Compression-to-ventilation ratio and incidence of rearrest-A secondary analysis of the ROC CCC trial

Incidence, risk factors, and impact of post-return of spontaneous circulation events in patients with out-of-hospital cardiac arrest: A population-based study in Tokyo, Japan

AIM

Patients with the return of spontaneous circulation (ROSC) after out-of-hospital cardiac arrest (OHCA) are unstable and often experience rearrest, after which ROSC may be reattained. This study investigated the incidence and risk factors of post-ROSC events (rearrest and subsequent reattainment of ROSC) and their impact on outcomes in patients with prehospital ROSC following OHCA.

METHODS

Patients with OHCA and prehospital ROSC were identified from the Tokyo Fire Department database between 1 January 2018 and 31 December 2022. The factors associated with post-ROSC events and their impact on 1-month favourable neurological outcome (cerebral performance category scale: 1 or 2) were assessed using multivariable logistic regression analysis.

RESULTS

Overall, 64,000 individuals experienced OHCA, and 6,190 (9.7%) had ROSC. Rearrest was confirmed in 28.4% of patients with ROSC, and was associated with age, time of emergency call, location of cardiac arrest, dispatcher instruction regarding cardiopulmonary resuscitation, first recorded cardiac rhythm, bystander cardiopulmonary resuscitation, defibrillation by a bystander, response time, and prehospital interventions. ROSC reattainment was confirmed in 34.5% of patients with rearrest and associated with the first recorded cardiac rhythm and defibrillation by a bystander. Patients without rearrests had the highest proportion of favourable neurological outcomes, followed by those with solved and unsolved rearrests (38.6% vs. 22.4% and 4.4%, P < 0.001). The difference remained significant after adjustment for confounders.

CONCLUSION

This study revealed population-based incidence and risk factors of post-ROSC events. Rearrest was common, leading to unfavourable neurological outcome; however, its deleterious impact may be mitigated by successful resuscitation efforts.

The association of clinical, treatment, and demographic characteristics with rearrest in a national dataset

INTRODUCTION

Following initial resuscitation from out-of-hospital cardiac arrest, rearrest frequently occurs and has been associated with adverse outcomes. We aimed to identify clinical, treatment, and demographic characteristics associated with prehospital rearrest at the encounter and agency levels.

METHODS

Adult non-traumatic cardiac arrest patients who achieved ROSC following EMS resuscitation in the 2018-2021 ESO annual datasets were included in this study. Patients were excluded if they had a documented DNR/POLST or achieved ROSC after bystander CPR only. Rearrest was defined as post-ROSC CPR initiation, administration of ≥ 1 milligram of adrenaline, defibrillation, or a documented non-perfusing rhythm on arrival at the receiving hospital. Multivariable logistic regression modeling was used to evaluate the association between rearrest and case characteristics. Linear regression modeling was used to evaluate the association between agency-level factors (ROSC rate, scene time, and scene termination rate), and rearrest rate.

RESULTS

Among the 53,027 cases included, 16,116 (30.4%) experienced rearrest. Factors including longer response intervals, longer 'low-flow' intervals, unwitnessed OHCA, and a lack of bystander CPR were associated with rearrest. Among agencies that treated ≥ 30 patients with outcome data, the agency-level rate of rearrest was inversely associated with agency-level rate of survival to discharge to home (R2 = -0.393, p < 0.001).

CONCLUSIONS

This multiagency retrospective study found that factors associated with increased ischaemic burden following OHCA were associated with rearrest. Agency-level rearrest frequency was inversely associated with agency-level survival to home. Interventions that decrease the burden of ischemia sustained by OHCA patients may decrease the rate of rearrest and increase survival.

Association between prehospital time and in-hospital outcomes in out-of-hospital cardiac arrests according to resuscitation outcomes consortium epidemiologic registry

INTRODUCTION

For out-of-hospital cardiac arrests (OHCAs), time is of the essence. While the relationship between EMS response time (ERT) and OHCA outcomes is well studied, a more comprehensive assessment of the effects of other intervention time is needed, which is essential to guide clinical practice.

OBJECTIVES

Evaluating how a longer total pre-hospital time (TPT), ERT, advance life support response time (ART) and EMS cardiopulmonary resuscitation time (ECT) increase the mortality rates, unfavorable neurological outcomes, and severe complications at discharge of OHCAs.

METHODS

31,926 OHCAs from the USA and Canada were identified in Resuscitation Outcomes Consortium Epidemiologic Registry. Twelve adjusted models were used to analyze the relationship between the prehospital time (TPT, ERT, ART and ECT) and three outcomes (in hospital mortality, unfavorable neurological outcomes, and severe complications for surviving OHCAs).

RESULTS

Every 10-min increase in TPT was associated with a 0.14-fold increase in the risk of death (adjusted odds ratio [OR] = 1.14, 95 % confidence interval [CI] = 1.10-1.17) and a 0.13-fold increase of adverse neurological outcomes (OR = 1.13, CI =1.08-1.18). The risk of patient mortality markedly increased with every 5 min increase in ERT (OR = 1.36, CI = 1.26-1.47), ART (OR =1.10, CI = 1.06-1.15), and ECT (OR = 1.46, CI = 1.37-1.56). Adverse neurological outcome was associated with ERT and ECT, and severe complications with ERT and ART.

CONCLUSION

Prolonged prehospital time, particularly ERT and ECT, are closely associated with in-hospital mortality, unfavorable neurological functions, and severe complications at discharge in OHCAs.

Machine learning-based analysis of regional differences in out-of-hospital cardiopulmonary arrest outcomes and resuscitation interventions in Japan

Refining out-of-hospital cardiopulmonary arrest (OHCA) resuscitation protocols for local emergency practices is vital. The lack of comprehensive evaluation methods for individualized protocols impedes targeted improvements. Thus, we employed machine learning to assess emergency medical service (EMS) records for examining regional disparities in time reduction strategies. In this retrospective study, we examined Japanese EMS records and neurological outcomes from 2015 to 2020 using nationwide data. We included patients aged ≥ 18 years with cardiogenic OHCA and visualized EMS activity time variations across prefectures. A five-layer neural network generated a neurological outcome predictive model that was trained on 80% of the data and tested on the remaining 20%. We evaluated interventions associated with changes in prognosis by simulating these changes after adjusting for time factors, including EMS contact to hospital arrival and initial defibrillation or drug administration. The study encompassed 460,540 patients, with the model's area under the curve and accuracy being 0.96 and 0.95, respectively. Reducing transport time and defibrillation improved outcomes universally, while combining transport time and drug administration showed varied efficacy. In conclusion, the association of emergency activity time with neurological outcomes varied across Japanese prefectures, suggesting the need to set targets for reducing activity time in localized emergency protocols.

Association between a Post-Resuscitation Care Bundle and the Odds of Field Rearrest after Successful Resuscitation from Out-of-Hospital Cardiac Arrest: A Pre/Post Study

OBJECTIVES

Rearrest after successful resuscitation from out-of-hospital cardiac arrest (OHCA) is common and is associated with worse patient outcomes. However, little is known about the effect of interventions designed to prevent rearrest. We assessed the association between a prehospital care protocol for immediate management after return of spontaneous circulation (ROSC) and rates of field rearrest and survival to discharge in patients with prehospital ROSC.

METHODS

This was a retrospective study of adult patients with OHCA and field ROSC within a large EMS system before (April 2017-August 2018) and after (April 2019-February 2020) implementation of a structured prehospital post-ROSC care protocol. The protocol was introduced in September 2018 and provided on-scene stabilization direction including guidance on ventilation and blood pressure support. Field data and hospital outcomes were used to compare the frequency of field rearrest, hospital survival, and survival with good neurologic outcome before and after protocol implementation. Logistic regression was used to assess the association between the post-implementation period and these outcomes, and odds ratios were reported. The association between individual interventions on these outcomes was also explored.

RESULTS

There were 2,706 patients with ROSC after OHCA in the pre-implementation period and 1,780 patients in the post-implementation period. The rate of prehospital rearrest was 43% pre-implementation vs 45% post-implementation (RD 2%, 95% CI -1, 4%). In the adjusted analysis, introduction of the protocol was not associated with decreased odds of rearrest (OR 0.87, 95% CI 0.73, 1.04), survival to hospital discharge (OR 1.01, 95% CI 0.81, 1.24), or survival with good neurologic outcome (OR 0.81, 95% CI 0.61, 1.06). Post-implementation, post-ROSC administration of saline and push-dose epinephrine increased from 11% to 25% (RD 14%, 95% CI 11, 17%) and from 3% to 12% (RD 9% 95% CI 7, 11%), respectively. In an exploratory analysis, push-dose epinephrine was associated with a decreased odds of rearrest (OR 0.68, 95% CI 0.50, 0.94).

CONCLUSIONS

Introduction of a post-ROSC care protocol for patients with prehospital ROSC after OHCA was not associated with reduced odds of field rearrest. When elements of the care bundle were considered individually, push-dose epinephrine was associated with decreased odds of rearrest.

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.

Rearrest during hospitalisation in adult comatose out-of-hospital cardiac arrest patients: Risk factors and prognostic impact, and predictors of favourable long-term outcomes

BACKGROUND

Rearrest occurs commonly after initial resuscitation following out-of-hospital cardiac arrest (OHCA). We determined (1) the predictors of rearrest during hospitalisation that can be identified in the hours immediately after OHCA, (2) the association between rearrest and favourable long-term outcomes, and (3) the predictors of favourable long-term outcomes in rearrest patients.

METHODS

Conditional multivariable logistic regression analyses were performed using the Korean Hypothermia Network prospective registry data, which included details of adult OHCA patients treated with targeted temperature management at 22 teaching hospitals in South Korea.

RESULTS

Among the 1,233 patients, 260 (21.1%) experienced rearrest. Of the 192 patients resuscitated from first rearrest, 33 (17.2%) achieved 6-month favourable outcomes. Arrhythmia, heart failure, ST-segment elevation, lower initial Glasgow coma scale (GCS) motor score, higher initial lactate level, and antiarrhythmic drug use within 1 h were independently associated with rearrest. Higher lactate level and antiarrhythmic drug use were associated with shockable first rearrest, while arrhythmia, heart failure, ST-segment elevation, and lower GCS motor score were associated with non-shockable first rearrest. Rearrest was independently associated with a lower likelihood of 6-month favourable outcomes (P = 0.003). Initial shockable rhythm after OHCA, absence of diabetes, shorter cumulative time to restoration of spontaneous circulation, coronary angiography, and hypophosphataemia within 7 d were independently associated with 6-month favourable outcomes in the patients resuscitated from first rearrest.

CONCLUSIONS

Rearrest during hospitalisation after OHCA was inversely associated with 6-month favourable outcomes. We identified several risk factors for rearrest and prognostic factors for patients resuscitated from first rearrest.

Effects of pre-hospital re-arrest on outcomes based on transfer to a heart attack centre in patients with out-of-hospital cardiac arrest

AIM

We aimed to investigate the interaction effects between transfer to a heart attack centre [HAC] and prehospital re-arrest on the clinical outcomes of patients with out-of-hospital cardiac arrest [OHCA].

METHODS

We included adult patients with OHCA of presumed cardiac aetiology from January 2012 to December 2018. The main exposure variable was prehospital re-arrest, defined as recurrence of cardiac arrest with a loss of palpable pulse upon hospital arrival. The other exposure variable was the resuscitation capacity of the receiving hospital [HAC or Non-HAC]. The outcome variable was neurological recovery. A multivariable logistic regression was performed to determine the interaction effects.

RESULTS

The final analysis included 6935 patients. Of these, 21.9% (n = 1521) experienced prehospital re-arrest, whereas 41.3% (n = 2866) were transferred to a non-HAC. The prehospital re-arrest group associated with poor neurological recovery (adjusted odds ratio [AOR], 0.25; 95% confidence interval [CI], 0.21-0.29;). Transfer to an HAC had beneficial effects on neurological recovery (AOR, 3.40 [95% CI, 3.04-3.85]. In the interaction model, wherein prehospital re-arrest patients who were transferred to a non-HAC were used as reference, the AOR of prehospital re-arrest patients who were transferred to an HAC, non-re-arrest patients who were transferred to a non-HAC, and non-re-arrest patients who were transferred to a non-HAC was 2.41 (95% CI, 1.73-3.35), 3.09 (95% CI, 2.33-4.10), and 11.07 (95% CI, 8.40-14.59) respectively (interaction p = 0.001).

CONCLUSION

Transport to a heart attack centre was beneficial to the clinical outcomes of patients who achieved prehospital ROSC after OHCA. The magnitude of that benefit was significantly modified by whether prehospital re-arrest had occurred.

Duration of exposure to a prehospital advanced airway and neurological outcome for out-of-hospital cardiac arrest: A retrospective cohort study

BACKGROUND

Out-of-hospital cardiac arrest (OHCA) studies have focused on the benefits and harms of placing an intra-arrest advanced airway, but few studies have evaluated the benefits and harms after successful placement. We hypothesize that increased time in the tumultuous prehospital environment after intra-arrest advanced airway placement results in reduced patient survival.

METHODS

This was a secondary analysis of adult, non-traumatic, OHCA patients with an advanced airway placed in the PRIMED trial. The exposure variable was the time interval between successful advanced airway placement and Emergency Department (ED) arrival. The outcome was cerebral performance category (CPC) 1 or 2 at hospital discharge. Multivariable logistic regression, adjusted for Utstein variables and resuscitation-associated time intervals, was used to estimate adjusted odds ratios (aOR).

RESULTS

The cohort of complete cases included 4779 patients. The median time exposed to a prehospital advanced airway was 27 min (IQR 20-35). The total prehospital time was 39.4 min (IQR 32.3-48.1). An advanced airway was placed intra-arrest in 3830 cases (80.1%) and post-return of spontaneous circulation (post-ROSC) in 949 cases (19.9%). Overall, 486 (10.2%) of the cohort achieved the CPC outcome, but this was higher in the post-ROSC (21.7%) versus intra-arrest (7.5%) cohort. CPC was not associated with the time interval from advanced airway placement to ED arrival in the intra-arrest airway cohort (aOR 0.98, 95%CI 0.94-1.01).

CONCLUSIONS

In OHCA patients who receive an intra-arrest advanced airway, longer time intervals exposed to a prehospital advanced airway are not associated with reduced patient survival.

Survival and Rearrest in out-of-Hospital Cardiac Arrest Patients with Prehospital Return of Spontaneous Circulation: A Prospective Multi-Regional Observational Study

OBJECTIVE

We aimed to determine the factors associated with rearrest after prehospital return of spontaneous circulation (ROSC) and examine the factors associated with survival despite rearrest.

METHODS

We conducted a prospective multi-regional observational study of out-of-hospital cardiac arrest (OHCA) patients between August 2015 and July 2016. Patients received prehospital advanced cardiovascular life support performed by emergency medical technicians (EMTs). EMTs were directly supervised by medical directors (physicians) via real-time smartphone video calls [Smart Advanced Life Support (SALS)]. The study participants were categorized into rearrest (+) and rearrest (-) groups depending on whether rearrest occurred after prehospital ROSC. After rearrest, patients were further classified as survivors or non-survivors at discharge.

RESULTS

SALS was performed in 1,711 OHCA patients. Prehospital ROSC occurred in 345 patients (20.2%); of these patients, 189 (54.8%) experienced rearrest [rearrest (+) group] and 156 did not experience rearrest [rearrest (-) group]. Multivariate analysis showed that a longer interval from collapse to first prehospital ROSC was independently associated with rearrest [odds ratio (OR) 1.081; 95% confidence interval (CI) 1.050-1.114]. The presence of an initial shockable rhythm was independently associated with survival after rearrest (OR 6.920; 95% CI 2.749-17.422). As a predictor of rearrest, the interval from collapse to first prehospital ROSC (cut-off: 24 min) had a sensitivity of 77% and a specificity of 54% (AUC = 0.715 [95% CI 0.661-0.769]).

CONCLUSIONS

A longer interval from collapse to first prehospital ROSC was associated with rearrest, and an initial shockable rhythm was associated with survival despite the occurrence of rearrest. Emergency medical service providers and physicians should be prepared to deal with rearrest when pulses are obtained late in the resuscitation.

Prehospital Epinephrine as a Potential Factor Associated with Prehospital Rearrest

Objective: To investigate the impact of epinephrine on prehospital rearrest and re-attainment of prehospital return of spontaneous circulation (ROSC). Methods: Data for 9,292 (≥ 8 years) out-of-hospital cardiac arrest (OHCA) patients transported to hospitals by emergency medical services were collected in Ishikawa Prefecture, Japan during 2010-2018. Univariate and multivariable analyses were retrospectively performed for 1,163 patients with prehospital ROSC. Results: Of 1,163 patients, rearrest occurred in 272 (23.4%) but not in 891 (76.6%). Both single and multiple doses of epinephrine administered before prehospital ROSC (adjusted odds ratio (OR): 3.62, 95% confidence interval (CI): 2.42-5.46 for 1 mg, and 4.27, 2.58-6.79 for ≥ 2 mg) were main factors associated with rearrest. The association between initial and rearrest rhythms was significantly associated with epinephrine administration (p = 0.02). However, the rearrest rhythm was primarily associated with the initial rhythm (p < 0.01). The majority of patients with the non-shockable initial rhythm had pulseless electrical activity (PEA) as the rearrest rhythm, regardless of epinephrine administration (80.4% for administration, 81.6% for no administration). When the initial rhythm was shockable, the primary rearrest rhythms in patients with and without epinephrine administration before prehospital ROSC were PEA (52.2%) and ventricular fibrillation/pulseless ventricular tachycardia (56.8%), respectively. Only epinephrine administration after rearrest was associated with prehospital re-attainment of ROSC (adjusted OR: 2.49, 95% CI: 1.20-5.19). Stepwise multivariable logistic regression analyses revealed that neurologically favorable outcome was poorer in patients with rearrest than those without rearrest (9.9% vs. 25.0%, adjusted OR: 0.42, 95% CI: 0.23-0.73). The total prehospital doses of epinephrine were associated with poorer neurological outcome in a dose-dependent manner (adjusted OR: 0.22, 95% CI: 0.13-0.36 for 1 mg; 0.09, 0.04-0.19 for 2 mg; 0.03, 0.01-0.09 for ≥ 3 mg, no epinephrine as a reference). Transportation to hospitals with a unit for post-resuscitation care was associated with better neurological outcome (adjusted OR: 1.53, 95% CI: 1.02-2.32). Conclusions: The requirement for epinephrine administration before prehospital ROSC was associated with subsequent rearrest. Routine epinephrine administrations and rearrest were associated with poorer neurological outcome of OHCA patients with prehospital ROSC.

Effects of intra-resuscitation antiarrhythmic administration on rearrest occurrence and intra-resuscitation ECG characteristics in the ROC ALPS trial

BACKGROUND

Intra-resuscitation antiarrhythmic drugs may improve resuscitation outcomes, in part by avoiding rearrest, a condition associated with poor out-of-hospital cardiac arrest (OHCA) outcomes. However, antiarrhythmics may also alter defibrillation threshold. The objective of this study was to investigate the relationship between rearrest and intra-resuscitation antiarrhythmic drugs in the context of the Resuscitation Outcomes Consortium (ROC) amiodarone, lidocaine, and placebo (ALPS) trial.

HYPOTHESIS

Rearrest rates would be lower in cases treated with amiodarone or lidocaine, versus saline placebo, prior to first return of spontaneous circulation (ROSC). We also hypothesized antiarrhythmic effects would be quantifiable through analysis of the prehospital electrocardiogram.

METHODS

We conducted a secondary analysis of the ROC ALPS trial. Cases that first achieved prehospital ROSC after randomized administration of study drug were included in the analysis. Rearrest, defined as loss of pulses following ROSC, was ascertained from emergency medical services records. Rearrest rate was calculated overall, as well as by ALPS treatment group. Multivariable logistic regression models were constructed to assess the association between treatment group and rearrest, as well as rearrest and both survival to hospital discharge and survival with neurologic function. Amplitude spectrum area, median slope, and centroid frequency of the ventricular fibrillation (VF) ECG were calculated and compared across treatment groups.

RESULTS

A total of 1144 (40.4%) cases with study drug prior to first ROSC were included. Rearrest rate was 44.0% overall; 42.9% for placebo, 45.7% for lidocaine, and 43.0% for amiodarone. In multivariable logistic regression models, ALPS treatment group was not associated with rearrest, though rearrest was associated with poor survival and neurologic outcomes. AMSA and median slope measures of the first available VF were associated with rearrest case status, while median slope and centroid frequency were associated with ALPS treatment group.

CONCLUSION

Rearrest rates did not differ between antiarrhythmic and placebo treatment groups. ECG waveform characteristics were correlated with treatment group and rearrest. Rearrest was inversely associated with survival and neurologic outcomes.