Impact of the COVID-19 pandemic on pediatric out-of-hospital cardiac arrest outcomes in Japan

This study investigates the impact of the COVID-19 pandemic on pediatric out-of-hospital cardiac arrest (OHCA) outcomes in Japan, aiming to address a critical research gap. Analyzing data from the All-Japan Utstein registry covering pediatric OHCA cases from 2018 to 2021, the study observed no significant changes in one-month survival, neurological outcomes, or overall performance when comparing the pre-pandemic (2018-2019) and pandemic (2020-2021) periods among 6765 cases. However, a notable reduction in pre-hospital return of spontaneous circulation (ROSC) during the pandemic (15.1-13.1%, p = .020) was identified. Bystander-initiated chest compressions and rescue breaths declined (71.1-65.8%, 22.3-13.0%, respectively; both p < .001), while bystander-initiated automated external defibrillator (AED) use increased (3.7-4.9%, p = .029). Multivariate logistic regression analyses identified factors associated with reduced pre-hospital ROSC during the pandemic. Post-pandemic, there was no noticeable change in the one-month survival rate. The lack of significant change in survival may be attributed to the negative effects of reduced chest compressions and ventilation being offset by the positive impact of widespread AED availability in Japan. These findings underscore the importance of innovative tools and systems for safe bystander cardiopulmonary resuscitation during a pandemic, providing insights to optimize pediatric OHCA care.

External Validation of Updated Prediction Models for Neurological Outcomes at 90 Days in Patients With Out-of-Hospital Cardiac Arrest

BACKGROUND

Few prediction models for individuals with early-stage out-of-hospital cardiac arrest (OHCA) have undergone external validation. This study aimed to externally validate updated prediction models for OHCA outcomes using a large nationwide dataset.

METHODS AND RESULTS

We performed a secondary analysis of the JAAM-OHCA (Comprehensive Registry of In-Hospital Intensive Care for Out-of-Hospital Cardiac Arrest Survival and the Japanese Association for Acute Medicine Out-of-Hospital Cardiac Arrest) registry. Previously developed prediction models for patients with cardiac arrest who achieved the return of spontaneous circulation were updated. External validation was conducted using data from 56 institutions from the JAAM-OHCA registry. The primary outcome was a dichotomized 90-day cerebral performance category score. Two models were updated using the derivation set (n=3337). Model 1 included patient demographics, prehospital information, and the initial rhythm upon hospital admission; Model 2 included information obtained in the hospital immediately after the return of spontaneous circulation. In the validation set (n=4250), Models 1 and 2 exhibited a C-statistic of 0.945 (95% CI, 0.935-0.955) and 0.958 (95% CI, 0.951-0.960), respectively. Both models were well-calibrated to the observed outcomes. The decision curve analysis showed that Model 2 demonstrated higher net benefits at all risk thresholds than Model 1. A web-based calculator was developed to estimate the probability of poor outcomes (https://pcas-prediction.shinyapps.io/90d_lasso/).

CONCLUSIONS

The updated models offer valuable information to medical professionals in the prediction of long-term neurological outcomes for patients with OHCA, potentially playing a vital role in clinical decision-making processes.

Effect of crew ratio of advanced life support-trained personnel on patients with out-of-hospital cardiac arrest: A systematic review and meta-analysis

BACKGROUND/PURPOSE

This review aimed to investigate the effect of crew ratios of on-scene advanced life support (ALS)-trained personnel on patients with out-of-hospital cardiac arrest (OHCA).

METHODS

We systematically searched PubMed, Ovid EMBASE, and the Cochrane Central Register of Controlled Trials databases from the inception date until September 30, 2022, for eligible studies. Two reviewers independently screened the studies for relevance, extracted data, and quality. We compared the effect of the ratio of on-scene ALS-trained personnel >50 % to those with a ratio ≤50 % among prehospital personnel on the clinical outcomes of OHCA patients. The primary outcome was survival-to-discharge and secondary outcomes were any return of spontaneous circulation (ROSC), sustained ROSC (≥2 h), and favourable neurological outcome at discharge (cerebral performance category scores: 1 or 2). Pooled odds ratios (ORs) were calculated, and the certainty of evidence was assessed.

RESULTS

From 10,864 references, we identified four non-randomised studies, including 16,475 patients. Two studies were performed in Japan and two in Taiwan. There were significant differences in survival-to-discharge (OR: 1.24, 95 % confidence interval [CI]: 1.07-1.44, I2: 7 %), any ROSC (OR:1.22, 95 % CI: 1.04-1.43, I2: 74 %) and sustained ROSC (OR: 1.39, 95 % CI: 1.16-1.65, I2: 40 %), but insignificant differences in favourable neurological outcome at discharge. The overall certainty of evidence was rated as very low for all outcomes.

CONCLUSION

Prehospital ALS care with a ratio of on-scene ALS-trained personnel >50 % could improve OHCA patient outcomes than crew ratios ≤50 %. Further studies are required to reach a robust conclusion.

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, β=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.

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.

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.

Comparison of various vasopressin doses to epinephrine during cardiopulmonary resuscitation in asphyxiated neonatal piglets

BACKGROUND

Current neonatal resuscitation guidelines recommend epinephrine for cardiac arrest. Vasopressin might be an alternative during asphyxial cardiac arrest. We aimed to compare vasopressin and epinephrine on incidence and time to return of spontaneous circulation (ROSC) in asphyxiated newborn piglets.

DESIGN/METHODS

Newborn piglets (n = 8/group) were anesthetized, intubated, instrumented, and exposed to 30 min of normocapnic hypoxia, followed by asphyxia and asystolic cardiac arrest. Piglets were randomized to 0.2, 0.4, or 0.8IU/kg vasopressin, or 0.02 mg/kg epinephrine. Hemodynamic parameters were continuously measured.

RESULTS

Median (IQR) time to ROSC was 172(103-418)s, 157(100-413)s, 122(93-289)s, and 276(117-480)s for 0.2, 0.4, 0.8IU/kg vasopressin, and 0.02 mg/kg epinephrine groups, respectively (p = 0.59). The number of piglets that achieved ROSC was 6(75%), 6(75%), 7(88%), and 5(63%) for 0.2, 0.4, 0.8IU/kg vasopressin, and 0.02 mg/kg epinephrine, respectively (p = 0.94). The epinephrine group had a 60% (3/5) rate of post-ROSC survival compared to 83% (5/6), 83% (5/6), and 57% (4/7) in the 0.2, 0.4, and 0.8IU/kg vasopressin groups, respectively (p = 0.61).

CONCLUSION

Time to and incidence of ROSC were not different between all vasopressin dosages and epinephrine. However, non-significantly lower time to ROSC and higher post-ROSC survival in vasopressin groups warrant further investigation.

IMPACT

Time to and incidence of ROSC were not statistically different between all vasopressin dosages and epinephrine. Non-significantly lower time to ROSC and higher post-ROSC survival in vasopressin-treated piglets. Overall poorer hemodynamic recovery following ROSC in epinephrine piglets compared to vasopressin groups. Human neonatal clinical trials examining the efficacy of vasopressin during asphyxial cardiac arrest will begin recruitment soon.

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.

The Impact of Out-of-Hospital Time and Prehospital Intubation on Return of Spontaneous Circulation following Resuscitative Thoracotomy in Traumatic Cardiac Arrest

INTRODUCTION

Resuscitative thoracotomy (RT) is a critical procedure performed in certain trauma patients in extremis, with extremely low survival rates. Currently, there is a paucity of data pertaining to prehospital variables and their predictive role in survival outcomes in traumatic cardiac arrest (TCA) patients requiring RT. The aim of the study was to determine the impact of prehospital intubation and out-of-hospital time (OOHT) on return of spontaneous circulation (ROSC) and survival in TCA requiring RT.

METHODS

This was a retrospective cohort study of trauma patients presenting to two level-1 trauma centers, St. Michael's Hospital and Sunnybrook Health Sciences Center, in Toronto, Canada (January 1, 2005-December 31, 2020). Our exposures of interest were any prehospital intubation attempt and OOHT. Primary and secondary outcome measures were ROSC post-RT and survival to hospital discharge, respectively, and data analysis was performed using univariate logistic regression.

RESULTS

A total of 195 patients were included, of which 86% were male, and the mean age was 33 years. ROSC and survival to hospital discharge were achieved in 30% and 5% of patients, respectively. Of those who survived to discharge, 89% sustained penetrating trauma. There was no association between OOHT and ROSC (OR = 1.00, 95% CI 0.97-1.03) or survival (OR = 0.99, 95% CI 0.94-1.05). The odds of ROSC were lower in penetrating trauma in the presence of any prehospital intubation attempt (OR = 0.39, 95% CI 0.19-0.82, p = 0.01). ROSC was less likely among all patients with no prehospital signs of life (SOL) compared to those who had prehospital SOL (OR = 0.30, 95% CI 0.13-0.69, p < 0.01).

CONCLUSIONS

There was a significant association between prehospital intubation and lower likelihoods of ROSC in the penetrating TCA population requiring RT, as well as with the absence of prehospital SOL in all patients. OOHT did not appear to significantly impact ROSC or survival.

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.

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.

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.

Prehospital Advanced Airway Management and Ventilation for Out-of-Hospital Cardiac Arrest with Prehospital Return of Spontaneous Circulation: A Prospective Observational Cohort Study in Japan

BACKGROUND

The relationship among advanced airway management (AAM), ventilation, and oxygenation in patients with out-of-hospital cardiac arrest (OHCA) who achieve prehospital return of spontaneous circulation (ROSC) has not been validated. This study was designed to evaluate ventilation and oxygenation for each AAM technique (supraglottic devices [SGA] or endotracheal intubation [ETI]) using arterial blood gas (ABG) results immediately after hospital arrival.

METHODS

This observational cohort study, using data from the Japanese Association for Acute Medicine OHCA Registry, included patients with OHCA with prehospital and hospital arrival ROSC between July 1, 2014, and December 31, 2019. The primary outcomes were the partial pressure of carbon dioxide in the arterial blood (PaCO2) and partial pressure of oxygen in the arterial blood (PaO2) in the initial ABG at the hospital for each AAM technique (SGA or ETI) performed by paramedics. The secondary outcome was favorable neurological outcome (cerebral performance category [CPC] 1 or 2) for specific PaCO2 levels, which were defined as good ventilation (PaCO2 ≤45 mmHg) and insufficient ventilation (PaCO2 >45 mmHg).

RESULTS

This study included 1,527 patients. Regarding AAM, 1,114 and 413 patients were ventilated using SGA and ETI, respectively. The median PaCO2 and PaO2 levels were 74.50 mmHg and 151.35 mmHg in the SGA group, while 66.30 mmHg and 173.50 mmHg in the ETI group. PaCO2 was significantly lower in the ETI group than in the SGA group (12.55 mmHg; 95% CI 15.27 to 8.20, P-value < 0.001), while no significant difference was found in PaO2 by multivariate linear regression analysis. After stabilizing inverse probability of weighting (IPW), the adjusted odds ratio for favorable neurological outcome at 1 month was significant in the good ventilation group compared to the insufficient ventilation cohort (adjusted odds ratio = 2.12, 95%CI: 1.40 to 3.19, P value < 0.001).

CONCLUSION

The study showed that in OHCA patients with prehospital ROSC, the PaCO2 levels in the initial ABG were lower in the group with AAM by ETI than in the SGA group. Furthermore, patients with prehospital ROSC and PaCO2 ≤45 mmHg on arrival had an increased odds of favorable neurological outcome after stabilized IPW adjustment.

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.

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.

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.

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 .

From flatline to lifeline: A scoping review of the Lazarus phenomenon

BACKGROUND

The Lazarus phenomenon or autoresuscitation (autoROSC) is the return of spontaneous circulation (ROSC) after the termination of the cardiopulmonary resuscitation (CPR) efforts.

PURPOSE

The purpose of the current scoping review is to present the available data in the literature regarding autoROSC.

METHODS

We reviewed four scientific databases to identify all studies which reported autoROSC cases in patients who underwent CPR. We then extracted all information relevant to CPR and autoROSC. The review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews.

RESULTS

We identified 66 studies describing 76 autoROSC cases. The majority of cardiac arrests were in-hospital (44, 57.89%). Median time from termination of CPR to autoROSC was 5 min. Regarding the outcome, 52 (77.61%) patients died and 11 (14.47%) patients had intact neurological outcome. A higher mortality rate was identified in patients with respiratory comorbidities. Overall, 24 (31.58%) patients survived.

CONCLUSION

AutoROSC is probably an under-reported event in the medical community. Healthcare professionals should be aware of the phenomenon and actively monitor for it, when appropriate.

Prediction of Return of Spontaneous Circulation in a Pediatric Swine Model of Cardiac Arrest Using Low-Resolution Multimodal Physiological Waveforms

Monitoring physiological waveforms, specifically hemodynamic variables (e.g., blood pressure waveforms) and end-tidal CO2 (EtCO2), during pediatric cardiopulmonary resuscitation (CPR) has been demonstrated to improve survival rates and outcomes when compared to standard depth-guided CPR. However, waveform guidance has largely been based on thresholds for single parameters and therefore does not leverage all the information contained in multimodal data. We hypothesize that the combination of multimodal physiological features improves the prediction of the return of spontaneous circulation (ROSC), the clinical indicator of short-term CPR success. We used machine learning algorithms to evaluate features extracted from eight low-resolution (4 samples per minute) physiological waveforms to predict ROSC. The waveforms were acquired from the 2nd to 10th minute of CPR in pediatric swine models of cardiac arrest (N = 89, 8-12 kg). The waveforms were divided into segments with increasing length (both forward and backward) for feature extraction, and machine learning algorithms were trained for ROSC prediction. For the full CPR period (2nd to 10th minute), the area under the receiver operating characteristics curve (AUC) was 0.93 (95% CI: 0.87-0.99) for the multivariate model, 0.70 (0.55-0.85) for EtCO2 and 0.80 (0.67-0.93) for coronary perfusion pressure. The best prediction performances were achieved when the period from the 6th to the 10th minute was included. Poor predictions were observed for some individual waveforms, e.g., right atrial pressure. In conclusion, multimodal waveform features carry relevant information for ROSC prediction. Using multimodal waveform features in CPR guidance has the potential to improve resuscitation success and reduce mortality.

Non-shockable rhythms: A parametric model for the immediate probability of return of spontaneous circulation

BACKGROUND

Cardiac arrest can present with asystole, Pulseless Electrical Activity (PEA), or Ventricular Fibrillation/Tachycardia (VF/VT). We investigated the transition intensity of Return of spontaneous circulation (ROSC) from PEA and asystole during in-hospital resuscitation.

MATERIALS AND METHODS

We included 770 episodes of cardiac arrest. PEA was defined as ECG with >12 QRS complexes per min, asystole by an isoelectric signal >5 seconds. The observed times of PEA to ROSC transitions were fitted to five different parametric time-to-event models. At values ≤0.1, transition intensities roughly represent next-minute probabilities allowing for direct interpretation. Different entities of PEA and asystole, dependent on whether it was the primary or a secondary rhythm, were included as covariates.

RESULTS

The transition intensities to ROSC from primary PEA and PEA after asystole were unimodal with peaks of 0.12 at 3 min and 0.09 at 6 min, respectively. Transition intensities to ROSC from PEA after VF/VT, or following transient ROSC, exhibited high initial values of 0.32 and 0.26 at 3 minutes, respectively, but decreased. The transition intensity to ROSC from initial asystole and asystole after PEA were both about 0.01 and 0.02; while asystole after VF/VT had an intensity to ROSC of 0.15 initially which decreased. The transition intensity from asystole after temporary ROSC was constant at 0.08.

CONCLUSION

The immediate probability of ROSC develops differently in PEA and asystole depending on the preceding rhythm and the duration of the resuscitation attempt. This knowledge may aid simple bedside prognostication and electronic resuscitation algorithms for monitors/defibrillators.

Stay and play or load and go? The association of on-scene advanced life support interventions with return of spontaneous circulation following traumatic cardiac arrest

INTRODUCTION

Traumatic out-of-hospital cardiac arrest (tOHCA) has a mortality rate over 95%. Many current protocols dictate rapid intra-arrest transport of these patients. We hypothesized that on-scene advanced life support (ALS) would increase the odds of arriving at the emergency department with ROSC (ROSC at ED) in comparison to performance of no ALS or ALS en route.

METHODS

We utilized the 2018-2021 ESO Research Collaborative public use datasets for this study, which contain patient care records from ~2000 EMS agencies across the US. All OHCA patients with an etiology of "trauma" or "exsanguination" were screened (n=15,691). The time of advanced airway management, vascular access, and chest decompression was determined for each patient. Logistic regression modeling was used to evaluate the association of ALS intervention timing with ROSC at ED.

RESULTS

4942 patients met inclusion criteria. 14.6% of patients had ROSC at ED. In comparison to no vascular access, on-scene (aOR: 2.14 [1.31, 3.49]) but not en route vascular access was associated with increased odds of having ROSC at ED arrival. In comparison to no chest decompression, neither en route nor on-scene chest decompression were associated with ROSC at ED arrival. Similarly, in comparison to no advanced airway management, neither en route nor on-scene advanced airway management were associated with ROSC at ED arrival. The odds of ROSC at ED decreased by 3% (aOR: 0.97 [0.94, 0.99]) for every 1-minute increase in time to vascular access and decreased by 5% (aOR: 0.95 [0.94, 0.99]) for every 1-minute increase in time to epinephrine.

CONCLUSION

On-scene ALS interventions were associated with increased ROSC at ED in our study. These data suggest that initiating ALS prior to rapid transport to definitive care in the setting of tOHCA may increase the number of patients with a palpable pulse at ED arrival.

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.

Volumetric capnography and return of spontaneous circulation in an experimental model of pediatric asphyxial cardiac arrest

A secondary analysis of a randomized study was performed to study the relationship between volumetric capnography (VCAP) and arterial CO2 partial pressure (PCO2) during cardiopulmonary resuscitation (CPR) and to analyze the ability of these parameters to predict the return of spontaneous circulation (ROSC) in a pediatric animal model of asphyxial cardiac arrest (CA). Asphyxial CA was induced by sedation, muscle relaxation and extubation. CPR was started 2 min after CA occurred. Airway management was performed with early endotracheal intubation or bag-mask ventilation, according to randomization group. CPR was continued until ROSC or 24 min of resuscitation. End-tidal carbon dioxide (EtCO2), CO2 production (VCO2), and EtCO2/VCO2/kg ratio were continuously recorded. Seventy-nine piglets were included, 26 (32.9%) of whom achieved ROSC. EtCO2 was the best predictor of ROSC (AUC 0.72, p < 0.01 and optimal cutoff point of 21.6 mmHg). No statistical differences were obtained regarding VCO2, VCO2/kg and EtCO2/VCO2/kg ratios. VCO2 and VCO2/kg showed an inverse correlation with PCO2, with a higher correlation coefficient as resuscitation progressed. EtCO2 also had an inverse correlation with PCO2 from minute 18 to 24 of resuscitation. Our findings suggest that EtCO2 is the best VCAP-derived parameter for predicting ROSC. EtCO2 and VCO2 showed an inverse correlation with PCO2. Therefore, these parameters are not adequate to measure ventilation during CPR.

Trends in Return of Spontaneous Circulation and Survival to Hospital Discharge for In-Intensive Care Unit Cardiac Arrests

Rationale: Nearly 3 in 5 in-hospital cardiac arrests (IHCAs) occur in the intensive care unit (ICU), yet large-scale data on the outcomes of in-ICU cardiac arrests have not been published for over a decade. Objectives: We sought to examine outcomes of in-ICU cardiac arrests, evaluating both achievement of return of spontaneous circulation (ROSC) and subsequent survival to hospital discharge and how these have changed over time and by type of cardiac arrest. Methods: This was an observational study using the Get With The Guidelines-Resuscitation registry, an American Heart Association-sponsored, prospective, multisite registry of IHCAs in the United States, including adults 18 years of age and older with a confirmed initial cardiac arrest occurring in the ICU who underwent resuscitation. Outcomes included achievement of ROSC and survival to hospital discharge. Multivariable hierarchical logistic regression adjusting for patient-level factors and hospitals as random effects was used to evaluate ROSC and survival. Results: A total of 114,371 adult, in-ICU IHCAs from January 2006 to December 2018 were studied. The mean age was 63.8 years, 41.3% were women, and 82.1% had a nonshockable initial rhythm. Of the 114,371 ICU cardiac arrests, 70,610 (61.7%) achieved ROSC, and 21,747 (19.0%) survived until hospital discharge. The rate of ROSC improved from 2006 to 2018 (unadjusted rate, 55.0-65.4%; adjusted odds ratio [OR] per year, 1.04; 95% confidence interval [CI], 1.03-1.05). There was an increase in overall survival to discharge during this time (unadjusted rate, 16.7-20.5%; adjusted OR per year, 1.03; 95% CI, 1.03-1.04). The survival to discharge rate of the 70,610 patients who achieved ROSC increased slightly (unadjusted rate, 30.3-31.4%; adjusted OR per year, 1.02; 95% CI, 1.01, 1.02). Conclusions: There is an increase in survival to discharge for patients who experienced a cardiac arrest in the ICU between 2006 and 2018. There is an increase in achievement of ROSC and post-ROSC survival to discharge, although the increase in achievement of ROSC was greater than the increase in post-ROSC survival.

Autoresuscitation after circulatory arrest: an updated systematic review

PURPOSE

Current practice in organ donation after death determination by circulatory criteria (DCD) advises a five-minute observation period following circulatory arrest, monitoring for unassisted resumption of spontaneous circulation (i.e., autoresuscitation). In light of newer data, the objective of this updated systematic review was to determine whether a five-minute observation time was still adequate for death determination by circulatory criteria.

SOURCE

We searched four electronic databases from inception to 28 August 2021, for studies evaluating or describing autoresuscitation events after circulatory arrest. Citation screening and data abstraction were conducted independently and in duplicate. We assessed certainty in evidence using the GRADE framework.

PRINCIPAL FINDINGS

Eighteen new studies on autoresuscitation were identified, consisting of 14 case reports and four observational studies. Most studies evaluated adults (n = 15, 83%) and patients with unsuccessful resuscitation following cardiac arrest (n = 11, 61%). Overall, autoresuscitation was reported to occur between one and 20 min after circulatory arrest. Among all eligible studies identified by our reviews (n = 73), seven observational studies were identified. In observational studies of controlled withdrawal of life-sustaining measures with or without DCD (n = 6), 19 autoresuscitation events were reported in 1,049 patients (incidence 1.8%; 95% confidence interval, 1.1 to 2.8). All resumptions occurred within five minutes of circulatory arrest and all patients with autoresuscitation died.

CONCLUSION

A five-minute observation time is sufficient for controlled DCD (moderate certainty). An observation time greater than five minutes may be needed for uncontrolled DCD (low certainty). The findings of this systematic review will be incorporated into a Canadian guideline on death determination.

STUDY REGISTRATION

PROSPERO (CRD42021257827); registered 9 July 2021.

A unified hypothesis of SUDEP: Seizure-induced respiratory depression induced by adenosine may lead to SUDEP but can be prevented by autoresuscitation and other restorative respiratory response mechanisms mediated by the action of serotonin on the periaqueductal gray

Sudden unexpected death in epilepsy (SUDEP) is a major cause of death in people with epilepsy (PWE). Postictal apnea leading to cardiac arrest is the most common sequence of terminal events in witnessed cases of SUDEP, and postconvulsive central apnea has been proposed as a potential biomarker of SUDEP susceptibility. Research in SUDEP animal models has led to the serotonin and adenosine hypotheses of SUDEP. These neurotransmitters influence respiration, seizures, and lethality in animal models of SUDEP, and are implicated in human SUDEP cases. Adenosine released during seizures is proposed to be an important seizure termination mechanism. However, adenosine also depresses respiration, and this effect is mediated, in part, by inhibition of neuronal activity in subcortical structures that modulate respiration, including the periaqueductal gray (PAG). Drugs that enhance the action of adenosine increase postictal death in SUDEP models. Serotonin is also released during seizures, but enhances respiration in response to an elevated carbon dioxide level, which often occurs postictally. This effect of serotonin can potentially compensate, in part, for the adenosine-mediated respiratory depression, acting to facilitate autoresuscitation and other restorative respiratory response mechanisms. A number of drugs that enhance the action of serotonin prevent postictal death in several SUDEP models and reduce postictal respiratory depression in PWE. This effect of serotonergic drugs may be mediated, in part, by actions on brainstem sites that modulate respiration, including the PAG. Enhanced activity in the PAG increases respiration in response to hypoxia and other exigent conditions and can be activated by electrical stimulation. Thus, we propose the unifying hypothesis that seizure-induced adenosine release leads to respiratory depression. This can be reversed by serotonergic action on autoresuscitation and other restorative respiratory responses acting, in part, via the PAG. Therefore, we hypothesize that serotonergic or direct activation of this brainstem site may be a useful approach for SUDEP prevention.

Epinephrine vs placebo in neonatal resuscitation: ROSC and brain MRS/MRI in term piglets

BACKGROUND

We aimed to investigate the effect of epinephrine vs placebo on return of spontaneous circulation (ROSC) and brain magnetic resonance spectroscopy and imaging (MRS/MRI) in newborn piglets with hypoxic cardiac arrest (CA).

METHODS

Twenty-five piglets underwent hypoxia induced by endotracheal tube clamping until CA. The animals were randomized to CPR + intravenous epinephrine or CPR + placebo (normal saline). The primary outcome was ROSC, and secondary outcomes included time-to-ROSC, brain MRS/MRI, and composite endpoint of death or severe brain MRS/MRI abnormality.

RESULTS

ROSC was more frequent in animals treated with epinephrine than placebo; 10/13 vs 4/12, RR = 2.31 (95% CI: 1.09-5.77). We found no difference in time-to-ROSC (120 (113-211) vs 153 (116-503) seconds, p = 0.7) or 6-h survival (7/13 vs 3/12, p = 0.2). Among survivors, there was no difference between groups in brain MRS/MRI. We found no difference in the composite endpoint of death or severe brain MRS/MRI abnormality; RR = 0.7 (95% CI: 0.37-1.19).

CONCLUSIONS

Resuscitation with epinephrine compared to placebo improved ROSC frequency after hypoxic CA in newborn piglets. We found no difference in time-to-ROSC or the composite endpoint of death or severe brain MRS/MRI abnormality.

IMPACT

In a newborn piglet model of hypoxic cardiac arrest, resuscitation with epinephrine compared to placebo improved the rate of return of spontaneous circulation and more than doubled the 6-h survival. Brain MRS/MRI biomarkers were used to evaluate the effect of epinephrine vs placebo. We found no difference between groups in the composite endpoint of death or severe brain MRS/MRI abnormality. This study adds to the limited evidence regarding the effect and safety of epinephrine; the lack of high-quality evidence from randomized clinical trials was highlighted in the latest ILCOR 2020 guidelines, and newborn animal studies were specifically requested.

Delayed Presentation of Spontaneous Shockable Rhythm After Death: Another Subtype of Lazarus Phenomenon?

Lazarus phenomenon was defined as spontaneous circulatory restoration after death. It is important because survival discharge is possible. A 44-year-old woman developed traumatic cardiac arrest. She was declared dead after 30 minutes of resuscitation. Suddenly, pulseless ventricular tachycardia was shown after 6 minutes of death declaration. Resuscitation with epinephrine injection was resumed but was terminated after 7 minutes, and she was declared dead once more. A case where an electrocardiography appears spontaneously should be classified as a subtype of the Lazarus phenomenon. If the transition from asystole to spontaneous shockable rhythm follows a mechanism similar to that of the Lazarus phenomenon, active resuscitation and monitoring for a period of time following death declaration should be considered.

Association between prehospital FPS and ROSC in adults with OHCA : A retrospective multicenter study using the German Resuscitation Registry and Intubation Registry (FiPS-CPR)

BACKGROUND

Advanced airway management (AAM) is part of the standard treatment during advanced cardiac life support (ACLS). Current studies underline the importance of a first-pass intubation success (FPS) during in-hospital ACLS. It was shown that a failed initial intubation attempt in out-of-hospital cardiac arrest (OHCA) patients in the emergency department is an independent risk factor for the decreased effectiveness of ACLS measured by the return of spontaneous circulation (ROSC).

OBJECTIVE

This study first examines the association between prehospital FPS and ROSC in adults with OHCA and second identifies factors associated with FPS and ROSC. The initial hypothesis was that FPS would increase the probability of ROSC as well as decrease the time to ROSC.

MATERIAL AND METHODS

A retrospective multicenter analysis of 180 adult non-traumatic OHCA patients on whom advanced airway management (AAM) was performed between July 2017 and December 2018 in five different German physician-staffed ambulance stations. For information on FPS the Intubation Registry, and for information on ROSC the German Resuscitation Registry were used. In addition to yes/no questions, multiple answers and free text answers are possible in those questionnaires. The main outcome variables were 'FPS', 'ROSC' and 'time to ROSC'. Mann-Whitney tests, χ²-tests, Fisher's exact tests and multivariate binary logistic regressions were used for the statistical evaluation. Demographic factors, characteristics of the performer, selected equipment, laryngoscopy type, intubation method, medications, verification of tube position, respiratory evaluation, complications and time to ROSC were examined with respect to the influence on FPS. Concerning ROSC, the following factors were examined: demographic factors, initial heart rhythm, initial breathing, medications, defibrillation and AAM.

RESULTS

An FPS was recorded in 150 patients (83.3%), and ROSC was achieved in 82 patients (45.5%) after an average time of 22.16 min. There was a positive association between FPS and ROSC (p = 0.027). In patients with FPS, a trend for shorter time to ROSC was observed (p = 0.059; FPS 18 min; no FPS 28 min). The use of capnography (odds ratio, OR = 7.384, 95% confidence interval, CI 1.886-28.917) and complications during AAM (OR = 0.033, 95% CI: 0.007-0.153) were independently associated with FPS. The independent factor associated with ROSC was FPS (OR = 5.281, 95% CI: 1.800-15.494).

CONCLUSION

In prehospitally resuscitated adult OHCA patients with AAM, FPS is associated with a higher chance of ROSC.

Sudden Electrocardiogram Rhythm Changes after Return of Spontaneous Circulation in Porcine Models of Out-of-Hospital Cardiac Arrest: A Phenomenological Report

BACKGROUND

Observation of the electrocardiogram (ECG) immediately following return of spontaneous circulation (ROSC) in resuscitated swine has revealed the interesting phenomenon of sudden ECG rhythm changes (SERC) that occur in the absence of pharmacological, surgical, or other medical interventions.

OBJECTIVE

We sought to identify, quantify, and characterize post-ROSC SERC in successfully resuscitated swine.

METHODS

We reviewed all LabChart data from resuscitated approximately 4- to 6-month-old swine used for various experimental protocols from 2006 to 2019. We identified those that achieved sustained ROSC and analyzed their entire post-ROSC periods for evidence of SERC in the ECG, and arterial and venous pressure tracings. Presence or absence of SERC was confirmed independently by two reviewers (ACK, DDS). We measured the interval from ROSC to first SERC, analyzed the following metrics, and calculated the change from 60 sec pre-SERC (or from ROSC if less than 60 sec) to 60 sec post-SERC: heart rate, central arterial pressure (CAP), and central venous pressure (CVP).

RESULTS

A total of 52 pigs achieved and sustained ROSC. Of these, we confirmed at least one SERC in 25 (48.1%). Two pigs (8%) each had two unique SERC events. Median interval from ROSC to first SERC was 3.8 min (inter-quartile range 1.0-6.9 min; range 16 sec to 67.5 min). We observed two distinct types of SERC: type 1) the post-SERC heart rate and arterial pressure increased (72% of cases); and type 2) the post-SERC heart rate and arterial pressure decreased (28% of cases). For type 1 cases, the mean (standard deviation [SD]) heart rate increased by 33.6 (45.7) beats per minute (bpm). The mean (SD) CAP increased by 20.6 (19.2) mmHg. For type 2 cases, the mean (SD) heart rate decreased by 39.7 (62.3) bpm. The mean (SD) CAP decreased by 21.9 (15.6) mmHg.

CONCLUSIONS

SERC occurred in nearly half of all cases with sustained ROSC and can occur multiple times per case. First SERC most often occurred within the first 4 minutes following ROSC. Heart rate, CAP, and CVP changed at the moment of SERC. We are proceeding to examine whether this phenomenon occurs in humans post-cardiac arrest and ROSC.

Glucocorticoid receptor expression in patients with cardiac arrest in the early period after the return of spontaneous circulation: a prospective observational single-centre study

OBJECTIVES

Rapid changes in glucocorticoid (GC) levels and adrenal insufficiency are related to the development of post-cardiac arrest (CA) syndrome. However, GC receptor (GR) expression changes have not been studied. Hence, this study aimed to investigate the association of early changes in GR expression and prognosis and immune response in patients who experienced CA.

DESIGN

Prospective observational study.

SETTING

Emergency department.

PARTICIPANTS

Patients (85) in the early period of return of spontaneous circulation (ROSC) after CA were admitted between October 2018 and October 2019. After a physical examination, age-matched and sex-matched healthy individuals (40) were recruited for the control group.

PRIMARY AND SECONDARY OUTCOME MEASURES

GR expression and cell counts of circulatory T and B lymphocytes, natural killer cells and regulatory T (Treg) cells were assessed. Plasma total cortisol and adrenocorticotrophic hormone (ACTH) levels were also tested.

RESULTS

All cell counts were lower, and plasma total cortisol levels were higher (p<0.001) in patients who experienced CA than in the healthy control group. GR expression in Treg cells and CD3+CD4+ T lymphocytes were not significantly different, but the mean fluorescence intensity and GR expression in other cells were lower in patients who experienced CA (p<0.05) than in the healthy control group. ACTH levels were not different. There were no significant differences between survivors and non-survivors.

CONCLUSIONS

This study revealed that GR expression and cell counts rapidly decreased, whereas plasma total cortisol levels increased in the early period after ROSC among patients who experienced CA. Our findings provide important information about GR level and function, and immunosuppressive status in these patients. Assessing GR expression in patients who experienced CA may help screening for those who are more sensitive to GC therapy.

Tibial Intraosseous Administration of Epinephrine Is Effective in Restoring Return of Spontaneous Circulation in a Pediatric Normovolemic But Not Hypovolemic Cardiac Arrest Model

OBJECTIVE

We compared the efficacy of tibial intraosseous (TIO) administration of epinephrine in a pediatric normovolemic versus hypovolemic cardiac arrest model to determine the incidence of return of spontaneous circulation (ROSC) and plasma epinephrine concentrations over time.

METHODS

This experimental study evaluated the pharmacokinetics of epinephrine and/or incidence of ROSC after TIO administration in either a normovolemic or hypovolemic pediatric swine model.

RESULTS

All subjects in the TIO normovolemia cardiac arrest group experienced ROSC after TIO administration of epinephrine. In contrast, subjects experiencing hypovolemia and cardiac arrest were significantly less likely to experience ROSC when epinephrine was administered TIO versus intravenous (TIO hypovolemia: 14% [1/7] vs IV hypovolemia: 71% [5/7]; P = 0.031). The TIO hypovolemia group exhibited significantly lower plasma epinephrine concentrations versus IV hypovolemia at 60, 90, 120, and 150 seconds (P < 0.05). Although the maximum concentration of plasma epinephrine was similar, the TIO hypovolemia group exhibited significantly slower time to maximum concentration times versus TIO normovolemia subjects (P = 0.004).

CONCLUSIONS

Tibial intraosseous administration of epinephrine reliably facilitated ROSC among normovolemic cardiac arrest pediatric patients, which is consistent with published reports. However, TIO administration of epinephrine was ineffective in restoring ROSC among subjects experiencing hypovolemia and cardiac arrest. Tibial intraosseous-administered epinephrine during hypovolemia and cardiac arrest may have resulted in a potential sequestration of epinephrine in the tibia. Central or peripheral intravascular access attempts should not be abandoned after successful TIO placement in the resuscitation of patients experiencing concurrent hypovolemia and cardiac arrest.

Autoresuscitation of Poloxamer 188 in Pigs With Traumatic Severe Hemorrhage

BACKGROUND

Poloxamer 188 (P188) is a copolymer surfactant with plasma membrane stabilizing action. This study investigated the effects of P188 on blood volume and coagulation in pigs after traumatic hemorrhage and hypotensive resuscitation.

METHODS

Femur fracture was performed in 17 anesthetized pigs, followed by hemorrhage of 55% of estimated blood volume and a 10 min shock period. Afterwards, pigs were randomized to be resuscitated with either normal saline (n = 9, 4 mL/kg, NS group) or P188 (n = 8, 1.33 mL/kg at 150 mg/mL, plus 2.67 mL NS/kg, P188 group). Pigs were monitored for 2 h or until death. Hemodynamics were recorded and blood samples were taken at baseline (BL), after hemorrhage, shock, resuscitation, and at 2 h for blood and coagulation analysis using Rotem®.

RESULTS

All but one pig in each group survived to 2 h. Femur fracture and hemorrhage reduced mean arterial pressure to half of the BL and elevated heart rate to double of the BL (both P < 0.05). Resuscitation with NS or P188 did not return these measurements to BL. Compared to NS, resuscitation with P188 resulted in a smaller reduction of blood volume (76 ± 3% in P188 and 60 ± 2% in NS); higher base excess (3.3 ± 0.9 vs. 0.5 ± 0.9 mM); and lower hematocrit (24 ± 1 vs. 28 ± 1%) and Ca++ (24 ± 1 vs. 28 ± 1 mM). Resuscitation with P188 prolonged aPTT (43 ± 12 vs. 22 ± 3 s, all P < 0.05).

CONCLUSIONS

Following traumatic hemorrhage and hypotensive resuscitation, P188 improved circulation volume and base deficit, but induced slower clotting initiation in pigs. Thus, P188 may have limited benefit as an initial small volume resuscitation adjunct following hemorrhage.

Prehospital predictors for return of spontaneous circulation in traumatic cardiac arrest

BACKGROUND

Traumatic cardiac arrests (TCAs) are associated with high mortality and the majority of deaths occur at the prehospital scene. The aim of the present study was to assess, in a prehospital physician-led emergency medical system, the factors associated with sustained return of spontaneous circulation (ROSC) in TCA, including advanced life procedures. The secondary objectives were to assess factors associated with 30-day survival in TCA, evaluate neurological recovery in survivors, and describe the frequency of organ donation among patients experiencing a TCA.

METHODS

We conducted a retrospective study of all TCA patients included in the French nationwide cardiac arrest registry from July 2011 to November 2020. Multivariable logistic regression analysis was used to identify factors independently associated with ROSC.

RESULTS

A total of 120,045 out-of-hospital cardiac arrests were included in the registry, among which 4,922 TCA were eligible for analysis. Return of spontaneous circulation was sustained on-scene in 21.1% (n = 1,037) patients. Factors significantly associated with sustained ROSC were not-asystolic initial rhythms (pulseless electric activity (odds ratio [OR], 1.81; 95% confidence interval [CI], 1.40-2.35; p < 0.001), shockable rhythm (OR, 1.83; 95% CI, 1.12-2.98; p = 0.016), spontaneous activity (OR, 3.66; 95% CI, 2.70-4.96; p < 0.001), and gasping at the mobile medical team (MMT) arrival (OR, 1.40; 95% CI, 1.02-1.94; p = 0.042). The MMT interventions significantly associated with ROSC were as follows: intravenous fluid resuscitation (OR, 3.19; 95% CI, 2.69-3.78; p < 0.001), packed red cells transfusion (OR, 2.54; 95% CI, 1.84-3.51; p < 0.001), and external hemorrhage control (OR, 1.74; 95% CI, 1.31-2.30; p < 0.001). Among patients who survived (n = 67), neurological outcome at Day 30 was favorable (cerebral performance categories 1-2) in 72.2% cases (n = 39/54) and 1.4% (n = 67/4,855) of deceased patients donated one or more organ.

CONCLUSION

Sustained ROSC was frequently achieved in patients not in asystole at MMT arrival, and higher ROSC rates were achieved in patients benefiting from specific advanced life support interventions. Organ donation was somewhat possible in TCA patients undergoing on-scene resuscitation.

LEVEL OF EVIDENCE

Prognostic and epidemiologic, Level III.