[Analysis of factors affecting the return of spontaneous circulation in elderly patients with out-of-hospital cardiac arrest].

OBJECTIVE: To investigate the factors that influence the return of spontaneous circulation (ROSC) in elderly patients suffering from out-of-hospital cardiac arrest (OHCA). METHODS: A retrospective study was used to collect the clinical data of OHCA patients admitted to the emergency center of Zhengzhou People's Hospital from July 2016 to July 2019 based on the pre-hospital emergency database of Utstein model. Patients' gender, age, cardiac arrest (CA) etiology, presence or absence of bystander cardiopulmonary resuscitation (CPR), emergency response time, initial cardiac rhythm, ventilation method, use of epinephrine, defibrillation and ROSC were included. The patients were divided into elderly and young groups according to whether age ≥ 60 years old, and the differences in various indicators between the two groups were compared. Univariate Logistic regression analysis was used to analyze the relationship between emergency response time and ROSC in elderly patients and multivariate Logistic regression analysis was used to identify factors influencing ROSC in elderly patients. RESULTS: A total of 3 429 adult OHCA patients were enrolled in this study, including 2 105 elderly patients (61.39%), and 1 324 young and middle-aged patients (38.61%). Compared to the young group, the proportion of females, non-cardiac causes and asystole as the initial rhythm was higher in the elderly group, the emergency response time was shorter, the rate of defibrillation and tracheal intubation, and the success rate of ROSC were lower (all P < 0.05). Among them, the proportion of cardiac arrest as the initial rhythm in elderly male patients was significantly higher than that of young male patients (P < 0.05); the proportion of non-cardiac causes in elderly female patients was significantly higher than that of young female patients, and the proportion of defibrillation was significantly lower than that of young female patients (all P < 0.05). Multivariate Logistic regression analysis showed that cardiac arrest as the initial rhythm was strongly associated with ROSC in elderly male patients [odds ratio (OR) = 0.126, 95% confidence interval (95%CI) was 0.045-0.352, P < 0.05]. Univariate Logistic regression analysis of the relationship between emergency response time and ROSC in elderly patients showed that although there was no significant difference in the ROSC success rate among elderly patients with various emergency response times, an emergency response time within 10 minutes was beneficial for ROSC in elderly patients. CONCLUSIONS: The success rate of ROSC is very low in elderly OHCA patients aged ≥60 years. Although the CPR-related indicators of elderly patients are significantly different from those of young patients, there are gender differences. The association between the elderly male patients and cardiac arrest as the initial rhythm is stronger, while OHCA caused by non-cardiac diseases is more common and defibrillable rhythm is less common in elderly female patients. It may be more beneficial for elderly patients to shorten the emergency response time and increase bystander CPR.

The design of the PRINCESS 2 trial: A randomized trial to study the impact of ultrafast hypothermia on complete neurologic recovery after out-of-hospital cardiac arrest with initial shockable rhythm.

BACKGROUND: Delayed hypothermia, initiated after hospital arrival, several hours after cardiac arrest with 8-10 hours to reach the target temperature, is likely to have limited impact on overall survival. However, the effect of ultrafast hypothermia, i.e., delivered intra-arrest or immediately after return of spontaneous circulation (ROSC), on functional neurologic outcome after out-of-hospital cardiac arrest (OHCA) is unclear. In two prior trials, prehospital trans-nasal evaporative intra-arrest cooling was safe, feasible and reduced time to target temperature compared to delayed cooling. Both studies showed trends towards improved neurologic recovery in patients with shockable rhythms. The aim of the PRINCESS2-study is to assess whether cooling, initiated either intra-arrest or immediately after ROSC, followed by in-hospital hypothermia, significantly increases survival with complete neurologic recovery as compared to standard normothermia care, in OHCA patients with shockable rhythms. METHODS/DESIGN: In this investigator-initiated, randomized, controlled trial, the emergency medical services (EMS) will randomize patients at the scene of cardiac arrest to either trans-nasal cooling within 20 minutes from EMS arrival with subsequent hypothermia at 33°C for 24 hours after hospital admission (intervention), or to standard of care with no prehospital or in-hospital cooling (control). Fever (>37,7°C) will be avoided for the first 72 hours in both groups. All patients will receive post resuscitation care and withdrawal of life support procedures according to current guidelines. Primary outcome is survival with complete neurologic recovery at 90 days, defined as modified Rankin scale (mRS) 0-1. Key secondary outcomes include survival to hospital discharge, survival at 90 days and mRS 0-3 at 90 days. In total, 1022 patients are required to detect an absolute difference of 9% (from 45 to 54%) in survival with neurologic recovery (80% power and one-sided α=0,025, ß=0,2) and assuming 2,5% lost to follow-up. Recruitment starts in Q1 2024 and we expect maximum enrolment to be achieved during Q4 2024 at 20-25 European and US sites. DISCUSSION: This trial will assess the impact of ultrafast hypothermia applied on the scene of cardiac arrest, as compared to normothermia, on 90-day survival with complete neurologic recovery in OHCA patients with initial shockable rhythm. TRIAL REGISTRATION: NCT06025123.

Is the lactate value predictive of the return of spontaneous circulation during CPR in nontraumatic OHCA?

AIM OF THE STUDY: Cardiac arrest is a major public health issue, in which emergency medical services (EMS) initiating or continuing resuscitation in about 50% to 60% of cases. The aim of this study was to determine whether blood lactate levels and their course during cardiopulmonary resuscitation are prognostic indicators of the return of spontaneous cardiac activity (ROSC) in non-traumatic out-of-hospital cardiac arrest (OHCA). METHODS: This was a prospective, interventional, multi-center study between 2017 and 2020. Patients above the age of 18 years (>50 years for women) who had non-traumatic OHCA and did not achieve ROSC before the arrival of the EMS, and for whom the medical team decided to initiate or continue cardiopulmonary resuscitation have been included. The primary endpoint was the return of spontaneous cardiac activity during out-of-hospital cardiopulmonary resuscitation, and secondary endpoint was survival at day 28. The lactate was initially measured simultaneously on a venous and capillary sample and then in capillary samples throughout the CPR, using POC device. RESULTS: A total 60 patients were included. Median age was 71 [IQR: 62-84] and 21.3% were female. Among them, 25% underwent ROSC in out-of-hospital setting, and 13,3% were alive at D-28. The median venous lactate value in all patients at T0 (time at which the EMS set up the peripheral venous line) was 6.2 mmol/L [IQR: 4.6-8.1], with no difference between patients with or without ROSC: 6.4 mmol/L [IQR:4.7-7.9] for patients with ROSC and 6.2 mmol/L [IQR: 4.7-8] for patients without ROSC (p = 0.87). The variables independently associated with ROSC were initial EtCo2 value (aOR = 1.12; 95% CI 1.01-1.25); the initial shockable rhythm (aOR = 10.2; 95% CI 1.18-88.2); and the pre-ROSC adrenaline dose (aOR = 0.54; 95% CI 0.35-0.82). CONCLUSION: In this prospective multi-center study, there was no independent association between lactate values during cardiopulmonary resuscitation and ROSC in non-traumatic OHCA. However, the post-ROSC pre-hospital kinetics of lactate (i.e., during the first 30 min) seem to be associated with survival.

Validation of Utstein-Based score to predict return of spontaneous circulation (UB-ROSC) in patients with out-of-hospital cardiac arrest.

BACKGROUND AND AIMS: The Utstein Based-ROSC (UB-ROSC) score has been developed to predict ROSC in OHCA victims. Aim of the study was to validate the UB-ROSC score using two Utstein-based OHCA registries: the SWiss REgistry of Cardiac Arrest (SWISSRECA) and the Lombardia Cardiac Arrest Registry (Lombardia CARe), northern Italy. METHODS: Consecutive patients with OHCA of any etiology occurring between January 1st, 2019 and December 31st 2021 were included in this retrospective validation study. UB-ROSC score was computed for each patient and categorized in one of three subgroups: low, medium or high likelihood of ROSC according to the UB-ROSC cut-offs (≤-19; -18 to 12; ≥13). To assess the performance of the UB-ROSC score in this new cohort, we assessed both discrimination and calibration. The score was plotted against the survival to hospital admission. RESULTS: A total of 12.577 patients were included in the study. A sustained ROSC was obtained in 2.719 patients (22%). The UB-ROSC model resulted well calibrated and showed a good discrimination (AUC 0.71, 95% CI 0.70-0.72). In the low likelihood subgroup of UB-ROSC, only 10% of patients achieved ROSC, whereas the proportion raised to 36% for a score between -18 and 12 (OR 5.0, 95% CI 2.9-8.6, p < 0.001) and to 85% for a score ≥13 (OR 49.4, 95% CI 14.3-170.6, p < 0.001). CONCLUSIONS: UB-ROSC score represents a reliable tool to predict ROSC probability in OHCA patients. Its application may help the medical decision-making process, providing a realistic stratification of the probability for ROSC.

Supraglottic Airway Versus Tracheal Intubation for Airway Management in Out-of-Hospital Cardiac Arrest: A Systematic Review, Meta-Analysis, and Trial Sequential Analysis of Randomized Controlled Trials.

OBJECTIVES: Given the uncertainty regarding the optimal approach for airway management for adult patients with out-of-hospital cardiac arrest (OHCA), we conducted a systematic review and meta-analysis to compare the use of supraglottic airways (SGAs) with tracheal intubation for initial airway management in OHCA. DATA SOURCES: We searched MEDLINE, PubMed, Embase, Cochrane Library, as well as unpublished sources, from inception to February 7, 2023. STUDY SELECTION: We included randomized controlled trials (RCTs) of adult OHCA patients randomized to SGA compared with tracheal intubation for initial prehospital airway management. DATA EXTRACTION: Reviewers screened abstracts, full texts, and extracted data independently and in duplicate. We pooled data using a random-effects model. We used the modified Cochrane risk of bias 2 tool and assessed certainty of evidence using the Grading Recommendations Assessment, Development, and Evaluation approach. We preregistered the protocol on PROSPERO (CRD42022342935). DATA SYNTHESIS: We included four RCTs ( n = 13,412 patients). Compared with tracheal intubation , SGA use probably increases return of spontaneous circulation (ROSC) (relative risk [RR] 1.09; 95% CI, 1.02-1.15; moderate certainty) and leads to a faster time to airway placement (mean difference 2.5 min less; 95% CI, 1.6-3.4 min less; high certainty). SGA use may have no effect on survival at longest follow-up (RR 1.06; 95% CI, 0.84-1.34; low certainty), has an uncertain effect on survival with good functional outcome (RR 1.11; 95% CI, 0.82-1.50; very low certainty), and may have no effect on risk of aspiration (RR 1.04; 95% CI, 0.94 to 1.16; low certainty). CONCLUSIONS: In adult patients with OHCA, compared with tracheal intubation, the use of SGA for initial airway management probably leads to more ROSC, and faster time to airway placement, but may have no effect on longer-term survival outcomes or aspiration events.

Neurological outcomes and quality of life in post-cardiac arrest patients with return of spontaneous circulation supported by ECMO: A retrospective case series.

Post-cardiac arrest brain injury constitutes a significant contributor to morbidity and mortality, leading to cognitive impairment and subsequent disability. Individuals within this patient cohort grapple with uncertainty regarding the potential advantages of extracorporeal life support (ECMO) cannulation. This study elucidates the neurological outcomes and quality of life of post-cardiac arrest patients who attained spontaneous circulation and underwent ECMO cannulation. This is a retrospective case study within a local context, the research involved 32 patients who received ECMO support following an intrahospital cardiac arrest with return of spontaneous circulation (ROSC). An additional 32 patients experienced cardiac arrest with ROSC before undergoing cannulation. The average age was 41 years, with the primary causes of cardiac arrest identified as acute coronary syndrome (46.8%), pulmonary thromboembolism (21.88%), and hypoxemia (18.7%). The most prevalent arrest rhythm was asystole (37.5%), followed by ventricular fibrillation (34.4%). The mean SOFA score was 7 points (IQR 6.5-9), APACHE II score was 12 (IQR 9-16), RESP score was -1 (IQR -1 to -4) in cases of respiratory ECMO, and SAVE score was -3 (IQR -5 to 2) in cases of cardiac ECMO. Overall survival was 71%, and at 6 months, the Barthel score was 75 points, modified Rankin score was 2, cerebral performance categories score was 1, and the SF-12 had an average score of 30. Notably, there were no significant associations between the time, cause, or rhythm of cardiac arrest and neurological outcomes. Importantly, cardiac arrest is not a contraindication for ECMO cannulation. A meticulous assessment of candidates who have achieved spontaneous circulation after cardiac arrest, considering the absence of early signs of poor neurological prognosis, is crucial in patient selection. Larger prospective studies are warranted to validate and extend these findings.

Higher Prehospital Blood Glucose Levels Associated With Return of Spontaneous Circulation in Out-of-Hospital Non-traumatic Cardiac Arrests.

OBJECTIVE: Cardiac arrest leads to an array of metabolic disturbances. We aimed to investigate the association between prehospital blood glucose levels (BGLs) and rates of return of spontaneous circulation (ROSC) in non-traumatic out-of-hospital cardiac arrests (OHCAs). METHODS: A retrospective analysis of adult non-traumatic OHCAs within Kalamazoo County, MI, from January 2018 to May 2020 using the Michigan Emergency Medical Services Information System database was performed. Demographic data, Utstein variables, and BGLs (hypoglycemia < 70 mg/dL, euglycemia 70-120 mg/dL, and hyperglycemia >120 mg/dL) were abstracted. Chi-square and Wilcoxon rank sum tests were used to evaluate the relationship between BGL and ROSC. RESULTS: In total, 314 patients met the inclusion criteria. The mean age was 62.9 years. ROSC was achieved in 147 (46.8%) patients. Fifty (15.9%), 75 (23.9%), and 189 (60.2%) patients were hypoglycemic, euglycemic, and hyperglycemic, respectively. An association was found between the glycemic group and ROSC (P < .0001), with an estimated odds of ROSC being 77% lower (95% confidence interval, 46%-90%) for hypoglycemic than euglycemic or hyperglycemic patients. The point difference between median ROSC-yes BGL (median [interquartile range] = 160 mg/dL [110-225 mg/dL]) was 33 mg/dL (95% CI, 13-51 mg/dL) greater than the ROSC-no group (median [interquartile range] = 127 mg/dL [75-190 mg/dL], P = .001). CONCLUSION: Non-traumatic OHCA patients achieving ROSC had a significantly higher prehospital BGL than the ROSC-no group. Further study is warranted to investigate the role intra-arrest BGL may have as a prognostic marker for ROSC.

Association of small adult ventilation bags with return of spontaneous circulation in out of hospital cardiac arrest.

INTRODUCTION: Little is known about the impact of tidal volumes delivered by emergency medical services (EMS) to adult patients with out-of-hospital cardiac arrest (OHCA). A large urban EMS system changed from standard adult ventilation bags to small adult bags. We hypothesized that the incidence of return of spontaneous circulation (ROSC) at the end of EMS care would increase after this change. METHODS: We performed a retrospective analysis evaluating adults treated with advanced airway placement for nontraumatic OHCA between January 1, 2015 and December 31, 2021. We compared rates of ROSC, ventilation rate, and mean end tidal carbon dioxide (ETCO2) by minute before and after the smaller ventilation bag implementation using linear and logistic regression. RESULTS: Of the 1,994 patients included, 1,331 (67%) were treated with a small adult bag. ROSC at the end of EMS care was lower in the small bag cohort than the large bag cohort, 33% vs 40% (p = 0.003). After adjustment, small bag use was associated with lower odds of ROSC at the end of EMS care [OR 0.74, 95% CI 0.61 - 0.91]. Ventilation rates did not differ between cohorts. ETCO2 values were lower in the large bag cohort (33.2 ± 17.2 mmHg vs. 36.9 ± 19.2 mmHg, p < 0.01). CONCLUSION: Use of a small adult bag during OHCA was associated with lower odds of ROSC at the end of EMS care. The effects on acid base status, hemodynamics, and delivered minute ventilation remain unclear and warrant additional study.

Do we need standardized management after termination-of-resuscitation attempts? Autoresuscitation in a 67-year-old woman.

BACKGROUND: Autoresuscitation is the phenomenon of spontaneous return of circulation after cessation of CPR, also known as the Lazarus phenomenon. Most of the evidence is based on case reports and a few systematic reviews. The occurrence of autoresuscitation may lead to self-reproach and dismay in affected emergency personnel and may rise questions about the correct procedure after terminating resuscitative efforts. In contrast to existing cardiac arrest guidelines there is no standardized approach to terminating resuscitative attempts. CASE: We report a case of out of hospital autoresuscitation in a 67-year-old female after 60 min of advanced cardiac life support. After shock refractory shockable rhythm, we recorded pulseless electrical activity and fixed pupils, consequently resuscitation was terminated. About 50 min later the patient surprisingly showed signs of life. Due to the suggestive history a coronary angiography was performed, showing severe coronary heart disease which necessitated surgical intervention. After ACBP surgery and intensive care followed by treatment on the cardiological ward, she was finally discharged to neurological rehabilitation. CONCLUSION: As already proposed by existing literature, there should be at least a 10-min interval of close monitoring after abandoning CPR. Transport of a deceased patient should only take place after secure signs of death can be detected. Further investigation is needed to determine which patients are most likely to benefit from an extended observation period. Our case reports highlights the difficulties in death declaration and the importance of close monitoring after abandoning CPR.

Out-of-Hospital Arterial to End-Tidal Carbon Dioxide Gradient in Patients With Return of Spontaneous Circulation After Out-of-Hospital Cardiac Arrest: A Retrospective Study.

STUDY OBJECTIVE: End-tidal carbon dioxide (etCO2) is used to guide ventilation after achieving return of spontaneous circulation (ROSC) in certain out-of-hospital systems, despite an unknown difference between arterial and end-tidal CO2 (partial pressure of carbon dioxide [paCO2]-etCO2 difference) levels in this population. The primary aim of this study was to evaluate and quantify the paCO2-etCO2 difference in out-of-hospital patients with ROSC after nontraumatic cardiac arrest. METHODS: This retrospective single-center study included patients aged 18 years and older with sustained ROSC after nontraumatic out-of-hospital cardiac arrest. In patients with an existing out-of-hospital arterial blood gas analysis within 30 minutes after achieving ROSC, matching etCO2 values were evaluated. Linear regression and Bland-Altman plot analysis were performed to ascertain the primary endpoint of interest. RESULTS: We included data of 60 patients in the final analysis. The mean paCO2-etCO2 difference was 32 (±18) mmHg. Only a moderate correlation (R2=0.453) between paCO2 and etCO2 was found. Bland-Altman analysis showed a bias of 32 mmHg (95% confidence interval [CI], 27 to 36) [the upper limit of agreement of 67 mmHg (95% CI, 59 to 74) and the lower limit of agreement of -3 mmHg (95% CI, -11 to 5)]. CONCLUSION: The paCO2-etCO2 difference in patients with ROSC after out-of-hospital cardiac arrest is far from physiologic ranges, and the between-patient variability is high. Therefore, etCO2-guided adaption of ventilation might not provide adequate accuracy in this setting.

Effect of stomach inflation during cardiopulmonary resuscitation on return of spontaneous circulation in out-of-hospital cardiac arrest patients: A retrospective observational study.

BACKGROUND: Gastric inflation caused by excessive ventilation is a common complication of cardiopulmonary resuscitation. Gastric inflation may further compromise ventilation via increases in intrathoracic pressure, leading to decreased venous return and cardiac output, which may impair out-of-hospital cardiac arrest (OHCA) outcomes. The purpose of this study was to measure the gastric volume of OHCA patients using computed tomography (CT) scan images and evaluate the effect of gastric inflation on return of spontaneous circulation (ROSC). METHODS: In this single-center, retrospective, observational study, CT scan was conducted after ROSC or immediately after death. Total gastric volume was measured. Primary outcome was ROSC. Achievement of ROSC was compared in the gastric distention group and the no gastric distention group; gastric distension was defined as total gastric volume in the ≥75th percentile. Additionally, factors associated with gastric distention were examined. RESULTS: A total of 446 cases were enrolled in the study; 120 cases (27%) achieved ROSC. The median gastric volume was 400 ml for all OHCA subjects; 1068 ml in gastric distention group vs. 287 ml in no gastric distention group. There was no difference in ROSC between the groups (27/112 [24.1%] vs. 93/334 [27.8%], p = 0.440). Gastric distention did not have a significant impact, even after adjustments (adjusted odds ratio 0.73, 95% confidence interval [0.42-1.29]). Increased gastric volume was associated with longer emergency medical service activity time. CONCLUSIONS: We observed a median gastric volume of 400 ml in patients after OHCA resuscitation. In our setting, gastric distention did not prevent ROSC.

Skeletal muscle oxygenation during cardiopulmonary resuscitation as a predictor of return of spontaneous circulation: a pilot study.

BACKGROUND: Near-infrared spectroscopy (NIRS) provides regional tissue oxygenation (rSO2) even in pulseless states, such as out-of-hospital cardiac arrest (OHCA). Brain rSO2 seems to be important predictor of return of spontaneous circulation (ROSC) during cardiopulmonary resuscitation (CPR). Aim of our study was to explore feasibility for monitoring and detecting changes of skeletal muscle rSO2 during resuscitation. METHODS: Skeletal muscle and brain rSO2 were measured by NIRS (SenSmart Model X-100, Nonin, USA) during CPR in adult patient with OHCA. Start (basal) rSO2, maximal during CPR (maximal) and difference between maximal-minimal rSO2 (delta-rSO2), were recorded. Patients were divided into ROSC and NO-ROSC group. RESULTS: 20 patients [age: 66.0ys (60.5-79.5), 65% male] with OHCA [50% witnessed, 70% BLS, time to ALS 13.5 min (11.0-19.0)] were finally analyzed. ROSC was confirmed in 5 (25%) patients. Basal and maximal skeletal muscle rSO2 were higher in ROSC compared to NO-ROSC group [49.0% (39.7-53.7) vs. 15.0% (12.0-25.2), P = 0.006; 76.0% (52.7-80.5) vs. 34.0% (18.0-49.5), P = 0.005, respectively]. There was non-linear cubic relationship between time of collapse and basal skeletal muscle rSO2 in witnessed OHCA and without BLS (F-ratio = 9.7713, P = 0.0261). There was correlation between maximal skeletal muscle and brain rSO2 (n = 18, rho: 0.578, P = 0.0121). CONCLUSIONS: Recording of skeletal muscle rSO2 during CPR in patients with OHCA is feasible. Basal and maximal skeletal muscle rSO2 were higher in ROSC compared to NO-ROSC group. Clinical trial registration number ClinicalTrials.gov, NCT04058925, registered on: 16th August 2019. URL of trial registry record: https://www. CLINICALTRIALS: gov/ct2/show/NCT04058925?titles=Tissue+Oxygenation+During+Cardiopulmonary+Resuscitation+as+a+Predictor+of+Return+of+Spontaneous+Circulation&draw=2&rank=1 .

Out-of-hospital cardiac arrest in children: an epidemiological study based on the German Resuscitation Registry identifying modifiable factors for return of spontaneous circulation.

AIM: This work provides an epidemiological overview of out-of-hospital cardiac arrest (OHCA) in children in Germany between 2007 and 2021. We wanted to identify modifiable factors associated with survival. METHODS: Data from the German Resuscitation Registry (GRR) were used, and we included patients registered between 1st January 2007 and 31st December 2021. We included children aged between > 7 days and 17 years, where cardiopulmonary resuscitation (CPR) was started, and treatment was continued by emergency medical services (EMS). Incidences and descriptive analyses are presented for the overall cohort and each age group. Multivariate binary logistic regression was performed on the whole cohort to determine the influence of (1) CPR with/without ventilation started by bystander, (2) OHCA witnessed status and (3) night-time on the outcome hospital admission with return of spontaneous circulation (ROSC). RESULTS: OHCA in children aged < 1 year had the highest incidence of the same age group, with 23.42 per 100 000. Overall, hypoxia was the leading presumed cause of OHCA, whereas trauma and drowning accounted for a high proportion in children aged > 1 year. Bystander-witnessed OHCA and bystander CPR rate were highest in children aged 1-4 years, with 43.9% and 62.3%, respectively. In reference to EMS-started CPR, bystander CPR with ventilation were associated with an increased odds ratio for ROSC at hospital admission after adjusting for age, sex, year of OHCA and location of OHCA. CONCLUSION: This study provides an epidemiological overview of OHCA in children in Germany and identifies bystander CPR with ventilation as one primary factor for survival. Trial registrations German Clinical Trial Register: DRKS00030989, December 28th 2022.

Lack of Association of Initial Vasopressor Dosing with Survival and Cardiac Re-Arrest Likelihood After Return of Spontaneous Circulation.

BACKGROUND: Cardiac arrest occurs in approximately 350,000 patients outside the hospital and approximately 30,000 patients in the emergency department (ED) annually in the United States. When return of spontaneous circulation (ROSC) is achieved, hypotension is a common complication. However, optimal dosing of vasopressors is not clear. OBJECTIVE: The objective of this study was to determine if initial vasopressor dosing was associated with cardiac re-arrest in patients after ROSC. METHODS: This was a retrospective, single-center analysis of adult patients experiencing cardiac arrest prior to arrival or within the ED. Patients were assigned to one of four groups based on starting dose of vasopressor: low dose (LD; < 0.25 µg/kg/min), medium dose (MD; 0.25-0.49 µg/kg/min), high dose (HD; 0.5-0.99 µg/kg/min), and very high dose (VHD; ≥ 1 µg/kg/min). Data collection was performed primarily via manual chart review of medical records. The primary outcome was incidence of cardiac re-arrest within 1 h of vasopressor initiation. Multivariate logistic regression analysis was conducted to identify any covariates strongly associated with the primary outcome. RESULTS: No difference in cardiac re-arrest incidence was noted between groups. The VHD group was significantly more likely to require a second vasopressor (p = 0.003). The HD group had lower survival rates to hospital discharge compared with the LD and MD groups (p = 0.0033 and p = 0.0147). In the multivariate regression, longer duration of pre-vasopressor re-arrests and hyperkalemic cardiac arrest etiology were significant predictors of cardiac re-arrest after vasopressor initiation. CONCLUSIONS: Initial vasopressor dosing was not found to be associated with risk of cardiac re-arrest or, conversely, risk of adverse events.