Can a Software-Based Metronome Tool Enhance Compression Rate in a Realistic 911 Call Scenario Without Adversely Impacting Compression Depth for Dispatcher-Assisted CPR?

IntroductionImplementation of high-quality, dispatcher-assisted cardiopulmonary resuscitation (DA-CPR) is critical to improving survival from out-of-hospital cardiac arrest (OHCA). However, despite some studies demonstrating the use of a metronome in a stand-alone setting, no research has yet demonstrated the effectiveness of a metronome tool in improving DA-CPR in the context of a realistic 911 call or using instructions that have been tested in real-world emergency calls.HypothesisUse of the metronome tool will increase the proportion of callers able to perform CPR within the target rate without affecting depth.

METHODS

The prospective, randomized, controlled study involved simulated 911 cardiac arrest calls made by layperson-callers and handled by certified emergency medical dispatchers (EMDs) at four locations in Salt Lake City, Utah USA. Participants were randomized into two groups. In the experimental group, layperson-callers received CPR pre-arrival instructions with metronome assistance. In the control group, layperson-callers received only pre-arrival instructions. The primary outcome measures were correct compression rate (counts per minute [cpm]) and depth (mm).

RESULTS

A total of 148 layperson-callers (57.4% assigned to experimental group) participated in the study. There was a statistically significant association between the number of participants who achieved the target compression rate and experimental study group (P=.003), and the experimental group had a significantly higher median compression rate than the control group (100 cpm and 89 cpm, respectively; P=.013). Overall, there was no significant correlation between compression rate and depth.

CONCLUSION

An automated software metronome tool is effective in getting layperson-callers to achieve the target compression rate and compression depth in a realistic DA-CPR scenario.Scott G, Barron T, Gardett I, Broadbent M, Downs H, Devey L, Hinterman EJ, Clawson J, Olola C. Can a software-based metronome tool enhance compression rate in a realistic 911 call scenario without adversely impacting compression depth for dispatcher-assisted CPR? Prehosp Disaster Med. 2018;33(4):399-405.

The Association between Cardiopulmonary Resuscitation in Out-of-Hospital Settings and Chest Injuries: A Retrospective Observational Study

OBJECTIVES

The aim of this study was to assess the risk of cardiopulmonary resuscitation (CPR) performed in out-of-hospital settings for chest injuries in patients with out-of-hospital cardiac arrest (OHCA).

METHODS

This retrospective, observational study was conducted in an emergency critical care medical center in Japan. Non-traumatic OHCA patients transferred to the hospital from April 2013 through August 2016 were analyzed. The outcome was defined by chest injuries related to CPR, which is composite of rib fractures, sternal fractures, and pneumothoraces. A multivariate logistic regression analysis was performed to assess the independent risk factors for chest injuries related to CPR. The threshold of out-of-hospital CPR duration that increased risk of chest injuries was also assessed.

RESULTS

A total of 472 patients were identified, of whom 233 patients sustained chest injuries. The multivariate logistic regression model showed that the independent risk factors for chest injuries were age and out-of-hospital CPR duration (age: AOR=1.06 [95% CI, 1.04 to 1.07]; out-of-hospital CPR duration: AOR=1.03 [95% CI, 1.01 to 1.05]). In-hospital CPR duration was not an independent risk factor for chest injuries. When the duration of out-of-hospital CPR extended over 15 minutes, the likelihood of chest injuries increased; however, this association was not statistically significant.

CONCLUSIONS

Long duration of out-of-hospital CPR was an independent risk factor for chest injuries, possibly due to the difficulty of maintaining adequate quality of CPR. Further investigations to assess the efficacy of alternative CPR devices are expected in cases requiring long transportation times. Takayama W , Koguchi H , Endo A , Otomo Y . The association between cardiopulmonary resuscitation in out-of-hospital settings and chest injuries: a retrospective observational study. Prehosp Disaster Med. 2018;33(2):171-175.

Is Distance to the Nearest Registered Public Automated Defibrillator Associated with the Probability of Bystander Shock for Victims of Out-of-Hospital Cardiac Arrest?

Introduction Rapid access to defibrillation is a key element in the management of out-of-hospital cardiac arrests (OHCAs). Public automated external defibrillators (PAEDs) are becoming increasingly available, but little information exists regarding the relation between the proximity to the arrest and their usage in urban areas.

METHODS

This study is a retrospective, observational, cross-sectional analysis of non-traumatic OHCA during a 24-month period in the greater Montreal area (Quebec, Canada). Using logistic regression, bystander shock odds are described with regards to distance from the OHCA scene to the nearest PAED, adjusted for prehospital care arrival delay and time of day, and stratifying for type of location.

RESULTS

Out of a total of 2,443 OHCA victims identified, 77 (3%) received bystander PAED shock, 622 (26%) occurred out-of-home, and 743 (30%) occurred during business hours. When controlling for time (business hours versus other hours) and minimum response delay for prehospital care arrival, a marginal negative association was found between bystander shock and distance to the nearest PAED in logged meters (aOR=0.80; CI, 0.64-0.99) for out-of-home cardiac arrests. No significant association was found between distance and bystander shock for at-home arrests. Out-of-home victims had significantly higher odds of receiving bystander shock up to 175 meters of distance to a PAED inclusively (aOR=2.52; CI, 1.07-5.89).

CONCLUSION

For out-of-home cardiac arrests, proximity to a PAED was associated with bystander shock in the greater Montreal area. Strategies aiming to increase accessibility and use of these life-saving devices could further expand this advantage by assisting bystanders in rapidly locating nearby PAEDs. Neves Briard J , de Montigny L , Ross D , de Champlain F , Segal E . Is distance to the nearest registered public automated defibrillator associated with the probability of bystander shock for victims of out-of-hospital cardiac arrest? Prehosp Disaster Med. 2018;33(2):153-159.

When is a Cardiac Arrest Non-Cardiac?

Introduction While the overall survival rate for out-of-hospital cardiac arrest (OHCA) is low, ranging from 5%-10%, several characteristics have been shown to decrease mortality, such as presence of bystander cardiopulmonary resuscitation (CPR), witnessed vs unwitnessed events, and favorable initial rhythm (VF/VT). More recently, studies have shown that modified CPR algorithms, such as chest-compression only or cardio-cerebral resuscitation, can further increase survival rates in OHCA. Most of these studies have included only OHCA patients with "presumed cardiac etiology," on the assumption that airway management is of lesser impact than chest compressions in these patients. However, prehospital personnel often lack objective and consistent criteria to assess whether an OHCA is of cardiac or non-cardiac etiology. Hypothesis/Problem The relative proportions of cardiac vs non-cardiac etiology in published data sets of OHCA in the peer-reviewed literature were examined in order to assess the variability of prehospital clinical etiology assessment.

METHODS

A Medline (US National Library of Medicine, National Institutes of Health; Bethesda, Maryland USA) search was performed using the subject headings "OHCA" and "Emergency Medical Services" (EMS). Studies were included if they reported prevalence of cardiac etiology among OHCA in the entire patient sample, or in all arms of a comparison study. Studies that either did not report etiology of OHCA, or that excluded all cardiac or non-cardiac etiologies prior to reporting clinical data, were excluded.

RESULTS

Twenty-four studies were identified, containing 27 datasets of OHCA which reported the prevalence of presumed cardiac vs non-cardiac etiology. These 27 datasets were drawn from 15 different countries. The prevalence of cardiac etiology among OHCA ranged from 50% to 91%. No obvious patterns were found regarding database size, year of publication, or global region (continent) of origin.

CONCLUSIONS

There exists significant variation in published rates of cardiac etiology among OHCAs. While some of this variation likely reflects different actual rates of cardiac etiologies in the sampled populations, varying definitions of cardiac etiology among prehospital personnel or varying implementation of existing definitions may also play a role. Different proportions of cardiac vs non-cardiac etiology of OHCA in a sample could result in entirely different interpretations of data. A more specific consensus definition of cardiac etiology than that which currently exists in the Utstein template may provide better guidance to prehospital personnel and EMS researchers in the future. Carter RM , Cone DC . When is a cardiac arrest non-cardiac? Prehosp Disaster Med. 2017;32(5):523-527.

Exploring How Lay Rescuers Overcome Barriers to Provide Cardiopulmonary Resuscitation: A Qualitative Study

BACKGROUND

Survival rates after out-of-hospital cardiac arrest (OHCA) vary considerably among regions. The chance of survival is increased significantly by lay rescuer cardiopulmonary resuscitation (CPR) before Emergency Medical Services (EMS) arrival. It is well known that for bystanders, reasons for not providing CPR when witnessing an OHCA incident may be fear and the feeling of being exposed to risk. The aim of this study was to gain a better understanding of why barriers to providing CPR are overcome.

METHODS

Using a semi-structured interview guide, 10 lay rescuers were interviewed after participating in eight OHCA incidents. Qualitative content analysis was used. The lay rescuers were questioned about their CPR-knowledge, expectations, and reactions to the EMS and from others involved in the OHCA incident. They also were questioned about attitudes towards providing CPR in an OHCA incident in different contexts.

RESULTS

The lay rescuers reported that they were prepared to provide CPR to anybody, anywhere. Comprehending the severity in the OHCA incident, both trained and untrained lay rescuers provided CPR. They considered CPR provision to be the expected behavior of any community citizen and the EMS to act professionally and urgently. However, when asked to imagine an OHCA in an unclear setting, they revealed hesitation about providing CPR because of risk to their own safety.

CONCLUSION

Mutual trust between community citizens and towards social institutions may be reasons for overcoming barriers in providing CPR by lay rescuers. A normative obligation to act, regardless of CPR training and, importantly, without facing any adverse legal reactions, also seems to be an important factor behind CPR provision. Mathiesen WT , Bjørshol CA , Høyland S , Braut GS , Søreide E . Exploring how lay rescuers overcome barriers to provide cardiopulmonary resuscitation: a qualitative study. Prehosp Disaster Med. 2017;32(1):27-32.

Emergency Medical Services Utilization in EMS Priority Conditions in Beirut, Lebanon

BACKGROUND

Early activation and use of Emergency Medical Services (EMS) are associated with improved patient outcomes in EMS priority conditions in developed EMS systems. This study describes patterns of EMS use and identifies predictors of EMS utilization in EMS priority conditions in Lebanon METHODS: This was a cross-sectional study of a random sample of adult patients presenting to the emergency department (ED) of a tertiary care center in Beirut with the following EMS priority conditions: chest pain, major trauma, respiratory distress, cardiac arrest, respiratory arrest, and airway obstruction. Patient/proxy survey (20 questions) and chart review were completed. The responses to survey questions were "disagree," "neutral," or "agree" and were scored as one, two, or three with three corresponding to higher likelihood of EMS use. A total scale score ranging from 20 to 60 was created and transformed from 0% to 100%. Data were analyzed based on mode of presentation (EMS vs other).

RESULTS

Among the 481 patients enrolled, only 112 (23.3%) used EMS. Mean age for study population was 63.7 years (SD=18.8 years) with 56.5% males. Mean clinical severity score (Emergency Severity Index [ESI]) was 2.5 (SD=0.7) and mean pain score was 3.1 (SD=3.5) at ED presentation. Over one-half (58.8%) needed admission to hospital with 21.8% to an intensive care unit care level and with a mortality rate of 7.3%. Significant associations were found between EMS use and the following variables: severity of illness, degree of pain, familiarity with EMS activation, previous EMS use, perceived EMS benefit, availability of EMS services, trust in EMS response times and treatment, advice from family, and unavailability of immediate private mode of transport (P≤.05). Functional screening, or requiring full assistance (OR=4.77; 95% CI, 1.85-12.29); acute symptoms onset ≤ one hour (OR=2.14; 95% CI, 1.08-4.26); and higher scale scores (OR=2.99; 95% CI, 2.20-4.07) were significant predictors of EMS use. Patients with lower clinical severity (OR=0.53; 95% CI, 0.35-0.81) and those with chest pain (OR=0.05; 95% CI, 0.02-0.12) or respiratory distress (OR=0.15; 95% CI, 0.07-0.31) using cardiac arrest as a reference were less likely to use EMS.

CONCLUSION

Emergency Medical Services use in EMS priority conditions in Lebanon is low. Several predictors of EMS use were identified. Emergency Medical Services initiatives addressing underutilization should result from this proposed assessment of the perspective of the EMS system's end user. El Sayed M , Tamim H , Al-Hajj Chehadeh A , Kazzi AA . Emergency Medical Services utilization in EMS priority conditions in Beirut, Lebanon. Prehosp Disaster Med. 2016;31(6):621-627.

Clinical Outcomes in Cardiac Arrest Patients Following Prehospital Treatment with Therapeutic Hypothermia

INTRODUCTION

Recent studies have brought to question the efficacy of the use of prehospital therapeutic hypothermia for victims of out-of-hospital cardiac arrest (OHCA). Though guidelines recommend therapeutic hypothermia as a critical link in the chain of survival, the safety of this intervention, with the possibility of minimal treatment benefit, becomes important. Hypothesis/Problem This study examined prehospital therapeutic hypothermia for OHCA, its association with survival, and its complication profile in a large, metropolitan, fire-based Emergency Medical Services (EMS) system, where bystander cardiopulmonary resuscitation (CPR) and post-arrest care are in the process of being optimized.

METHODS

This evaluation was a retrospective chart review of all OHCA patients with return of spontaneous circulation (ROSC) treated with therapeutic hypothermia, from January 1, 2013 through November 30, 2013. The primary outcomes were the proportion of patients with initiation of prehospital therapeutic hypothermia with survival to hospital admission, the proportion of patients with initiation of prehospital therapeutic hypothermia with survival to hospital discharge, and the complication profile of therapeutic hypothermia in this population. The complication profile included several clinical, radiographic, and laboratory parameters. Exclusion criteria included: no prehospital therapeutic hypothermia initiation; no ROSC; and age of 17 year old or younger.

RESULTS

Fifty-one post-cardiac arrest patients were identified that met inclusion criteria. The mean age was 61 years (SD=14.7 years), and 33 (72%) were male. The initial rhythm was ventricular fibrillation or pulseless ventricular tachycardia in 17 (37%) patients, and bystander CPR was performed in 28 (61%) patients with ROSC. Thirty-nine (85%) patients survived to hospital admission. Twenty-one patients (48%; 95% CI, 33-64) were administered vasopressors, 10 patients (24%; 95% CI, 10-37) were administered diuretics, and 19 patients (44%; 95% CI, 29-60) were administered antibiotics. Initial chest radiograph (CXR) findings were normal in 12 (29%) patients. Overall, 13 (28%; 95% CI, 15-42) study patients survived to hospital discharge.

CONCLUSION

Recent reports have questioned the efficacy and safety of prehospital therapeutic hypothermia. In this evaluation, in the setting of unstandardized post-arrest care, 85% of the patients survived to hospital admission and 28% survived to hospital discharge, with a complication profile which was similar to that noted in other studies. This suggests that further evidence may be needed before EMS systems stop administering therapeutic hypothermia to appropriately selected patients. In less-optimized systems, therapeutic hypothermia may still be an essential link in the chain of survival.

Burden of cardiovascular morbidity and mortality following humanitarian emergencies: a systematic literature review

BACKGROUND

The global burden of cardiovascular mortality is increasing, as is the number of large-scale humanitarian emergencies. The interaction between these phenomena is not well understood. This review aims to clarify the relationship between humanitarian emergencies and cardiovascular morbidity and mortality.

METHODS

With assistance from a research librarian, electronic databases (PubMed, Scopus, CINAHL, and Global Health) were searched in January 2014. Findings were supplemented by reviewing citations of included trials. Observational studies reporting the effect of natural disasters and conflict events on cardiovascular morbidity and mortality in adults since 1997 were included. Studies without a comparison group were not included. Double-data extraction was utilized to abstract information on acute coronary syndrome (ACS), acute decompensated heart failure (ADHF), and sudden cardiac death (SCD). Review Manager 5.0 (Version 5.2, The Nordic Cochrane Centre; Copenhagen Denmark,) was used to create figures for qualitative synthesis.

RESULTS

The search retrieved 1,697 unique records; 24 studies were included (17 studies of natural disasters and seven studies of conflict). These studies involved 14,583 cardiac events. All studies utilized retrospective designs: four were population-based, 15 were single-center, and five were multicenter studies. Twenty-three studies utilized historical controls in the primary analysis, and one utilized primarily geographical controls.

DISCUSSION

Conflicts are associated with an increase in long-term morbidity from ACS; the short-term effects of conflict vary by study. Natural disasters exhibit heterogeneous effects, including increased occurrence of ACS, ADHF, and SCD.

CONCLUSIONS

In certain settings, humanitarian emergencies are associated with increased cardiac morbidity and mortality that may persist for years following the event. Humanitarian aid organizations should consider morbidity from noncommunicable disease when planning relief and recuperation projects.

Cardiopulmonary Resuscitation in Resource-limited Health Systems-Considerations for Training and Delivery

In the past 50 years, cardiopulmonary resuscitation (CPR) has gained widespread recognition as a life-saving skill that can be taught successfully to the general public. Cardiopulmonary resuscitation can be considered a cost-effective intervention that requires minimal classroom training and low-cost equipment and supplies; it is commonly taught throughout much of the developed world. But, the simplicity of CPR training and its access for the general public may be misleading, as outcomes for patients in cardiopulmonary arrest are poor and survival is dependent upon a comprehensive "chain-of-survival," which is something not achieved easily in resource-limited health care settings. In addition to the significant financial and physical resources needed to both train and develop basic CPR capabilities within a community, there is a range of ethical questions that should also be considered. This report describes some of the financial and ethical challenges that might result from CPR training in low- and middle-income countries (LMICs). It is determined that for many health care systems, CPR training may have financial and ethically-deleterious, unintended consequences. Evidence shows Basic Life Support (BLS) skills training in a community is an effective intervention to improve public health. But, health care systems with limited resources should include CPR training only after considering the full implications of that intervention.