Factors affecting short- and long-term prognosis among 1069 patients with out-of-hospital cardiac arrest and pulseless electrical activity

Temporal trends in out-of-hospital cardiac arrest with an initial non-shockable rhythm in Singapore

Aim

Out-of-hospital cardiac arrest (OHCA) with an initial non-shockable rhythm is the predominant form of OHCA in adults. We evaluated its 10-year trends in epidemiology and management in Singapore.

Methods

Using the national OHCA registry we studied the trends of 20,844 Emergency Medical Services-attended adult OHCA from April 2010 to December 2019. Survival to hospital discharge was the primary outcome. Trends and outcomes were analyzed using linear and logistic regression, respectively.

Results

Incidence rates of adult OHCAs increased during the study period, driven by non-shockable OHCA. Compared to shockable OHCA, non-shockable OHCAs were significantly older, had more co-morbidities, unwitnessed and residential arrests, longer no-flow time, and received less bystander cardiopulmonary resuscitation (CPR) and in-hospital interventions (p < 0.001). Amongst non-shockable OHCA, age, co-morbidities, residential arrests, no-flow time, time to patient, bystander CPR and epinephrine administration increased during the study period, while presumed cardiac etiology decreased (p < 0.05). Unlike shockable OHCA, survival for non-shockable OHCA did not improve (p < 0.001 for trend difference). The likelihood of survival for non-shockable OHCA significantly increased with witnessed arrest (adjusted odds ratio (aOR) 2.02) and bystander CPR (aOR 3.25), but decreased with presumed cardiac etiology (aOR 0.65), epinephrine administration (aOR 0.66), time to patient (aOR 0.93) and age (aOR 0.98). Significant two-way interactions were observed for no-flow time and residential arrest with bystander CPR (aOR 0.96 and 0.40 respectively).

Conclusion

The incidence of non-shockable OHCA increased between 2010 and 2019. Despite increased interventions, survival did not improve for non-shockable OHCA, in contrast to the improved survival for shockable OHCA.

Determinants of survival in sudden cardiac arrest manifesting with pulseless electrical activity

OBJECTIVE

The proportion of sudden cardiac arrests (SCA) manifesting with pulseless electrical activity (PEA) has increased significantly, and the survival rate remains lower than ventricular fibrillation (VF). However, a subgroup of PEA-SCA cases does survive and may yield key predictors of improved outcomes when compared to non-survivors. We aimed to identify key predictors of survival from PEA-SCA.

METHODS

Our study sample is drawn from two ongoing community-based, prospective studies of out-of-hospital SCA: Oregon SUDS from the Portland, OR metro area (Pop. approx. 1 million; 2002-2017) and Ventura PRESTO from Ventura County, CA (Pop. approx. 850,000, 2015-2021). For the present sub-study, we included SCA cases with PEA as the presenting rhythm where emergency medical services (EMS) personnel attempted resuscitation.

RESULTS

We identified 1,704 PEA-SCA cases, of which 173 (10.2%) were survivors and 1,531 (89.8%) non-survivors. Patients whose PEA-SCA occurred in a healthcare unit (16.9%) or public location (18.1%) had higher survival than those whose PEA-SCA occurred at home (9.3%) or in a care facility (5.7%). Young age, witness status, PEA-SCA location and pre-existing COPD/asthma were independent predictors of survival. Among witnessed cases the survival rate was 10% even if EMS response time was >10 minutes.

CONCLUSIONS

Key determinants for survival from PEA-SCA were young age, witnessed status, public location and pre-existing COPD/asthma. Survival outcomes in witnessed PEA cases were better than expected, even with delayed EMS response.

Point-of-Care Ultrasound Use by EMS Providers in Out-of-Hospital Cardiac Arrest

AIM

Paramedics received training in point-of-care ultrasound (POCUS) to assess for cardiac contractility during management of medical out-of-hospital cardiac arrest (OHCA). The primary outcome was the percentage of adequate POCUS video acquisition and accurate video interpretation during OHCA resuscitations. Secondary outcomes included POCUS impact on patient management and resuscitation protocol adherence.

METHODS

A prospective, observational cohort study of paramedics was performed following a four-hour training session, which included a didactic lecture and hands-on POCUS instruction. The Prehospital Echocardiogram in Cardiac Arrest (PECA) protocol was developed and integrated into the resuscitation algorithm for medical non-shockable OHCA. The ultrasound (US) images were reviewed by a single POCUS expert investigator to determine the adequacy of the POCUS video acquisition and accuracy of the video interpretation. Change in patient management and resuscitation protocol adherence data, including end-tidal carbon dioxide (EtCO2) monitoring following advanced airway placement, adrenaline administration, and compression pauses under ten seconds, were queried from the prehospital electronic health record (EHR).

RESULTS

Captured images were deemed adequate in 42/49 (85.7%) scans and paramedic interpretation of sonography was accurate in 43/49 (87.7%) scans. The POCUS results altered patient management in 14/49 (28.6%) cases. Paramedics adhered to EtCO2 monitoring in 36/36 (100.0%) patients with an advanced airway, adrenaline administration for 38/38 (100.0%) patients, and compression pauses under ten seconds for 36/38 (94.7%) patients.

CONCLUSION

Paramedics were able to accurately obtain and interpret cardiac POCUS videos during medical OHCA while adhering to a resuscitation protocol. These findings suggest that POCUS can be effectively integrated into paramedic protocols for medical OHCA.

Higher chances of survival to hospital admission after out-of-hospital cardiac arrest in patients with previously diagnosed heart disease

Aim

This study aimed to determine whether patients suffering from out-of-hospital cardiac arrest (OHCA) with a pre-OHCA diagnosis of heart disease have higher survival chances than patients without such a diagnosis and to explore possible underlying mechanisms.

Methods

A retrospective cohort study in 3760 OHCA patients from the Netherlands (2010–2016) was performed. Information from emergency medical services, treating hospitals, general practitioner, resuscitation ECGs and civil registry was used to assess medical histories and the presence of pre-OHCA diagnosis of heart disease. We used multivariable regression analysis to calculate associations with survival to hospital admission or discharge, immediate causes of OHCA (acute myocardial infarction (AMI) vs non-AMI) and initial recorded rhythm.

Results

Overall, 48.1% of OHCA patients had pre-OHCA heart disease. These patients had higher odds to survive to hospital admission than patients without pre-OHCA heart disease (OR 1.25 (95%CI 1.05 to 1.47)), despite being older and more often having cardiovascular risk factors and some non-cardiac comorbidities. These patients also had higher odds of shockable initial rhythm (SIR) (OR 1.60 (1. 36 to 1.89)) and a lower odds of AMI as immediate cause of OHCA (OR 0.33 (0.25 to 0.42)). Their chances of survival to hospital discharge were not significantly larger (OR 1.16 (0.95 to 1.42)).

Conclusion

Having pre-OHCA diagnosed heart disease is associated with better odds to survive to hospital admission, but not to hospital discharge. This is associated with higher odds of a SIR and in a subgroup with available diagnosis a lower proportion of AMI as immediate cause of OHCA.

Pulseless electrical activity vs. asystole in adult in-hospital cardiac arrest: Predictors and outcomes

AIM

This observational cohort study aimed to identify factors associated with pulseless electrical activity (PEA) and asystole in in-hospital cardiac arrest (IHCA) patients and to determine whether differences in outcome based on the initial rhythm were explained by patient- and cardiac arrest characteristics.

METHODS

Adults with IHCA from 2017 to 2018 were included from the Danish IHCA Registry (DANARREST). Additional data came from population-based registries. Unadjusted (RRs) and adjusted risk ratios (aRRs) were estimated for predictors of initial rhythm, return of spontaneous circulation (ROSC), and survival.

RESULTS

We included 1495 PEA and 1285 asystole patients. The patients did not differ substantially in patient characteristics. Female sex, age>90 years, pulmonary disease, and obesity were associated with initial asystole. Ischemic heart disease and witnessed and monitored cardiac arrest were associated with initial PEA. In unadjusted and adjusted analyses, PEA was associated with increased ROSC (aRR = 1.21, 95% confidence interval [CI] 1.10; 1.33). PEA was also associated with increased 30-day and 1-year survival in the unadjusted analysis, while there was no clear association between the initial rhythm and 30-day (aRR = 0.88, 95% CI 0.71; 1.11) and 1-year (aRR = 0.85, 95% CI 0.69; 1.04) survival when patient- and cardiac arrest characteristics were adjusted for.

CONCLUSION

In patients with IHCA presenting with PEA or asystole, there were no major differences in patient demographics and comorbidities. The patients differed substantially in cardiac arrest characteristics. Initial PEA was associated with higher risk of ROSC, but there was no difference in 30-day and 1-year survival.

Effects of the COVID-19 pandemic on out-of-hospital cardiac arrest care in Detroit

Introduction

In response to the COVID-19 pandemic in Detroit, an earlier termination of resuscitation protocol was initiated in March 2020. To characterize pre-hospital cardiac arrest careduring COVID-19 in Detroit, we analyzed out-of-hospital cardiac arrest (OHCA) rate of ROSC (return of spontaneous circulation) and patient characteristics before and during the COVID-19 pandemic.

Methods

OHCA data was analyzed between March 10th, 2020 – April 30th, 2020 and March 10th, 2019 – April 30th, 2019. ROSC, patient demographics, arrest location, initial rhythms, bystander CPR and field termination were compared before and during the pandemic. Descriptive statistics were utilized to compare arrest characteristics between years, and the odds of achieving vs. not achieving ROSC. 2020 vs. 2019 as a predictor for ROSC was assessed with logistic regression.

Results

471 patients were included. Arrests increased to 291 during the pandemic vs. 180 in 2019 (62% increase). Age (mean difference + 6; 95% CI: +2.4 to +9.5), arrest location (nursing home OR = 2.42; 95% CI: 1.42–4.31; public place OR = 0.47; 95% CI: 0.25–0.88), BLS response (OR = 0.68; 95% CI: 0.47–0.99), and field termination of resuscitation (OR = 2.36; 95% CI: 1.36–4.07) differed significantly in 2020 compared to 2019. No significant difference was found in the confounder-adjusted odds of ROSC in 2020 vs 2019 (OR = 0.61; 95% CI: 0.34–1.11).

Conclusion

OHCA increased by 62% during COVID-19 in Detroit, without a significant change in prehospital ROSC. The rate of ROSC remained similar despite the implementation of an early termination of resuscitation protocol in response to COVID-19.

Association between wide QRS pulseless electrical activity and hyperkalemia in cardiac arrest patients

AIM

We evaluated the relationship between hyperkalemia and wide QRS complex in patients with pulseless electrical activity (PEA) cardiac arrest.

METHODS

This was a single-center, retrospective observational study of patients over the age of 18 treated for cardiac arrest at a tertiary referral hospital whose initial electrocardiogram rhythm was PEA from February 2010 to December 2019. Wide QRS PEA was defined as a QRS interval of 120 ms or more. Hyperkalemia was defined as serum potassium level > 5.5 mmol/L. The primary outcome was hyperkalemia. Multivariable logistic regression analysis was used to evaluate the relationship between wide QRS and hyperkalemia.

RESULTS

Among 617 patients, we analyzed 111 episodes in the wide QRS group and 506 episodes in the narrow QRS group. The potassium level in the wide QRS group was significantly higher than in the narrow QRS group (5.4 mmol/L, IQR 4.4-6.7 vs. 4.6 mmol/L, IQR 4.0-5.6, P < 0.001). Among all patients, 49.6% (n = 55/111) in the wide QRS group had hyperkalemia, which was significantly higher than the 26.7% (n = 135/506) in the narrow QRS group (P < 0.001). In multivariable logistic regression analysis, wide QRS PEA was significantly associated with hyperkalemia (odds ratio = 2.86, 95% confidence interval: 1.80-4.53, P < 0.001).

CONCLUSIONS

Wide QRS PEA as an initial cardiac rhythm was significantly associated with hyperkalemia in cardiac arrest patients.

Analysis of the emergency medical service call centre actions in patients with cardiac arrest

Background/Aim: Cardiac arrest (CA) is a leading cause of mortality in the last forty years worldwide. Immediately initiated cardiopulmonary resuscitation (CPR) improves chances for survival. Aim of this study was to determine the efficiency of the Emergency medical service (EMS) dispatch centre in the absence of the uniform emergency medical dispatch assessment protocols in the management of cardiac arrest. Methods: The retrospective and observational study was conducted in Institute for Emergency Medical Service Novi Sad (IEMS Novi Sad) Serbia during a one-year follow-up. The study included patients with out-of-hospital cardiac arrests who underwent CPR. Results: EMS teams of the IEMS Novi Sad had 198 CPRs in the follow-up period. In 142 (71.72 %) calls, the EMS dispatcher got information that the patient was unconscious. The reported reaction time I by the dispatchers for the unconscious patients was 1.37 ± 1.27 minutes, actual duration of the conversation between the dispatcher and a caller - was longer: 138.21 ± 103.02 seconds (p < 0.001). The average conversation time with a caller was 61.37 ± 31.13 seconds. In 6 (4.22 %) cases, the EMS team was dispatched to a patient before the phone call was terminated. At the moment of arrival, all patients were unconscious, 194 (94.37 %) were pulseless, while the remaining 8 (5.63 %) experienced cardiac arrest during the examination. The cardiac arrest was witnessed by a layman in 120 (84.51 %) cases and CPR was initiated by bystanders, before the arrival of the EMS team, only in 13 (10.83 %) patients. Twenty-seven (19.01 %) patients arrived in a hospital with vital signs. Conclusion: The absence of the uniform EMS dispatch assessment protocols for the triage of incoming calls and phone assisted CPR for lay rescuers decreases the survival rate of patients with cardiac arrest.

Factors associated with shockable versus non-shockable rhythms in patients with in-hospital cardiac arrest

AIM

To identify factors associated with the initial rhythm in patients with in-hospital cardiac arrest and to assess whether potential differences in outcomes based on the initial rhythm can be explained by patient and event characteristics.

METHODS

Adult patients (≥18 years old) with in-hospital cardiac arrest in 2017 and 2018 were included from the Danish In-Hospital Cardiac Arrest Registry (DANARREST). We used population-based registries to obtain data on comorbidities, cardiac procedures, and medications. Unadjusted and adjusted risk ratios (RRs) for initial rhythm, return of spontaneous circulation (ROSC), and survival were estimated in separate models including an incremental number of prespecified variables.

RESULTS

A total of 3422 patients with in-hospital cardiac arrest were included, of which 639 (19%) had an initial shockable rhythm. Monitored cardiac arrest, witnessed cardiac arrest, and specific cardiac diseases (i.e. ischemic heart disease, dysrhythmias, and valvular heart disease) were associated with initial shockable rhythm. Conversely, higher age, female sex, and specific non-cardiovascular comorbidities (e.g. overweight and obesity, renal disease, and pulmonary cancer) were associated with an initial non-shockable rhythm. Initial shockable rhythm remained strongly associated with increased ROSC (RR = 1.63, 95%CI 1.51-1.76), 30-day survival (RR = 2.31, 95%CI 2.02-2.64), and 1-year survival (RR = 2.36, 95%CI 2.02-2.76) compared to initial non-shockable rhythm in the adjusted analyses.

CONCLUSION

In this study, specific patient and cardiac arrest characteristics were associated with initial rhythm in patients with in-hospital cardiac arrest. However, differences in patient and cardiac arrest characteristics did not fully explain the association with survival for initial shockable rhythm compared to a non-shockable rhythm.

A review of pre-hospital case series among those with time to double external defibrillation and neurologic outcomes

BACKGROUND

Double external defibrillation (DED) has been used as a final effort to terminate refractory ventricular fibrillation/pulseless ventricular tachycardiac (rVF/pVT). Data surrounding time to DED and patient-centered outcomes remains limited.

OBJECTIVES

This study summarizes patient-level data from case-series of observed survival and neurologic outcomes following the use of DED for rVF/pVT among those with data regarding time to DED.

METHODS

We conducted a literature search of PubMed, MEDLINE (OVID interface), and Scopus from January 1, 2000, through January 5, 2020. The literature was screened according to inclusion and exclusion criteria. Two investigators independently conducted the literature search, study selection, and data extraction.

RESULTS

Our database search identified 3139 records. Of these, 1660 studies were eliminated following inspection of the titles and 22 studies underwent full-text screening, three included in the final analysis, describing a total of 29 cases. All studies were considered to have critical risk of bias. For the critical outcomes of survival to discharge and neurologically intact survival we identified that patients who received DED before 30 min from collapse compared to those who received DED after 30 min had better survival to discharge (33.3% [5/15] vs. 7.1% [1/14]) and neurologically intact survival (20.0% [3/15] vs. 7.1% [1/14]). Overall, 20.6% of patients survived to discharge, 13.8% with neurologically intact survival. It is noteworthy that the patients who were discharged with a CPC of 1 received two, four, five, and three standard shocks before receiving DED, and the time between their onset of cardiac arrest to their first DED attempt was recorded to be 15, 26, 26, and 32 min, respectively.

CONCLUSION

We would like to indicate that there is not enough evidence to suggest that early use of pre-hospital DED is associated with improved outcomes. Further research should strive to address these issues before conclusions can be drawn.

Non-perfusing cardiac rhythms in asphyxiated newborn piglets

Aim

We recently demonstrated that asphyxiated piglets commonly had bradycardia displayed on electrocardiography (ECG) while no carotid blood flow (CBF) or audible heart sounds could be detected. Such pulseless electrical activity (PEA) in newborn infants has not previously been thoroughly described. The aim of this study was to further investigate the occurrence of non-perfusing cardiac rhythms in asphyxiated piglets and the potential implications for the success of cardiopulmonary resuscitation (CPR) and short-term survival.

Methods

Neonatal piglets (1–4 days, 1.7–2.4kg) had their right common carotid artery exposed and enclosed with a real-time ultrasonic flow probe. Heart rate (HR) was continuously measured and recorded using ECG. This allowed simultaneous monitoring of HR via ECG and CBF. The piglets were asphyxiated until cardiac arrest, defined as no CBF and no audible beat upon precordial auscultation. CPR was performed until return of spontaneous circulation (ROSC, defined as a HR ≥100 bpm). ECG traces were retrospectively assessed.

Results

Nine out of 21 piglets (43%) had QRS-complexes on their ECG while no CBF and no audible heart sounds could be detected. Five (56%) of the piglets with PEA and 12/12 (100%) piglets with asystole at cardiac arrest obtained ROSC (p = 0.02). Thirty-three per cent of the piglets with PEA versus 58% with asystole survived to 4 hours post-ROSC (p = 0.39).

Conclusion

Cardiac arrest in the presence of a non-perfusing cardiac rhythm on ECG is common in asphyxiated piglets. Clinical arrest in the presence of a non-perfusing cardiac rhythm on ECG may reduce the success of CPR.

The use of dispatcher assistance in improving the quality of cardiopulmonary resuscitation: A randomised controlled trial

AIMS

The introduction of dispatcher assistance (DA) services has led to increased bystander cardiopulmonary resuscitation (CPR) participation rates. However, the extent to which DA improves CPR quality remains unclear. This study aimed to evaluate the efficacy of DA in improving CPR quality among healthcare professionals and laypersons within a multi-ethnic Southeast Asian population.

METHODS

A parallel, randomised controlled, open label trial was performed. Four hundred and twelve participants were recruited via convenience sampling in a public location. In a simulated cardiac-arrest scenario, the participants were randomised to perform CPR with DA over the phone (DA+) or CPR without DA (DA-). The ratio of participant assignment to DA+ and DA- was 1:1. The primary outcomes were CPR compression depth, compression rate, no-flow time, complete release of pressure between compressions, and hand location. The assessment involved CPR manikins and human assessors.

RESULTS

A larger proportion of participants in DA + achieved the correct compression rate (34.3% vs 18.1%, p < 0.001). There was no difference in the other primary outcomes. A subgroup analysis revealed that healthcare professionals in DA+ had a higher proportion of correct hand location compared to those in DA- (82.1% vs. 53.5%, p < 0.05). There was no significant difference in CPR quality among laypersons with valid CPR certification regardless of whether they received DA.

CONCLUSION

DA should be provided to laypersons without valid CPR certification, as well as healthcare professionals. The identification of gaps in the current DA protocol highlights areas where specific changes can be made to improve CPR quality.

Guideline removal of atropine and survival after adult in-hospital cardiac arrest with a non-shockable rhythm

AIM

To determine whether the removal of atropine from the 2010 ACLS guidelines for non-shockable cardiac arrests was associated with a change in survival.

METHODS

Using the Get With The Guidelines^®-Resuscitation registry, we included adults with an index in-hospital cardiac arrest between 2006 and 2015. The primary outcome was survival to hospital discharge. Secondary outcomes included return of spontaneous circulation and favorable functional outcome. An interrupted time-series analysis was used to compare survival before (pre-guidelines) and after (post-guidelines) introduction of the 2010 guidelines. A difference-in-difference approach was used to compare the interrupted time-series results between the non-shockable and shockable cohorts to account for guideline changes unrelated to atropine.

RESULTS

We included 20,499 non-shockable and 3968 shockable cardiac arrests. Patient characteristics were similar between the pre-guidelines and post-guidelines period. Atropine was used for 8653 (87%) non-shockable and 680 (35%) shockable cardiac arrests in the pre-guidelines period and 3643 (35%) non-shockable and 320 (16%) shockable cardiac arrests in the post-guidelines period. The change over time in survival from the pre-guidelines to the post-guidelines period was not significantly different for the non-shockable compared to the shockable cohort (risk difference: 2.0% [95%CI: -0.8, 4.8] per year, p = 0.17). The immediate change in survival after introducing the guidelines was also not different between the cohorts (risk difference: 3.5% [95%CI: -2.6, 9.7], p = 0.26). Results were similar for the secondary outcomes and in multiple sensitivity analyses.

CONCLUSIONS

The removal of atropine from the 2010 guidelines was not associated with a significant change in survival.

The predictive value of bedside ultrasound to restore spontaneous circulation in patients with pulseless electrical activity: A systematic review and meta-analysis

Background

The prognosis of pulseless electrical activity is dismal. However, it is still challengable to decide when to terminate or continue resuscitation efforts. The aim of this study was to determine whether the use of bedside ultrasound (US) could predict the restoration of spontaneous circulation (ROSC) in patients with pulseless electrical activity (PEA) through the identification of cardiac activity.

Methods

This was a systematic review and meta-analysis of studies that used US to predict ROSC. A search of electronic databases (Cochrane Central, MEDLINE, EMBASE) was conducted up to June 2017, and the assessment of study quality was performed with the Newcastle-Ottawa Scale. Statistical analysis was performed with Review Manager 5.3 and Stata 12.

Results

Eleven studies that enrolled a total of 777 PEA patients were included. A total of 230 patients experienced ROSC. Of these, 188 had sonographically identified cardiac activity (pseudo-PEA). A meta-analysis showed that PEA patients with cardiac activity on US were more likely to obtain ROSC compared to those with cardiac standstill: risk ratio (RR) = 4.35 (95% confidence interval [CI], 2.20–8.63; p<0,00001) with significant statistical heterogeneity (I² = 60%). Subgroup analyses were conducted: US evaluation using only on the subxiphoid view: RR = 1.99 (95% CI, 0.79–5.02; p = 0.15); evaluation using various views: RR = 4.09 (95% CI,2.70–6.02; p<0.00001).

Conclusions

In cardiac arrest patients who present with PEA, bedside US has an important role in predicting ROSC. The presence of cardiac activity in PEA patients may encourage more aggressive resuscitation.

Outcome Predictors of Patients in Out-Of-Hospital Cardiac Arrests with Pre-Hospital Defibrillation in Hong Kong

Objective

To report the epidemiology, outcomes and the predictors of survival in patients with out-of-hospital cardiac arrest (OHCA) with pre-hospital shockable cardiac rhythms in Hong Kong.

Methods

It was a prospective study based on data from the cardiac arrest registry of emergency departments (ED) in two regional hospitals in Hong Kong from 1st August 2010 to 31st January 2012. All non-traumatic patients aged 18 years or above presented with OHCA with shockable pre-hospital cardiac rhythm and received pre-hospital defibrillation were included. The characteristics of patients, pre-hospital data, management and outcomes were recorded in a standardised form compatible with Utstein template at the time of patient consultation. Binominal logistic regression was applied to evaluate the relationship between survival to admission (STA) and patients' variables.

Results

A total of 135 patients fulfilled the inclusion criteria. The mean age was 67.0 years old. The STA rate was 34.8% and the survival to discharge (STD) rate was 6.7%. Factors independently associated with better prognosis in terms of STA were presence of bystander cardiopulmonary resuscitation (CPR) (OR 5.76, 95% CI=1.08-30.5), restoration of spontaneous circulation (ROSC) before arrival to ED (OR 43.94, 95% CI= 4.19-460.43) and short time from calling emergency medical services (EMS) to first defibrillation (OR 0.82, 95% CI=0.70-0.96).

Conclusion

STA rate for adults presenting with shockable OHCA in our study was 34.8%. Patients with shockable OHCA with bystander CPR, short call-to-shock time and achieved ROSC before arrival to ED are significantly associated with higher STA rate.

Role of Cardiac Imaging in Evaluating Risk for Sudden Cardiac Death

Sudden cardiac death (SCD) is a major cause of death from cardiovascular disease. Our ability to predict patients at the highest risk of developing lethal ventricular arrhythmias remains limited. Despite recent studies evaluating risk stratification tools, there is no optimal strategy. Cardiac imaging provides the opportunity to assess left ventricular ejection fraction, strain, fibrosis, and sympathetic innervation, all of which are pathophysiologically related to SCD risk. These modalities may play a role in the identification of vulnerable anatomic substrates that provide the pathophysiologic basis for SCD. Further studies are required to identify optimal imaging platform for risk assessment.

Clinical predictors of shockable versus non-shockable rhythms in patients with out-of-hospital cardiac arrest

AIM

To identify factors associated with a non-shockable rhythm as first recorded heart rhythm.

METHODS

Patients ≥18 years old suffering out-of-hospital cardiac arrest between 2001 and 2012 were identified in the population-based Danish Cardiac Arrest Registry. Danish administrative registries were used to identify chronic diseases (within 10 years) and drug prescriptions (within 180 days). A multivariable logistic regression model, including patient related and cardiac arrest related characteristics, was used to estimate odds ratios (OR) for factors associated with non-shockable rhythm.

RESULTS

A total of 29,863 patients were included: 6600 (22.1%) patients with a shockable rhythm and 23,263 (77.9%) patients with a non-shockable rhythm. A non-shockable rhythm was associated with female gender, arrest in private home, unwitnessed arrest, no bystander CPR, and longer time to first rhythm analysis compared to patients with shockable rhythm. In the adjusted multivariable regression model, pre-existing non-cardiovascular disease and drug prescription were associated with a non-shockable rhythm e.g. chronic obstructive lung disease (OR 1.44 [95% CI: 1.32-1.58]); and the prescription for antidepressants (OR 1.49 [95% CI: 1.35-1.65]), antipsychotics (OR 2.30 [95% CI: 1.96-2.69]) analgesics (OR 1.32 [95% CI: 1.23-1.41]), corticosteroids (OR 1.64 [95% CI: 1.44-1.85]), and antibiotics (OR 1.59 [95% CI: 1.40-1.81]). In contrast, the prescription of cardiovascular drugs and a history of cardiovascular disease e.g. ischemic heart disease was associated with a lower risk of non-shockable rhythm (OR 0.66 [95% CI: 0.60-0.71]).

CONCLUSION

This study demonstrate that non-cardiovascular disease and medication prescription are associated with a non-shockable rhythm while cardiovascular disease and medication prescription are associated with a shockable rhythm as first recorded rhythm in patients with OHCA.

Conduction disorders in bradyasystolic out-of-hospital cardiac arrest

AIMS

Bradyasystolic heart rhythms are often recorded in out-of-hospital cardiac arrest (OHCA). Atrioventricular (AV) conduction disorders might lead to OHCA, but the prevalence of AV-conduction disorders and other bradyasystolic rhythms in OHCA is unknown. These patients might benefit from pre-hospital pacing. We aimed to determine the prevalence of different types of bradyasystolic heart rhythms in OHCA, including third degree AV-block, and document survival rates.

METHODS

We used data from the ARREST-registry of OHCA in the Netherlands. Patients with bradyasystolic OHCA in 2006-2012 were included. ECGs were classified according to the presence of P-waves and QRS complexes in five rhythm groups. Differences in survival to discharge in relation to resuscitation characteristics, rhythm and pacing were tested using Chi-Square test and multivariate regression analysis.

RESULTS

We included 2333 patients with a bradyasystolic rhythm; 371 patients (16%) presented with a third degree AV-block. In total 45 patients (1.9%, 95%-CI 1.4-2.5%) survived. A third degree AV-block (adjusted OR 0.86, 95%-CI 0.38-1.96) or pacing (adjusted OR 0.89, 95%-CI 0.21-3.78) was not associated with survival. Pacing was initiated in 110 patients (4.7%), after a long delay (median 18.7min). The strongest association with survival was found for the presence of a bradycardia (vs. asystole) (adjusted OR 4.20, 95%-CI 1.79-9.83), bystander witnessed (OR 4.13, 95%-CI 1.45-11.8) and EMS witnessed collapse (OR 5.18, 95%-CI 2.77-9.67).

CONCLUSION

In bradyasystolic OHCA, 16% of all patients present with third degree AV-block, but survival for these and other bradyasystolic patients remains poor. Pacing is seldom initiated, often delayed, and rarely beneficial.

Trends in traumatic out-of-hospital cardiac arrest in Perth, Western Australia from 1997 to 2014

AIM

This study aims to describe and compare traumatic and medical out-of-hospital cardiac arrest (OHCA) occurring in Perth, Western Australia, between 1997 and 2014.

METHODS

The St John Ambulance Western Australia (SJA-WA) OHCA Database was used to identify all adult (≥ 16 years) cases. We calculated annual crude and age-sex standardised incidence rates (ASIRs) for traumatic and medical OHCA and investigated trends over time.

RESULTS

Over the study period, SJA-WA attended 1,354 traumatic OHCA and 16,076 medical OHCA cases. The mean annual crude incidence rate of traumatic OHCA in adults attended by SJA-WA was 6.0 per 100,000 (73.9 per 100,000 for medical cases), with the majority resulting from motor vehicle collisions (56.7%). We noted no change to either incidence or mechanism of injury over the study period (p>0.05). Compared to medical OHCA, traumatic OHCA cases were less likely to receive bystander cardiopulmonary resuscitation (CPR) (20.4% vs. 24.5%, p=0.001) or have resuscitation commenced by paramedics (38.9% vs. 44.8%, p<0.001). However, rates of bystander CPR and resuscitation commenced by paramedics increased significantly over time in traumatic OHCA (p<0.001). In cases where resuscitation was commenced by paramedics there was no difference in the proportion who died at the scene (37.2% traumatic vs. 34.3% medical, p=0.17), however, fewer traumatic OHCAs survived to hospital discharge (1.7% vs. 8.7%, p<0.001).

CONCLUSIONS

Despite temporal increases in rates of bystander CPR and paramedic resuscitation, traumatic OHCA survival remains poor with only nine patients surviving from traumatic OHCA over the 18-year period.

Sudden cardiac death risk stratification

Arrhythmic sudden cardiac death (SCD) may be caused by ventricular tachycardia/fibrillation or pulseless electric activity/asystole. Effective risk stratification to identify patients at risk of arrhythmic SCD is essential for targeting our healthcare and research resources to tackle this important public health issue. Although our understanding of SCD because of pulseless electric activity/asystole is growing, the overwhelming majority of research in risk stratification has focused on SCD-ventricular tachycardia/ventricular fibrillation. This review focuses on existing and novel risk stratification tools for SCD-ventricular tachycardia/ventricular fibrillation. For patients with left ventricular dysfunction or myocardial infarction, advances in imaging, measures of cardiac autonomic function, and measures of repolarization have shown considerable promise in refining risk. Yet the majority of SCD-ventricular tachycardia/ventricular fibrillation occurs in patients without known cardiac disease. Biomarkers and novel imaging techniques may provide further risk stratification in the general population beyond traditional risk stratification for coronary artery disease alone. Despite these advances, significant challenges in risk stratification remain that must be overcome before a meaningful impact on SCD can be realized.

Cardiac arrest: resuscitation and reperfusion

The modern treatment of cardiac arrest is an increasingly complex medical procedure with a rapidly changing array of therapeutic approaches designed to restore life to victims of sudden death. The 2 primary goals of providing artificial circulation and defibrillation to halt ventricular fibrillation remain of paramount importance for saving lives. They have undergone significant improvements in technology and dissemination into the community subsequent to their establishment 60 years ago. The evolution of artificial circulation includes efforts to optimize manual cardiopulmonary resuscitation, external mechanical cardiopulmonary resuscitation devices designed to augment circulation, and may soon advance further into the rapid deployment of specially designed internal emergency cardiopulmonary bypass devices. The development of defibrillation technologies has progressed from bulky internal defibrillators paddles applied directly to the heart, to manually controlled external defibrillators, to automatic external defibrillators that can now be obtained over-the-counter for widespread use in the community or home. But the modern treatment of cardiac arrest now involves more than merely providing circulation and defibrillation. As suggested by a 3-phase model of treatment, newer approaches targeting patients who have had a more prolonged cardiac arrest include treatment of the metabolic phase of cardiac arrest with therapeutic hypothermia, agents to treat or prevent reperfusion injury, new strategies specifically focused on pulseless electric activity, which is the presenting rhythm in at least one third of cardiac arrests, and aggressive post resuscitation care. There are discoveries at the cellular and molecular level about ischemia and reperfusion pathobiology that may be translated into future new therapies. On the near horizon is the combination of advanced cardiopulmonary bypass plus a cocktail of multiple agents targeted at restoration of normal metabolism and prevention of reperfusion injury, as this holds the promise of restoring life to many patients for whom our current therapies fail.

Cardiac Arrest Resuscitation

Cardiac arrest is a dynamic disease that tests the multitasking and leadership abilities of emergency physicians. Providers must simultaneously manage the logistics of resuscitation while searching for the cause of cardiac arrest. The astute clinician will also realize that he or she is orchestrating only one portion of a larger series of events, each of which directly affects patient outcomes. Resuscitation science is rapidly evolving, and emergency providers must be familiar with the latest evidence and controversies surrounding resuscitative techniques. This article reviews evidence, discusses controversies, and offers strategies to provide quality cardiac arrest resuscitation.

Cardiac arrest with initial arrest rhythm of pulseless electrical activity: do rhythm characteristics correlate with outcome?

OBJECTIVES

Cardiac arrest is a leading cause of death in the United States, with pulseless electrical activity (PEA) as a common initial arrest rhythm. We sought to determine if rate of electrical activity and QRS width correlate with survival in patients who present with PEA out-of-hospital cardiac arrest.

METHODS AND RESULTS

This is a retrospective review of patients with PEA out-of-hospital cardiac arrest with first documented cardiac rhythm of PEA from January 2010 to September 2013. Demographic, arrest and initial rhythm characteristics, and patient outcome were abstracted via systematic chart review. The initial 20 seconds of each rhythm strip were used to ascertain electrical rate and QRS width. Primary outcome was survival to hospital discharge. Four hundred fourteen patients were eligible for the study. One hundred fifty-two patients did not have sufficient data for analysis. Two hundred sixty-two patients were included in the final analysis with mean age, 66 years. There were 23 (8.8%) survivors and 17 (6.5%) neurologically intact survivors. Mean heart rate was 58 (confidence interval, 54-63) beats per minute, and mean QRS interval was 100 (confidence interval, 95-106) milliseconds. Twenty-nine point seven percent of patients had wide QRS complexes, and 70.3% were narrow. There was no difference in survival in patients based on heart rate (13.1% vs 7.4%, P = .16) or QRS interval (8.7% vs 7.7%, P = .79).

CONCLUSIONS

In this single emergency medical services agency study, neither PEA electrical rate nor QRS width correlated with survival or neurologic outcome.

The role of professional societies in limiting indication creep

New technology is a major driver of health care inflation. One contributor to this inflation is indication creep, the diffusion of interventions that have been proven beneficial in specific patient populations into untested broader populations who may be less likely to benefit. Professional societies sometimes promote indication creep, as we illustrate with the case of therapeutic hypothermia after cardiac arrest. Professional societies are in a unique position to limit indication creep. We propose that, at a minimum, professional societies should refrain from recommending new diagnostic and therapeutic technologies in their guidelines until they have been proven beneficial in the targeted populations. In some circumstances, professional societies could be more active in combatting indication creep, either recommending against expanded use of clinical interventions when evidence is lacking, or coordinating efforts to collect data in these broader populations.

A simplified and structured teaching tool for the evaluation and management of pulseless electrical activity

Cardiac arrest victims who present with pulseless electrical activity (PEA) usually have a grave prognosis. Several conditions, however, have cause-specific treatments which, if applied immediately, can lead to quick and sustained recovery. Current teaching focuses on recollection of numerous conditions that start with the letters H or T as potential causes of PEA. This teaching method is too complex, difficult to recall during resuscitation, and does not provide guidance to the most effective initial interventions. This review proposes a structured algorithm that is based on the differentiation of the PEA rhythm into narrow- or wide-complex subcategories, which simplifies the working differential and initial treatment approach. This, in conjunction with bedside ultrasound, can quickly point towards the most likely cause of PEA and thus guide resuscitation.

Evaluating the effectiveness of CPR for in-hospital cardiac arrest

Cardiopulmonary resuscitation (CPR) is one of the most commonly performed medical interventions. However, the true effectiveness of CPR remains unknown as it presents significant challenges for evaluation and research. Many resuscitation practices are driven by nonquantitative reasoning and may not be evidence based. Several studies have been published on survival after in-hospital CPR. However, the reported survival rates from one hospital to another vary significantly due to a number of reasons such as type of hospital, presence of specialized cardiac units, patient demographics, differences in inclusion criteria, outcome definitions and so on. Further research is indicated to evaluate the true effectiveness of CPR for in-hospital cardiac arrest.

Survival advantage from ventricular fibrillation and pulseless electrical activity in women compared to men: the Oregon Sudden Unexpected Death Study

OBJECTIVE

Studies evaluating a possible survival advantage from sudden cardiac arrest (SCA) in women have produced mixed results possibly due to a lack of comprehensive analyses. We hypothesized that race, socioeconomic status (SES), and elements of the lifetime clinical history influence gender effects and need to be incorporated within analyses of survival.

METHODS

Cases of SCA were identified from the ongoing, prospective, multiple-source Oregon Sudden Unexpected Death Study (population approximately one million). Subjects included were age ≥18 years who underwent attempted resuscitation by EMS providers. Pearson's chi-square tests and independent samples t tests or analysis of variance were used for univariate comparisons. We evaluated gender and race differences in survival adjusted for age, circumstances of arrest, disease burden, and socioeconomic status using a logistic regression model predicting survival.

RESULTS

A total of 1,296 cases had resuscitation attempted (2002-2007; mean age 65 years, male 67%). Women were older than men (68 vs. 63 years, p < 0.0001) and were more likely to have return of spontaneous circulation (41% vs. 33%, p = 0.004). Women were more likely to present with pulseless electrical activity (PEA) and asystole (p < 0.0001), and overall, PEA was more common among African Americans (p = 0.04). Higher survival to hospital discharge was observed in women compared to men presenting with ventricular fibrillation/tachycardia (34% vs. 24%, p = 0.02) or with PEA (10% vs. 3%, p = 0.007). In a multivariate model adjusting for age, race, presenting arrhythmia, arrest circumstances, arrest location, disease burden, and SES, women were more likely than men to survive to hospital discharge [odds ratio 1.85; 95% confidence interval (1.12-3.04)].

CONCLUSIONS

Despite older age, higher prevalence of SCA in the home, and higher rates of PEA, women had a survival advantage from ventricular fibrillation and pulseless electrical activity.

Self-instructional CPR training for parents of high risk infants

OBJECTIVE

Premature infants (PRE) and infants with congenital heart disease (CHD) are at high risk for respiratory or cardiac arrest in their first year. Bystander cardiopulmonary resuscitation (CPR) is a major predictor of resuscitation outcome. The purpose of this study was to assess the usefulness of a self-instructional DVD kit (Infant CPRAnytime) for families of high-risk infants. We hypothesized that comfort level of performing CPR would increase, parents would share the kit with others, and review it during the year.

METHODS

Parents of PRE (<35 weeks or <2500 g) or CHD infants received a self-instructional CPR kit. One parent completed a questionnaire, reviewed the DVD, and practiced CPR before discharge. They were asked to share the kit with other care providers, practice CPR every 3 months, and complete questionnaires at 4 and 12 months.

RESULTS

We enrolled 311 subjects: 238 PRE and 73 CHD. Comfort level performing CPR increased from 2.8 at baseline to 3.5 at 12 months (p=0.023). The kit was shared with 3.1 additional persons and reviewed by the parent 1.8 times over 12 months. Eight emergency rescue events were reported: choking (3) and CPR (5). All events requiring CPR were in infants with CHD. Six infants survived with reported good or stable neurologic status.

CONCLUSIONS

Self-instructional tools provide an excellent method of CPR training for parents of high risk infants. Caregiver comfort increased over 12 months and parents continued to review the kit during the first year. An additional 3.1 persons used the kit for CPR training.

Update on cardiopulmonary resuscitation guidelines of interest to anesthesiologists

BACKGROUND AND OBJECTIVES

The new cardiopulmonary resuscitation (CPR) guidelines emphasize the importance of high-quality chest compressions and modify some routines. The objective of this report was to review the main changes in resuscitation practiced by anesthesiologists.

CONTENTS

The emphasis on high-quality chest compressions with adequate rate and depth allowing full recoil of the chest and with minimal interruptions is highlighted in this update. One should not take more than ten seconds checking the pulse before starting CPR. The universal relationship of 30:2 is maintained, modifying its order, initiating with chest compressions, followed by airways and breathing (C-A-B instead of A-B-C). The procedure "look, listen, and feel whether the patient is breathing" was removed from the algorithm, and the use of cricoid pressure during ventilations is not recommended any more. The rate of chest compressions was changed for at least one hundred per minute instead of approximately one hundred per minute, and its depth in adults was changed to 5 cm instead of the prior recommendation of 4 to 5 cm. The single shock is maintained, and it should be of 120 to 200 J when it is biphasic; and 360 J when it is monophasic. In advanced cardiac life support, the use of capnography and capnometry to confirm intubation and monitoring the quality of CPR is a formal recommendation. Atropine is no longer recommended for routine use in the treatment of pulseless electrical activity or asystole.

CONCLUSIONS

Updating the phases of the new CPR guidelines is important, and continuous learning is recommended. This will improve the quality of resuscitation and survival of patients in cardiac arrest.

Early selective trans-nasal cooling during CPR improves success of resuscitation in a porcine model of prolonged pulseless electrical activity cardiac arrest

AIM OF STUDY

In the present study, we investigated trans-nasal cooling in settings of pulseless electrical activity (PEA). We hypothesized that early trans-nasal cooling during CPR improves outcomes when cardiac arrest is associated with PEA.

METHODS

Ventricular fibrillation (VF) was electrically induced in 16 domestic male pigs weighing 40±3 kg. After 14 min of untreated VF, PEA was induced following delivery of one or more electrical shocks. One min after onset of PEA, CPR was started, including chest compression and ventilation. Each animal received 5 min of CPR prior to defibrillation attempt. CPR and resuscitation efforts were discontinued at 15 min unless return to spontaneous circulation was achieved. In 8 animals, selective trans-nasal cooling was begun coincident with start of CPR and 8 randomized controls were identically treated except for trans-nasal cooling. Mean aortic pressure was continuously measured together with aortic and right atrial pressure and nasal, body and right jugular vein temperatures. Coronary perfusion pressure (CPP) was computed from measured data.

RESULTS

Six of eight animals were resuscitated after early trans-nasal cooling, while only one untreated control was resuscitated (p=0.012). Nasal, body and jugular vein temperatures decreased after cooling. At PC (precordial compression) 5 min, the cooled group recorded a higher CPP (25±5 mmHg) than the non-cooled group (15±4 mmHg, p=0.001).

CONCLUSION

When selective trans-nasal cooling was initiated during CPR in the animal model of prolonged cardiac arrest with PEA, CPP was higher and the likelihood of return of spontaneous circulation was improved.