The eight-minute defibrillation response interval debunked: or is it?

Out-of-hospital cardiac arrest in Bahrain: National retrospective cohort study

Aim

There is limited research on Out-of-hospital cardiac arrest (OHCA) in the Gulf Cooperation Council (GCC) and especially in Bahrain. This is the first study to describe the incidence, characteristics, and outcomes of OHCA in Bahrain.

Methods

This was a retrospective national observational study on OHCA patients in Bahrain using the Utstein framework for resuscitation. Data was collected between 1st July 2022 to 30th June 2023 from the electronic medical records of the only three governmental hospitals emergency departments (EDs) and National Ambulance (NA).

Results

The annual incidence of OHCA attended by (Emergency Medical Services) EMS was nearly 21 per 100,000 population. The majority were males (n = 228, 68.8 %) with median age of 65 years (IQR=49-78). Most OHCA cases were witnessed (n = 265, 81 %), with (n = 247, 76 %) happened at home/residence. Rates for bystander CPR was low (n = 122, 36.8 %) and bystander automated external defibrillator (AED) was not performed in any of the cases. The OHCA cases transported by the NA was (n = 314, 94.8 %), with median response time of 9 min (IQR=7-12). However, only (n = 20, 6.0 %) were witnessed by EMS, and (n = 7, 2.1 %) received EMS defibrillation for shockable rhythms. First monitored rhythms included shockable rhythm in (n = 28, 8.5 %) versus non-shockable rhythm in (n = 303, 91.5 %). In the EDs, return of spontaneous circulation was achieved in (n = 60, 18.1 %) cases. But survival rate to hospital discharge at 30-day was (n = 4, 1.2 %) and survival rate to hospital discharge with good neurological outcomes was (n = 0, 0 %). Conclusion: In Bahrain the estimated annual incidence of OHCA is 21 individuals per 100,000 population, with a very low survival rate. Solutions should focus on community-level CPR and AED training, evaluating OHCA care provided by EMS, and establishing OHCA registry.

Modifiable Factors Associated With Survival After Out-of-Hospital Cardiac Arrest in the Pan-Asian Resuscitation Outcomes Study

STUDY OBJECTIVE

The study aims to identify modifiable factors associated with improved out-of-hospital cardiac arrest survival among communities in the Pan-Asian Resuscitation Outcomes Study (PAROS) Clinical Research Network: Japan, Singapore, South Korea, Malaysia, Taiwan, Thailand, and the United Arab Emirates (Dubai).

METHODS

This was a prospective, international, multicenter cohort study of out-of-hospital cardiac arrest in the Asia-Pacific. Arrests caused by trauma, patients who were not transported by emergency medical services (EMS), and pediatric out-of-hospital cardiac arrest cases (<18 years) were excluded from the analysis. Modifiable out-of-hospital factors (bystander cardiopulmonary resuscitation [CPR] and defibrillation, out-of-hospital defibrillation, advanced airway, and drug administration) were compared for all out-of-hospital cardiac arrest patients presenting to EMS and participating hospitals. The primary outcome measure was survival to hospital discharge or 30 days of hospitalization (if not discharged). We used multilevel mixed-effects logistic regression models to identify factors independently associated with out-of-hospital cardiac arrest survival, accounting for clustering within each community.

RESULTS

Of 66,780 out-of-hospital cardiac arrest cases reported between January 2009 and December 2012, we included 56,765 in the analysis. In the adjusted model, modifiable factors associated with improved out-of-hospital cardiac arrest outcomes included bystander CPR (odds ratio [OR] 1.43; 95% confidence interval [CI] 1.31 to 1.55), response time less than or equal to 8 minutes (OR 1.52; 95% CI 1.35 to 1.71), and out-of-hospital defibrillation (OR 2.31; 95% CI 1.96 to 2.72). Out-of-hospital advanced airway (OR 0.73; 95% CI 0.67 to 0.80) was negatively associated with out-of-hospital cardiac arrest survival.

CONCLUSION

In the PAROS cohort, bystander CPR, out-of-hospital defibrillation, and response time less than or equal to 8 minutes were positively associated with increased out-of-hospital cardiac arrest survival, whereas out-of-hospital advanced airway was associated with decreased out-of-hospital cardiac arrest survival. Developing EMS systems should focus on basic life support interventions in out-of-hospital cardiac arrest resuscitation.

Reducing Time to First on Scene: An Ambulance-Community First Responder Scheme

The importance of early access to prehospital care has been demonstrated in many medical emergencies. This work aims to describe the potential time benefit of implementing a student Community First Responder scheme to support ambulance services in an inner-city setting in the United Kingdom. Twenty final and penultimate year medical students in the UK were trained in the "First Person on Scene" Business and Technology Education Council (BTEC) qualification. Over 12 months, they attended 89 emergency calls in an inner-city setting as Community First Responders (CFRs), alongside the West Midlands Ambulance Service, UK. At the end of this period, a qualitative survey investigated the perceived educational value of the scheme. The mean CFR response time across all calls was an average of 3 minutes and 8 seconds less than ambulance crew response times. The largest difference was to calls relating to falls (12 min). The difference varied throughout the day, peaking between 16:00 and 18:00. All questionnaire respondents stated that they felt more prepared in assessing and treating acutely unwell patients. In this paper, the authors present a symbiotic solution which has both reduced time to first on scene and provided training and experience in medical emergencies for senior medical students.

Emergency medical services response time and mortality in an urban setting

BACKGROUND

A common tenet in emergency medical services (EMS) is that faster response equates to better patient outcome, translated by some EMS operations into a goal of a response time of 8 minutes or less for advanced life support (ALS) units responding to life-threatening events.

OBJECTIVE

To explore whether an 8-minute EMS response time was associated with mortality.

METHODS

This was a one-year retrospective cohort study of adults with a life-threatening event as assessed at the time of the 9-1-1 call (Medical Priority Dispatch System Echo- or Delta-level event). The study setting was an urban all-ALS EMS system serving a population of approximately 1 million. Response time was defined as 9-1-1 call receipt to ALS unit arrival on scene, and outcome was defined as all-cause mortality at hospital discharge. Potential covariates included patient acuity, age, gender, and combined scene and transport interval time. Stratified analysis and logistic regression were used to assess the response time-mortality association.

RESULTS

There were 7,760 unit responses that met the inclusion criteria; 1,865 (24%) were ≥8 minutes. The average patient age was 56.7 years (standard deviation = 21.5). For patients with a response time ≥8 minutes, 7.1% died, compared with 6.4% for patients with a response time ≤7 minutes 59 seconds (risk difference 0.7%; 95% confidence interval [CI]: -0.5%, 2.0%). The adjusted odds ratio of mortality for ≥8 minutes was 1.19 (95% CI: 0.97, 1.47). An exploratory analysis suggested there may be a small beneficial effect of response ≤7 minutes 59 seconds for those who survived to become an inpatient (adjusted odds ratio = 1.30; 95% CI: 1.00, 1.69).

CONCLUSIONS

These results call into question the clinical effectiveness of a dichotomous 8-minute ALS response time on decreasing mortality for the majority of adult patients identified as having a life-threatening event at the time of the 9-1-1 call. However, this study does not suggest that rapid EMS response is undesirable or unimportant for certain patients. This analysis highlights the need for further research on who may benefit from rapid EMS response, whether these individuals can be identified at the time of the 9-1-1 call, and what the optimum response time is.

Ambulance staging for potentially dangerous scenes: another hidden component of response time

BACKGROUND

Emergency medical services (EMS) responses to some scenes are potentially more dangerous than others, requiring EMS systems to develop policies that stage medical responders away from the scene until law enforcement has the area secured.

OBJECTIVES

We sought to characterize the calls that are staged and to demonstrate the effect of staging on the response time interval and differences in red lights and sirens (RLS) transport to the hospital between staged calls (SC) and nonstaged calls (NSC).

METHODS

This was a retrospective cohort study of all 9-1-1 calls received during calendar year 2006 in a midwestern, high-performance system. Descriptive statistics, Mann-Whitney U test, and chi-square analysis were used as appropriate; p < 0.05 was considered significant.

RESULTS

There were 62,157 emergency calls for which responders arrived on scene during the study period; 4,414 (7.1%) were SC and 57,743 (92.9%) were NSC. By protocol, dispatchers ordered EMS to stage on five categories: 924 for assault/rape (20.9%), 393 for unknown problem/man down (8.9%), 918 for overdose (20.8%), 734 for psychiatric/suicide attempt (16.6%), and 413 for stab/gunshot wound (9.4%). Dispatchers ordered staging using their own discretion for 1,032 (23.4%) calls. The median response time interval (call received until ambulance arrived at the scene) was 10 minutes 55 seconds (i.e., 10:55 minutes) (interquartile range [IQR]: 8:00-14:27) for SC and 6:16 minutes (IQR: 4:42-8:28) for NSC (p < 0.0001). Patients were transported to the hospital for 3,104 (70.3%) of SC, 223 (7.2%) with RLS; patients were transported to the hospital for 41,716 (72.2%) of NSC, 2,802 (6.7%) with RLS. There was no difference in the rate of RLS return between SC and NSC (p = 0.314).

CONCLUSION

The practice of staging ambulances while police secure potentially dangerous scenes added approximately 4.5 minutes to the response time. We were unable to demonstrate a difference in RLS return to the hospital (our proxy for patient acuity) between SC and NSC.

Impact of advanced cardiac life support-skilled paramedics on survival from out-of-hospital cardiac arrest in a statewide emergency medical service

BACKGROUND

Prehospital research has found little evidence in support of advanced cardiac life support (ACLS) for out-of-hospital cardiac arrest. However, these studies generally examine city-based emergency medical services (EMS) systems. The training and experience of ACLS-skilled paramedics differs internationally, and this may also contribute to negative findings. Additionally, the frequency of negative outcome in out-of-hospital cardiac arrest suggests that it is difficult to establish sufficient numbers to detect an effect.

PURPOSE

To examine the effect of ACLS on cardiac arrest in Queensland, Australia. Queensland has a population of 3.8 million and an area of over 1.7 million km2, and is served by a statewide EMS system, which deploys resources using a two-tier model. Advanced treatments such as intubation and cardioactive drug administration are provided by extensively trained intensive care paramedics.

METHODS

An observational, retrospective design was used to examine all cases of cardiac arrest attended by the Queensland Ambulance Service from January 2000 to December 2002. Logistic regression was used to examine the effect of the presence of an intensive care paramedic on survival to hospital discharge, adjusting for age, sex, initial rhythm, the presence of a witness and bystander cardiopulmonary resuscitation.

RESULTS

The presence of an intensive care paramedic had a significant effect on survival (OR = 1.43, 95% CI = 1.02 to 1.99).

CONCLUSIONS

Highly trained ACLS-skilled paramedics provide added survival benefit in EMS systems not optimised for early defibrillation. The reasons for this benefit are multifactorial, but may be the result of greater skill level and more informed use of the full range of prehospital interventions.

Can a simple reminder letter improve numbering of single-family residences?

OBJECTIVE

To determine if a single mailing from the local volunteer fire department can increase the number of homes with proper, visible address numbering. Proper numbering is essential in rapidly locating a house during an emergency response.

METHODS

The study was conducted at a suburban/rural fire department providing EMS and fire suppression services to a 22 square mile area with residential mailboxes located at the street. During a hazard identification pre-plan tour, each house was examined and assigned a classification: (A) No number visible on the house or mailbox (improper); (B) Number on only one side of the mailbox (improper); (C) Number on both sides or the end of the mailbox, or visible on the house (proper). The homeowners of all residences with improper numbering (A or B) were sent a one-page letter, discussing the need for proper numbering. The tour was repeated six weeks later to determine whether deficiencies had been corrected. It was prospectively determined that a 25% improvement was sought.

RESULTS

During the pre-plan tour, 73 houses were classified as type A, 454 as type B, and 1706 as type C. At the re-visit, 135 (26%) of the type A and B homes had been properly numbered. Correction of deficiencies was better at type A homes (37, or 51%) than at type B homes (98, or 22%) (p < 0.001 by Chi-square).

CONCLUSION

For houses with improper numbering, a single mailing from the fire department can be effective in encouraging residents to post proper numbers.

Advanced cardiac life support in out-of-hospital cardiac arrest

BACKGROUND

The Ontario Prehospital Advanced Life Support (OPALS) Study tested the incremental effect on the rate of survival after out-of-hospital cardiac arrest of adding a program of advanced life support to a program of rapid defibrillation.

METHODS

This multicenter, controlled clinical trial was conducted in 17 cities before and after advanced-life-support programs were instituted and enrolled 5638 patients who had had cardiac arrest outside the hospital. Of those patients, 1391 were enrolled during the rapid-defibrillation phase and 4247 during the subsequent advanced-life-support phase. Paramedics were trained in standard advanced life support, which includes endotracheal intubation and the administration of intravenous drugs.

RESULTS

From the rapid-defibrillation phase to the advanced-life-support phase, the rate of admission to a hospital increased significantly (10.9 percent vs. 14.6 percent, P<0.001), but the rate of survival to hospital discharge did not (5.0 percent vs. 5.1 percent, P=0.83). The multivariate odds ratio for survival after advanced life support was 1.1 (95 percent confidence interval, 0.8 to 1.5); after an arrest witnessed by a bystander, 4.4 (95 percent confidence interval, 3.1 to 6.4); after cardiopulmonary resuscitation administered by a bystander, 3.7 (95 percent confidence interval, 2.5 to 5.4); and after rapid defibrillation, 3.4 (95 percent confidence interval, 1.4 to 8.4). There was no improvement in the rate of survival with the use of advanced life support in any subgroup.

CONCLUSIONS

The addition of advanced-life-support interventions did not improve the rate of survival after out-of-hospital cardiac arrest in a previously optimized emergency-medical-services system of rapid defibrillation. In order to save lives, health care planners should make cardiopulmonary resuscitation by citizens and rapid-defibrillation responses a priority for the resources of emergency-medical-services systems.