The scene time interval and basic life support termination of resuscitation rule in adult out-of-hospital cardiac arrest

Termination of Resuscitation Rules and Survival Among Patients With Out-of-Hospital Cardiac Arrest: A Systematic Review and Meta-Analysis

Importance

Termination of resuscitation (TOR) rules may help guide prehospital decisions to stop resuscitation, with potential effects on patient outcomes and health resource use. Rules with high sensitivity risk increasing inappropriate transport of nonsurvivors, while rules without excellent specificity risk missed survivors. Further examination of the performance of TOR rules in estimating survival of out-of-hospital cardiac arrest (OHCA) is needed.

Objective

To determine whether TOR rules can accurately identify patients who will not survive an OHCA.

Data Sources

For this systematic review and meta-analysis, the MEDLINE, Embase, CINAHL, Cochrane Library, and Web of Science databases were searched from database inception up to January 11, 2024. There were no restrictions on language, publication date, or time frame of the study.

Study Selection

Two reviewers independently screened records, first by title and abstract and then by full text. Randomized clinical trials, case-control studies, cohort studies, cross-sectional studies, retrospective analyses, and modeling studies were included. Systematic reviews and meta-analyses were reviewed to identify primary studies. Studies predicting outcomes other than death, in-hospital studies, animal studies, and non-peer-reviewed studies were excluded.

Data Extraction and Synthesis

Data were extracted by one reviewer and checked by a second. Two reviewers assessed risk of bias using the Revised Quality Assessment Tool for Diagnostic Accuracy Studies. Cochrane Screening and Diagnostic Tests Methods Group recommendations were followed when conducting a bivariate random-effects meta-analysis. This review followed the Preferred Reporting Items for a Systematic Review and Meta-Analysis of Diagnostic Test Accuracy Studies (PRISMA-DTA) statement and is registered with the International Prospective Register of Systematic Reviews (CRD42019131010).

Main Outcomes and Measures

Sensitivity and specificity tables with 95% CIs and bivariate summary receiver operating characteristic (SROC) curves were produced. Estimates of effects at different prevalence levels were calculated. These estimates were used to evaluate the practical implications of TOR rule use at different prevalence levels.

Results

This review included 43 nonrandomized studies published between 1993 and 2023, addressing 29 TOR rules and involving 1 125 587 cases. Fifteen studies reported the derivation of 20 TOR rules. Thirty-three studies reported external data validations of 17 TOR rules. Seven TOR rules had data to facilitate meta-analysis. One clinical study was identified. The universal termination of resuscitation rule had the best performance, with pooled sensitivity of 0.62 (95% CI, 0.54-0.71), pooled specificity of 0.88 (95% CI, 0.82-0.94), and a diagnostic odds ratio of 20.45 (95% CI, 13.15-31.83).

Conclusions and Relevance

In this review, there was insufficient robust evidence to support widespread implementation of TOR rules in clinical practice. These findings suggest that adoption of TOR rules may lead to missed survivors and increased resource utilization.

Prehospital National Early Warning Score as a predictor of massive transfusion in adult trauma patients

BACKGROUND

Previous studies have shown that an elevated prehospital National Early Warning Score (preNEWS) is associated with increased levels of adverse outcomes in patients with trauma. However, whether preNEWS is a predictor of massive transfusion (MT) in patients with trauma is currently unknown. This study investigated the accuracy of preNEWS in predicting MT and hospital mortality among trauma patients.

METHODS

We analyzed adult trauma patients who were treated and transported by emergency medical services (EMS) between January 2018 and December 2019. The main exposure was the preNEWS calculated for the scene. The primary outcome was the predictive ability for MT, and the secondary outcome was 24 h mortality. We compared the prognostic performance of preNEWS with the shock index, modified shock index, and reverse shock index, and reverse shock index multiplied by Glasgow Coma Scale in the prehospital setting.

RESULTS

In total, 41,852 patients were included, and 1456 (3.5%) received MT. preNEWS showed the highest area under the receiver operating characteristic (AUROC) curve for predicting MT (0.8504; 95% confidence interval [CI], 0.840-0.860) and 24 h mortality (AUROC 0.873; 95% CI, 0.863-0.883). The sensitivity of preNEWS for MT was 0.755, and the specificity of preNEWS for MT was 0.793. All indicies had a high negative predictive value and low positive predictive value.

CONCLUSION

preNEWS is a useful, rapid predictor for MT and 24 h mortality. Calculation of preNEWS would be helpful for making the decision at the scene such as transfer straightforward to trauma center and advanced treatment.

Modification of termination of resuscitation rule with compression time interval in South Korea

This study aimed to validate the predictive performance of the termination of resuscitation (TOR) rule and examine the compression time interval (CTI) as a criterion for modifying the rule. This retrospective observational study analyzed adult out-of-hospital cardiac arrest (OHCA) patients attended by emergency medical service (EMS) providers in mixed urban-rural areas in Korea in 2020 and 2021. We evaluated the predictive performance of basic life support (BLS) and the Korean Cardiac Arrest Research Consortium (KoCARC) TOR rule using the false-positive rate (FPR) and positive predictive value (PPV). We modified the age cutoff criterion and examined the CTI as a new criterion. According to the TOR rule, 1827 OHCA patients were classified into two groups. The predictive performance of the BLS TOR rule had an FPR of 11.7% (95% confidence interval (CI): 5.9-17.5) and PPV of 98.4% (97.6-99.2) for mortality, and an FPR of 3.6% (0.0-7.8) and PPV of 78.6% (75.9-81.3) for poor neurological outcomes at hospital discharge. The predictive performance of the KoCARC TOR rule had an FPR of 5.0% (1.1-8.9) and PPV of 98.9% (98.0-99.8) for mortality, and an FPR of 3.7% (0.0-7.8) and PPV of 50.0% (45.7-54.3) for poor neurological outcomes at hospital discharge. The modified cutoff value for age was 68 years, with an area under the receiver operating characteristic curve over 0.7. In the group that met the BLS TOR rule, the cutoff of the CTI for death was not determined and was 21 min for poor neurological outcomes. In the group that met the KoCARC TOR rule, the cutoff of the CTI for death and poor neurological outcomes at the time of hospital discharge was 25 min and 21 min, respectively. The BLS TOR and KoCARC TOR rules showed inappropriate predictive performance for mortality and poor neurological outcomes. However, the predictive performance of the TOR rule could be supplemented by modifying the age criterion and adding the CTI criterion of the KoCARC.

Comparison of prehospital resuscitation quality during scene evacuation and early ambulance transport in out-of-hospital cardiac arrest between residential location and non-residential location

BACKGROUND

High-quality prehospital cardiopulmonary resuscitation (CPR) is important for out-of-hospital cardiac arrest (OHCA). We aimed to evaluate prehospital CPR quality during scene evacuation and early ambulance transport in patients with OHCA according to the type of cardiac arrest location.

METHODS

This retrospective observational cohort study enrolled patients with non-traumatic adult OHCA in Seoul between July 2020 and March 2022. Prehospital CPR quality data extracted from defibrillators were merged with the national OHCA database. The location of cardiac arrest was categorized into two groups (residential and non-residential). CPR quality indices including no-flow (any pause >1.5 s) fraction were compared according to the type of arrest location at each minute of EMS scene evacuation and early ambulance transport (5 min prior to 5 min after ambulance departure).

RESULTS

A total of 1,222 OHCAs were enrolled in the final analysis after serial exclusion. A total of 966 OHCAs (79.1%) occurred in the residential areas. The CPR quality deteriorated during the scene evacuation in both location type. The mean no-flow fractions were significantly higher in residential places than in non-residential places. The mean proportion of adequate compression depth and rate was lower in cardiac arrests in residential places. The discrepancy in EMS CPR quality during scene evacuation was more prominent when mechanical CPR devices were not used.

CONCLUSION

Deterioration of CPR quality was observed just before and during early ambulance transport, especially when the cardiac arrest location was a residential area or when only manual CPR was provided.

Evaluation of optimal scene time interval for out-of-hospital cardiac arrest using a deep neural network

AIM

This study aims to develop a cardiac arrest prediction model using deep learning (CAPD) algorithm and to validate the developed algorithm by evaluating the change in out-of-hospital cardiac arrest patient prognosis according to the increase in scene time interval (STI).

METHODS

We conducted a retrospective cohort study using smart advanced life support trial data collected by the National Emergency Center from January 2016 to December 2019. The smart advanced life support data were randomly partitioned into derivation and validation datasets. The performance of the CAPD model using the patient's age, sex, event witness, bystander cardiopulmonary resuscitation (CPR), administration of epinephrine, initial shockable rhythm, prehospital defibrillation, provision of advanced life support, response time interval, and STI as prediction variables for prediction of a patient's prognosis was compared with conventional machine learning methods. After fixing other values of the input data, the changes in prognosis of the patient with respect to the increase in STI was observed.

RESULTS

A total of 16,992 patients were included in this study. The area under the receiver operating characteristic curve values for predicting prehospital return of spontaneous circulation (ROSC) and favorable neurological outcomes were 0.828 (95% confidence interval 0.826-0.830) and 0.907 (0.914-0.910), respectively. Our algorithm significantly outperformed other artificial intelligence algorithms and conventional methods. The neurological recovery rate was predicted to decrease to 1/3 of that at the beginning of cardiopulmonary resuscitation when the STI was 28 min, and the prehospital ROSC was predicted to decrease to 1/2 of its initial level when the STI was 30 min.

CONCLUSION

The CAPD exhibits potential and effectiveness in identifying patients with ROSC and favorable neurological outcomes for prehospital resuscitation.

Association between the number of prehospital defibrillation attempts and neurologic outcomes in out-of-hospital cardiac arrest patients without on-scene return of spontaneous circulation

Objective

Delivery of prehospital defibrillation for shockable rhythms by emergency medical service providers is crucial for successful resuscitation in out-of-hospital cardiac arrest (OHCA) patients. The optimal range of prehospital defibrillation attempts for refractory shockable rhythms is unknown. This study evaluated the association between the number of prehospital defibrillation attempts and neurologic outcomes in OHCA patients.

Methods

A retrospective observational study was conducted using the nationwide OHCA registry. Adult OHCA patients who were treated by emergency medical service providers due to presumed cardiac origin with initial shockable rhythm were enrolled from 2013 to 2016. The final analysis was performed on patients without on-scene return of spontaneous circulation. The number of prehospital defibrillation attempts was categorized as follows: 2–3, 4–5, and ≥6 attempts. The primary outcome was a good neurologic recovery at hospital discharge. Multivariate logistic regression analysis was performed to evaluate the association between neurologic outcomes and the number of prehospital defibrillation attempts.

Results

A total of 4,513 patients were included in the final analysis. The numbers of patients for whom 2–3, 4–5, and ≥6 defibrillation attempts were made were 2,720 (60.3%), 1,090 (24.2%), and 703 (15.5%), respectively. Poorer outcomes were associated with ≥6 defibrillation attempts: survival to hospital discharge (adjusted odds ratio, 0.38; 95% confidence interval, 0.21–0.65) and good neurologic recovery (adjusted odds ratio, 0.42; 95% confidence interval, 0.21–0.84).

Conclusion

Six or more prehospital defibrillation attempts were associated with poorer neurologic outcomes in OHCA patients with an initial shockable rhythm who were unresponsive to on-scene defibrillation and resuscitation.

Outcomes of patients with OHCA of presumed cardiac etiology that did not achieve prehospital restoration of spontaneous circulation: The All-Japan Utstein Registry experience

BACKGROUND

Correct identification of futile prehospital resuscitation for out-of-hospital cardiac arrest (OHCA) may reduce unnecessary transports. Prehospital return of spontaneous circulation (ROSC) is considered by many to be an important predictor of outcome. The purpose of this study was to evaluate OHCA victims without prehospital ROSC characteristics and their outcomes in relation to the universal Termination of Resuscitation (TOR) rule.

METHODS

A retrospective, population-based review of OHCA victims without prehospital ROSC from January 1, 2010 to December 31, 2017 in the All-Japan Utstein Registry. We compared those that met the universal TOR rule and those that did not for the primary outcome: one-month survival with neurologically favorable Cerebral Performance Category (CPC) 1 or 2.

RESULTS

989,929 OHCA cases, 18 years of age or older, were registered in the All-Japan Utstein Registry and 525,801 cases were of presumed cardiac origin and had no prehospital ROSC. Of these, the one-month CPC was 1 or 2 for 3957 cases (0.8%). In the 'no ROSC' group who also met the TOR rule, the number of cases was 433,571 with a one-month survival of 0.9% (3799 cases), and the proportion with a CPC 1or 2 was 0.2% (699 cases).

CONCLUSIONS

Continued resuscitation and transport of cases with no field ROSC who fulfill the TOR rule is futile and could be considered for adoption in Japan.

Education, Implementation, and Teams: 2020 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations

For this 2020 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations, the Education, Implementation, and Teams Task Force applied the population, intervention, comparator, outcome, study design, time frame format and performed 15 systematic reviews, applying the Grading of Recommendations, Assessment, Development, and Evaluation guidance. Furthermore, 4 scoping reviews and 7 evidence updates assessed any new evidence to determine if a change in any existing treatment recommendation was required. The topics covered included training for the treatment of opioid overdose; basic life support, including automated external defibrillator training; measuring implementation and performance in communities, and cardiac arrest centers; advanced life support training, including team and leadership training and rapid response teams; measuring cardiopulmonary resuscitation performance, feedback devices, and debriefing; and the use of social media to improve cardiopulmonary resuscitation application.

Education, Implementation, and Teams: 2020 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations

For this 2020 International Consensus on Cardiopulmonary Resuscitation and Emergency Cardiovascular Care Science With Treatment Recommendations, the Education, Implementation, and Teams Task Force applied the population, intervention, comparator, outcome, study design, time frame format and performed 15 systematic reviews, applying the Grading of Recommendations, Assessment, Development, and Evaluation guidance. Furthermore, 4 scoping reviews and 7 evidence updates assessed any new evidence to determine if a change in any existing treatment recommendation was required. The topics covered included training for the treatment of opioid overdose; basic life support, including automated external defibrillator training; measuring implementation and performance in communities, and cardiac arrest centers; advanced life support training, including team and leadership training and rapid response teams; measuring cardiopulmonary resuscitation performance, feedback devices, and debriefing; and the use of social media to improve cardiopulmonary resuscitation application.

Supportive Therapy: Extracorporeal Membrane Oxygenation

Acute high-risk pulmonary embolism (PE) is characterized by life-threatening hemodynamic instability that may lead to refractory cardiac arrest. Recently, extracorporeal membrane oxygenation (ECMO) has been used to provide primary cardiopulmonary support for select high-risk PE patients or before surgical embolectomy. This article reviews the growing body of literature regarding ECMO support of acute high-risk PE.

Diagnostic performance of the basic and advanced life support termination of resuscitation rules: A systematic review and diagnostic meta-analysis

AIM

To minimize termination of resuscitation (TOR) in potential survivors, the desired positive predictive value (PPV) for mortality and specificity of universal TOR-rules are ≥99%. In lack of a quantitative summary of the collective evidence, we performed a diagnostic meta-analysis to provide an overall estimate of the performance of the basic and advanced life support (BLS and ALS) termination rules.

DATA SOURCES

We searched PubMed/EMBASE/Web-of-Science/CINAHL and Cochrane (until September 2019) for studies on either or both TOR-rules in non-traumatic, adult cardiac arrest. PRISMA-DTA-guidelines were followed.

RESULTS

There were 19 studies: 16 reported on the BLS-rule (205.073 patients, TOR-advice in 57%), 11 on the ALS-rule (161.850 patients, TOR-advice in 24%). Pooled specificities were 0.95 (0.89-0.98) and 0.98 (0.95-1.00) respectively, with a PPV of 0.99 (0.99-1.00) and 1.00 (0.99-1.00). Specificities were significantly lower in non-Western than Western regions: 0.84 (0.73-0.92) vs. 0.99 (0.97-0.99), p < 0.001 for the BLS rule. For the ALS-rule, specificities were 0.94 (0.87-0.97) vs. 1.00 (0.99-1.00), p < 0.001. For non-Western regions, 16 (BLS) or 6 (ALS) out of 100 potential survivors met the TOR-criteria. Meta-regression demonstrated decreasing performance in settings with lower rates of in-field shocks.

CONCLUSIONS

Despite an overall high PPV, this meta-analysis highlights a clinically important variation in diagnostic performance of the BLS and ALS TOR-rules. Lower specificity and PPV were seen in non-Western regions, and populations with lower rates of in-field defibrillation. Improved insight in the varying diagnostic performance is highly needed, and local validation of the rules is warranted to prevent in-field termination of potential survivors.

Factors for modifying the termination of resuscitation rule in out-of-hospital cardiac arrest

BACKGROUND

False positive rate (FPR) of the current basic life support (BLS) termination of resuscitation (TOR) rule in out-of-hospital cardiac arrest (OHCA) patients (not witnessed; no return of spontaneous circulation prior to transport; and no shocks were delivered) has been ethically challenging. We validated the current BLS TOR rule with using nationwide Korean Cardiac Arrest Research Consortium (KoCARC) registry and identified the factors for modifying the rules.

METHODS

This prospective, multicenter, registry-based study was performed using the nontraumatic OHCA registry data between October 2015 and June 2017. Independent factors associated with poor neurologic outcome were identified to propose new KoCARC TOR rules by using multivariable analysis. The diagnostic performances of the TOR rules were calculated respectively.

RESULTS

Among 4,360 OHCA patients, 2,801 (64.2%) satisfied all 3 criteria of the BLS TOR rule. The FPR and positive predictive value of the BLS TOR rule were 5.9% and 99.3%. Asystole as initial rhythm and age > 60 years were found as new factors for modifying the TOR rule. New KoCARC TOR rules, combination of asystole and age > 60 years with current TOR rule, showed lower FPR (0.3%-2.1%) and higher positive predictive value (99.7%-99.9%) for predicting poor neurologic outcome at discharge.

CONCLUSIONS

In this recent nationwide cohort, the current BLS TOR rule showed high FPR (5.9%) for predicting poor neurologic outcome. We anticipate that our new KoCARC TOR rules, application of 2 new factors (asystole as initial rhythm and age > 60 years) with BLS TOR rule, could reduce unwarranted death.

The Effect of Transport Time Interval on Neurological Recovery after Out-of-Hospital Cardiac Arrest in Patients without a Prehospital Return of Spontaneous Circulation

BACKGROUND

Longer transport adversely affects outcomes in out-of-hospital cardiac arrest (OHCA) patients who do not return to spontaneous circulation (ROSC). The aim of this study was to determine the association between the transport time interval (TTI) and neurological outcomes in OHCA patients without ROSC.

METHODS

We analyzed adult OHCA patients with presumed cardiac etiology and without prehospital ROSC from 2012 to 2015. The study population was divided into 2 groups according to STI (short STI [1-5 minutes] and long STI [≥ 6 minutes]). The primary exposure was TTI, which was categorized as short (1-5 minutes), intermediate (6-10 minutes), or long (≥ 11 minutes). The primary outcome was a good neurological recovery at discharge. Multiple logistic regression analysis was used in each STI group.

RESULTS

Among 57,822 patients, 23,043 (40%), 20,985 (36%), and 13,794 (24%) were classified as short, intermediate, and long TTI group. A good neurological recovery occurred in 1.0%, 0.6%, and 0.3% of the patients in the short, intermediate and long TTI group, respectively. Among 12,652 patients with short STI, a good neurological recovery occurred in 2.2%, 1.0%, and 0.4% of the patients in the short, intermediate and long TTI group, respectively. Among 45,570 patients with long STI, a good neurological recovery occurred in 0.7%, 0.5%, and 0.3% of the patients in the short, intermediate and long TTI group, respectively. When short TTI was used as a reference, the adjusted odds ratios (AOR) of TTI for good neurological recovery was different between short STI group and long STI group (AOR [95% confidence interval, 0.46 [0.32-0.67] vs. 0.72 [0.59-0.89], respectively, for intermediate TTI and 0.31 [0.17-0.55] vs. 0.49 [0.37-0.65], respectively, for long TTI).

CONCLUSION

A longer TTI adversely affected the likelihood of a good neurological recovery in OHCA patients without prehospital ROSC. This negative effect was more prominent in short STI group.

Effect of typhoons on the Korean national emergency medical service system

Objective

While the effect of typhoons on emergency medicine has been evaluated, data are scarce on their effects on the emergency medical service (EMS). This study evaluated the effect of typhoons on EMS patients and performance.

Methods

The study period was January 2010 to December 2012. Meteorological data regarding typhoons were provided by the Korean Meteorological Administration. EMS data were retrieved from the EMS database of the national emergency management agency. The database includes ambulance run sheets, which contain clinical and operational data. In this case-crossover study, the cases and controls were EMS calls on the day of typhoon warnings and calls one week prior to the typhoon warnings, respectively.

Results

During the study period, 11 typhoons affected Korea. A total of 14,521 cases were selected for analysis. Overall, there were no obvious differences between the case and control groups. However, there were statistically significant differences in age, place, and time requests. There were fewer patients between 0 and 15 years of age (P=0.01) and more unconscious patients (P=0.01) in the case group. The EMS operational performance, as measured by the times elapsed between call to start, call to field, and call to hospital did not differ significantly. There was also no significant difference in the time from hospital arrival between the cases (28.67, standard deviation 16.37) and controls (28.97, standard deviation 28.91) (P=0.39).

Conclusion

Typhoons did not significantly affect the EMS system in this study. Further study is necessary to understand the reasons for this finding.

Association of the Emergency Medical Services-Related Time Interval with Survival Outcomes of Out-of-Hospital Cardiac Arrest Cases in Four Asian Metropolitan Cities Using the Scoop-and-Run Emergency Medical Services Model

BACKGROUND

Response time interval (RTI) and scene time interval (STI) are key time variables in the out-of-hospital cardiac arrest (OHCA) cases treated and transported via emergency medical services (EMS).

OBJECTIVE

We evaluated distribution and interactive association of RTI and STI with survival outcomes of OHCA in four Asian metropolitan cities.

METHODS

An OHCA cohort from Pan-Asian Resuscitation Outcome Study (PAROS) conducted between January 2009 and December 2011 was analyzed. Adult EMS-treated cardiac arrests with presumed cardiac origin were included. A multivariable logistic regression model with an interaction term was used to evaluate the effect of STI according to different RTI categories on survival outcomes. Risk-adjusted predicted rates of survival outcomes were calculated and compared with observed rate.

RESULTS

A total of 16,974 OHCA cases were analyzed after serial exclusion. Median RTI was 6.0 min (interquartile range [IQR] 5.0-8.0 min) and median STI was 12.0 min (IQR 8.0-16.1). The prolonged STI in the longest RTI group was associated with a lower rate of survival to discharge or of survival 30 days after arrest (adjusted odds ratio [aOR] 0.59; 95% confidence interval [CI] 0.42-0.81), as well as a poorer neurologic outcome (aOR 0.63; 95% CI 0.41-0.97) without an increasing chance of prehospital return of spontaneous circulation (aOR 1.12; 95% CI 0.88-1.45).

CONCLUSIONS

Prolonged STI in OHCA with a delayed response time had a negative association with survival outcomes in four Asian metropolitan cities using the scoop-and-run EMS model. Establishing an optimal STI based on the response time could be considered.

Initial blood pH during cardiopulmonary resuscitation in out-of-hospital cardiac arrest patients: a multicenter observational registry-based study

BACKGROUND

When an out-of-hospital cardiac arrest (OHCA) patient receives cardiopulmonary resuscitation (CPR) in the emergency department (ED), blood laboratory test results can be obtained by using point-of-care testing during CPR. In the present study, the relationship between blood laboratory test results during CPR and outcomes of OHCA patients was investigated.

METHODS

This study was a multicenter retrospective analysis of prospective registered data that included 2716 OHCA patients. Data from the EDs of three university hospitals in different areas were collected from January 2009 to December 2014. Univariate and multivariable analyses were conducted to elucidate the factors associated with survival to discharge and neurological outcomes. A final analysis was conducted by including patients who had no prehospital return of spontaneous circulation and those who underwent rapid blood laboratory examination during CPR.

RESULTS

Overall, 2229 OHCA patients were included in the final analysis. Among them, the rate of survival to discharge and a good Cerebral Performance Categories Scale score were 14% and 4.4%, respectively. The pH level was independently related to survival to hospital discharge (adjusted OR 6.287, 95% CI 2.601-15.197; p < 0.001) and good neurological recovery (adjusted OR 15.395, 95% CI 3.439-68.911; p < 0.001). None of the neurologically intact patients had low pH levels (< 6.8) or excessive potassium levels (> 8.5 mEq/L) during CPR.

CONCLUSIONS

Among the blood laboratory test results during CPR of OHCA patients, pH and potassium levels were observed as independent factors associated with survival to hospital discharge, and pH level was considered as an independent factor related to neurological recovery.

Significance of blood pH value and automated external defibrillator shock in determining the outcomes of out-of-hospital cardiac arrest patients

Background:

The prognosis of out-of-hospital cardiac arrest is generally poor. It is known that the survival of out-of-hospital cardiac arrest patients depends on treatments delivered in a very short time frame. Identifying outcome-associated factors may provide valuable information for decision-making in clinical practices.

Aim:

The objective of the present study was to assess the associations between various factors (e.g. serum biomarker levels and prehospital factors) and outcomes in adult, non-traumatic out-of-hospital cardiac arrest patients.

Methods:

Data from 386 consecutive out-of-hospital cardiac arrest patients treated from January 2012 to December 2015 at Taoyuan Chang Gung Memorial Hospital (Taiwan, ROC) were collected. While performing cardiopulmonary resuscitation in the emergency room, the levels of creatinine, aspartate aminotransferase, sodium, potassium, troponin-I, hydrogen bicarbonate and haemoglobin were determined, blood pH and pCO2 were measured and the white blood cell count was calculated. The response time and scene time interval were also recorded.

Results:

Here we found that out-of-hospital cardiac arrest patients with blood pH values of <7.34 had a lower chance of survival to 24 h (Odds Ratio (OR) = 2.77), survival to discharge (OR = 7.06) and a good neurological outcome (OR = 64.59). Moreover, patients without an automated external defibrillator shock had a lower chance of being discharged (OR = 4.27) and enjoying good neurological outcomes (OR = 25.09).

Conclusion:

Our data suggest that the blood pH and an automated external defibrillator shockable rhythm are two easily measurable factors strongly associated with the outcomes of out-of-hospital cardiac arrest patients.

Neurological Favorable Outcomes Associated with EMS Compliance and On-Scene Resuscitation Time Protocol

PURPOSE

Korean national emergency care protocol for EMS providers recommends a minimum of 5 minutes of on-scene resuscitation before transport to hospital in cases of Out-of-Hospital Cardiac Arrest (OHCA). We compared survival outcome of OHCA patients according to scene time interval (STI)-protocol compliance of EMS.

METHODS

EMS treated adult OHCAs with presumed cardiac etiology during a two-year period were analyzed. Non-compliance was defined as hospital transport with STI less than 6 minutes without return of spontaneous circulation (ROSC) on scene. Propensity score for compliance with protocol was calculated and based on the calculated propensity score, 1:1 matching was performed between compliance and non-compliance group. Univariate analysis as well as multivariable logistic model was used to evaluate the effect of compliance to survival outcome.

RESULTS

Among a total of 28,100 OHCAs, EMS transported 7,026 (25.0%) cardiac arrests without ROSC on the scene with an STI less than 6 minutes. A total of 6,854 cases in each group were matched using propensity score matching. Overall survival to discharge rate did not differ in both groups (4.6% for compliance group vs. 4.5 for non-compliance group, p = 0.78). Adjusted odds ratio of compliance for survival to discharge were 1.12 (95% CI 0.92-1.36). More patients with favorable neurological outcome was shown in compliance group (2.5% vs. 1.7%, p < 0.01) and adjusted odds ratio was 1.91 (95% CI 1.42-2.59).

CONCLUSIONS

Although survival to discharge rate did not differ for patient with EMS non-compliance with STI protocol, lesser patients survived with favorable neurological outcomes when EMS did not stay for sufficient time on scene in OHCA before transport.

An Ethical Justification for Termination of Resuscitation Protocols for Pediatric Patients

OBJECTIVE

The aim of this article was to compare specific characteristics and outcomes among adult and pediatric out-of-hospital cardiac arrest (OHCA) patients to show that the existing literature warrants the design and implementation of pediatric studies that would specifically evaluate termination of resuscitation protocols. We also address the emotional and practical concerns associated with ceasing resuscitation efforts on scene when treating pediatric patients.

METHODS

Relevant prospective and retrospective studies were used to compare characteristics and outcomes between adult and pediatric OHCA patients. Characteristics analyzed were nonwitnessed arrests, absence of shockable rhythm, no return of spontaneous circulation, and survival to hospital discharge.

RESULTS

Cases of unwitnessed arrests by emergency medical services providers are substantially the same in pediatric patients (41.0%-96.3%) compared with their adult counterparts (47.4%-97.7%). The adult studies revealed 57.6% to 92.2% of patients without an initial shockable rhythm. The pediatric studies showed a range of 64.0% to 98.0%. The range of adult patients without return of spontaneous circulation was 54.8% to 95.4%, and the range in pediatric patients was 68.2% to 95.6%. Survival rates among the adult studies ranged from 0.8% to 9.3% (mean, 5.0%; median, 5.2%), and in the pediatric studies they were 2.0% to 26.2% (mean, 9.2%; median, 7.7%).

CONCLUSIONS

The data compared demonstrate that characteristics and outcomes are virtually identical between adult and pediatric OHCA patients. We also found the 3 chief barriers hindering further research to be invalid impediments to moving forward. This review warrants designing pediatric studies that would specifically correlate termination of resuscitation protocols with patient survival and include predictive values.

Features of hospital and emergency medical service in out-of-hospital cardiac arrest patients with shockable rhythm

OBJECTIVE

Predicting the outcome of out-of-hospital cardiac arrest (OHCA) patients is crucial. We examined hospital characteristics and parameters of emergency medical service (including scene time interval and direct ambulance delivery to intensive heart hospitals) as survival or outcome predictors.

STUDY DESIGN

Data from 546 consecutive OHCA shockable patients treated between January 2012 and December 2015 in Taoyuan City (Taiwan, ROC) were collected. In addition to demographic data, location of arrest, initial rhythm, availability of a hospital with or without 24/7 percutaneous coronary intervention (PCI), emergency medical service (EMS) time, provision of cardiopulmonary resuscitation by a bystander, presence of a witness at collapse, and level of life support were analysed.

RESULTS

Multivariate analysis showed that hospitalisation with immediate PCI availability was an independent predictor (OR: 4.32; 95% CI: 1.27-14.70) solely for the outcome of survival until discharge. The presence of a witness while collapsing (OR: 3.52; 95% CI: 1.03-11.98), EMS response time (OR: 0.83; 95% CI: 0.70-0.98), and scene time interval (STI; OR: 0.89; 95% CI: 0.81-0.99) were valuable for predicting the neurological outcome.

CONCLUSIONS

Direct ambulance delivery to intensive heart hospitals that had 24/7 PCI availability was associated with a higher probability of surviving until discharge in OHCA patients with shockable rhythms. Similarly, a witnessed collapse was correlated with being discharged alive from hospital and recovering with good cerebral performance. In addition, longer response time and scene time interval indicated poorer survival and neurological outcome.

Adult "termination-of-resuscitation" (TOR)-criteria may not be suitable for children - a retrospective analysis

Background

Only a small number of patients survive out-of-hospital-cardiac-arrest (OHCA). The duration of CPR varies considerably and transportation of patients under CPR is often unsuccessful. Termination-of-resuscitation (TOR)-criteria aim to preclude futile resuscitation efforts.

Our goal was to find out to which extent existing TOR-criteria can be transferred to paediatric OHCA-patients with special regard to their prognostic value.

Methods

We performed a retrospective analysis of an eleven-year single centre patient cohort. 43 paediatric patients admitted to our institution after emergency-medical-system (EMS)-confirmed OHCA from 2003 to 2013 were included. Morrison’s BLS- and ALS-TOR-rules as well as the Trauma-TOR-criteria by the American Association of EMS Physicians were evaluated for application in children, by calculating sensitivity, specificity, negative and positive predictive value for death-, as well as survival-prediction in our cohort.

Results

26 patients achieved ROSC and 14 were discharged alive (n = 7 PCPC 1/2, n = 7 PCPC 5). Sensitivity for BLS-TOR-criteria predicting death was 48.3%, specificity 92.9%, the PPV 93.3% and the NPV 46.4%. ALS-TOR-criteria for death had a sensitivity of 10.3%, specificity of 100%, a PPV of 100% and an NPV of 35%.

Conclusion

Retrospective application of the BLS-TOR-rule in our patient cohort identified the resuscitation of one later survivor as futile. ALS-TOR-criteria did not give false predictions of death. The proportion of CPRs that could have been abandoned is 48.2% for the BLS-TOR and only 10.3% for the ALS-TOR-rule. Both rules therefore appear not to be transferable to a paediatric population.

Termination of resuscitation in the prehospital setting: A comparison of decisions in clinical practice vs. recommendations of a termination rule

BACKGROUND

Of the proposed algorithms that provide guidance for in-field termination of resuscitation (TOR) decisions, the guidelines for cardiopulmonary resuscitation (CPR) refer to the basic and advanced life support (ALS)-TOR rules. To assess the potential consequences of implementation of the ALS-TOR rule, we performed a case-by-case evaluation of our in-field termination decisions and assessed the corresponding recommendations of the ALS-TOR rule.

METHODS

Cohort of non-traumatic out-of-hospital cardiac arrest (OHCA)-patients who were resuscitated by the ALS-practising emergency medical service (EMS) in the Nijmegen area (2008-2011). The ALS-TOR rule recommends termination in case all following criteria are met: unwitnessed arrest, no bystander CPR, no shock delivery, no return of spontaneous circulation (ROSC).

RESULTS

Of the 598 cases reviewed, resuscitative efforts were terminated in the field in 46% and 15% survived to discharge. The ALS-TOR rule would have recommended in-field termination in only 6% of patients, due to high percentages of witnessed arrests (73%) and bystander CPR (54%). In current practice, absence of ROSC was the most important determinant of termination [aOR 35.6 (95% CI 18.3-69.3)]. Weaker associations were found for: unwitnessed and non-public arrests, non-shockable initial rhythms and longer EMS-response times.

CONCLUSION

While designed to optimise hospital transportations, application of the ALS-TOR rule would almost double our hospital transportation rate to over 90% of OHCA-cases due to the favourable arrest circumstances in our region. Prior to implementation of the ALS-TOR rule, local evaluation of the potential consequences for the efficiency of triage is to be recommended and initiatives to improve field-triage for ALS-based EMS-systems are eagerly awaited.

For how long can two emergency medical technicians perform high-quality cardiopulmonary resuscitation?

OBJECTIVE

To determine the duration and obstacles to prolonged on-scene cardiopulmonary resuscitation (CPR), and establish how long a pair of emergency medical technicians (EMTs) can provide high-quality CPR.

METHOD

Intermediate-level EMTs in Gyeonggi-do Province, Republic of Korea completed a survey regarding on-scene CPR. EMTs undergoing routine training took part in a simulation using mannequins. Parameters including compression depth, total number and rate of compressions; occurrence of incorrect hand position and incomplete chest recoil were collected over 16 2-min cycles of CPR (32 min total), with EMTs working in pairs.

RESULT

The simulation study included 43 EMTs. The median duration of on-scene CPR was 3.7 min. Fear of decrease in performance was the main obstacle to continued CPR (n = 188/254 [74.0%]). Standards for high-quality CPR were met at each of the 16 steps of the simulation. Compression rate increased significantly with time. There were no significant changes in any other parameter.

CONCLUSION

Pairs of EMTs maintained high-quality CPR for 16 cycles (32 min) with no decrease in performance. Our findings could provide evidence to recommend guidelines for duration of on-scene CPR for cardiac arrest, particularly in countries where the level and number of ambulance crews are limited.

Presumed Regional Incidence Rate of Out-of-Hospital Cardiac Arrest in Korea

The regional incidence rates of out-of-hospital cardiac arrest (OHCA) were traditionally calculated with the residential population as the denominator. The aim of this study was to estimate the true incidence rate of OHCA and to investigate characteristics of regions with overestimated and underestimated OHCA incidence rates. We used the national OHCA database from 2006 to 2010. The nighttime residential and daytime transient populations were investigated from the 2010 Census. The daytime population was calculated by adding the daytime influx of population to, and subtracting the daytime outflow from, the nighttime residential population. Conventional age-standardized incidence rates (CASRs) and daytime corrected age-standardized incidence rates (DASRs) for OHCA per 100,000 person-years were calculated in each county. A total of 97,291 OHCAs were eligible. The age-standardized incidence rates of OHCAs per 100,000 person-years were 34.6 (95% CI: 34.3-35.0) in the daytime and 24.8 (95% CI: 24.5-25.1) in the nighttime among males, and 14.9 (95% CI: 14.7-15.1) in the daytime, and 10.4 (95% CI: 10.2-10.6) in the nighttime among females. The difference between the CASR and DASR ranged from 35.4 to -11.6 in males and from 6.1 to -1.0 in females. Through the Bland-Altman plot analysis, we found the difference between the CASR and DASR increased as the average CASR and DASR increased as well as with the larger daytime transient population. The conventional incidence rate was overestimated in counties with many OHCA cases and in metropolitan cities with large daytime population influx and nighttime outflow, while it was underestimated in residential counties around metropolitan cities.