Moderating effects of out-of-hospital cardiac arrest characteristics on the association between EMS response time and survival

Increasing cost-effectiveness of AEDs using algorithms to optimise location

OBJECTIVES

Volunteer responder systems (VRSs) aim to decrease time to defibrillation by dispatching trained volunteers to automated external defibrillators (AEDs) and out-of-hospital cardiac arrest (OHCA) victims. AEDs are often underutilized due to poor placement. This study provides a cost-effectiveness analysis of adding AEDs at strategic locations to maximize quality-adjusted life years (QALYs).

METHODS

We simulated combined volunteer, police, firefighter, and emergency medical service response scenarios to OHCAs, and applied our methods to a case study of Amsterdam, the Netherlands. We compared the competing strategies of placing additional AEDs, using steps of 40 extra AEDs (0, 40, …, 1480), in addition to the existing 369 AEDs. Incremental cost-effectiveness ratios (ICERs) were calculated for each increase in additional AEDs, from a societal perspective. The effect of AED connection and time to connection on survival to hospital admission and neurological outcome at discharge was estimated using logistic regression, using OHCA data from Amsterdam from 2006 to 2018. Other model inputs were obtained from literature.

RESULTS

Purchasing up to 1120 additional AEDs (ICER €75,669/QALY) was cost-effective at a willingness-to-pay threshold of €80,000/QALY, when positioned strategically. Compared to current practice, adding 1120 AEDs resulted in a gain of 0.111 QALYs (95% CI 0.110-0.112) at an increased cost of €3792 per OHCA (95% CI €3778-€3807). Health benefits per AED diminished as more AEDs were added.

CONCLUSIONS

Our study identified cost-effective strategies to position AEDs at strategic locations in a VRS. The case study findings advocate for a substantial increase in the number of AEDs in Amsterdam.

Does Single Dose Epinephrine Improve Outcomes for Patients with Out-of-Hospital Cardiac Arrest and Bystander CPR or a Shockable Rhythm?

BACKGROUND

A single dose epinephrine protocol (SDEP) for out-of-hospital cardiac arrest (OHCA) achieves similar survival to hospital discharge (SHD) rates as a multidose epinephrine protocol (MDEP). However, it is unknown if a SDEP improves SHD rates among patients with a shockable rhythm or those receiving bystander cardiopulmonary resuscitation (CPR).

METHODS

This pre-post study, spanning 11/01/2016-10/29/2019 at 5 North Carolina EMS systems, compared pre-implementation MDEP and post-implementation SDEP in patients ≥18 years old with non-traumatic OHCA. Data on initial rhythm type, performance of bystander CPR, and the primary outcome of SHD were sourced from the Cardiac Arrest Registry to Enhance Survival. We compared SDEP vs MDEP performance in each rhythm (shockable and non-shockable) and CPR (bystander CPR or no bystander CPR) subgroup using Generalized Estimating Equations to account for clustering among EMS systems and to adjust for age, sex, race, witnessed arrest, arrest location, AED availability, EMS response interval, and presence of a shockable rhythm or receiving bystander CPR. The interaction of SDEP implementation with rhythm type and bystander CPR was evaluated.

RESULTS

Of 1690 patients accrued (899 MDEP, 791 SDEP), 19.2% (324/1690) had shockable rhythms and 38.9% (658/1690) received bystander CPR. After adjusting for confounders, SHD was increased after SDEP implementation among patients with bystander CPR (aOR 1.61, 95%CI 1.03-2.53). However, SHD was similar in the SDEP cohort vs MDEP cohort among patients without bystander CPR (aOR 0.81, 95%CI 0.60-1.09), with a shockable rhythm (aOR 0.96, 95%CI 0.48-1.91), and with a non-shockable rhythm (aOR 1.26, 95%CI 0.89-1.77). In the adjusted model, the interaction between SDEP implementation and bystander CPR was significant for SHD (p = 0.002).

CONCLUSION

Adjusting for confounders, the SDEP increased SHD in patients who received bystander CPR and there was a significant interaction between SDEP and bystander CPR. Single dose epinephrine protocol and MDEP had similar SHD rates regardless of rhythm type.

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

INTRODUCTION

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

OBJECTIVES

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

METHODS

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

RESULTS

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

CONCLUSION

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

Implementation and use of a supraglottic airway device in the management of out-of-hospital cardiac arrest by firefighter first responders - A prospective feasibility study

Aim

We wanted to assess the implementation and use of a supraglottic airway (SGA) for on-call firefighter first responders in out-of-hospital cardiac arrest.

Methods

We trained 502 firefighter first responders, located at 35 fire stations in the South-East of Norway, in the use of SGA during cardiopulmonary resuscitation in adult out-of-hospital cardiac arrest. Training consisted of 45 minutes of theoretical and practical training in small groups.Primary outcome was successful ventilation with SGA assessed by both firefighter first responders and first paramedic arriving on-scene. Secondary outcomes included time expenditure and complications related to the procedure, evaluation of the training, and descriptive characteristics of the out-of-hospital cardiac arrest cases.

Results

An SGA was used by firefighter first responders in 23 out-of-hospital cardiac arrests, and successful ventilation was achieved in 20 (87%) cases. Air-leak was described in the three unsuccessful cases. The median procedural time was 30 seconds (IQR = 15-40), with no observed procedural complications. Firefighter first responders arrived in median time 9 minutes (IQR = 6-10 min) before the ambulance. They performed chest compressions on all patients and 6 (26%) of the patients received shock with semi-automatic external defibrillator. After training, all participants were able to successfully ventilate a manikin with the SGA. The cost of the SGA equipment for all fire stations was 3955 GBP.

Conclusion

Implementation of an SGA for firefighter first responders in out-of-hospital cardiac arrest management seems feasible, safe and can be introduced with limited amount of training and limited use of resources.

Improving EMS response times for out-of-hospital cardiac arrest in urban areas using drone-like vertical take-off and landing air ambulances: An international, simulation-based cohort study

BACKGROUND

Advances in vertical take-off and landing (VTOL) technologies may enable drone-like crewed air ambulances to rapidly respond to out-of-hospital cardiac arrest (OHCA) in urban areas. We estimated the impact of incorporating VTOL air ambulances on OHCA response intervals in two large urban centres in France and Canada.

METHODS

We included adult OHCAs occurring between Jan. 2017-Dec. 2018 within Greater Paris in France and Metro Vancouver in Canada. Both regions utilize tiered OHCA response with basic (BLS)- and advanced life support (ALS)-capable units. We simulated incorporating 1-2 ALS-capable VTOL air ambulances dedicated to OHCA response in each study region, and computed time intervals from call reception by emergency medical services (EMS) to arrival of the: (1) first ALS unit ("call-to-ALS arrival interval"); and (2) first EMS unit ("call-to-first EMS arrival interval").

RESULTS

There were 6,217 OHCAs included during the study period (3,760 in Greater Paris and 2,457 in Metro Vancouver). Historical median call-to-ALS arrival intervals were 21 min [IQR 16-29] in Greater Paris and 12 min [IQR 9-17] in Metro Vancouver, while median call-to-first EMS arrival intervals were 11 min [IQR 8-14] and 7 min [IQR 5-8] respectively. Incorporating 1-2 VTOL air ambulances improved median call-to-ALS arrival intervals to 7-9 min and call-to-first EMS arrival intervals to 6-8 min in both study regions (all P < 0.001).

CONCLUSION

VTOL air ambulances dedicated to OHCA response may improve EMS response intervals, with substantial improvements in ALS response metrics.

Bystander cardiopulmonary resuscitation, automated external defibrillator use, and survival after out-of-hospital cardiac arrest

INTRODUCTION

We aimed to investigate the association between bystander cardiopulmonary resuscitation (CPR) with and without automated external defibrillator (AED) use and neurological outcomes after out-of-hospital cardiac arrest (OHCA) in Korea.

METHODS

This cross-sectional study used a nationwide Korean OHCA registry between 2015 and 2019. Patients were categorised into no bystander CPR and bystander CPR with and without AED use groups. The primary outcome was good neurological recovery at discharge. We also analysed the interaction effects of place of arrest, response time, and whether the OHCA was witnessed.

RESULTS

In total, 93,623 patients were included. Among them, 35,486 (37.9%) were in the no bystander CPR group, 56,187 (60.0%) were in the bystander CPR without AED use group, and 1950 (2.1%) were in the bystander CPR with AED use group. Good neurological recovery was demonstrated in 1286 (3.6%), 3877 (6.9%), and 208 (10.7%) patients in the no CPR, bystander CPR without AED use, and bystander CPR with AED use groups, respectively. Compared to the no bystander CPR group, the adjusted odds ratio (95% confidence intervals) for good neurological recovery was 1.54 (1.45-1.65) and 1.37 (1.15-1.63) in the bystander CPR without and with AED use groups, respectively. The effect of bystander CPR with AED use was more apparent in OHCAs with witnessed arrest and prolonged response time (≥8 min).

CONCLUSION

Bystander CPR was associated with better neurological recovery compared to no bystander CPR; however, the benefits of AED use were not significant. Efforts to disseminate bystander AED availability and ensure proper utilisation are warranted.

Clinical outcomes following out-of-hospital cardiac arrest: The minute-by-minute impact of bystander cardiopulmonary resuscitation

AIMS

The time-dependent prognostic role of bystander cardiopulmonary resuscitation (CPR) for out-of-hospital cardiac arrest (OHCA) patients has not been described with great precision, especially for neurologic outcomes. Our objective was to assess the association between bystander CPR, emergency medical service (EMS) response time, and OHCA patients' outcomes.

METHODS

This cohort study used the Resuscitation Outcomes Consortium Cardiac Epidemiologic Registries. Bystander-witnessed adult OHCA treated by EMS were included. The primary outcome was survival to hospital discharge and secondary outcome was survival with a good neurologic outcome (modified Rankin scale 0-2). Multivariable logistic regression models were used to assess the associations and interactions between bystander CPR, EMS response time and clinical outcomes.

RESULTS

Out of 229,637 patients, 41,012 were included (18,867 [46.0%] without bystander CPR and 22,145 [54.0%] with bystander CPR). Bystander CPR was independently associated with higher survival (adjusted odds ratio [AOR] = 1.70 [95%CI 1.61-1.80]) and survival with a good neurologic outcome (AOR = 1.87 [95%CI 1.70-2.06]), while longer EMS response times were independently associated with lower survival to hospital discharge (each additional minute of EMS response time: AOR = 0.92 [95%CI 0.91-0.93], p < 0.001) and lower survival with a good neurologic outcome (AOR = 0.88 [95%CI 0.86-0.89], p < 0.001). There was no interaction between bystander CPR and EMS response time's association with survival (p = 0.12) and neurologic outcomes (p = 0.65).

CONCLUSIONS

Although bystander CPR is associated with an immediate increase in odds of survival and of good neurologic outcome for OHCA patients, it does not influence the negative association between longer EMS response time and survival and good neurologic outcome.

Impact of the coronavirus disease 2019 (COVID-19) pandemic on the operational efficiency of emergency medical services and its association with out-of-hospital cardiac arrest survival rates: A population-based cohort study in Kobe, Japan

Aim

To identify whether the coronavirus disease 2019 (COVID-19) pandemic affects the operational efficiency of emergency medical services (EMS) and the survival rate of out-of-hospital cardiac arrest (OHCA) in prehospital settings.

Methods

We conducted a population-based cohort study in Kobe, Japan, between March 1, 2020, and September 31, 2022. In study 1, the operational efficiency of EMS, such as the total out-of-service time for ambulances, the daily occupancy rate of EMS, and response time, was compared between the pandemic and nonpandemic periods. In study 2, the impacts of the changes in EMS operational efficiency were investigated among patients with OHCA, with 1-month survival as the primary outcome and return of spontaneous circulation, 24-h survival, 1-week survival, and favorable neurological outcomes as the secondary outcomes. Logistic regression analysis was conducted to identify the factors associated with survival among patients with OHCA.

Results

The total out-of-service time, occupancy rate, and response time significantly increased during the pandemic period (p < 0.001). The response time during the pandemic period increased significantly per pandemic wave. Regarding OHCA outcomes, 1-month survival rates during the pandemic period significantly decreased compared with those during the nonpandemic period (pandemic 3.7% vs. nonpandemic 5.7%; p < 0.01). Similarly, 24-h survival (9.9% vs. 12.8%), and favorable neurological outcomes significantly decreased during the pandemic period. In the logistic regression analysis, response time was associated with lower OHCA survival in all outcomes (p < 0.05).

Conclusion

The COVID-19 pandemic has been associated with reduced operational efficiency of EMS and decreased OHCA survival rates. Further research is required to improve the efficiency of EMS and OHCA survival rates.

One and Done Epinephrine in Out-of-Hospital Cardiac Arrest? Outcomes in a Multiagency United States Study

BACKGROUND

Cardiac arrest guidelines recommend epinephrine every 3-5 minutes during cardiac arrest resuscitation. However, it is unclear if multiple epinephrine doses are associated with improved outcomes. The objective of this study was to determine if a single-dose epinephrine protocol was associated with improved survival compared to traditional multidose protocols.

METHODS

We conducted a pre-post study across five North Carolina EMS agencies from 11/1/2016 to 10/29/2019. Patients ≥18 years old with attempted resuscitation for non-traumatic prehospital cardiac arrest were included. Data were collected 1 year before and after implementation of the single-dose epinephrine protocol. Prior to implementation, all agencies used a multidose epinephrine protocol. The Cardiac Arrest Registry to Enhance Survival (CARES) was used to obtain patient outcomes. Study outcomes were survival to hospital discharge (primary) and return of spontaneous circulation (ROSC). Analysis was by intention to treat. Outcomes were compared pre- vs. post-implementation using generalized estimating equations to account for clustering within EMS agencies. Adjusted analyses included age, sex, race, shockable vs. non-shockable rhythm, witnessed arrest, automatic external defibrillator availability, EMS response interval, and bystander cardiopulmonary resuscitation.

RESULTS

During the study period there were 1,690 encounters (899 pre- and 791 post-implementation). The population was 74.7% white, 61.1% male, and had a median age of 65 (IQR 53-76) years. Survival to hospital discharge was similar pre- vs. post-implementation [13.6% (122/899) vs. 15.4% (122/791); OR 1.19, 95%CI 0.89-1.59]. However, ROSC was more common post-implementation [42.3% (380/899) vs. 32.5% (257/791); OR 0.66, 95%CI 0.54-0.81]. After adjusting for covariates, the single-dose protocol was associated with similar survival to discharge rates (aOR 0.88, 95%CI 0.77-1.29), but with decreased ROSC rates (aOR 0.58, 95%CI 0.47-0.72).

CONCLUSION

A prehospital single-dose epinephrine protocol was associated with similar survival to hospital discharge, but decreased ROSC rates compared to the traditional multidose epinephrine protocol.

Application of Automated External Defibrillators in Motorcycle Ambulances in Thailand’s Emergency Medical Services

Background

Access time to emergency patients is a critical factor that affects the outcomes of life-or-death situations, especially in the cases of out-of-hospital cardiac arrests (OHCA). This study focused on developing a new model of emergency medical services (EMS) using a motorcycle-based ambulance (motorlance) with an automated external defibrillator (AED). There are currently no studies regarding access time for this vehicle. This study aimed at utilization of an AED in conjunction with motorlance and comparing the response time between a traditional ambulance and a motorlance.

Methods

This was a prospective study conducted in the EMS department of Srinagarind Hospital, located in Khon Kaen, Thailand, over a five-month period, from September 2021 to January 2022. Data were recorded employing a national standard of operations record form used for Thailand EMS departments nationwide.

Results

The 891 cases were divided into two groups which were motorlance and ambulance. The activation times for motorlance and ambulance were 0.44 minutes and 1.42 minutes, respectively (p < 0.001) and the response time in the motorlance group was 7.20 minutes compared with 9.25 minutes in the ambulance group. In OHCA, the motorlance with AED arrived at patients location and assisted to continue resuscitation at the hospital 88.9% of the time.

Conclusion

AED used in conjunction with motorcycle ambulances had shorter periods of both activation time and response time compared to ambulances. The use of AEDs clearly increases the number of continuous resuscitations in out-of-hospital cardiac arrest patients.

The epidemiology of out-of-hospital cardiac arrest in Australia and New Zealand: A binational report from the Australasian Resuscitation Outcomes Consortium (Aus-ROC)

INTRODUCTION

The Australasian Resuscitation Outcomes Consortium (Aus-ROC) out-of-hospital cardiac arrest (OHCA) Epistry (Epidemiological Registry) now covers 100% of Australia and New Zealand (NZ). This study reports and compares the Utstein demographics, arrest characteristics and outcomes of OHCA patients across our region.

METHODS

We included all OHCA cases throughout 2019 as submitted to the Epistry by the eight Australian and two NZ emergency medical services (EMS). We calculated crude and age-standardised incidence rates and performed a national and EMS regional comparison.

RESULTS

We obtained data for 31,778 OHCA cases for 2019: 26,637 in Australia and 5,141 in NZ. Crude incidence was 107.9 per 100,000 person-years in Australia and 103.2/100,000 in NZ. Overall, the majority of OHCAs occurred in adults (96%), males (66%), private residences (76%), were unwitnessed (63%), of presumed medical aetiology (83%), and had an initial monitored rhythm of asystole (64%). In non-EMS-witnessed cases, 38% received bystander CPR and 2% received public defibrillation. Wide variation was seen between EMS regions for all OHCA demographics, arrest characteristics and outcomes. In patients who received an EMS-attempted resuscitation (13,664/31,778): 28% (range across EMS=13.1% to 36.7%) had return of spontaneous circulation (ROSC) at hospital arrival and 13% (range across EMS=9.9% to 20.7%) survived to hospital discharge/30-days. Survival in the Utstein comparator group (bystander-witnessed in shockable rhythm) varied across the EMS regions between 27.4% to 42.0%.

CONCLUSION

OHCA across Australia and NZ has varied incidence, characteristics and survival. Understanding the variation in survival and modifiable predictors is key to informing strategies to improve outcomes.