Atomic Force Microscopy and High-Resolution Spectrophotometry for Study of Anoxemia and Normoxemia in Model Experiment In Vitro.

The oxygen content in the blood may decrease under the influence of various physicochemical factors and different diseases. The state of hypoxemia is especially dangerous for critically ill patients. In this paper, we describe and analyze the changes in the characteristics of red blood cells (RBCs) with decreasing levels of oxygen in the RBC suspension from normoxemia to hypoxemia/anoxemia in an in vitro model experiment. The RBCs were stored in hypoxemia/anoxemia and normoxemia conditions in closed and open tubes correspondingly. For the quantitative study of RBC parameter changes, we used atomic force microscopy, digital spectrophotometry, and nonlinear curve fitting of the optical spectra. In both closed and open tubes, at the end of the storage period by day 29, only 2% of discocytes remained, and mainly irreversible types, such as microspherocytes and ghosts, were observed. RBC hemolysis occurred at a level of 25-30%. Addition of the storage solution, depending on the concentration, changed the influence of hypoxemia on RBCs. The reversibility of the change in hemoglobin derivatives was checked. Based on the experimental data and model approach, we assume that there is an optimal level of hypoxemia at which the imbalance between the oxidative and antioxidant systems, the rate of formation of reactive oxygen species, and, accordingly, the disturbances in RBCs, will be minimal.

Serum Levels of VEGF-A and Its Receptors in Patients in Different Phases of Hemorrhagic and Ischemic Strokes.

Vascular endothelial growth factors (VEGFs) are important regulators of angiogenesis, neuroprotection, and neurogenesis. Studies have indicated the association of VEGF dysregulation with the development of neurodegenerative and cerebrovascular diseases. We studied the changes in serum levels of VEGF-A, VEGFR-1, and VEGFR-2 in patients at various phases of ischemic and hemorrhagic strokes. Quantitative assessment of VEGF-A, VEGFR-1, and VEGFR-2 in serum of patients with hemorrhagic or ischemic stroke was performed by enzyme immunoassay in the hyper-acute (1−24 h from the onset), acute (up to 1−7 days), and early subacute (7 days to 3 months) phases of stroke, and then compared with the control group and each other. Results of our retrospective study demonstrated different levels of VEGF-A and its receptors at various phases of ischemic and hemorrhagic strokes. In ischemic stroke, increased VEGFR-2 level was found in the hyper-acute (p = 0.045) and acute phases (p = 0.024), while elevated VEGF-A and reduced VEGFR-1 levels were revealed in the early subacute phase (p = 0.048 and p = 0.012, respectively). In hemorrhagic stroke, no significant changes in levels of VEGF-A and its receptors were identified in the hyper-acute phase. In the acute and early subacute phases there was an increase in levels of VEGF-A (p < 0.001 and p = 0.006, respectively) and VEGFR-2 (p < 0.001 and p = 0.012, respectively). Serum levels of VEGF-A and its receptors in patients with hemorrhagic and ischemic stroke indicate different pathogenic pathways depending on the phase of the disease.

Perioperative Noninvasive Ventilation After Adult or Pediatric Surgery: A Comprehensive Review.

Postoperative pulmonary complications and acute respiratory failure are among the leading causes of adverse postoperative outcomes. Noninvasive ventilation may safely and effectively prevent acute respiratory failure in high-risk patients after cardiothoracic surgery and after abdominal surgery. Moreover, noninvasive ventilation can be used to treat postoperative hypoxemia, particularly after abdominal surgery. Noninvasive ventilation also can be helpful to prevent or manage intraoperative acute respiratory failure during non-general anesthesia, primarily in patients with poor respiratory function. Finally, noninvasive ventilation is superior to standard preoxygenation in delaying desaturation during intubation in morbidly obese and in critically ill hypoxemic patients. The few available studies in children suggest that noninvasive ventilation could be safe and valuable in treating hypoxemic or hypercapnic acute respiratory failure after cardiac surgery; on the other hand, it could be dangerous after tracheoesophageal correction.

Six-Month Quality of Life in COVID-19 Intensive Care Unit Survivors.

OBJECTIVES: Because there is increasing evidence of serious deterioration in long-term quality of life (QoL) in coronavirus 2019 (COVID-19) intensive care unit (ICU) survivors, the authors identified predictors of poor quality of life in these patients. DESIGN: Prospective cohort study. SETTING: Research hospital repurposed into a COVID-19 center. PARTICIPANTS: Consecutive patients admitted in COVID-19 ICUs between March and June 2020. INTERVENTIONS: An SF-36 questionnaire, which included physical and mental items, was used six months after patient's discharge. MEASUREMENTS AND MAIN RESULTS: A total of 403 patients were managed in the ICU, with a hospital mortality of 181 of 403 (44.9%), and 16 (4.0%) patients died within six months. Among the 125 questionnaire responders, only 32.0% and 52% had a normal quality of life in terms of the physical and mental component of health. Multivariate analysis identified low-molecular-weight heparin treatment in the ICU as the only modifiable factor associated with an increase in physical component of QoL odds ratio (OR) 3.341 (95% confidence interval 1.298-8.599), p = 0.012, and age ≥52 years OR 0.223 and female sex OR 0.321 were significantly associated with a decrease in the physical component. Medical history of cerebrovascular insufficiency was significantly associated with a decrease in mental component of QoL OR 0.125, and the only factor associated with an increase in the mental health component was body mass index ≥27.6 kg/m2 OR 7.466. CONCLUSIONS: In COVID-19 ICU survivors the authors identified treatment with low- molecular-weight heparin as a predictor of improved physical component of QoL at 6 months.

Effect of Volatile Anesthetics on Myocardial Infarction After Coronary Artery Surgery: A Post Hoc Analysis of a Randomized Trial.

OBJECTIVE: To investigate the effect of volatile anesthetics on the rates of postoperative myocardial infarction (MI) and cardiac death after coronary artery bypass graft (CABG). DESIGN: A post hoc analysis of a randomized trial. SETTING: Cardiac surgical operating rooms. PARTICIPANTS: Patients undergoing elective, isolated CABG. INTERVENTIONS: Patients were randomized to receive a volatile anesthetic (desflurane, isoflurane, or sevoflurane) or total intravenous anesthesia (TIVA). The primary outcome was hemodynamically relevant MI (MI requiring high-dose inotropic support or prolonged intensive care unit stay) occurring within 48 hours from surgery. The secondary outcome was 1-year death due to cardiac causes. MEASUREMENTS AND MAIN RESULTS: A total of 5,400 patients were enrolled between April 2014 and September 2017 (2,709 patients randomized to the volatile anesthetics group and 2,691 to TIVA). The mean age was 62 ± 8.4 years, and the median baseline ejection fraction was 57% (50-67), without differences between the 2 groups. Patients in the volatile group had a lower incidence of MI with hemodynamic complications both in the per-protocol (14 of 2,530 [0.6%] v 27 of 2,501 [1.1%] in the TIVA group; p = 0.038) and as-treated analyses (16 of 2,708 [0.6%] v 29 of 2,617 [1.1%] in the TIVA group; p = 0.039), but not in the intention-to-treat analysis (17 of 2,663 [0.6%] v 28 of 2,667 [1.0%] in the TIVA group; p = 0.10). Overall, deaths due to cardiac causes were lower in the volatile group (23 of 2,685 [0.9%] v 40 of 2,668 [1.5%] than in the TIVA group; p = 0.03). CONCLUSIONS: An anesthetic regimen, including volatile agents, may be associated with a lower rate of postoperative MI with hemodynamic complication in patients undergoing CABG. Furthermore, it may reduce long-term cardiac mortality.

Pneumonia and Related Conditions in Critically Ill Patients-Insights from Basic and Experimental Studies.

Pneumonia is an acute infectious disease with high morbidity and mortality rates. Pneumonia's development, severity and outcome depend on age, comorbidities and the host immune response. In this study, we combined theoretical and experimental investigations to characterize pneumonia and its comorbidities as well as to assess the host immune response measured by TREC/KREC levels in patients with pneumonia. The theoretical study was carried out using the Columbia Open Health Data (COHD) resource, which provides access to clinical concept prevalence and co-occurrence from electronic health records. The experimental study included TREC/KREC assays in young adults (18-40 years) with community-acquired (CAP) (n = 164) or nosocomial (NP) (n = 99) pneumonia and healthy controls (n = 170). Co-occurring rates between pneumonia, sepsis, acute respiratory distress syndrome (ARDS) and some other related conditions common in intensive care units were the top among 4170, 3382 and 963 comorbidities in pneumonia, sepsis and ARDS, respectively. CAP patients had higher TREC levels, while NP patients had lower TREC/KREC levels compared to controls. Low TREC and KREC levels were predictive for the development of NP, ARDS, sepsis and lethal outcome (AUCTREC in the range 0.71-0.82, AUCKREC in the range 0.67-0.74). TREC/KREC analysis can be considered as a potential prognostic test in patients with pneumonia.

Optically transparent electrodes to study living cells: A mini review.

The use of electrochemical methods to study living systems, including cells, has been of interest to researchers for a long time. Thus, controlling the polarization of the electrode contacting living cells, one can influence, for example, their proliferation or the synthesis of specific proteins. Moreover, the electrochemical approach formed the basis of the biocompatibility improvement of the materials contacting with body tissues that use in carbon hemosorbents and implants development. It became possible to reach a fundamentally new level in the study of cell activity with the introduction of optically transparent electrodes in this area. The advantage of the using of optically transparent electrodes is the possibility of simultaneous analysis of living cells by electrochemical and microscopic methods. The use of such materials allowed approaching to the study of the influence of the electrode potential on adhesion activity and morphology of the different cell types (HeLa cells, endothelial cell, etc.) more detailed. There are a negligible number of publications in this area despite the advantages of the usage of optically transparent electrodes to study living cells. This mini-review is devoted to some aspects of the interaction of living cells with conductive materials and current advances in the use of optically transparent electrodes for the study of living cells, as well as the prospects for their use in cellular technologies.

Long-Term Outcomes after Sepsis.

Sepsis is one of the most serious problems in modern medicine. Long-term outcomes in septic shock patients are very discouraging: 75% individuals who survived sepsis and septic shock demonstrate signs of organ failure and experience persistent functional deficit. Acute sepsis and its management in an intensive care unit (ICU) to a great extent determine the pathogenesis of further complications. We believe that the concept of phenoptosis proposed by Prof. Skulachev deserves a special attention from anesthesiologists and ICU doctors. According to this concept, septic shock is a suicidal mechanism of programmed organism death, which protects human population from dangerously infected individuals. The article suggests a potential approach to the sepsis treatment based on the notion that septic shock can be prevented by identification and blockade of receptors involved in the processing of phenoptotic signal induced by lipopolysaccharide and other substances that initiate septic shock. In view of this, the search for agents that can block molecular mechanisms of the phenoptotic signal transmission seems very promising.

Corticosteroids for Patients With Coronavirus Disease 2019 (COVID-19) With Different Disease Severity: A Meta-Analysis of Randomized Clinical Trials.

OBJECTIVES: Efficacy and safety of corticosteroids in patients with 2019-nCoV (novel coronavirus 2019) infection still are debated. Because large randomized clinical trials (RCTs) and a well-conducted meta-analysis on the use of corticosteroids, focused on patients with coronavirus disease (COVID-19) in intensive care units, recently were published, a meta-analysis of RCTs on corticosteroids therapy in patients with different disease severity was performed to evaluate the effect on survival. DESIGN: A meta-analyses of RCTs was performed. SETTING: Patients admitted to hospital. PARTICIPANTS: Patients with coronavirus disease. INTERVENTIONS: Administration of corticosteroids. MEASUREMENTS AND MAIN RESULTS: A search was performed for RCTs of adult patients with acute hypoxemic failure related to 2019-nCoV infection who received corticosteroids versus any comparator. The primary endpoint was mortality rate. Five RCTs involving 7,692 patients were included. Overall mortality of patients treated with corticosteroids was slightly but significantly lower than mortality of controls (26% v 28%, relative risk {RR} = 0.89 [95% confidence interval {CI} 0.82-0.96], p = 0.003). The same beneficial effect was found in the subgroup of patients requiring mechanical ventilation (RR = 0.85 [95% CI 0.72-1.00], p = 0.05 number needed to treat {NNT} = 19). Remarkably, corticosteroids increased mortality in the subgroup of patients not requiring oxygen (17% v 13%, RR = 1.23 [95% CI 1.00-1.62], p = 0.05 number needed to harm {NNH} = 29). Tests for comparison between mechanically ventilated subgroups and those not requiring oxygen confirmed that treatment with corticosteroids had a statistically significant different effect on survival. Patients treated with corticosteroids had a significantly lower risk of need for mechanical ventilation. CONCLUSIONS: Corticosteroids may be considered in severe critically ill patients with COVID-19 but must be discouraged in patients not requiring oxygen therapy. Urgently, further trials are warranted before implementing this treatment worldwide.

[Education for resuscitation]. / Lehre in der Reanimation: Leitlinien des European Resuscitation Council 2021.

These European Resuscitation Council education guidelines are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations. This section provides guidance to citizens and healthcare professionals with regard to teaching and learning the knowledge, skills and attitudes of resuscitation with the ultimate aim of improving patient survival after cardiac arrest.

[Basic life support]. / Basismaßnahmen zur Wiederbelebung Erwachsener (Basic Life Support): Leitlinien des European Resuscitation Council 2021.

The European Resuscitation Council has produced these basic life support guidelines, which are based on the 2020 International Consensus on Cardiopulmonary Resuscitation Science with Treatment Recommendations. The topics covered include cardiac arrest recognition, alerting emergency services, chest compressions, rescue breaths, automated external defibrillation (AED), cardiopulmonary resuscitation (CPR) quality measurement, new technologies, safety, and foreign body airway obstruction.

Identifying the role of cytochrome c in post-resuscitation pathophysiology.

Cytochrome c, an electron carrier that normally resides in the mitochondrial intermembrane space, may translocate to the cytosol under ischemic and hypoxic conditions and contribute to mitochondrial permeability transition pore opening. In addition, reperfusion of brain tissue following ischemia initiates a cell death cascade that includes cytochrome c-mediated induction of apoptosis. Further studies are needed to determine the contribution of cytochrome c in the regulation of cell death, as well as its value as an in vivo prognostic marker after cardiac arrest and resuscitation.

Prevalence and Impact of Malnutrition Risk on Outcomes in Critically Ill Patients with Traumatic Brain Injury and Stroke: A Retrospective Cohort Study Using Electronic Health Records.

BACKGROUND: Malnutrition is a critical concern in ICU settings. It is associated with increased morbidity and mortality, yet its prevalence and impact on clinical outcomes in patients with stroke and traumatic brain injury (TBI) remain underexplored. OBJECTIVE: To evaluate the prevalence and impact of malnutrition risk on clinical outcomes in ICU patients with TBI, ischemic stroke, and hemorrhagic stroke, and to identify key risk factors associated with malnutrition risk. METHODS: This retrospective cohort study utilized electronic health records encompassing ICU admissions from 2017 to 2023. Patients with either stroke or TBI were included, with malnutrition risk assessed using the prognostic nutritional index. Data were extracted and analyzed to determine patient characteristics, clinical and laboratory parameters, and outcomes. RESULTS: This study included 1352 patients (267 TBI, 825 ischemic stroke, and 260 hemorrhagic stroke patients, >30% with pneumonia at admission). Severe malnutrition risk at admission was observed in over 60% of patients. Stroke patients, particularly those with hemorrhagic stroke, exhibited a higher risk of malnutrition compared to TBI patients. Malnutrition risk was associated with significantly higher hospital mortality and increased need for mechanical ventilation. Predictive factors for malnutrition risk included advanced age, higher SOFA scores, lower FOUR and GCS scores, and the presence of pneumonia at admission. CONCLUSIONS: Risk of malnutrition is highly prevalent among ICU patients with TBI, ischemic, and hemorrhagic stroke, significantly impacting mortality and other clinical outcomes. Identifying and managing malnutrition early in the ICU setting is crucial for improving patient outcomes. Further prospective, multicenter studies are needed to validate these findings and develop effective interventions.

The Tri-Steps Model of Critical Conditions in Intensive Care: Introducing a New Paradigm for Chronic Critical Illness.

Background: The prevailing model for understanding chronic critical illness is a biphasic model, suggesting phases of acute and chronic critical conditions. A major challenge within this model is the difficulty in determining the timing of the process chronicity. It is likely that the triad of symptoms (inflammation, catabolism, and immunosuppression [ICIS]) could be associated with this particular point. We aimed to explore the impact of the symptom triad (inflammation, catabolism, immunosuppression) on the outcomes of patients hospitalized in intensive care units (ICUs). Methods: The eICU-CRD database with 200,859 ICU admissions was analyzed. Adult patients with the ICIS triad, identified by elevated CRP (>20 mg/L), reduced albumin (<30 g/L), and low lymphocyte counts (<0.8 × 109/L), were included. The cumulative risk of developing ICIS was assessed using the Nelson-Aalen estimator. Results: This retrospective cohort study included 894 patients (485 males, 54%), with 60 (6.7%) developing ICIS. The cumulative risk of ICIS by day 21 was 22.5%, with incidence peaks on days 2-3 and 10-12 after ICU admission. Patients with the ICIS triad had a 2.5-fold higher mortality risk (p = 0.009) and double the likelihood of using vasopressors (p = 0.008). The triad onset day did not significantly affect mortality (p = 0.104). Patients with ICIS also experienced extended hospital (p = 0.041) and ICU stays (p < 0.001). Conclusions: The symptom triad (inflammation, catabolism, immunosuppression) during hospitalization increases mortality risk by 2.5 times (p = 0.009) and reflects the chronicity of the critical condition. Identifying two incidence peaks allows the proposal of a new Tri-steps model of chronic critical illness with acute, extended, and chronic phases.

Adductor Canal Block Versus Femoral Nerve Block in Total Knee Arthroplasty: Network Meta-Analysis.

OBJECTIVES: The quality of postoperative analgesia in total knee arthroplasty is crucial for patient recovery, rehabilitation, and hospital stay duration. In line with the above, а single-shot adductor canal block has been considered as an improved method over continuous femoral nerve block. However, continuous adductor canal block and single-shot femoral nerve block have been not adequately addressed in the discussion. This study aimed to compare the effectiveness of various types of adductor and femoral nerve blocks on clinically relevant outcomes in patients following total knee arthroplasty. METHODS: A systematic review and network meta-analysis were conducted following "PRISMA-NMA" and Cochrane Handbook guidelines. The eligibility criteria included randomized trials and, where these were lacking for a comparison, nonrandomized studies involving adults undergoing primary total knee arthroplasty, comparing single-shot adductor canal block, continuous adductor canal block, single-shot femoral nerve block, and continuous femoral nerve block. RESULTS: A total of 36 studies involving 3308 patients were included. Single-shot adductor canal block showed higher pain scores and opioid consumption but better functional recovery at 24 h compared with continuous femoral nerve block. However, this trend vanishes by the 48 h assessment postsurgery. Continuous adductor canal block required higher opioid consumption but better functional recovery and shorter hospital stay compared with continuous femoral nerve block. Single-shot adductor canal block showed higher pain scores but comparable opioid consumption and functional recovery to continuous adductor canal block. DISCUSSION: The shift from continuous femoral nerve block to single-shot adductor canal block as the preferred method for pain relief after total knee arthroplasty may be premature. While the latter improves mobility, it falls short in pain control and does not shorten hospital stays. Continuous adductor canal block shows promise but is currently underappreciated, and single-shot femoral nerve block is often overshadowed by other techniques in regional anesthesia. Further high-quality, multicenter randomized controlled trials are needed to validate these findings.

Effects of Lithium Ions on tPA-Induced Hemorrhagic Transformation under Stroke.

Thrombolytic therapy with the tissue plasminogen activator (tPA) is a therapeutic option for acute ischemic stroke. However, this approach is subject to several limitations, particularly the increased risk of hemorrhagic transformation (HT). Lithium salts show neuroprotective effects in stroke, but their effects on HT mechanisms are still unknown. In our study, we use the models of photothrombosis (PT)-induced brain ischemia and oxygen-glucose deprivation (OGD) to investigate the effect of Li+ on tPA-induced changes in brain and endothelial cell cultures. We found that tPA did not affect lesion volume or exacerbate neurological deficits but disrupted the blood-brain barrier. We demonstrate that poststroke treatment with Li+ improves neurological status and increases blood-brain barrier integrity after thrombolytic therapy. Under conditions of OGD, tPA treatment increased MMP-2/9 levels in endothelial cells, and preincubation with LiCl abolished this MMP activation. Moreover, we observed the effect of Li+ on glycolysis in tPA-treated endothelial cells, which we hypothesized to have an effect on MMP expression.

Intraoperative electroencephalogram patterns as predictors of postoperative delirium in older patients: a systematic review and meta-analysis.

Background: Postoperative delirium (POD) significantly affects patient outcomes after surgery, leading to increased morbidity, extended hospital stays, and potential long-term cognitive decline. This study assessed the predictive value of intraoperative electroencephalography (EEG) patterns for POD in adults. Methods: This systematic review and meta-analysis followed the PRISMA and Cochrane Handbook guidelines. A thorough literature search was conducted using PubMed, Medline, and CENTRAL databases focusing on intraoperative native EEG signal analysis in adult patients. The primary outcome was the relationship between the burst suppression EEG pattern and POD development. Results: From the initial 435 articles identified, 19 studies with a total of 7,229 patients were included in the systematic review, with 10 included in the meta-analysis (3,705 patients). In patients exhibiting burst suppression, the POD incidence was 22.1% vs. 13.4% in those without this EEG pattern (p=0.015). Furthermore, an extended burst suppression duration associated with a higher likelihood of POD occurrence (p = 0.016). Interestingly, the burst suppression ratio showed no significant association with POD. Conclusions: This study revealed a 41% increase in the relative risk of developing POD in cases where a burst suppression pattern was present. These results underscore the clinical relevance of intraoperative EEG monitoring in predicting POD in older patients, suggesting its potential role in preventive strategies. Systematic Review Registration: This study was registered on International Platform for Registered Protocols for Systematic Reviews and Meta-Analyses: INPLASY202420001, https://doi.org/10.37766/inplasy2024.2.0001.

Serial Changes in Blood-Cell-Count-Derived and CRP-Derived Inflammatory Indices of COVID-19 Patients.

The aim of the study was to investigate the serial changes in inflammatory indices derived from blood cell counts and C-reactive protein (CRP) levels in COVID-19 patients with good and poor outcomes. We retrospectively analyzed the serial changes in the inflammatory indices in 169 COVID-19 patients. Comparative analyses were performed on the first and last days of a hospital stay or death and serially from day 1 to day 30 from the symptom onset. On admission, non-survivors had higher CRP to lymphocytes ratio (CLR) and multi-inflammatory index (MII) values than survivors, while at the time of discharge/death, the largest differences were found for the neutrophil to lymphocyte ratio (NLR), systemic inflammation response index (SIRI), and MII. A significant decrease in NLR, CLR, and MII by the time of discharge was documented in the survivors, and a significant increase in NLR was documented in the non-survivors. The NLR was the only one that remained significant from days 7-30 of disease in intergroup comparisons. The correlation between the indices and the outcome was observed starting from days 13-15. The changes in the index values over time proved to be more helpful in predicting COVID-19 outcomes than those measured on admission. The values of the inflammatory indices could reliably predict the outcome no earlier than days 13-15 of the disease.

Morphologic Findings in the Cerebral Cortex in COVID-19: Association of Microglial Changes with Clinical and Demographic Variables.

Despite the enormous interest in COVID-19, there is no clear understanding of the mechanisms underlying the neurological symptoms in COVID-19. Microglia have been hypothesized to be a potential mediator of the neurological manifestations associated with COVID-19. In most existing studies to date, morphological changes in internal organs, including the brain, are considered in isolation from clinical data and defined as a consequence of COVID-19. We performed histological immunohistochemical (IHC) studies of brain autopsy materials of 18 patients who had died from COVID-19. We evaluated the relationship of microglial changes with the clinical and demographic characteristics of the patients. The results revealed neuronal alterations and circulatory disturbances. We found an inverse correlation between the integral density Iba-1 (microglia/macrophage-specific marker) IHC staining and the duration of the disease (R = -0.81, p = 0.001), which may indicate a reduced activity of microglia and do not exclude their damage in the long-term course of COVID-19. The integral density of Iba-1 IHC staining was not associated with other clinical and demographic factors. We observed a significantly higher number of microglial cells in close contact with neurons in female patients, which confirms gender differences in the course of the disease, indicating the need to study the disease from the standpoint of personalized medicine.

Rare Variants in Primary Immunodeficiency Genes and Their Functional Partners in Severe COVID-19.

The development of severe COVID-19, which is a complex multisystem disease, is thought to be associated with many genes whose action is modulated by numerous environmental and genetic factors. In this study, we focused on the ideas of the omnigenic model of heritability of complex traits, which assumes that a small number of core genes and a large pool of peripheral genes expressed in disease-relevant tissues contribute to the genetics of complex traits through interconnected networks. We hypothesized that primary immunodeficiency disease (PID) genes may be considered as core genes in severe COVID-19, and their functional partners (FPs) from protein-protein interaction networks may be considered as peripheral near-core genes. We used whole-exome sequencing data from patients aged ≤ 45 years with severe (n = 9) and non-severe COVID-19 (n = 11), and assessed the cumulative contribution of rare high-impact variants to disease severity. In patients with severe COVID-19, an excess of rare high-impact variants was observed at the whole-exome level, but maximal association signals were detected for PID + FP gene subsets among the genes intolerant to LoF variants, haploinsufficient and essential. Our exploratory study may serve as a model for new directions in the research of host genetics in severe COVID-19.