Life-Threatening Tracheal Diverticulum Rupture Following Laparoscopic Cholecystectomy: A Rare Case Report.

BACKGROUND We present an exceptional case of asystole and tracheal diverticulum rupture as a result of cardiopulmonary resuscitation (CPR) immediately following laparoscopic cholecystectomy performed at Riga 1st Hospital. Tracheal rupture after tracheal intubation is a severe but very rare complication that can be fatal. We present an incidental finding of the tracheal diverticulum and its rupture during CPR. CASE REPORT A 71-year-old woman (American Society of Anesthesiologists class II, body mass index 28.58) underwent a planned laparoscopic cholecystectomy. Preoperative chest X-ray showed no abnormalities. Endotracheal intubation was performed, with the first attempt with a 7-mm inner diameter cuffed endotracheal tube without an introducer. Five minutes after rapid desufflation of the pneumoperitoneum, severe bradycardia and hypotension occurred, followed by asystole. CPR was performed for a total of 2 min, until spontaneous circulation returned. Twenty hours after surgery, subcutaneous emphysema appeared on the chest. Computed tomography scan of the chest revealed subcutaneous neck emphysema, bilateral pneumothorax, extensive pneumomediastinitis, and a pocket-like, air-filled tissue defect measuring 10×32 mm in the distal third of the trachea, with suspected rupture. Two hours after the diagnosis was established, the emergent surgery was performed. The patient was completely recovered after 15 days. CONCLUSIONS Our case illustrates that tracheal diverticula is sometimes diagnosed by accident and too late, which then can lead to life-threatening situations. Tracheal rupture can be made not only by mechanical piercing by an endotracheal tube but also during interventions, such as CPR. Rapid desufflation of the pneumoperitoneum can lead to asystole, induced by the Bezold-Jarisch reflex.

A Case of Coronary Artery Perforation Caused by Manual Cardiopulmonary Resuscitation in the Catheterization Laboratory.

Cardiopulmonary resuscitation (CPR) is essential for the survival of cardiac arrest patients, but it can cause severe traumatic complications. In the catheterization laboratory, various physical constraints complicate the appropriate performance of CPR. However, we are not aware of reports of CPR complications in this setting. Here, we report a case of coronary artery perforation (CAP) caused by manual CPR in the catheterization laboratory. The patient, a 68-year-old woman, initially underwent successful percutaneous coronary intervention (PCI) for unstable angina. Back in the ward, the patient experienced acute stent thrombosis, which resulted in cardiac arrest, and another PCI was performed under ongoing manual CPR. Although revascularization was successful, sudden CAP occurred, leading to cardiac tamponade. Despite extensive treatment efforts, the patient died 18 hours later.Initially, the compression site of CPR was on the midline of the sternum; however, the compression site shifted to the left, to just above the left anterior descending artery, by the time that CAP was detected via angiography. This corresponded to the area where rib fractures were observed upon computed tomography, suggesting the possibility of traumatic CAP due to manual CPR. The physical constraints in the catheterization laboratory can lead to an inappropriate CPR technique and severe traumatic complications.

Bleeding and Thrombosis in Patients With Out-of-Hospital Ventricular Tachycardia/Ventricular Fibrillation Arrest Treated With Extracorporeal Cardiopulmonary Resuscitation.

BACKGROUND: Extracorporeal cardiopulmonary resuscitation improves outcomes after out-of-hospital cardiac arrest. However, bleeding and thrombosis are common complications. We aimed to describe the incidence and predictors of bleeding and thrombosis and their association with in-hospital mortality. METHODS AND RESULTS: Consecutive patients presenting with refractory ventricular tachycardia/ventricular fibrillation out-of-hospital cardiac arrest between December 2015 and March 2022 who met the criteria for extracorporeal cardiopulmonary resuscitation initiation at our center were included. Major bleeding was defined by the Extracorporeal Life Support Organization's criteria. Adjusted analyses were done to seek out risk factors for bleeding and thrombosis and evaluate their association with mortality. Major bleeding occurred in 135 of 200 patients (67.5%), with traumatic bleeding from cardiopulmonary resuscitation in 73 (36.5%). Baseline demographics and arrest characteristics were similar between groups. In multivariable analysis, decreasing levels of fibrinogen were independently associated with bleeding (adjusted hazard ratio [aHR], 0.98 per every 10 mg/dL rise [95% CI, 0.96-0.99]). Patients who died had a higher rate of bleeds per day (0.21 versus 0.03, P<0.001) though bleeding was not significantly associated with in-hospital death (aHR, 0.81 [95% CI. 0.55-1.19]). A thrombotic event occurred in 23.5% (47/200) of patients. Venous thromboembolism occurred in 11% (22/200) and arterial thrombi in 15.5% (31/200). Clinical characteristics were comparable between groups. In adjusted analyses, no risk factors for thrombosis were identified. Thrombosis was not associated with in-hospital death (aHR, 0.65 [95% CI, 0.42-1.03]). CONCLUSIONS: Bleeding is a frequent complication of extracorporeal cardiopulmonary resuscitation that is associated with decreased fibrinogen levels on admission whereas thrombosis is less common. Neither bleeding nor thrombosis was significantly associated with in-hospital mortality.

Observation of the effect of hypothermia therapy combined with optimized nursing on brain protection after cardiopulmonary resuscitation: A retrospective case-control study.

This study aimed to investigate the impact of optimized emergency nursing in conjunction with mild hypothermia nursing on neurological prognosis, hemodynamics, and complications in patients with cardiac arrest. A retrospective analysis was conducted on the medical records of 124 patients who received successful cardiopulmonary resuscitation (CPR) at Fujian Provincial Hospital South Branch. The patients were divided into control and observation groups, each consisting of 62 cases. The brain function of both groups was assessed using the Glasgow Coma Scale and the National Institutes of Health Stroke Scale. Additionally, serum neuron-specific enolase level was measured in both groups. The vital signs and hemodynamics of both groups were analyzed, and the complications and satisfaction experienced by the 2 groups were compared. The experimental group exhibited significantly improved neurological function than the control group (P < .05). Furthermore, the heart rate in the experimental group was significantly lower than the control group (P < .05). However, no significant differences were observed in blood oxygen saturation, mean arterial pressure, central venous pressure, and systolic blood pressure between the 2 groups (P > 0.05). Moreover, the implementation of optimized nursing practices significantly reduced complications and improved the quality of life and satisfaction of post-CPR patients (P < .05). The integration of optimized emergency nursing practices in conjunction with CPR improves neurological outcomes in patients with cardiac arrest.

Differences in Pathophysiology and Treatment Efficacy Based on Heterogeneous Out-of-Hospital Cardiac Arrest.

Out-of-hospital cardiac arrest (OHCA) is heterogeneous in terms of etiology and severity. Owing to this heterogeneity, differences in outcome and treatment efficacy have been reported from case to case; however, few reviews have focused on the heterogeneity of OHCA. We conducted a literature review to identify differences in the prognosis and treatment efficacy in terms of CA-related waveforms (shockable or non-shockable), age (adult or pediatric), and post-CA syndrome severity and to determine the preferred treatment for patients with OHCA to improve outcomes.

Brain computed tomography after resuscitation from in-hospital cardiac arrest.

BACKGROUND: Few data characterize the role of brain computed tomography (CT) after resuscitation from in-hospital cardiac arrest (IHCA). We hypothesized that identifying a neurological etiology of arrest or cerebral edema on brain CT are less common after IHCA than after resuscitation from out-of-hospital cardiac arrest (OHCA). METHODS: We included all patients comatose after resuscitation from IHCA or OHCA in this retrospective cohort analysis. We abstracted patient and arrest clinical characteristics, as well as pH and lactate, to estimate systemic illness severity. Brain CT characteristics included quantitative measurement of the grey-to-white ratio (GWR) at the level of the basal ganglia and qualitative assessment of sulcal and cisternal effacement. We compared GWR distribution by stratum (no edema ≥1.30, mild-to-moderate <1.30 and >1.20, severe ≤1.20) and newly identified neurological arrest etiology between IHCA and OHCA groups. RESULTS: We included 2,306 subjects, of whom 420 (18.2%) suffered IHCA. Fewer IHCA subjects underwent post-arrest brain CT versus OHCA subjects (149 (35.5%) vs 1,555 (82.4%), p < 0.001). Cerebral edema for IHCA versus OHCA was more often absent (60.1% vs. 47.5%) or mild-to-moderate (34.3% vs. 27.9%) and less often severe (5.6% vs. 24.6%). A neurological etiology of arrest was identified on brain CT in 0.5% of IHCA versus 3.2% of OHCA. CONCLUSIONS: Although severe edema was less frequent in IHCA relative to OHCA, mild-to-moderate or severe edema occurred in one in three patients after IHCA. Unsuspected neurological etiologies of arrest were rarely discovered by CT scan in IHCA patients.

Pulmonary fat embolism in non-survivors after cardiopulmonary resuscitation.

BACKGROUND: Blunt trauma acting against the human body presents the fundamental cause of pulmonary fat embolism (PFE) and fat embolism syndrome. The aim of the present study was to investigate PFE in non-survivors after cardiopulmonary resuscitation (CPR). METHODS: This was a prospective cohort study conducted in University Hospital Ostrava, Czech Republic. Within a 4-year study period, all non-survivors after CPR because of out-of-hospital cardiac arrest were assessed for the study eligibility. The presence/seriousness of PFE was determined by microscopic examination of cryo-sections of lung tissue (staining with Oil Red O). RESULTS: In total, 106 persons after unsuccessful CPR were enrolled in the study. The most frequent cause of death in the study population (63.2% of cases) was cardiac disease (ischemic heart disease); PFE was not determined as the cause of death in any of our study cases. Sternal fractures were identified 66.9%, rib fractures (usually multiple) in 80.2% of study cases; the median number of rib fractures was 10.2 fractures per person. Serious intra-thoracic injuries were found in 34.9% of cases. Microscopic examination of lung cryo-sections revealed PFE in 40 (37.7%) study cases; PFE was most frequently evaluated as grade I or II. Occurrence of sternal and rib fractures was significantly higher in persons with PFE than between persons without PFE (p = 0.033 and p = <0.001). Number of rib fractures was also significantly higher in persons with PFE. The occurrence of serious intra-thoracic injuries was comparable in both our study groups (p = 0.089). CONCLUSIONS: PFE presents a common resuscitation injury which can be found in more than 30% of persons after CPR. Persons with resuscitation skeletal chest fractures have significantly higher risk of PFE development. During autopsy of persons after unsuccessful CPR, it is necessary to distinguish CPR-associated injuries including PFE from injuries that arise from other mechanisms.

Misinformation on resuscitation and first aid as an uncontrolled problem that demands close attention: a brief scoping review.

OBJECTIVES: Misinformation is currently recognised by the World Health Organization as an apparent threat to public health. This study aimed to provide an outline of published evidence on misinformation related to the potentially life-saving interventions - first aid and cardiopulmonary resuscitation (CPR). STUDY DESIGN: A scoping review. METHODS: The review was conducted in accordance with the PRISMA Extension for Scoping Reviews. English-language publications describing original studies that evaluated the quality of publicly available information on first aid and/or CPR were included without limitations to the year of publication. RESULTS: Forty-four original studies published between 1982 and 2023 were reviewed. Annual number of publications varied from 0 to 6. The studies have focused on the evaluation of information concerning initial care of cardiac arrest, choking, heart attack, poisoning, burns, and other emergencies. Forty three studies (97.7 %) have reported varying frequencies of misinformation, when public sources, including websites, YouTube videos, and modern artificial intelligence-based chatbots, omitted life-saving instructions on first aid or CPR or contained incorrect information that contradicted relevant international guidelines. Eleven studies (25.0 %) have also revealed potentially harmful advice, which, if followed by an unsuspecting person, may cause direct injury or death of a victim. CONCLUSIONS: Misinformation concerning CPR and first aid cannot be ignored and demands close attention from relevant stakeholders to mitigate its harmful impacts. More studies are urgently needed to determine optimal methods for detecting and measuring misinformation, to understand mechanisms that drive its spread, and to develop effective measures to correct and prevent misinformation.

Effect of resuscitative endovascular balloon occlusion of the aorta in nontraumatic out-of-hospital cardiac arrest: a multinational, multicenter, randomized, controlled trial.

BACKGROUND: Out-of-hospital cardiac arrest (OHCA) is a significant public health issue worldwide and is associated with low survival rates and poor neurological outcomes. The generation of optimal coronary perfusion pressure (CPP) via high-quality chest compressions is a key factor in enhancing survival rates. However, it is often challenging to provide adequate CPP in real-world cardiopulmonary resuscitation (CPR) scenarios. Based on animal studies and human trials on improving CPP in patients with nontraumatic OHCA, resuscitative endovascular balloon occlusion of the aorta (REBOA) is a promising technique in these cases. This study aims to investigate the benefits of REBOA adjunct to CPR compared with conventional CPR for the clinical management of nontraumatic OHCA. METHODS: This is a parallel-group, randomized, controlled, multinational trial that will be conducted at two urban academic tertiary hospitals in Korea and Taiwan. Patients aged 20-80 years presenting with witnessed OHCA will be enrolled in this study. Eligible participants must fulfill the inclusion criteria, and written informed consent should be collected from their legal representatives. Patients will be randomly assigned to the intervention (REBOA-CPR) or control (conventional CPR) group. The intervention group will receive REBOA and standard advanced cardiovascular life support (ACLS). Meanwhile, the control group will receive ACLS based on the 2020 American Heart Association guidelines. The primary outcome is the return of spontaneous circulation (ROSC). The secondary outcomes include sustained ROSC, survival to admission, survival to discharge, neurological outcome, and hemodynamic changes. DISCUSSION: Our upcoming trial can provide essential evidence regarding the efficacy of REBOA, a mechanical method for enhancing CPP, in OHCA resuscitation. Our study aims to determine whether REBOA can improve treatment strategies for patients with nontraumatic OHCA based on clinical outcomes, thereby potentially providing valuable insights and guiding further advancements in this critical public health area. TRIAL REGISTRATION: ClinicalTrials.gov NCT06031623. Registered on September 9, 2023.

Blood-brain barrier permeability for the first 24 hours in hypoxic-ischemic brain injury following cardiac arrest.

BACKGROUND: This study aimed to explore the changes in blood-brain barrier (BBB) permeability and intracranial pressure (ICP) for the first 24 h after the return of spontaneous circulation (ROSC) and their association with injury severity of cardiac arrest. METHODS: This prospective study analysed the BBB permeability assessed using the albumin quotient (Qa) and ICP every 2 h for the first 24 h after ROSC. The injury severity of cardiac arrest was assessed using Pittsburgh Cardiac Arrest Category (PCAC) scores. The primary outcome was the time course of changes in the BBB permeability and ICP for the first 24 h after ROSC and their association with injury severity (PCAC scores of 1-4). RESULTS: Qa and ICP were measured 274 and 197 times, respectively, in 32 enrolled patients. Overall, the BBB permeability increased progressively over time after ROSC, and then it increased significantly at 18 h after ROSC compared with the baseline. In contrast, the ICP revealed non-significant changes for the first 24 h after ROSC. The Qa in the PCAC 2 group was < 0.01, indicating normal or mild BBB disruption at all time points, whereas the PCAC 3 and 4 groups showed a significant increase in BBB permeability at 14 and 22 h, and 12 and 14 h after ROSC, respectively. CONCLUSION: BBB permeability increased progressively over time for the first 24 h after ROSC despite post-resuscitation care, whereas ICP did not change over time. BBB permeability has an individual pattern when stratified by injury severity.

Multi-phase implementation of automated external defibrillator use by nurses during in-hospital cardiac arrest and its impact on survival.

OBJECTIVE: We sought to evaluate the impact of a medical directive allowing nurses to use defibrillators in automated external defibrillator-mode (AED) on in-hospital cardiac arrest (IHCA) outcomes. METHODS: We completed a health record review of consecutive IHCA for which resuscitation was attempted using a pragmatic multi-phase before-after cohort design. We report Utstein outcomes before (Jan.2012-Aug.2013;Control) the implementation of the AED medical directive following usual practice (Sept.2013-Aug.2016;Phase 1), and following the addition of a theory-based educational video (Sept.2016-Dec.2017;Phase 2). RESULTS: There were 753 IHCA with the following characteristics (Before n = 195; Phase 1n = 372; Phase 2n = 186): mean age 66, 60.0% male, 79.3% witnessed, 29.1% noncardiac-monitored medical ward, 23.9% cardiac cause, and initial ventricular fibrillation/tachycardia (VF/VT) 27.2%. Comparing the Before, Phase 1 and 2: an AED was used 0 time (0.0%), 21 times (5.7%), 15 times (8.1%); mean times to 1st analysis were 7 min, 3 min and 1 min (p < 0.0001); mean times to 1st shock were 12 min, 10 min and 8 min (p = 0.32); return of spontaneous circulation (ROSC) was 63.6%, 59.4% and 58.1% (p = 0.77); survival was 24.6%, 21.0% and 25.8% (p = 0.37). Among IHCA in VF/VT (n = 165), time to 1st analysis and 1st shock decreased by 5 min (p = 0.01) and 6 min (p = 0.23), and ROSC and survival increased by 3.0% (p = 0.80) and 15.6% (p = 0.31). There was no survival benefit overall (1.2%; p = 0.37) or within noncardiac-monitored areas (-7.2%; p = 0.24). CONCLUSIONS: The implementation of a medical directive allowing for AED use by nurses successfully improved key outcomes for IHCA victims, particularly following the theory-based education video and among the VF/VT group.

Isolated injury of the caudate lobe of the liver due to cardiopulmonary resuscitation.

Chest compressions are the mainstay of cardiopulmonary resuscitation. Secondary injuries are frequently reported, most frequently to the thorax and less frequently to the abdomen. Review of existing literature highlights liver lacerations as the most common abdominal injury following cardiopulmonary resuscitation; however, an isolated hepatic caudate lobe injury due to CPR has not yet been reported. We discuss existing literature regarding resuscitation-related injuries, report a case of an isolated hepatic caudate lobe injury due to cardiopulmonary resuscitation, and discuss possible mechanisms of injury.

Impact of a national initiative to provide civilian cardiopulmonary resuscitation training courses on the rates of bystander intervention by citizens and survival after out-of-hospital cardiac arrest.

BACKGROUND: The impact of a national initiative to provide cardiopulmonary resuscitation (CPR) education to the public on the rates of citizen-initiated CPR and survival following out-of-hospital cardiac arrest (OHCA) remains uncertain. METHODS: We examined 358,025 cases of citizen-witnessed OHCA with presumed cardiac origin, recorded in the Japanese nationwide registry from 2005 to 2020. We assessed the relationship between the number of individuals certified in CPR courses, citizen interventions, and neurologically favorable survival at one month. RESULTS: The cumulative number of certified citizens has linearly increased from 9,930,327 in 2005 to 34,938,322 in 2020 (incidence rate ratio for annual number = 1.03, p < 0.001), encompassing 32.3% of the Japanese population aged 15 and above. Similarly, the prevalence of citizen-initiated CPR has consistently increased from 40.6% in 2005 to 56.8% in 2020 (P for trend < 0.001). Greater citizen CPR engagement was significantly associated with better outcome in initial shockable rhythm patients [chest compression only: odds ratio (OR) 1.24; 95% confidence interval (CI) 1.02-1.51; P = 0.029; chest compression with rescue breathing: OR 1.33; 95% CI 1.08-1.62; P = 0.006; defibrillation with chest compression: OR 2.27; 95% CI 1.83-2.83; P < 0.001; defibrillation with chest compression and rescue breathing: OR 2.15; 95% CI 1.70-2.73; P < 0.001 vs. no citizen CPR]. CONCLUSIONS: The incidence of citizen-initiated CPR across Japan has consistently and proportionately increased with the rising number of individuals certified in CPR courses. Greater citizen CPR involvement has been linked to neurologically favorable survival, particularly in cases with an initial shockable rhythm.

Ideal chest compression site for cardiopulmonary resuscitation in fontan circulation patients with dextrocardia.

BACKGROUND: We aimed to identify the ideal chest compression site for cardiopulmonary resuscitation (CPR) in patients with a single ventricle with dextrocardia corrected by Fontan surgery. METHODS: The most recent stored chest computed tomography images of all patients with a single ventricle who underwent Fontan surgery were retrospectively analysed. We reported that the ideal chest compression site is the largest part of the compressed single ventricle. To identify the ideal chest compression site, we measured the distance from the midline of the sternum to the point of the maximum sagittal area of the single ventricle as a deviation and calculated the area fraction of the compressed structures. RESULTS: 58 patients (67.2% male) were analysed. The mean right deviation from the midline of the sternum to the ideal compression site was similar to the mean sternum width (32.85 ± 15.61 vs. 31.05 ± 6.75 mm). When chest compression was performed at the ideal site, the area fraction of the single ventricle significantly increased by 7%, which was greater than that of conventional compression (0.15 ± 0.10 vs. 0.22 ± 0.11, P < 0.05). CONCLUSIONS: When performing CPR on a patient with Fontan circulation with dextrocardia, right-sided chest compression may be better than the conventional location.

Association Between Advanced Airway Management With Adrenaline Injection and Prognosis in Adult Patients With Asystole Asphyxia Out-of-hospital Cardiac Arrest.

BACKGROUND: The neurological prognosis of asphyxia is poor and the effect of advanced airway management (AAM) in the prehospital setting remains unclear. This study aimed to evaluate the association between AAM with adrenaline injection and prognosis in adult patients with asystole asphyxia out-of-hospital cardiac arrest (OHCA). METHODS: This study assessed all-Japan Utstein cohort registry data between January 1, 2013 and December 31, 2019. We used propensity score matching analyses before logistic regression analysis to evaluate the effect of AAM on favorable neurological outcome. RESULTS: There were 879,057 OHCA cases, including 70,299 cases of asphyxia OHCAs. We extracted the data of 13,642 cases provided with adrenaline injection by emergency medical service. We divided 7,945 asphyxia OHCA cases in asystole into 5,592 and 2,353 with and without AAM, respectively. After 1:1 propensity score matching, 2,338 asphyxia OHCA cases with AAM were matched with 2,338 cases without AAM. Favorable neurological outcome was not significantly different between the AAM and no AAM groups (adjusted odds ratio [OR] 1.1; 95% confidence interval [CI], 0.5-2.5). However, the return of spontaneous circulation (ROSC) (adjusted OR 1.7; 95% CI, 1.5-1.9) and 1-month survival (adjusted OR 1.5; 95% CI, 1.1-1.9) were improved in the AAM group. CONCLUSION: AAM with adrenaline injection for patients with asphyxia OHCA in asystole was associated with improved ROSC and 1-month survival rate but showed no differences in neurologically favorable outcome. Further prospective studies may comprehensively evaluate the effect of AAM for patients with asphyxia.

Cardiac Arrest With or Without Need for Extracorporeal Life Support After Congenital Cardiac Surgery.

BACKGROUND: Postoperative cardiac arrest (CA) with or without need for extracorporeal cardiopulmonary resuscitation (ECPR) is one of the most significant complications in the early postoperative period after pediatric cardiac operation. The objective of this study was to develop and to validate a predictive model of postoperative CA with or without ECPR. METHODS: In this retrospective cohort study, we reviewed data from patients who underwent cardiac surgery with cardiopulmonary bypass (CPB) between July 20, 2020, and December 31, 2021. Variables included demographic data, presence of preoperative risk factors, The Society of Thoracic Surgeons-European Association for Cardio-Thoracic Surgery mortality categories, perioperative data, residual lesion score (RLS), and vasoactive-inotropic score (VIS). We used multivariable logistic regression analysis to develop a predictive model. RESULTS: The incidence of CA with or without ECPR was 4.4% (n = 24/544). Patients who experienced postoperative CA with or without ECPR were younger (age, 130 [54-816.5] days vs 626 [127.5-2497.5] days; P < .050) and required longer CPB (253 [154-332.5] minutes vs 130 [87-186] minutes; P < .010) and cross-clamp (116.5 [75.5-143.5] minutes vs 64 [30-111] minutes; P < .020) times; 37.5% of patients with an outcome had at least 1 preoperative risk factor (vs 16.9%; P < .010). Our multivariable logistic regression determined that the presence of at least 1 preoperative risk factor (P = .005), CPB duration (P = .003), intraoperative residual lesion score (P = .009), and postsurgery vasoactive-inotropic score (P = .010) were predictors of the incidence of CA with or without ECPR. CONCLUSIONS: We developed a predictive model of postoperative CA with or without ECPR after congenital cardiac operation. Our model performed better than the individual scores and risk factors.

The impact of COVID-19 pandemic on out-of-hospital cardiac arrest: An individual patient data meta-analysis.

AIM: Prior studies have reported increased out-of-hospital cardiac arrests (OHCA) incidence and lower survival during the COVID-19 pandemic. We evaluated how the COVID-19 pandemic affected OHCA incidence, bystander CPR rate and patients' outcomes, accounting for regional COVID-19 incidence and OHCA characteristics. METHODS: Individual patient data meta-analysis of studies which provided a comparison of OHCA incidence during the first pandemic wave (COVID-period) with a reference period of the previous year(s) (pre-COVID period). We computed COVID-19 incidence per 100,000 inhabitants in each of 97 regions per each week and divided it into its quartiles. RESULTS: We considered a total of 49,882 patients in 10 studies. OHCA incidence increased significantly compared to previous years in regions where weekly COVID-19 incidence was in the fourth quartile (>136/100,000/week), and patients in these regions had a lower odds of bystander CPR (OR 0.49, 95%CI 0.29-0.81, p = 0.005). Overall, the COVID-period was associated with an increase in medical etiology (89.2% vs 87.5%, p < 0.001) and OHCAs at home (74.7% vs 67.4%, p < 0.001), and a decrease in shockable initial rhythm (16.5% vs 20.3%, p < 0.001). The COVID-period was independently associated with pre-hospital death (OR 1.73, 95%CI 1.55-1.93, p < 0.001) and negatively associated with survival to hospital admission (OR 0.68, 95%CI 0.64-0.72, p < 0.001) and survival to discharge (OR 0.50, 95%CI 0.46-0.54, p < 0.001). CONCLUSIONS: During the first COVID-19 pandemic wave, there was higher OHCA incidence and lower bystander CPR rate in regions with a high-burden of COVID-19. COVID-19 was also associated with a change in patient characteristics and lower survival independently of COVID-19 incidence in the region where OHCA occurred.