Spanish EDs between March and April 2020. The non-COVID-19 cohort included patients with lower respiratory tract bacterial infections admitted between January 2016 and April 2018.We built a multivariable linear model to investigate the independent predictive factors related to RR and a logistic multivariate regression model to analyse the presence of 'silent hypoxaemia'.

RESULTS

We included 1094 patients with COVID-19 and 477 patients without COVID-19. On admission, RR was lower (20±7 vs 24±8/min, p<0.0001), while SpO2 higher (95±5% vs 90±7%, p<0.0001) in patients with COVID-19 versus patients without COVID-19. RR was negatively associated with SpO2 (RR decreasing with increasing age, beta=-0.37, 95% CI (-0.43; -0.31), p<0.0001), positively associated with age (RR increasing with increasing age, beta=0.05, 95% CI (0.03; 0.07), p<0.0001) and negatively associated with COVID-19 status (RR lower in patients with COVID-19, beta=-1.90, 95% CI (-2.65; -1.15), p<0.0001). The negative RR/SpO2 correlation differed between patients with COVID-19 aged <80 and ≥80 years old (p=0.04). Patients with COVID-19 aged ≥80 years old had lower RR than patients without COVID-19 aged ≥80 years old at SpO2 values <95% (22±7 vs 24±8/min, p=0.004). 'Silent hypoxaemia' defined as RR <20/min with SpO2 <95% was observed in 162 (14.8%) patients with COVID-19 and in 79 (16.6%) patients without COVID-19 (p=0.4). 'Silent hypoxaemia' was associated with age ≥80 years (OR=1.01 (1.01; 1.03), p<0.0001) but not with gender, comorbidities and COVID-19 status.

CONCLUSION

The RR/SpO2 relationship before oxygen administration does not differ between patients with COVID-19 and those without COVID-19, except in elderly patients.

EVALUATION OF PATIENTS WITH COVID-19 IN THE EARLY HYPOXEMIC STAGE AND PATIENTS WITH VIRAL RESPIRATORY TRACT INFECTION IN TERMS OF PULMONARY HYPERTENSION

Arterial hypoxemia occurs in many COVID-19 patients. Hypoxemia is one of the causes of pulmonary hypertension (PH). Main pulmonary artery dilatation and the main pulmonary artery diameter (mPAD) to ascending aorta diameter (AAD) ratio of ≥1 are significant findings regarding PH. In this study, COVID-19 patients and non-COVID-19 patients with viral respiratory tract infection were evaluated retrospectively in terms of PH. A total of 124 patients (71 male and 53 female), age range 18-85 years, were included in the study as case group and control group. Thoracic computed tomography (CT) images, blood and biochemical parameters, and demographic information were compared between the case group and control group. The normality of numerical variables was examined with Kolmogorov-Smirnov test and homogeneity of the variances with Levene's test. This is the first study researching the effect of early hypoxemic stage COVID-19 infection on development of PH. As a result, it was specified that COVID-19 infection had no effects on mPAD, whereas it had a positive effect on AAD and thus led to a decrease in the mPAD/AAD ratio. Through these values, which could be easily calculated from thoracic CT images, the changes caused by COVID-19 infection on vessel diameters were put forward.

Obstructive sleep apnea: a major risk factor for COVID-19 encephalopathy?

BACKGROUND

This study evaluates the impact of high risk of obstructive sleep apnea (OSA) on coronavirus disease 2019 (COVID-19) acute encephalopathy (AE).

METHODS

Between 3/1/2020 and 11/1/2021, 97 consecutive patients were evaluated at the Geneva University Hospitals with a neurological diagnosis of COVID-19 AE. They were divided in two groups depending on the presence or absence of high risk for OSA based on the modified NOSAS score (mNOSAS, respectively ≥ 8 and < 8). We compared patients' characteristics (clinical, biological, brain MRI, EEG, pulmonary CT). The severity of COVID-19 AE relied on the RASS and CAM scores.

RESULTS

Most COVID-19 AE patients presented with a high mNOSAS, suggesting high risk of OSA (> 80%). Patients with a high mNOSAS had a more severe form of COVID-19 AE (84.8% versus 27.8%), longer mean duration of COVID-19 AE (27.9 versus 16.9 days), higher mRS at discharge (≥ 3 in 58.2% versus 16.7%), and increased prevalence of brain vessels enhancement (98.1% versus 20.0%). High risk of OSA was associated with a 14 fold increased risk of developing a severe COVID-19 AE (OR = 14.52).

DISCUSSION

These observations suggest an association between high risk of OSA and COVID-19 AE severity. High risk of OSA could be a predisposing factor leading to severe COVID-19 AE and consecutive long-term sequalae.

Risk Factors Associated with Severity and Death from COVID-19 in Iran: A Systematic Review and Meta-Analysis Study

Objectives: This study aims to investigate the risk factors associated with severity and death from COVID-19 through a systematic review and meta-analysis of the published documents in Iran. Methods: A systematic search was performed based on all articles indexed in Scopus, Embase, Web of Science (WOS), PubMed, and Google Scholar in English and Scientific Information Database (SID) and Iranian Research Institute for Information Science and Technology (IRA)NDOC indexes in Persian. To assess quality, we used the Newcastle Ottawa Scale. Publication bias was assessed using Egger's tests. Forest plots were used for a graphical description of the results. We used HRs, and ORs reported for the association between risk factors and COVID-19 severity and death. Results: Sixty-nine studies were included in the meta-analysis, of which 62 and 13 had assessed risk factors for death and severity, respectively. The results showed a significant association between death from COVID-19 and age, male gender, diabetes, hypertension, cardiovascular disease (CVD), cerebrovascular disease, chronic kidney disease (CKD), Headache, and Dyspnea. We observed a significant association between increased white blood cell (WBC), decreased Lymphocyte, increased blood urea nitrogen (BUN), increased creatinine, vitamin D deficiency, and death from COVID-19. There was only a significant relationship between CVD and disease severity. Conclusion: It is recommended that the predictive risk factors of COVID-19 severity and death mentioned in this study to be used for therapeutic and health interventions, to update clinical guidelines and determine patients' prognoses.

Morphological prediction of lethal outcomes in the evaluation of lung tissue structural changes in patients on respiratory support with СOVID-19: Ukrainian experience

The impact of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on lung tissue in patients on respiratory support is of significant scientific interest in predicting mortality. This study aimed to analyze post-mortem histological changes in the lung tissue of COVID-19 patients on respiratory support using vital radiology semiotics. A total of 41 autopsies were performed on patients who died of SARS-CoV-2 and had confirmed COVID-19 by polymerase chain reaction (PCR) and radiological evidence of lung tissue consolidation and ground glass opacity. The results showed that the duration of COVID-19 in patients on respiratory support was significantly associated with the development of all stages of diffuse alveolar damage, acute fibrous organizing pneumonia, pulmonary capillary congestion, fibrin thrombi, perivascular inflammation, alveolar hemorrhage, proliferating interstitial fibroblasts, and pulmonary embolism. The prediction model for lethal outcomes based on the duration of total respiratory support had a sensitivity of 68.3% and a specificity of 87.5%. In conclusion, for COVID-19 patients on long-term respiratory support with radiological signs of ground glass opacity and lung consolidation, post-mortem morphological features included various stages of diffuse alveolar lung damage, pulmonary capillary congestion, fibrin clots, and perivascular inflammation.

Effective Outcome of HBOT as an Adjuvant Therapy in Patients Diagnosed with COVID-19 in a Tertiary Care Hospital – A Preliminary Study

Introduction

Hyperbaricoxygen therapy (HBOT) is breathing100% oxygen in pressurised chamber. This therapy ensures quick oxygen delivery to the bloodstream. In patients with severe COVID-19 pneumonia, progressive hypoxemia occurs. Oxygen therapy hasa significant role in its management.

Aim of the study

The objective was to study the efficacy of hyperbaric oxygen therapy (HBOT) as adjuvant therapy for reducing the requirement of additional oxygen supplementationin patients with moderate to severe ARDS diagnosed with COVID-19.

Methods

A single-centre prospective pilot cohort study was conducted ata tertiary care hospital from December 2020 to February 2021 over two months. Fifty patients with COVID-19 needingoxygen, satisfying the selection criteria, were included. Hyperbaricoxygen therapy wasgiven to all patients. The patient received30-45 minutes of hyperbaric oxygen with 15 minutes of pressurizing and depressurizing at 2.0 atmosphere absolute (ATA) with or without airbrakesas per the critical care team. Oxygen requirement, PaO2, andcondition at discharge were considered as primary outcome variables.

Results

Among the 50 participants studied, the mean age was 53.64±13.26 years. Out of 50 participants, 49(98.00%) had PaO2≤80 mmHg, and one (2.00%) had >80 PaO2. All the participants 50(100%) had PaO2 as 90 mmHg after three sittings.

Conclusion

This studyshows promising results in using HBOT to overcome respiratory failure in COVID-19. HBOT reduced the need for oxygen by improving the oxygen saturation levels.

Comparison of prognostic scores for inpatients with COVID-19: a retrospective monocentric cohort study

Background

The SARS-CoV-2 pandemic led to a steep increase in hospital and intensive care unit (ICU) admissions for acute respiratory failure worldwide. Early identification of patients at risk of clinical deterioration is crucial in terms of appropriate care delivery and resource allocation. We aimed to evaluate and compare the prognostic performance of Sequential Organ Failure Assessment (SOFA), Quick Sequential Organ Failure Assessment (qSOFA), Confusion, Uraemia, Respiratory Rate, Blood Pressure and Age ≥65 (CURB-65), Respiratory Rate and Oxygenation (ROX) index and Coronavirus Clinical Characterisation Consortium (4C) score to predict death and ICU admission among patients admitted to the hospital for acute COVID-19 infection.

Methods and analysis

Consecutive adult patients admitted to the Geneva University Hospitals during two successive COVID-19 flares in spring and autumn 2020 were included. Discriminative performance of these prediction rules, obtained during the first 24 hours of hospital admission, were computed to predict death or ICU admission. We further exluded patients with therapeutic limitations and reported areas under the curve (AUCs) for 30-day mortality and ICU admission in sensitivity analyses.

Results

A total of 2122 patients were included. 216 patients (10.2%) required ICU admission and 303 (14.3%) died within 30 days post admission. 4C score had the best discriminatory performance to predict 30-day mortality (AUC 0.82, 95% CI 0.80 to 0.85), compared with SOFA (AUC 0.75, 95% CI 0.72 to 0.78), qSOFA (AUC 0.59, 95% CI 0.56 to 0.62), CURB-65 (AUC 0.75, 95% CI 0.72 to 0.78) and ROX index (AUC 0.68, 95% CI 0.65 to 0.72). ROX index had the greatest discriminatory performance (AUC 0.79, 95% CI 0.76 to 0.83) to predict ICU admission compared with 4C score (AUC 0.62, 95% CI 0.59 to 0.66), CURB-65 (AUC 0.60, 95% CI 0.56 to 0.64), SOFA (AUC 0.74, 95% CI 0.71 to 0.77) and qSOFA (AUC 0.59, 95% CI 0.55 to 0.62).

Conclusion

Scores including age and/or comorbidities (4C and CURB-65) have the best discriminatory performance to predict mortality among inpatients with COVID-19, while scores including quantitative assessment of hypoxaemia (SOFA and ROX index) perform best to predict ICU admission. Exclusion of patients with therapeutic limitations improved the discriminatory performance of prognostic scores relying on age and/or comorbidities to predict ICU admission.

COVID-19 smart diagnosis in the Emergency Department: all-in in practice

Introduction

Coronavirus Disease 19 (COVID-19) diagnosis has been a major problem in most Emergency Departments (EDs) and other senior care facilities. Various clinical manifestations, and the several radiologic and laboratory data combined with the misleading test results to identify the virus, are responsible for certain misdiagnoses, especially in suspected cases needing urgent management and treatment. Although emergency and other front-line physicians struggle to manage COVID-19 patients, still existent cases with ambiguous diagnosis trammel the ED safety and responsibility.

Areas Covered

This review article summarizes on a large scale the common information for the medical history, clinical examinations, radiology and laboratory data for SARS-CoV-2. We summarize the available literature using the PubMed, Science Direct and EMBASE databases published until December 2021 on the general information for COVID-19 diagnosis, and, finally, we propose algorithms for a precise and on-the-spot diagnosis the disease.

Expert Opinion

COVID-19 diagnosis has appeared to be such ambiguous, and physicians need to correlate medical history, medical examination, potential extrapulmonary manifestations, along with laboratory and radiologic data, for a prompt COVID-19 diagnosis.

OUP accepted manuscript

Lack of awareness of cognitive impairment (i.e. anosognosia) could be a key factor for distinguishing between neuropsychological post-COVID-19 condition phenotypes. In this context, the 2-fold aim of the present study was to (i) establish the prevalence of anosognosia for memory impairment, according to the severity of the infection in the acute phase and (ii) determine whether anosognosic patients with post-COVID syndrome have a different cognitive and psychiatric profile from nosognosic patients, with associated differences in brain functional connectivity. A battery of neuropsychological, psychiatric, olfactory, dyspnoea, fatigue and quality-of-life tests was administered 227.07 ± 42.69 days post-SARS-CoV-2 infection to 102 patients (mean age: 56.35 years, 65 men, no history of neurological, psychiatric, neuro-oncological or neurodevelopmental disorder prior to infection) who had experienced either a mild (not hospitalized; n = 45), moderate (conventional hospitalization; n = 34) or severe (hospitalization with intensive care unit stay and mechanical ventilation; n = 23) presentation in the acute phase. Patients were first divided into two groups according to the presence or absence of anosognosia for memory deficits (26 anosognosic patients and 76 nosognosic patients). Of these, 49 patients underwent an MRI. Structural images were visually analysed, and statistical intergroup analyses were then performed on behavioural and functional connectivity measures. Only 15.6% of patients who presented mild disease displayed anosognosia for memory dysfunction, compared with 32.4% of patients with moderate presentation and 34.8% of patients with severe disease. Compared with nosognosic patients, those with anosognosia for memory dysfunction performed significantly more poorly on objective cognitive and olfactory measures. By contrast, they gave significantly more positive subjective assessments of their quality of life, psychiatric status and fatigue. Interestingly, the proportion of patients exhibiting a lack of consciousness of olfactory deficits was significantly higher in the anosognosic group. Functional connectivity analyses revealed a significant decrease in connectivity, in the anosognosic group as compared with the nosognosic group, within and between the following networks: the left default mode, the bilateral somatosensory motor, the right executive control, the right salient ventral attention and the bilateral dorsal attention networks, as well as the right Lobules IV and V of the cerebellum. Lack of awareness of cognitive disorders and, to a broader extent, impairment of the self-monitoring brain system, may be a key factor for distinguishing between the clinical phenotypes of post-COVID syndrome with neuropsychological deficits.

Neurologic complications of coronavirus and other respiratory viral infections

In humans, several respiratory viruses can have neurologic implications affecting both central and peripheral nervous system. Neurologic manifestations can be linked to viral neurotropism and/or indirect effects of the infection due to endothelitis with vascular damage and ischemia, hypercoagulation state with thrombosis and hemorrhages, systemic inflammatory response, autoimmune reactions, and other damages. Among these respiratory viruses, recent and huge attention has been given to the coronaviruses, especially the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic started in 2020. Besides the common respiratory symptoms and the lung tropism of SARS-CoV-2 (COVID-19), neurologic manifestations are not rare and often present in the severe forms of the infection. The most common acute and subacute symptoms and signs include headache, fatigue, myalgia, anosmia, ageusia, sleep disturbances, whereas clinical syndromes include mainly encephalopathy, ischemic stroke, seizures, and autoimmune peripheral neuropathies. Although the pathogenetic mechanisms of COVID-19 in the various acute neurologic manifestations are partially understood, little is known about long-term consequences of the infection. These consequences concern both the so-called long-COVID (characterized by the persistence of neurological manifestations after the resolution of the acute viral phase), and the onset of new neurological symptoms that may be linked to the previous infection.

COVID-19 pneumonia: pathophysiology and management

Coronavirus disease 2019 (COVID-19) pneumonia is an evolving disease. We will focus on the development of its pathophysiologic characteristics over time, and how these time-related changes determine modifications in treatment. In the emergency department: the peculiar characteristic is the coexistence, in a significant fraction of patients, of severe hypoxaemia, near-normal lung computed tomography imaging, lung gas volume and respiratory mechanics. Despite high respiratory drive, dyspnoea and respiratory rate are often normal. The underlying mechanism is primarily altered lung perfusion. The anatomical prerequisites for PEEP (positive end-expiratory pressure) to work (lung oedema, atelectasis, and therefore recruitability) are lacking. In the high-dependency unit: the disease starts to worsen either because of its natural evolution or additional patient self-inflicted lung injury (P-SILI). Oedema and atelectasis may develop, increasing recruitability. Noninvasive supports are indicated if they result in a reversal of hypoxaemia and a decreased inspiratory effort. Otherwise, mechanical ventilation should be considered to avert P-SILI. In the intensive care unit: the primary characteristic of the advance of unresolved COVID-19 disease is a progressive shift from oedema or atelectasis to less reversible structural lung alterations to lung fibrosis. These later characteristics are associated with notable impairment of respiratory mechanics, increased arterial carbon dioxide tension (P_aCO2), decreased recruitability and lack of response to PEEP and prone positioning.

COVID-19 pneumonia cannot be correctly described, analysed and treated if the time-factor is not taken into accounthttps://bit.ly/3AOKxc4

Prognostic impact of CT severity score in childhood cancer with SARS-CoV-2

Background

CT chest severity score (CTSS) is a semi-quantitative measure done to correlate the severity of the pulmonary involvement on the CT with the severity of the disease.

The objectives of this study are to describe chest CT criteria and CTSS of the COVID-19 infection in pediatric oncology patients, to find a cut-off value of CTSS that can differentiate mild COVID-19 cases that can be managed at home and moderate to severe cases that need hospital care.

A retrospective cohort study was conducted on 64 pediatric oncology patients with confirmed COVID-19 infection between 1 April and 30 November 2020. They were classified clinically into mild, moderate, and severe groups. CT findings were evaluated for lung involvement and CTSS was calculated and range from 0 (clear lung) to 20 (all lung lobes were affected).

Results

Overall, 89% of patients had hematological malignancies and 92% were under active oncology treatment. The main CT findings were ground-glass opacity (70%) and consolidation patches (62.5%). In total, 85% of patients had bilateral lung involvement, ROC curve  showed that the area under the curve of CTSS for diagnosing severe type was 0.842 (95% CI 0.737–0.948). The CTSS cut-off of 6.5 had 90.9% sensitivity and 69% specificity, with 41.7% positive predictive value (PPV) and 96.9% negative predictive value (NPV). According to the Kaplan–Meier analysis, mortality risk was higher in patients with CT score > 7 than in those with CTSS < 7.

Conclusion

Pediatric oncology patients, especially those with hematological malignancies, are more vulnerable to COVID-19 infection. Chest CT severity score > 6.5 (about 35% lung involvement) can be used as a predictor of the need for hospitalization.

The Misattributed and Silent Causes of Poor COVID-19 Outcomes Among Pregnant Women

Abundant evidence strongly suggests that the condition of pregnancy makes women and their fetuses highly vulnerable to severe Corona-virus 2019 (COVID-19) complications. Here, two novel hypoxia-related conditions are proposed to play a pivotal role in better understanding the relationship between COVID-19, pregnancy and poor health outcomes. The first condition, "misattributed dyspnea (shortness of breath)" refers to respiratory symptoms common to both advanced pregnancy and COVID-19, which are mistakenly perceived as related to the former rather than to the latter; as a result, pregnant women with this condition receive no medical attention until the disease is in an advanced stage. The second condition, "silent hypoxia", refers to abnormally low blood oxygen saturation levels in COVID-19 patients, which occur in the absence of typical respiratory distress symptoms, such as dyspnea, thereby also leading to delayed diagnosis and treatment. The delay in diagnosis and referral to treatment, due to either "misattributed dypsnea" or "silent hypoxia", may lead to rapid deterioration and poor health outcome to both the mothers and their fetuses. This is particularly valid among women during advanced stages of pregnancy as the altered respiratory features make the consequences of the disease more challenging to cope with. Studies have demonstrated the importance of monitoring blood oxygen saturation by pulse oximetry as a reliable predictor of disease severity and outcome among COVID-19 patients. We propose the use of home pulse oximetry during pregnancy as a diagnostic measure that, together with proper medical guidance, may allow early diagnosis of hypoxia and better health outcomes.

What about the others: differential diagnosis of COVID-19 in a German emergency department

Background

The ongoing COVID-19 pandemic remains a major challenge for worldwide health care systems and in particular emergency medicine. An early and safe triage in the emergency department (ED) is especially crucial for proper therapy. Clinical symptoms of COVID-19 comprise those of many common diseases; thus, differential diagnosis remains challenging.

Method

We performed a retrospective study of 314 ED patients presenting with conceivable COVID-19 symptoms during the first wave in Germany. All were tested for COVID-19 with SARS-Cov-2-nasopharyngeal swabs. Forty-seven patients were positive. We analyzed the 267 COVID-19 negative patients for their main diagnosis and compared COVID-19 patients with COVID-19 negative respiratory infections for differences in laboratory parameters, symptoms, and vital signs.

Results

Among the 267 COVID-19 negative patients, 42.7% had respiratory, 14.2% had other infectious, and 11.2% had cardiovascular diseases. Further, 9.0% and 6.7% had oncological and gastroenterological diagnoses, respectively. Compared to COVID-19 negative airway infections, COVID-19 patients showed less dyspnea (OR 0.440; p = 0.024) but more dysgeusia (OR 7.631; p = 0.005). Their hospital stay was significantly longer (9.0 vs. 5.6 days; p = 0.014), and their mortality significantly higher (OR 3.979; p = 0.014).

Conclusion

For many common ED diagnoses, COVID-19 should be considered a differential diagnosis. COVID-19 cannot be distinguished from COVID-19 negative respiratory infections by clinical signs, symptoms, or laboratory results. When hospitalization is necessary, the clinical course of COVID-19 airway infections seems to be more severe compared to other respiratory infections.

Trial registration: German Clinical Trial Registry DRKS, DRKS-ID of the study: DRKS00021675 date of registration: May 8th, 2020, retrospectively registered.

A General Overview on the Hyperbaric Oxygen Therapy: Applications, Mechanisms and Translational Opportunities

Hyperbaric oxygen therapy (HBOT) consists of using of pure oxygen at increased pressure (in general, 2-3 atmospheres) leading to augmented oxygen levels in the blood (Hyperoxemia) and tissue (Hyperoxia). The increased pressure and oxygen bioavailability might be related to a plethora of applications, particularly in hypoxic regions, also exerting antimicrobial, immunomodulatory and angiogenic properties, among others. In this review, we will discuss in detail the physiological relevance of oxygen and the therapeutical basis of HBOT, collecting current indications and underlying mechanisms. Furthermore, potential areas of research will also be examined, including inflammatory and systemic maladies, COVID-19 and cancer. Finally, the adverse effects and contraindications associated with this therapy and future directions of research will be considered. Overall, we encourage further research in this field to extend the possible uses of this procedure. The inclusion of HBOT in future clinical research could be an additional support in the clinical management of multiple pathologies.

Pathogenesis of the initial stages of severe COVID-19

Since SARS-CoV-2 first appeared in humans, the scientific community has tried to gather as much information as possible in order to find effective strategies for the containment and treatment this pandemic coronavirus. We reviewed the current published literature on SARS-CoV-2 with an emphasis on the distribution of SARS-CoV-2 in tissues and body fluids, as well as data on the expression of its input receptors on the cell surface. COVID-19 affects many organ systems in many ways. These varied manifestations are associated with viral tropism and immune responses of the infected person, but the exact mechanisms are not yet fully understood. We emphasize the broad organotropism of SARS-CoV-2, as many studies have identified viral components (RNA, proteins) in many organs, including immune cells, pharynx, trachea, lungs, blood, heart, blood vessels, intestines, brain, kidneys, and male reproductive organs. Viral components are present in various body fluids, such as mucus, saliva, urine, cerebrospinal fluid, semen and breast milk. The main SARS-CoV-2 receptor, ACE2, is expressed at different levels in many tissues throughout the human body, but its expression levels do not always correspond to the detection of SARS-CoV-2, indicating a complex interaction between the virus and humans. We also highlight the role of the renin-angiotensin aldosterone system and its inhibitors in the context of COVID-19. In addition, SARS-CoV-2 has various strategies that are widely used in various tissues to evade innate antiviral immunity. Targeting immune evasion mediators of the virus can block its replication in COVID-19 patients. Together, these data shed light on the current understanding of the pathogenesis of SARS-CoV-2 and lay the groundwork for better diagnosis and treatment of patients with COVID-19.

COVID-19 encephalopathy: Clinical and neurobiological features

Severe acute respiratory coronavirus 2 (SARS-CoV-2) has been associated with neurological complications, including acute encephalopathy. To better understand the neuropathogenesis of this acute encephalopathy, we describe a series of patients with coronavirus disease 2019 (COVID-19) encephalopathy, highlighting its phenomenology and its neurobiological features. On May 10, 2020, 707 patients infected by SARS-CoV-2 were hospitalized at the Geneva University Hospitals; 31 (4.4%) consecutive patients with an acute encephalopathy (64.6 ± 12.1 years; 6.5% female) were included in this series, after exclusion of comorbid neurological conditions, such as stroke or meningitis. The severity of the COVID-19 encephalopathy was divided into severe and mild based on the Richmond Agitation Sedation Scale (RASS): severe cases (n = 14, 45.2%) were defined on a RASS < -3 at worst presentation. The severe form of this so-called COVID-19 encephalopathy presented more often a headache. The severity of the pneumonia was not associated with the severity of the COVID-19 encephalopathy: 28 of 31 (90%) patients did develop an acute respiratory distress syndrome, without any difference between groups (p = .665). Magnetic resonance imaging abnormalities were found in 92.0% (23 of 25 patients) with an intracranial vessel gadolinium enhancement in 85.0% (17 of 20 patients), while an increased cerebrospinal fluid/serum quotient of albumin suggestive of blood-brain barrier disruption was reported in 85.7% (6 of 7 patients). Reverse transcription-polymerase chain reaction for SARS-CoV-2 was negative for all patients in the cerebrospinal fluid. Although different pathophysiological mechanisms may contribute to this acute encephalopathy, our findings suggest the hypothesis of disturbed brain homeostasis and vascular dysfunction consistent with a SARS-CoV-2-induced endotheliitis.

Development and validation of a prognostic nomogram for predicting in-hospital mortality of COVID-19: a multicenter retrospective cohort study of 4086 cases in China

To establish an effective nomogram for predicting in-hospital mortality of COVID-19, a retrospective cohort study was conducted in two hospitals in Wuhan, China, with a total of 4,086 hospitalized COVID-19 cases. All patients have reached therapeutic endpoint (death or discharge). First, a total of 3,022 COVID-19 cases in Wuhan Huoshenshan hospital were divided chronologically into two sets, one (1,780 cases, including 47 died) for nomogram modeling and the other (1,242 cases, including 22 died) for internal validation. We then enrolled 1,064 COVID-19 cases (29 died) in Wuhan Taikang-Tongji hospital for external validation. Independent factors included age (HR for per year increment: 1.05), severity at admission (HR for per rank increment: 2.91), dyspnea (HR: 2.18), cardiovascular disease (HR: 3.25), and levels of lactate dehydrogenase (HR: 4.53), total bilirubin (HR: 2.56), blood glucose (HR: 2.56), and urea (HR: 2.14), which were finally selected into the nomogram. The C-index for the internal resampling (0.97, 95% CI: 0.95-0.98), the internal validation (0.96, 95% CI: 0.94-0.98), and the external validation (0.92, 95% CI: 0.86-0.98) demonstrated the fair discrimination ability. The calibration plots showed optimal agreement between nomogram prediction and actual observation. We established and validated a novel prognostic nomogram that could predict in-hospital mortality of COVID-19 patients.

Happy hypoxemia, or blunted ventilation?

Happy hypoxemia is an unspecified definition that is used in COVID-19 patients to define hypoxemia without dyspnoea. Dyspnoea is a very complex symptom, and although hypoxemia can cause breathlessness, dyspnoea is not related to hypoxemia, but is more closely related to inspiratory drive and mechanical alterations. The lack of dyspnoea in the early stages of the disease is likely related to the absence of increased inspiratory drive due to compensatory mechanisms of hypoxemia, while in the advanced stages there is no evidence of a lack of dyspnoea in COVID-19 patients.

Timing of Invasive Mechanical Ventilation and Mortality among Patients with Severe COVID-19-associated Acute Respiratory Distress Syndrome

Background

Severe acute respiratory distress syndrome associated with coronavirus disease-2019 (COVID-19) (CARDS) pneumonitis presents a clinical challenge as regards to the timing of intubation and ambiguity of outcome. There is a lack of clear consensus on when to switch patients from trials of noninvasive therapies to invasive mechanical ventilation. We investigated the effect of the timing of intubation from the time of admission on the clinical outcome of CARDS.

Aim and objective

The aim and objective was to analyze the effect of timing of intubation early (within 48 hours of admission to critical care unit) versus delayed (after 48 hours of admission to critical care unit) on mortality in severe CARDS patients.

Materials and methods

A retrospective observational study performed in a 28-bedded COVID-19 intensive care unit of a tertiary care hospital in Pune, India. All patients admitted between April 1, 2020, and October 15, 2020, with confirmed COVID-19 (RT-PCR positive) requiring mechanical ventilation were included in the study.

Results

The primary outcome was in-hospital mortality. Among 2,230 patients that were admitted to the hospital, 525 required critical care (23.5%), invasive mechanical ventilation was needed in 162 patients and 147 (28%) of critical care admission were included in the study cohort after exclusion. Seventy-five patients (51%) were intubated within 48 hours of critical care admission (early group) and 72 (48.9%) were intubated after 48 hours of critical care admission (delayed group). With regards to the total of 147 included patients; male patients were 74.1% with a median age of 59 years (interquartile range, 51-68 years). Diabetes (44.9%) and hypertension (43.5%) were the most common comorbidities. Higher admission acute physiology and chronic health evaluation II scores and lower absolute lymphocyte count were observed in patients intubated within 48 hours. The early intubated group had a mortality of 60% whereas the same was observed as 77.7% in delayed intubation group, and this difference was statistically significant (p = 0.02).

Conclusion

Current study concludes that early intubation is associated with improved survival rates in severe CARDS patients.

How to cite this article

Zirpe KG, Tiwari AM, Gurav SK, Deshmukh AM, Suryawanshi PB, Wankhede PP, et al. Timing of Invasive Mechanical Ventilation and Mortality among Patients with Severe COVID-19-associated Acute Respiratory Distress Syndrome. Indian J Crit Care Med 2021;25(5):493-498.

Cardiac inflammation in COVID-19: Lessons from heart failure

Cardiovascular disease (CVD) is the most common co-morbidity associated with COVID-19 and the fatality rate in COVID-19 patients with CVD is higher compared to other comorbidities, such as hypertension and diabetes. Preliminary data suggest that COVID-19 may also cause or worsen cardiac injury in infected patients through multiple mechanisms such as 'cytokine storm', endotheliosis, thrombosis, lymphocytopenia etc. Autopsies of COVID-19 patients reveal an infiltration of inflammatory mononuclear cells in the myocardium, confirming the role of the immune system in mediating cardiovascular damage in response to COVID-19 infection and also suggesting potential causal mechanisms for the development of new cardiac pathologies and/or exacerbation of underlying CVDs in infected patients. In this review, we discuss the potential underlying molecular mechanisms that drive COVID-19-mediated cardiac damage, as well as the short term and expected long-term cardiovascular ramifications of COVID-19 infection in patients.

Silent hypoxia: higher NO in red blood cells of COVID-19 patients

Background

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) that causes coronavirus disease 2019 (COVID-19) has spread to almost 100 countries, infected over 31 M patients and resulted in 961 K deaths worldwide as of 21st September 2020. The major clinical feature of severe COVID-19 requiring ventilation is acute respiratory distress syndrome (ARDS) with multi-functional failure as a result of a cytokine storm with increased serum levels of cytokines. The pathogenesis of the respiratory failure in COVID-19 is yet unknown, but diffuse alveolar damage with interstitial thickening leading to compromised gas exchange is a plausible mechanism. Hypoxia is seen in the COVID-19 patients, however, patients present with a distinct phenotype. Intracellular levels of nitric oxide (NO) play an important role in the vasodilation of small vessels. To elucidate the intracellular levels of NO inside of RBCs in COVID-19 patients compared with that of healthy control subjects.

Methods

We recruited 14 COVID-19 infected cases who had pulmonary involvement of their disease, 4 non-COVID-19 healthy controls (without pulmonary involvement and were not hypoxic) and 2 hypoxic non-COVID-19 patients subjects who presented at the Masih Daneshvari Hospital of Tehran, Iran between March–May 2020. Whole blood samples were harvested from patients and intracellular NO levels in 1 × 10⁶ red blood cells (RBC) was measured by DAF staining using flow cytometry (FACS Calibour, BD, CA, USA).

Results

The Mean florescent of intensity for NO was significantly enhanced in COVID-19 patients compared with healthy control subjects (P ≤ 0.05). As a further control for whether hypoxia induced this higher intracellular NO, we evaluated the levels of NO inside RBC of hypoxic patients. No significant differences in NO levels were seen between the hypoxic and non-hypoxic control group.

Conclusions

This pilot study demonstrates increased levels of intracellular NO in RBCs from COVID-19 patients. Future multi-centre studies should examine whether this is seen in a larger number of COVID-19 patients and whether NO therapy may be of use in these severe COVID-19 patients.

The pathophysiology of 'happy' hypoxemia in COVID-19

The novel coronavirus disease 2019 (COVID-19) pandemic is a global crisis, challenging healthcare systems worldwide. Many patients present with a remarkable disconnect in rest between profound hypoxemia yet without proportional signs of respiratory distress (i.e. happy hypoxemia) and rapid deterioration can occur. This particular clinical presentation in COVID-19 patients contrasts with the experience of physicians usually treating critically ill patients in respiratory failure and ensuring timely referral to the intensive care unit can, therefore, be challenging. A thorough understanding of the pathophysiological determinants of respiratory drive and hypoxemia may promote a more complete comprehension of a patient's clinical presentation and management. Preserved oxygen saturation despite low partial pressure of oxygen in arterial blood samples occur, due to leftward shift of the oxyhemoglobin dissociation curve induced by hypoxemia-driven hyperventilation as well as possible direct viral interactions with hemoglobin. Ventilation-perfusion mismatch, ranging from shunts to alveolar dead space ventilation, is the central hallmark and offers various therapeutic targets.