The Effects of Corticosteroids on Survival in Pediatric and Nonelderly Adult Patients Undergoing Cardiac Surgery: A Meta-analysis of Randomized Studies.

OBJECTIVE: Cardiac surgery can be complicated by the development of a systemic inflammatory response syndrome related to cardiopulmonary bypass. This potentially contributes to the occurrence of postoperative morbidity and mortality. Corticosteroids can be used to reduce such inflammation, but the overall balance between potential harm and benefit is unknown and may be age-dependent. The present meta-analysis aims to evaluate the effects of prophylactic corticosteroids in pediatric and non-elderly adult cardiac surgery patients. DESIGN: Systematic review and meta-analysis of randomized trials. SETTING: Cardiac surgery with cardiopulmonary bypass. PARTICIPANTS: Patients younger than 65 years old (pediatric and non-elderly adults). INTERVENTIONS: Perioperative use of corticosteroids versus placebo or standard care. MEASUREMENTS AND MAIN RESULTS: Two independent investigators searched PubMed, EMBASE and the Cochrane Library from inception to January 20, 2024. The primary outcome was mortality at the longest follow-up available. Secondary outcomes included acute kidney injury, atrial fibrillation, myocardial injury, cerebrovascular events, and infections. Our search strategy identified a total of 17 randomized trials involving 6,598 patients. Mortality was significantly reduced in the corticosteroid group (78/3321 [2.3%] vs. 116/3277 [3.5%]; risk ratio = 0.69; 95% confidence interval, 0.52 to 0.92; P = 0.01; I2 = 0%; NNT = 91). Moreover, the highest postoperative vasoactive inotropic score (VIS) was significantly lower in corticosteroid group (MD: -2.07, 95% CI -3.69 to -0.45, P = 0.01, I2 = 0%). No significant differences in secondary outcomes between the two treatment groups were recorded. CONCLUSIONS: This meta-analysis of randomized trials highlights the potential benefits of corticosteroids on survival in cardiac surgery for patients younger than 65 years old.

Potential for the lung recruitment and the risk of lung overdistension during 21 days of mechanical ventilation in patients with COVID-19 after noninvasive ventilation failure: the COVID-VENT observational trial.

BACKGROUND: Data on the lung respiratory mechanics and gas exchange in the time course of COVID-19-associated respiratory failure is limited. This study aimed to explore respiratory mechanics and gas exchange, the lung recruitability and risk of overdistension during the time course of mechanical ventilation. METHODS: This was a prospective observational study in critically ill mechanically ventilated patients (n = 116) with COVID-19 admitted into Intensive Care Units of Sechenov University. The primary endpoints were: «optimum¼ positive end-expiratory pressure (PEEP) level balanced between the lowest driving pressure and the highest SpO2 and number of patients with recruitable lung on Days 1 and 7 of mechanical ventilation. We measured driving pressure at different levels of PEEP (14, 12, 10 and 8 cmH2O) with preset tidal volume, and with the increase of tidal volume by 100 ml and 200 ml at preset PEEP level, and calculated static respiratory system compliance (CRS), PaO2/FiO2, alveolar dead space and ventilatory ratio on Days 1, 3, 5, 7, 10, 14 and 21. RESULTS: The «optimum¼ PEEP levels on Day 1 were 11.0 (10.0-12.8) cmH2O and 10.0 (9.0-12.0) cmH2O on Day 7. Positive response to recruitment was observed on Day 1 in 27.6% and on Day 7 in 9.2% of patients. PEEP increase from 10 to 14 cmH2O and VT increase by 100 and 200 ml led to a significant decrease in CRS from Day 1 to Day 14 (p < 0.05). Ventilatory ratio was 2.2 (1.7-2,7) in non-survivors and in 1.9 (1.6-2.6) survivors on Day 1 and decreased on Day 7 in survivors only (p < 0.01). PaO2/FiO2 was 105.5 (76.2-141.7) mmHg in non-survivors on Day 1 and 136.6 (106.7-160.8) in survivors (p = 0.002). In survivors, PaO2/FiO2 rose on Day 3 (p = 0.008) and then between Days 7 and 10 (p = 0.046). CONCLUSION: Lung recruitability was low in COVID-19 and decreased during the course of the disease, but lung overdistension occurred at «intermediate¼ PEEP and VT levels. In survivors gas exchange improvements after Day 7 mismatched CRS. TRIAL REGISTRATION: ClinicalTrials.gov, NCT04445961 . Registered 24 June 2020-Retrospectively registered.

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.

Stop COVID Cohort: An Observational Study of 3480 Patients Admitted to the Sechenov University Hospital Network in Moscow City for Suspected Coronavirus Disease 2019 (COVID-19) Infection.

BACKGROUND: The epidemiology, clinical course, and outcomes of patients with coronavirus disease 2019 (COVID-19) in the Russian population are unknown. Information on the differences between laboratory-confirmed and clinically diagnosed COVID-19 in real-life settings is lacking. METHODS: We extracted data from the medical records of adult patients who were consecutively admitted for suspected COVID-19 infection in Moscow between 8 April and 28 May 2020. RESULTS: Of the 4261 patients hospitalized for suspected COVID-19, outcomes were available for 3480 patients (median age, 56 years; interquartile range, 45-66). The most common comorbidities were hypertension, obesity, chronic cardiovascular disease, and diabetes. Half of the patients (n = 1728) had a positive reverse transcriptase-polymerase chain reaction (RT-PCR), while 1748 had a negative RT-PCR but had clinical symptoms and characteristic computed tomography signs suggestive of COVID-19. No significant differences in frequency of symptoms, laboratory test results, and risk factors for in-hospital mortality were found between those exclusively clinically diagnosed or with positive severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RT-PCR. In a multivariable logistic regression model the following were associated with in-hospital mortality: older age (per 1-year increase; odds ratio, 1.05; 95% confidence interval, 1.03-1.06), male sex (1.71; 1.24-2.37), chronic kidney disease (2.99; 1.89-4.64), diabetes (2.1; 1.46-2.99), chronic cardiovascular disease (1.78; 1.24-2.57), and dementia (2.73; 1.34-5.47). CONCLUSIONS: Age, male sex, and chronic comorbidities were risk factors for in-hospital mortality. The combination of clinical features was sufficient to diagnose COVID-19 infection, indicating that laboratory testing is not critical in real-life clinical practice.

The Impact of Anesthetic Regimen on Outcomes in Adult Cardiac Surgery: A Narrative Review.

Despite improvements in surgical techniques and perioperative care, cardiac surgery still is burdened by relatively high mortality and frequent major postoperative complications, including myocardial dysfunction, pulmonary complications, neurologic injury, and acute kidney injury. Although the surgeon's skills and volume and patient- and procedure-related risk factors play a major role in the success of cardiac surgery, there is growing evidence that also optimizing perioperative care may improve outcomes significantly. The present review focuses on the aspects of perioperative care that are strictly related to the anesthesia regimen, with special reference to volatile anesthetics and neuraxial anesthesia, whose effect on outcome in adult cardiac surgery has been investigated extensively.

Perioperative Dexmedetomidine Supplement Decreases Delirium Incidence After Adult Cardiac Surgery: A Randomized, Double-Blind, Controlled Study.

OBJECTIVE: Conflicting data exist on the effect of dexmedetomidine on delirium. For the present study, a randomized trial was performed to investigate the effect of perioperative dexmedetomidine on the rate of postoperative delirium after cardiac surgery. DESIGN: A randomized controlled trial. SETTING: University hospital. PARTICIPANTS: Patients (n = 169) undergoing elective cardiac surgery (coronary artery bypass graft surgery, valve surgery, or combined surgery) with cardiopulmonary bypass. INTERVENTIONS: Patients received a sevoflurane-based general anesthesia and were randomly assigned 1:1 to receive a dexmedetomidine infusion that started in the operating room (0.7 µg/kg/h) and continued into the intensive care unit (0.4 µg/kg/h) or an equivolume infusion of placebo. MEASUREMENTS AND MAIN RESULTS: A decrease in the rate of delirium in the dexmedetomidine group compared with the placebo group was demonstrated (6 of 84 [7.1%] v 16 of 85 [18.8%]; p = 0.02; odds ratio [OR] 0.33 [95% confidence interval {CI} 0.12-0.90]). Reduced intensive care unit and hospital lengths of stay also were observed (18 [18-22] hours v 22 [18-39] hours; p = 0.002 and 17 [7-20] days v 19 [8-21] days; p = 0.04, respectively). Mortality at 30 days was 2 (2.4%) in both groups. On multivariate analysis, only dexmedetomidine administration (OR 0.24 [95% CI 0.08-0.74]) and cardiopulmonary bypass time (OR 1.02 [95% CI 1.01-1.03] for increases of 1 min) were independent predictors of delirium development. CONCLUSIONS: Dexmedetomidine administered during and after general anesthesia for cardiac surgery with cardiopulmonary bypass decreased the rate of postoperative delirium and intensive care unit and hospital lengths of stay.

Therapeutic Hypothermia in Critically Ill Patients: A Systematic Review and Meta-Analysis of High Quality Randomized Trials.

OBJECTIVES: To investigate the effect of the application of therapeutic hypothermia (32-35°C) on survival and major clinical endpoints in critically ill patients. DATA SOURCES: We searched online database and clinical trial registries dated up to April 30, 2019, and references of relevant studies. STUDY SELECTION: Low risk of bias randomized trials which compared hypothermia applied for at least 24 hours and conventional therapy in critically ill patients were included. We excluded trials investigating therapeutic hypothermia in indications already supported by international guidelines (adult cardiac arrest and hypoxic-ischemic encephalopathy of newborns) or intraoperative hypothermia. DATA EXTRACTION: Titles and abstracts were reviewed independently by two authors. If the articles seemed eligible, full-text articles were reviewed, and data were abstracted using a structured template. DATA SYNTHESIS: Our search retained 14 low risk of bias randomized trials (2,670 patients) performed in three different settings: traumatic brain injury, serious infections, and stroke. Therapeutic hypothermia was associated with an increase in mortality at longest follow-up available (432/1,375 [31%] vs 330/1,295 [25%]; risk ratio, 1.24; 95% CI, 1.10-1.39; p = 0.0004; I = 0%). Pooled results showed no difference of good neurologic outcome among survivors between the two treatment arms (493/1,142 [43%] vs 486/1,067 [46%]; risk ratio, 1.04; 95% CI, 0.97-1.12; p = 0.27; I = 1%). Arrhythmias were significantly increased among patients undergoing therapeutic hypothermia. We found no difference between groups in pneumonia, serious infections, any infection, hemorrhage, renal failure, deep vein thrombosis, and uncontrollable intracranial hypertension. CONCLUSIONS: High-quality randomized evidence indicates that therapeutic hypothermia is associated with higher mortality and no difference in good neurologic outcome compared with normothermia in critically ill patients. Although there still might be a possibility that therapeutic hypothermia is beneficial in a specific setting, routine application of therapeutic hypothermia would better be avoided outside the settings indicated by international guidelines (adult cardiac arrest and hypoxic-ischemic encephalopathy of newborns).

Management of Challenging Cardiopulmonary Bypass Separation.

SEPARATION from cardiopulmonary bypass (CPB) after cardiac surgery is a progressive transition from full mechanical circulatory and respiratory support to spontaneous mechanical activity of the lungs and heart. During the separation phase, measurements of cardiac performance with transesophageal echocardiography (TEE) provide the rationale behind the diagnostic and therapeutic decision-making process. In many cases, it is possible to predict a complex separation from CPB, such as when there is known preoperative left or right ventricular dysfunction, bleeding, hypovolemia, vasoplegia, pulmonary hypertension, or owing to technical complications related to the surgery. Prompt diagnosis and therapeutic decisions regarding mechanical or pharmacologic support have to be made within a few minutes. In fact, a complex separation from CPB if not adequately treated leads to a poor outcome in the vast majority of cases. Unfortunately, no specific criteria defining complex separation from CPB and no management guidelines for these patients currently exist. Taking into account the above considerations, the aim of the present review is to describe the most common scenarios associated with a complex CPB separation and to suggest strategies, pharmacologic agents, and para-corporeal mechanical devices that can be adopted to manage patients with complex separation from CPB. The routine management strategies of complex CPB separation of 17 large cardiac centers from 14 countries in 5 continents will also be described.

Influence of Hypoxic and Hyperoxic Preconditioning on Endothelial Function in a Model of Myocardial Ischemia-Reperfusion Injury with Cardiopulmonary Bypass (Experimental Study).

The aim of the experiment was to evaluate the effect of preconditioning based on changes in inspiratory oxygen fraction on endothelial function in the model of ischemia-reperfusion injury of the myocardium in the condition of cardiopulmonary bypass. The prospective randomized study included 32 rabbits divided into four groups: hypoxic preconditioning, hyperoxic preconditioning, hypoxic-hyperoxic preconditioning, and control group. All animals were anesthetized and mechanically ventilated. We provided preconditioning, then started cardiopulmonary bypass, followed by induced acute myocardial infarction (ischemia 45 min, reperfusion 120 min). We investigated endothelin-1, nitric oxide metabolites, asymmetric dimethylarginine during cardiopulmonary bypass: before ischemia, after ischemia, and after reperfusion. We performed light microscopy of myocardium, kidney, lungs, and gut mucosa. The endothelin-1 level was much higher in the control group than in all preconditioning groups after ischemia. The endothelin-1 even further increased after reperfusion. The total concentration of nitric oxide metabolites was significantly higher after all types of preconditioning compared with the control group. The light microscopy of the myocardium and other organs revealed a diminished damage extent in the hypoxic-hyperoxic preconditioning group as compared to the control group. Hypoxic-hyperoxic preconditioning helps to maintain the balance of nitric oxide metabolites, reduces endothelin-1 hyperproduction, and enforces organ protection.

A Systematic Review and International Web-Based Survey of Randomized Controlled Trials in the Perioperative and Critical Care Setting: Interventions Increasing Mortality.

OBJECTIVE: Reducing mortality is a key target in critical care and perioperative medicine. The authors aimed to identify all nonsurgical interventions (drugs, techniques, strategies) shown by randomized trials to increase mortality in these clinical settings. DESIGN: A systematic review of the literature followed by a consensus-based voting process. SETTING: A web-based international consensus conference. PARTICIPANTS: Two hundred fifty-one physicians from 46 countries. INTERVENTIONS: The authors performed a systematic literature search and identified all randomized controlled trials (RCTs) showing a significant increase in unadjusted landmark mortality among surgical or critically ill patients. The authors reviewed such studies during a meeting by a core group of experts. Studies selected after such review advanced to web-based voting by clinicians in relation to agreement, clinical practice, and willingness to include each intervention in international guidelines. MEASUREMENTS AND MAIN RESULTS: The authors selected 12 RCTs dealing with 12 interventions increasing mortality: diaspirin-crosslinked hemoglobin (92% of agreement among web voters), overfeeding, nitric oxide synthase inhibitor in septic shock, human growth hormone, thyroxin in acute kidney injury, intravenous salbutamol in acute respiratory distress syndrome, plasma-derived protein C concentrate, aprotinin in high-risk cardiac surgery, cysteine prodrug, hypothermia in meningitis, methylprednisolone in traumatic brain injury, and albumin in traumatic brain injury (72% of agreement). Overall, a high consistency (ranging from 80% to 90%) between agreement and clinical practice was observed. CONCLUSION: The authors identified 12 clinical interventions showing increased mortality supported by randomized controlled trials with nonconflicting evidence, and wide agreement upon clinicians on a global scale.

Beyond the Surviving Sepsis Campaign Guidelines: a systematic review of interventions affecting mortality in sepsis.

INTRODUCTION: Sepsis-related mortality is decreasing over time after the introduction of "Surviving Sepsis Campaign" Guidelines in 2004. The last Guidelines version collects 93 recommendations, but several interventions supported by randomized evidence of mortality reduction are not included. EVIDENCE ACQUISITION: We performed a systematic review of all randomized controlled trials reporting a statistically significant mortality reduction in septic patients and compared the identified studies to the Surviving Sepsis Campaign Guidelines 2021 to highlight discrepancies. EVIDENCE SYNTHESIS: We identified 83 randomized controlled trials (58 interventions) influencing mortality in sepsis. Only 9/58 of these interventions were included in the Guidelines: lactate measurement and lactate-guided hemodynamic management, procalcitonin-guided antibiotics discontinuation, balanced crystalloids as first choice fluids, albumin infusion, avoidance of starches, noradrenaline as first line vasopressor, vasopressin as an adjunctive vasopressor to noradrenaline, neuromuscular blocking agents in moderate-severe sepsis-associated acute respiratory distress syndrome, and corticosteroids use. Only 11/93 Guidelines recommendations were supported by randomized evidence with mortality difference. Five of the interventions with survival benefit in literature (vitamin C, terlipressin, polymyxin B, liberal transfusion strategy and immunoglobulins) were recommended to avoid in the Guidelines, while 44 interventions were not mentioned, including three interventions (esmolol, omega 3, and external warming) with at least two randomized controlled trials with a documented survival benefit. CONCLUSIONS: Several discrepancies exist between the randomized controlled trials with mortality difference in septic patients and the latest Surviving Sepsis Campaign Guidelines. This systematic review can be of help for improving future guidelines and may guide research on specific promising topics.

Acute normovolemic hemodilution in cardiac surgery: Rationale and design of a multicenter randomized trial.

BACKGROUND: Minimizing the use of blood component can reduce known and unknown blood transfusion risks, preserve blood bank resources, and decrease healthcare costs. Red Blood Cell (RBC) transfusion is common after cardiac surgery and associated with adverse perioperative outcomes, including mortality. Acute normovolemic hemodilution (ANH) may reduce bleeding and the need for blood product transfusion after cardiac surgery. However, its blood-saving effect and impact on major outcomes remain uncertain. METHODS: This is a single-blinded, multinational, pragmatic, randomized controlled trial with a 1:1 allocation ratio conducted in Tertiary and University hospitals. The study is designed to enroll patients scheduled for elective cardiac surgery with planned cardiopulmonary bypass (CPB). Patients are randomized to receive ANH before CPB or the best available treatment without ANH. We identified an ANH volume of at least 650 ml as the critical threshold for clinically relevant benefits. Larger ANH volumes, however, are allowed and tailored to the patient's characteristics and clinical conditions. RESULTS: The primary outcome is the percentage of patients receiving RBCs transfusion from randomization until hospital discharge, which we hypothesize will be reduced from 35% to 28% with ANH. Secondary outcomes are all-cause 30-day mortality, acute kidney injury, bleeding complications, and ischemic complications. CONCLUSION: The trial is designed to determine whether ANH can safely reduce RBC transfusion after elective cardiac surgery with CPB. STUDY REGISTRATION: This trial was registered on ClinicalTrials.gov in April 2019 with the trial identification number NCT03913481.

Endothelial Function and Hypoxic-Hyperoxic Preconditioning in Coronary Surgery with a Cardiopulmonary Bypass: Randomized Clinical Trial.

A hypoxic-hyperoxic preconditioning (HHP) may be associated with cardioprotection by reducing endothelial damage and a beneficial effect on postoperative outcome in patients undergoing cardiac surgery with cardiopulmonary bypass (CPB). Patients (n = 120) were randomly assigned to an HHP and a control group. A safe, inhaled oxygen fraction for the hypoxic preconditioning phase (10-14% oxygen for 10 min) was determined by measuring the anaerobic threshold. At the hyperoxic phase, a 75-80% oxygen fraction was used for 30 min. The cumulative frequency of postoperative complications was 14 (23.3%) in the HHP vs. 23 (41.1%), p = 0.041. The nitrate decreased after surgery by up to 20% in the HHP group and up to 38% in the control group. Endothelin-1 and nitric oxide metabolites were stable in HHP but remained low for more than 24 h in the control group. The endothelial damage markers appeared to be predictors of postoperative complications. The HHP with individual parameters based on the anaerobic threshold is a safe procedure, and it can reduce the frequency of postoperative complications. The endothelial damage markers appeared to be predictors of postoperative complications.

A Comparative Cross-Sectional Study Assessing the Psycho-Emotional State of Intensive Care Units' Physicians and Nurses of COVID-19 Hospitals of a Russian Metropolis.

Working in intensive care units (ICUs) is stressful and potentially leads to various psycho-emotional disorders. Today, this issue represents a serious concern to the healthcare sector and affects the quality of healthcare provided. This study aimed to assess and compare the psycho-emotional state in COVID-19 and non-COVID-19 hospitals' ICU healthcare workers (HCWs). From January to July 2021, we conducted an anonymous cross-sectional web survey of ICU physicians and nurses (N = 1259) of various hospitals in a metropolis with a population of over 10 million people. The statistical distributions of non-COVID-19 ICU HCWs showed the following results: emotional exhaustion levels (low 14.6%, average 30.8%, and high 54.6%); depersonalization levels (low 11.6%, average 16.5%, and high 71.9%); and reduced personal accomplishment levels (low 23.5%, average 40.3%, and high 36.2%). The statistical distributions of COVID-19 ICU HCWs showed the following results: emotional exhaustion levels (low 16.5%, average 31.5%, and high 52%); depersonalization levels (low 7.4%, average 9.4%, and high 83.1%); and reduced personal accomplishment levels (low 25.4%, average 45.4%, and high 29.1%). This study found a strong correlation between emotional exhaustion, aggression, and depersonalization in non-COVID-19 ICU HCWs and also found a correlation between their age, aggression, emotional exhaustion, and occupational stress.

Outcomes of out-of-hospital cardiac arrest in patients with SARS-CoV-2 infection: a systematic review and meta-analysis.

INTRODUCTION: Out-of-hospital cardiac arrests increased during the COVID-19 pandemic and a direct mechanism of cardiac arrest in infected patients was hypothesized. Therefore, we conducted a systematic review and meta-analysis to assess outcomes of SARS-CoV-2 patients with out-of-hospital cardiac arrest. METHODS: PubMed and EMBASE were searched up to April 05, 2021. We included studies comparing out-of-hospital cardiac arrests patients with suspected or confirmed SARS-CoV-2 infection versus noninfected patients. The primary outcome was survival at hospital discharge or at 30 days. Secondary outcomes included return of spontaneous circulation, cardiac arrest witnessed and occurring at home, bystander-initiated cardiopulmonary resuscitation, proportion of nonshockable rhythm and resuscitation attempted, and ambulance arrival time. RESULTS: In the ten included studies, 18% (1341/7545) of out-of-hospital cardiac arrests occurred in patients with SARS-CoV-2 infection. Patients with out-of-hospital cardiac arrest and SARS-CoV-2 infection had reduced rates of survival (16/856 [1.9%] vs. 153/2344 [6.5%]; odds ratio (OR) = 0.33; 95% confidence interval (CI), 0.17-0.65; P = 0.001; I2 = 28%) and return of spontaneous circulation (188/861 [22%] vs. 640/2403 [27%]; OR = 0.75; 95% CI, 0.65-0.86; P < 0.001; I2 = 0%) when compared to noninfected patients. Ambulance arrived later (15 ± 10 vs. 13 ± 7.5 min; mean difference = 1.64; 95% CI, 0.41-2.88; P = 0.009; I2 = 61%) and nonshockable rhythms (744/803 [93%] vs. 1828/2217 [82%]; OR = 2.79; 95% CI, 2.08-3.73; P < 0.001; I2 = 0%) occurred more frequently. SARS-CoV-2 positive patients suffered a cardiac arrest at home more frequently (1186/1263 [94%] vs. 3598/4055 [89%]; OR = 1.86; 95% CI, 1.45-2.40; P<0.001; I2 = 0%) but witnessed rate (486/890 [55%] vs. 1385/2475 [56%]; OR = 0.97; 95% CI, 0.82-1.14; P = 0.63; I2 = 0%) and bystander-initiated cardiopulmonary resuscitation rate (439/828 [53%] vs. 1164/2304 [51%]; OR = 0.95; 95% CI, 0.73-1.24; P = 0.70; I2 = 53%) were similar. CONCLUSIONS: One-fifth of out-of-hospital cardiac arrest patients had SARS-CoV-2 infection. These patients had low rates of return of spontaneous circulation and survival and were characterized by higher nonshockable rhythms but similar bystander-initiated cardiopulmonary resuscitation rate. REVIEW REGISTRATION: PROSPERO - CRD42021243540.