High Oxygen Requirements Research Articles

Electrocardiographic predictors of disease severity, mortality, and advanced ventilatory support among hospitalized covid-19 patients: a two year single center retrospective, cohort study

Abstract Funding Acknowledgements Type of funding sources: None. Introduction For detecting myocardial injury in severe and critical COVID-19, the electrocardiogram (ECG) is neither sensitive nor specific; but in a resource-poor environment, it remains relevant. Changes in the ECG can be a potential marker of severe and critical COVID-19 to be used for predicting not only disease severity but also the prognosis for recovery. Methods The admitting and interval ECGs of 1,333 COVID-19 patients were reviewed in a two-year, single-center, retrospective cohort study. Each was evaluated for 29 pre-defined ECG patterns under the categories of rhythm, rate, McGinn-White and RV overload patterns, axis and QRS abnormalities, ischemia/infarct patterns, and AV blocks before univariate and multivariate regression analyses for correlation with disease severity; need for advanced ventilatory support; and in-hospital mortality. Results Of the 29 ECG patterns, 18 showed a significant association with the dependent variables on univariate analysis. Multivariate analysis revealed that atrial fibrillation, HR >100 bpm, low QRS voltage, QTc >500msec, diffuse nonspecific T-wave changes, and "any AMI" ECG patterns correlate with disease severity; need for advanced ventilatory support and in-hospital mortality. S1Q3 and S1Q3T3 increased the odds of critical disease and need for high oxygen requirement by 2.5-3 fold. Fractionated QRS increased odds of advanced ventilatory support. Conclusion The ECG can be useful for predicting the severity and outcome of more than moderate COVID-19. Their use can facilitate rapid triage, predict disease trajectory, and prompt a decision to intensify therapy early in the disease to make a positive impact on clinical outcomes.

1106. A Retrospective Assessment of the Effects of Baricitinib and Tocilizumab on COVID-19 Patients requiring High Flow Oxygen

Abstract Background SARS-CoV-2 has been a leading cause of mortality worldwide for over two years. It continues to be a group effort to discover treatment to prevent further deterioration during the disease course. Positive outcomes have been observed in select patients with immune modulator therapy. Although large randomized controlled trials have investigated the use of immunomodulators in COVID-19 therapy, few have compared the differences in safety profiles and clinical outcomes between the different drugs. We studied the differences in outcomes in hospitalized patients with COVID-19 pneumonia treated with baricitinib versus tocilizumab. Methods Adult patients admitted to Stony Brook University Hospital between April 2020 and April 2021 with high flow oxygen requirements due to severe COVID-19 pneumonia were retrospectively analyzed. The primary endpoint was the time to reduction of highest oxygen requirement 14 days after immune modulator therapy was administered or hospital discharge, whichever came first. Secondary endpoints include length of hospital stay (LOS), 28-day mortality, and serious adverse events. Results 132 patients with COVID-19 pneumonia were treated with immune modulators. One patient was excluded from primary and secondary analysis due to having received both tocilizumab and baricitinib. All patients received steroids and remdesivir. 73 received baricitinib and 58 received tocilizumab. Oxygen requirements at the initiation of either baricitnib or tocilizumab had a mean of 5.84±0.6 and 5.9±0.7, respectively using the WHO ordinal scale. The mean time to oxygen down titration in the baricitinib group was similar (5.7±2.6 and 6.07±2.7 days). In continuous variable analysis, patients who received baricitinib had a longer duration of fever (6.0 days vs 3.6 days, p=0.04) and lower serum ferritin (909.9 ng/ml vs. 1331.8 ng/ml, p=0.09). LOS was not similar between the groups (mean 24.4 vs. 25.8, p=0.89). Hospital mortality was not statistically significant between the two groups (32.9% vs. 27.6%, p=0.514). Conclusion This study suggests similar outcomes for oxygen requirements, hospital length of stay, and mortality between baricitinib and tocilizumab when given in conjunction with remdesivir and steroids for severe COVID-19 pneumonia. Disclosures Kathy Tin, D.O., Merck: Stocks/Bonds|Novavax: Stocks/Bonds|Pfizer: Stocks/Bonds Roderick Go, DO, Aptose Biosciences: Stocks/Bonds|Bristol Meyers Squibb: Stocks/Bonds|Cytodyn Inc.: Stocks/Bonds|Scynexis: Grant/Research Support.

Exploring right ventricular function applicability in a prediction model to identify preterm infants with early bronchopulmonary dysplasia (REPORT-BPD study): a mixed-methods observational cohort feasibility study protocol.

Bronchopulmonary dysplasia (BPD) is a chronic disease that affects the immature lungs of preterm infants. Infants born before 32 weeks of gestation are at a greater risk of developing BPD due to the need for respiratory support with higher oxygen requirement. Pulmonary vascular remodelling in early BPD can impose an additional burden on the right ventricle (RV) and RV dysfunction. This protocol outlines the study design and aims to formulate a prediction model to identify early BPD through the data generated from echo scans analysis. The mixed-methods observational cohort feasibility study, which comprises three work-packages (WPs), will be conducted at the regional neonatal unit, University Hospital Plymouth, Plymouth, UK. WP-I will recruit 40 preterm infants; each participant will have two heart scans performed in the first ten days after birth (DABs). WP-II will collect the documentation of the participating preterm infants' parents in the study neonatal unit diaries in the first 10 DABs. WP-III will involve semi-structured interviews of 10-15 parents of participating preterm infants and 10-15 health professionals who participated in WP-I. The study recruitment will be conducted over 18-months. The start date is 01 June 2022. WP-I and WP-II recruitment will occur during this period, while WP-III recruitment will occur during the second half. The results are expected to be submitted for publication by mid-2024. This paper outlines the study design. If the study successfully identifies the most sensitive echo parameter in recognising the RV dysfunction associated with early BPD, it will be an important finding in constructing an early BPD prediction model. ClinicalTrials.gov Identifier is NCT05235399.

Coronary Artery Bypass Grafting Following COVID-19 Infection: Difficulties and Challenges.

The COVID-19 pandemic has raised challenges and dilemmas to perform cardiac surgery in the patients following COVID-19 infection due to lasting adverse impacts of the disease on the lungs. A 74-years-old patient, recently infected by COVID-19, with previous myocardial infarction and multiple percutaneous coronary interventions, in-stent thrombosis to the left anterior descending artery, and low resting saturation, presented with chest pain and underwent urgent coronary artery bypass grafting. His postoperative period remained challenging due to high oxygen requirements. He had otherwise an uneventful recovery and was discharged on domiciliary oxygen, which was weaned off over three months and he continues to do well at six months of follow-up. Keywords: Cardiac surgery; COVID-19; coronary artery bypass surgery; pandemic.

PSAT001 A Case of Ectopic Cushing's Syndrome Complicated by COVID-19 Infection

Abstract Background Ectopic Cushing's syndrome is associated with high morbidity and mortality rates and patients can rapidly decline if not intervened on earlier. We report a case of Ectopic Cushing's syndrome and highlight the challenges that were encountered in managing this patient who subsequently developed Covid-19 infection during hospitalization. Clinical Case 61-year-old female with history of non-insulin dependent diabetes presented with increased confusion, elevated blood sugars and persistent hypokalemia. She was hypertensive, with exam findings of facial plethora, coarse chin hair growth, central adiposity with thin extremities. During evaluation Potassium was 2. 0 mmol/l (ref range 3.5-5), Cortisol 101.7 mcg/dl (AM ref range 6.2-19.4), ACTH 365 pg/ml (ref range 6-50), plasma renin activity of 1. 06 ng/ml/hr (ref range 0.25 - 5.82), and Aldosterone level of <1 ng/dl (supine ref range 3-16). CT abdomen/pelvis imaging revealed a 4.4×3.1 cm right pulmonary mass concerning for malignancy, two hepatic lesions suspicious for metastases and bilateral adrenal gland thickening with focal nodularity. Biopsy of the lung mass demonstrated a Grade I well differentiated neuroendocrine tumor. Unfortunately, ACTH staining was not performed on the biopsy specimen, but suspicion for ectopic hypercortisolemia remained high given her clinical presentation, resistant hypokalemia and neuroendocrine tumor. Gallium Dototate scan revealed increased uptake in the right lung infra-hilar mass and bilateral adrenal glands with decreased uptake in the liver lesions. Ketoconazole and Metyrapone were initiated along with Spironolactone and potassium supplements. She was thought to be a poor candidate for thoracic surgery and was seen by radiation oncology who recommended stereotactic body radiation therapy (SBRT) to the right lung lesion with IR guided bland embolization of the liver lesions. While awaiting further intervention, she decompensated developing hypoxic respiratory failure with high oxygen requirements and was found to have Covid-19 infection. She received convalescent plasma and Remdesevir. After much discussion, despite her endogenous hypercortisolemia, patient was given IV steroids per infectious disease and pulmonology recommendations. She continued to decline requiring intubation. Intravenous Etomidate infusion was started to decrease cortisol production. Despite many efforts, her hospital course was complicated by an upper GI bleed, acute L1-L3 fractures and significant hyperkalemia requiring hemodialysis. Family declined further intervention and withdrew treatment, shortly after which patient passed away. Discussion Ectopic cushing's disease may be associated with fatal progression of Covid-19 pneumonia and respiratory failure requiring emergent intervention. Due to endogenous hypercortisolemia, immune response may be blunted, and patients infected with Covid-19 infection may lack the typical clinical presentation and cytokine storm. Role of exogenous steroids in patients with Covid-19 infection with pre-existing endogenous hypercortisolemia is not clear with the concern being the resulting severe metabolic sequelae which may lead to adverse outcomes. Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m.

Efficacy of tocilizumab in treatment of COVID-19 pneumonia: A case-control study from a tertiary care hospital.

Coronavirus disease 2019 (COVID-19) is a viral infectious disease caused by the severe acute respiratory syndrome virus, which has affected billions of people across the globe. The pathogenesis of respiratory inflammation involves elevated concentration of interleukin-6; hence, interventions targeting interleukin-6 receptor, such as tocilizumab (TCZ), have been investigated as potential treatment amidst the dilemma of COVID-19 management. The aim of the study is to analyse the efficacy and safety of TCZ and record the outcome in COVID-19 patients. A retrospective case-control study of 80 patients in each group (N = 160) was carried out in a tertiary care hospital in Vadodara, Gujarat. Non-pregnant COVID-19-positive patients above 12 years of age were included in the study and were divided into case (those given TCZ) and control (those given standard treatment) groups after collecting their history and related data. From each group, further data was collected in the form of general and systemic examination, investigations and calculation of inflammatory and Sequential Organ Failure Assessment (SOFA) scores. Overall mortality was less in the case group compared to the control group. Patients with moderate to severe disease, age <55 years, patients having no comorbidity and patients with higher oxygen demand had lower deaths when given TCZ. Inflammatory score <3 and SOFA score <6 were associated with reduced mortality in the case group. Additionally, the study found significant results by simultaneously analysing two parameters in combination, which has not been done in any other study to the best of our knowledge. Adjuvant TCZ therapy had overall mortality benefit compared to standard treatment, with specific benefit observed in those with increasing disease severity, young to middle-age group, absence of comorbidity, higher oxygen requirements and lower inflammatory and SOFA scores.

ARDS AND NECROTIZING PNEUMONIA FROM BLASTOMYCES INFECTION

ARDS AND NECROTIZING PNEUMONIA FROM BLASTOMYCES INFECTION

Myocardial Work in Patients Hospitalized With COVID-19: Relation to Biomarkers, COVID-19 Severity, and All-Cause Mortality.

Background COVID-19 infection has been hypothesized to affect left ventricular function; however, the underlying mechanisms and the association to clinical outcome are not understood. The global work index (GWI) is a novel echocardiographic measure of systolic function that may offer insights on cardiac dysfunction in COVID-19. We hypothesized that GWI was associated with disease severity and all-cause death in patients with COVID-19. Methods and Results In a multicenter study of patients admitted with COVID-19 (n=305), 249 underwent pressure-strain loop analyses to quantify GWI at a median time of 4 days after admission. We examined the association of GWI to cardiac biomarkers (troponin and NT-proBNP [N-terminal pro-B-type natriuretic peptide]), disease severity (oxygen requirement and CRP [C-reactive protein]), and all-cause death. Patients with elevated troponin (n=71) exhibited significantly reduced GWI (1508 versus 1707 mm Hg%; P=0.018). A curvilinear association to NT-proBNP was observed, with increasing NT-proBNP once GWI decreased below 1446 mm Hg%. Moreover, GWI was significantly associated with a higher oxygen requirement (relative increase of 6% per 100-mm Hg% decrease). No association was observed with CRP. Of the 249 patients, 37 died during follow-up (median, 58 days). In multivariable Cox regression, GWI was associated with all-cause death (hazard ratio, 1.08 [95% CI, 1.01-1.15], per 100-mm Hg% decrease), but did not increase C-statistics when added to clinical parameters. Conclusions In patients admitted with COVID-19, our findings indicate that NT-proBNP and troponin may be associated with lower GWI, whereas CRP is not. GWI was independently associated with all-cause death, but did not provide prognostic information beyond readily available clinical parameters. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT04377035.

Body mass and cell size shape the tolerance of fishes to low oxygen in a temperature-dependent manner.

Aerobic metabolism generates 15–20 times more energy (ATP) than anaerobic metabolism, which is crucial in maintaining energy budgets in animals, fueling metabolism, activity, growth and reproduction. For ectothermic water‐breathers such as fishes, low dissolved oxygen may limit oxygen uptake and hence aerobic metabolism. Here, we assess, within a phylogenetic context, how abiotic and biotic drivers explain the variation in hypoxia tolerance observed in fishes. To do so, we assembled a database of hypoxia tolerance, measured as critical oxygen tensions (P crit) for 195 fish species. Overall, we found that hypoxia tolerance has a clear phylogenetic signal and is further modulated by temperature, body mass, cell size, salinity and metabolic rate. Marine fishes were more susceptible to hypoxia than freshwater fishes. This pattern is consistent with greater fluctuations in oxygen and temperature in freshwater habitats. Fishes with higher oxygen requirements (e.g. a high metabolic rate relative to body mass) also were more susceptible to hypoxia. We also found evidence that hypoxia and warming can act synergistically, as hypoxia tolerance was generally lower in warmer waters. However, we found significant interactions between temperature and the body and cell size of a fish. Constraints in oxygen uptake related to cellular surface area to volume ratios and effects of viscosity on the thickness of the boundary layers enveloping the gills could explain these thermal dependencies. The lower hypoxia tolerance in warmer waters was particularly pronounced for fishes with larger bodies and larger cell sizes. Previous studies have found a wide diversity in the direction and strength of relationships between P crit and body mass. By including interactions with temperature, our study may help resolve these divergent findings, explaining the size dependency of hypoxia tolerance in fish.

Risk factors for mortality in kidney transplant recipients with COVID‐19: a single centre experience and case–control study

BackgroundCOVID-19 infection is considered to cause high mortality in kidney transplant recipients (KTR). Old age, comorbidities and acute kidney injury are known risk factors for increased mortality in KTR. Nevertheless, mortality rates have varied across different regions. Differences in age, comorbidities and varying standards of care across geographies may explain some variations. However, it is still unclear whether post-transplant duration, induction therapy, antirejection therapy and co-infections contribute to increased mortality in KTR with COVID-19. The present study assessed risk factors in a large cohort from India.MethodsA matched case–control study was performed to analyze risk factors for death in KTR (N = 218) diagnosed with COVID-19 between April 2020 to July 2021 at the study centre. Cases were KTR who died (non-survivors, N = 30), whereas those who survived were taken as controls (survivors, N = 188).ResultsA high death-to-case ratio of 13.8% was observed amongst study group KTR infected with COVID-19. There was a high incidence (12.4%) of co-infections, with cytomegalovirus being the most common co-infection among non-survivors. Diarrhea, co-infection, high oxygen requirement, and need for mechanical ventilation were significantly associated with mortality on regression analyses. Antirejection therapy, lymphopenia and requirement for renal replacement therapy were associated with worse outcomes.ConclusionsThe mortality was much higher in KTR who required mechanical ventilation and had co-infections. Mortality did not vary with the type of transplant, post-transplant duration and usage of depletion induction therapy. An aggressive approach has to be taken for an early diagnosis and therapeutic intervention of associated infections.

Acute Heart Failure Associated with Carbon Monoxide Intoxication during Pregnancy: Two Case Reports

Carbon monoxide poisoning is a leading cause of mortality among accidental intoxications, it is responsible for severe tissular hypoxia leading to life-threatening complications. Pregnant women are more at risk to develop severe forms of intoxication due to their physiological changes and their higher oxygen requirements as well as for possible adverse fetal outcomes. We present two cases of monoxide intoxication in two pregnant women with acute heart failure and variant complications with different fetal outcomes.

Morphological and histological study of respiratory system of rabbits (Oryctolagus cuniculus)

The rabbits are considered small mammals that had, in comparison to big animals, they have a high metabolic rate and oxygen requirement. Because the larynx is located at a high angle to the oropharynx, it may immediately access the nasopharynx of rabbits categorized as nose breathers. The lungs were symmetrical in size, with the right lung being more prominent than the left and situated at the trachea's bottom. The trachea is located between the left and right bronchus. Twenty rabbits were transported to the laboratory, and by the appropriate laboratory, the instrument opened the thoracic cavity, and also the organs were filmed while the respiratory organs were removed. Due to the heart interposition and its left deviation, the left lung in rabbits is smaller than the right lung, which has just three lobes. The lungs also lack septa. The trachea is separated into two bronchi, the last of which is branched into tiny bronchioles. Achieve a histological and morphological description of rabbits' respiratory tract because the rabbits are valuable models in respiratory research due to their respiratory hyperresponsiveness, which resembles asthma in humans. The larynx is located lower than the oropharynx, where it may directly access the nasopharynx, and the rabbits are nasal breathers. The primary respiratory organs of rabbits are the left and right lung, trachea and bronchi, as in humans and rats. Still, it is supported by double cartilage in the conducting portion of the respiratory system. Keywords. Respiratory system, Oryctolagus cuniculus.

Hyperbaric oxygen for COVID-19 patients with severe hypoxia prior to vaccine availability

Introduction: Few treatments have demonstrated mortality benefits among hospitalized hypoxic COVID-19 patients. We evaluated the use of hyperbaric oxygen (HBO2) therapy as a therapeutic intervention among hospitalized patients with a high oxygen requirement prior to vaccine approval. Methods: We extracted data on patients with COVID-19 hypoxia who required oxygen supplementation ranging from a 6L nasal cannula up to a high-flow nasal cannula at 100% FiO2 at 60L/minute with a 100% non-rebreather mask at 15 L/minute and were eligible for off-label HBO2 therapy from October 2020 to February 2021. We followed the Monitored Emergency use of Unregistered and Investigational Interventions or (MEURI) in conjunction with the consistent re-evaluation of the protocol using the Plan-Do-Study-Act (PDSA) tool [1]. We compared patient characteristics and used Fisher’s exact test and a survival analysis to assess the primary endpoint of inpatient death. Results: HBO2 therapy was offered to 36 patients, of which 24 received treatment and 12 did not receive treatment. Patients who did not receive treatment were significantly older (p &lt; 0.01) and had worse baseline hypoxia (p = 0.06). Three of the 24 (13%) patients who received treatment died compared to six of 12 (50%) patients who did not receive treatment (RR ratio: 0.25, p = 0.04, 95% CI: 0.08 to 0.83). In the survival analysis, there was a statistically significant reduction in inpatient mortality in the treatment group (HR: 0.19, p = 0.02, 95% CI: 0.05-0.74). However, after adjusting for age and baseline hypoxia, there was no difference in inpatient mortality (hazard ratio: 0.48, p = 0.42, 95% CI: 0.08-2.86). Conclusions: The survival benefit of HBO2 therapy observed in our unadjusted analysis suggests that there may be therapeutic benefits of HBO2 in treating COVID-19 hypoxia as an adjunct to standard care.

Incidence, Predictors and Outcomes of Noninvasive Ventilation Failure in Very Preterm Infants.

Non-invasive ventilation (NIV) is now considered the first-line treatment for respiratory distress syndrome in preterm infants. We aimed to evaluate the rates of non-invasive ventilation failure rate in very preterm infants, as well as to identify its predictors and associated outcomes. We designed a single-center retrospective cohort study including infants ≤32 weeks gestational age and ≤1500 g. The NIV failure was defined as the need for intubation at <72 h of life. After applying inclusion and exclusion criteria, 154 patients were included in the study, with a mean GA of 29.7 ± two weeks. The NIV failure rate was 16.2% (n = 25) and it was associated with lower bronchopulmonary dysplasia (BPD)-free survival (OR 0.08; 95% CI 0.02–0.32) and higher incidence of intraventricular hemorrhage > II (OR 6.22; 95% CI 1.36–28.3). These infants were significantly smaller in GA and weight. Higher FiO2 during resuscitation (OR 1.14; 95% CI 1.06–1.22) and after surfactant administration (OR 1.17; 95% CI 1.05–1.31) represented independent risk factors for NIV failure. In conclusion, NIV failure is frequent and it could be predicted by a higher oxygen requirement during resuscitation and a modest response to surfactant therapy. Importantly, this NIV failure is associated with worse clinical outcomes.

High mortality among hospitalized adult patients with COVID-19 pneumonia in Peru: A single centre retrospective cohort study.

BackgroundPeru is the country with the world’s highest COVID-19 death rate per capita. Characteristics associated with increased mortality among adult patients with COVID-19 pneumonia in this setting are not well described.MethodsRetrospective, single-center cohort study including 1537 adult patients hospitalized with a diagnosis of SARS-CoV-2 pneumonia between May 2020 and August 2020 at a national hospital in Lima, Peru. The primary outcome measure was in-hospital mortality.ResultsIn-hospital mortality was 49.71%. The mean age was 60 ± 14.25 years, and 68.38% were males. We found an association between mortality and inflammatory markers, mainly leukocytes, D-dimer, lactate dehydrogenase, C-reactive protein and ferritin. A multivariate model adjusted for age, hypertension, diabetes mellitus, and corticosteroid use demonstrated that in-hospital mortality was associated with greater age (RR: 2.01, 95%CI: 1.59–2.52) and a higher level of oxygen requirement (RR: 2.77, 95%CI: 2.13–3.62). Conclusions: In-hospital mortality among COVID-19 patients in Peru is high and is associated with greater age and higher oxygen requirements.

Thoracic Society of Australia and New Zealand Position Statement on Acute Oxygen Use in Adults: 'Swimming between the flags'.

Oxygen is a life‐saving therapy but, when given inappropriately, may also be hazardous. Therefore, in the acute medical setting, oxygen should only be given as treatment for hypoxaemia and requires appropriate prescription, monitoring and review. This update to the Thoracic Society of Australia and New Zealand (TSANZ) guidance on acute oxygen therapy is a brief and practical resource for all healthcare workers involved with administering oxygen therapy to adults in the acute medical setting. It does not apply to intubated or paediatric patients. Recommendations are made in the following six clinical areas: assessment of hypoxaemia (including use of arterial blood gases); prescription of oxygen; peripheral oxygen saturation targets; delivery, including non‐invasive ventilation and humidified high‐flow nasal cannulae; the significance of high oxygen requirements; and acute hypercapnic respiratory failure. There are three sections which provide (1) a brief summary, (2) recommendations in detail with practice points and (3) a detailed explanation of the reasoning and evidence behind the recommendations. It is anticipated that these recommendations will be disseminated widely in structured programmes across Australia and New Zealand.

Respiratory reoxidation of NADH is a key contributor to high oxygen requirements of oxygen-limited cultures of Ogataea parapolymorpha.

While thermotolerance is an attractive trait for yeasts used in industrial ethanol production, oxygen requirements of known thermotolerant species are incompatible with process requirements. Analysis of oxygen-sufficient and oxygen-limited chemostat cultures of the facultatively fermentative, thermotolerant species Ogataea parapolymorpha showed its minimum oxygen requirements to be an order of magnitude larger than those reported for the thermotolerant yeast Kluyveromyces marxianus. High oxygen requirements of O. parapolymorpha coincided with a near absence of glycerol, a key NADH/NAD+ redox-cofactor-balancing product in many other yeasts, in oxygen-limited cultures. Genome analysis indicated absence of orthologs of the Saccharomyces cerevisiae glycerol-3-phosphate-phosphatase genes GPP1 and GPP2. Co-feeding of acetoin, whose conversion to 2,3-butanediol enables reoxidation of cytosolic NADH, supported a 2.5-fold increase of the biomass concentration in oxygen-limited cultures. An O. parapolymorpha strain in which key genes involved in mitochondrial reoxidation of NADH were inactivated did produce glycerol, but transcriptome analysis did not reveal a clear candidate for a responsible phosphatase. Expression of S. cerevisiae GPD2, which encodes NAD+-dependent glycerol-3-phosphate dehydrogenase, and GPP1 supported increased glycerol production by oxygen-limited chemostat cultures of O. parapolymorpha. These results identify dependence on respiration for NADH reoxidation as a key contributor to unexpectedly high oxygen requirements of O. parapolymorpha.

Application of an optimized and validated LC–MS/MS method for the quantification of free 3-nitrotyrosine in plasma, urine and liver tissue of lactating dairy cows

In dairy cows, the high energy demand and oxygen requirements during the transition period could increase oxidative stress (OS), impairing the challenging metabolic adaptation needed during this period. Also, OS and health could be affected by some environmental conditions such as heat stress. In this sense, 3-nytrotyrosine (3-NT) has been described as a biomarker of OS. Therefore, the aim of this study was to develop and validate a fast, reliable method for the accurate determination of free 3-NT in blood, urine and liver samples by liquid chromatography–tandem mass spectrometry (LC-MS/MS). To this end, during the transition period, 3-NT concentrations were analyzed in samples from dairy cows grouped according to different environmental conditions: cows that gave birth during winter (winter group, WG; n = 18) and cows that gave birth during spring (spring group, SG; n = 18). Additionally, other plasma parameters such as β-hydroxybutyrate acid (BHBA) and glucose concentrations and liver triacylglycerol (TAG) content and aspartate transaminase activity were exhaustively studied. Samples were collected at 21 (±3) days before the expected calving date, and at 7 (±3) and 21 (±3) days after calving. The analysis of the samples involved a purification step by solid-phase extraction. The method developed was validated in terms of linearity, specificity, precision, accuracy, recovery, matrix effect, dilution and analyte stability. The lower limit of quantification of the method was 1.02 ng/mL for plasma, 0.24 mg/L for urine and 0.05 mg/kg for liver tissue. Coefficients of variation for the concentrations tested were < 15% and accuracy was within 85–115%. 3-NT concentration was higher in cows of the SG than in those of the WG in the three matrices evaluated. BHBA and glucose concentrations were higher and lower, respectively, in cows of the SG. BHBA concentration was particularly higher in cows of the SG on day 21 postpartum. Liver TAG content and aspartate transaminase activity were also higher in cows of the SG on the postpartum days. These results suggest that the methodology developed and validated by LC-MS/MS for the quantification of 3-NT in different fluids and liver tissue could be a very useful parameter to evaluate OS in dairy cows during the transition period.

POS-789 DEATH IN KIDNEY TRANSPLANT RECIPIENTS WITH COVID-19 EXPERIENCE OF NEPHROLOGY DEPARTMENT OF SAHLOUL HOSPITAL

Infections related to the novel coronavirus SARS-CoV-2 had affected people from many countries and caused deaths worldwide.The COVID-19 pandemic has brought unprecedented challenges to the transplant community. The reduction in transplantation volume during this time is partly due to concerns over potentially increased susceptibility and worsened outcomes of COVID-19 in immunosuppressed recipients. Hospitalized kidney transplant recipients with COVID-19 are at a high risk of death in early reports. COVID-19 infections were diagnosed in 47 patients of our cohort of 300 kidney transplant recipients between March 2020 and August 2021; they were screened for baseline and transplant characteristics, functional parameters, comorbidities, and immunosuppressive therapies. A standard strategy of immunosuppression minimization was applied: discontinue the antimetabolite drug and reduce trough levels of calcineurin or mammalian target of rapamycin inhibitors. Among 300 kideny transplant recipients performed between 2008 and 2020 in our department, 47 patients (15.6%) have had an infection with the new Coronavirus (COVID-19). Their mean age was 41.57±16 years; 31 men and 16 woman. For these infected patients, the mean time of years of transplantation was 6.5 years. Comorbidities such as diabetes were noted in 8patients, arterial hypertension in 21 patients. Most common initial symptoms included fever, cough, or dyspnea. 22 patients (46.8%) required hospitalization because of hypoxia requiring oxygen therapy. Of those patients, 11 had computed tomography of the chest at admission which showed severe involvement. 10patients are reported to have been hospitalized in intensive care for high oxygen requirements following covid pneumonia.Immunosuppression reduction was initiated for all patients. All patients received cortticoistoides and Enoxaparin. The mortality rate following infection by covid 19 is 17.02%. All patients who died had severe pulmonary involvement. The clinical presentation of COVID-19 infection was similar to that reported in the general population. A standard strategy of immunosuppression minimization and treatment was applied. Patients with kidney transplants display a high risk of mortality. This work highlights the mortality excess in transplant recipients but medium-and longer-term outcomes remain uncertain and merit careful investigation.

The Effectiveness of COVID-19 Vaccines in Improving the Outcomes of Hospitalized COVID-19 Patients.

BackgroundWith the rapid spread of coronavirus disease 2019 (COVID-19), most countries took extreme measures to control the disease. Equitable access to safe and effective vaccines is critical to ending the COVID-19 pandemic. The Ministry of Health program in Saudi Arabia aimed to cover 17.4 million adults (70% of the adult population of Saudi Arabia) by the third quarter of 2021. We investigated the impact of the COVID-19 vaccine on the clinical course and outcomes of the admitted confirmed COVID-19 patients, in comparison to non-vaccinated patients.MethodologyA retrospective cross-sectional record review was conducted for all hospitalized confirmed COVID-19 patients at Dammam Medical Complex (Eastern Province, Saudi Arabia) from June to July 2021. Two groups were studied according to the vaccination status (i.e., vaccinated and non-vaccinated). Information regarding comorbidities, length of stay, high oxygen requirements, ICU admission, and mortality data were collected and analyzed using the Python programming language (version 3.7.6) with the use of SciPy library (1.4.1) and Statsmodels module (v0.11.1).ResultsThe sample included a total of 260 admitted confirmed COVID-19 cases. The mortality was significantly lower in the vaccinated group versus the non-vaccinated group with an odds ratio (OR) of 0.378 (CI 0.154-0.928). In addition, the OR of ICU admission was 0.476 (CI 0.218-1.042) and OR of endotracheal intubation was 0.561 (CI 0.249-1.265), but these did not reach statistical significance. We also detected a statistically significant relationship between mortality - regardless of vaccination status - and age ≥ 65 years (P=0.000, OR=7.51; 95%CI 3.13 to 18.04), chronic kidney disease (P=0.010, OR=5.62; CI 1.52 to 20.79), and renal transplant (P=0.037, OR=10.17; CI 1.15 to 89.76).Of note, most of our vaccinated patients received only a single dose (85%).ConclusionThere is a significant reduction in mortality cases as well as less complicated hospital courses among the vaccinated group, in spite of the fact that most of our admitted patients had only a single vaccine shot.Suboptimal response to the vaccines was observed in the elder, chronic kidney disease, and renal transplant patients, hence the poorer outcomes in comparison to other patients.