Emergency response time after out-of-hospital cardiac arrest

Recovering from prolonged cardiac arrest induced by electric shock: A case report

BACKGROUND

Cardiac arrest (CA) induced by electric shock is a rare occurrence, particularly in cases of prolonged CA. Currently, there is limited literature on similar incidents, and we present a relevant case report.

CASE SUMMARY

A 27-year-old Asian male man, experiencing respiratory CA due to electric shock, was successfully restored to sinus rhythm after 50 min of cardiopulmonary resuscitation and 8 electrical defibrillation sessions. In the subsequent stages, the patient received multiple organ function protection measures, leading to a successful recovery and eventual discharge from the hospital.

CONCLUSION

Prolonging resuscitation time can enhance the chances of survival for patients, this study provide valuable insights into the management of electric shock-induced CA.

Predictors, Prevalence, and Clinical Outcomes of Out-of-Hospital Cardiac Arrests in Croatia: A Nationwide Study

BACKGROUND

Out-of-hospital cardiac arrest (OHCA) remains a pivotal health challenge globally. In Croatia, there has been a knowledge gap regarding the prevalence, predictors, and outcomes of OHCA patients. This study aims to determine the prevalence, prediction, and outcomes of OHCA patients in Croatia.

METHODS

An extensive one-year analysis was performed on all OHCA treated by the Emergency Medical Service in Croatia, based on the Utstein recommendations. Data were extracted from Croatian Institute of Emergency Medicine databases, focusing on adult individuals who experienced sudden cardiac arrest in out-of-hospital settings in Croatia.

RESULTS

From 7773 OHCA cases, 9.5% achieved spontaneous circulation pre-hospital. Optimal outcomes corresponded to EMS intervention within ≤13 min post-arrest onset AUC = 0.577 (95% CI: 0.56-0.59; p < 0.001) and female gender OR = 1.81 (95% CI: 1.49-2.19; p < 0.001). Northern Croatia witnessed lower success rates relative to the capital city Zagreb OR = 0.68 (95% CI: 0.50-0.93; p = 0.015).

CONCLUSIONS

Early intervention by EMS, specifically within a 13-min period following the onset of a cardiac arrest, significantly enhances the probability of achieving successful OHCA outcomes. Gender differences and specific initial heart rhythms further influenced the likelihood of successful outcomes. Regional disparities, with reduced success rates in northern Croatia compared to the City of Zagreb, were evident.

Delayed arrival of advanced life support adversely affects the neurological outcome in a multi-tier emergency response system

AIM

Prehospital management of out-of-hospital cardiac arrest (OHCA) is based on basic life support, with the addition of advanced life support (ALS) if possible. This study aimed to investigate the effect of delayed arrival of ALS on neurological outcomes of patients with OHCA at hospital discharge.

METHODS

This was a retrospective study of a registry of patients with OHCA. A multi-tier emergency response system was established in the study area. ALS was initiated when the second-arrival team arrived at the scene. A restricted cubic spline curve was used to investigate the relationship between the response time interval of the second-arrival team and neurological outcomes at hospital discharge. Multivariable logistic regression analysis was performed to assess the independent association between the response time interval of the second-arrival team and neurological outcomes of patients at hospital discharge.

RESULTS

A total of 3186 adult OHCA patients who received ALS at the scene were included in the final analysis. A restricted cubic spline curve showed that a long response time interval of the second-arrival team was correlated with a high likelihood of poor neurological outcomes. Meanwhile, multivariable logistic regression analysis showed that a long response time interval of the second-arrival team was independently associated with poor neurological outcomes (odds ratio, 1.10; 95% confidence interval, 1.03-1.17).

CONCLUSION

In a multi-tiered prehospital emergency response system, the delayed arrival of ALS was associated with poor neurological outcomes at hospital discharge.

Prehospital Emergency Care in Low- and Middle-Income Countries: A Systematic Review

BACKGROUND

An under-developed and fragmented prehospital Emergency Medical Services (EMS) system is a major obstacle to the timely care of emergency patients. Insufficient emphasis on prehospital emergency systems in low- and middle-income countries (LMICs) currently causes a substantial number of avoidable deaths from time-sensitive illnesses, highlighting a critical need for improved prehospital emergency care systems. Therefore, this systematic review aimed to assess the prehospital emergency care services across LMICs.

METHODS

This systematic review used four electronic databases, namely: PubMed/MEDLINE, CINAHL, EMBASE, and SCOPUS, to search for published reports on prehospital emergency medical care in LMICs. Only peer-reviewed studies published in English language from January 1, 2010 through November 1, 2022 were included in the review. The Newcastle-Ottawa Scale (NOS) and Critical Appraisal Skills Programme (CASP) checklist were used to assess the methodological quality of the included studies. Further, the protocol of this systematic review has been registered on the International Prospective Register of Systematic Reviews (PROSPERO) database (Ref: CRD42022371936) and has been conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines.

RESULTS

Of the 4,909 identified studies, a total of 87 studies met the inclusion criteria and were therefore included in the review. Prehospital emergency care structure, transport care, prehospital times, health outcomes, quality of information exchange, and patient satisfaction were the most reported outcomes in the considered studies.

CONCLUSIONS

The prehospital care system in LMICs is fragmented and uncoordinated, lacking trained medical personnel and first responders, inadequate basic materials, and substandard infrastructure.

Impact of COVID-19 on Out-of-Hospital Cardiac Arrest in Korea

BACKGROUND

Coronavirus disease 2019 (COVID-19) is a global public health crisis that has had a significant impact on emergency medical services (EMS). Several studies have reported an increase in the incidence of out-of-hospital cardiac arrest (OHCA) and a decreased survival due to COVID-19, which has been limited to a short period or has been reported in some regions. This study aimed to investigate the effect of COVID-19 on OHCA patients using a nationwide database.

METHODS

We included adult OHCA patients treated by EMS providers from January 19, 2019 to January 20, 2021. The years before and after the first confirmed case in Korea were set as the non-COVID-19 and COVID-19 periods, respectively. The main exposure of interest was the COVID-19 period, and the primary outcome was prehospital return of spontaneous circulation (ROSC). Other OHCA variables were compared before and after the COVID-19 pandemic and analyzed. We performed a multivariable logistic regression analysis to understand the independent effect of the COVID-19 period on prehospital ROSC.

RESULTS

The final analysis included 51,921 eligible patients, including 25,355 (48.8%) during the non-COVID-19 period and 26,566 (51.2%) during the COVID-19 period. Prehospital ROSC deteriorated during the COVID-19 period (10.2% vs. 11.1%, P = 0.001). In the main analysis, the adjusted odds ratios (AORs) for prehospital ROSC showed no significant differences between the COVID-19 and non-COVID-19 periods (AOR [95% confidence interval], 1.02 [0.96-1.09]).

CONCLUSION

This study found that the proportion of prehospital ROSC was lower during the COVID-19 period than during the non-COVID-19 period; however, there was no statistical significance when adjusting for potential confounders. Continuous efforts are needed to restore the broken chain of survival in the prehospital phase and increase the survival rate of OHCA patients.

Tree-Based Algorithms and Association Rule Mining for Predicting Patients’ Neurological Outcomes After First-Aid Treatment for an Out-of-Hospital Cardiac Arrest During COVID-19 Pandemic: Application of Data Mining

Objective

The authors performed several tree-based algorithms and an association rules mining as data mining tools to find useful determinants for neurological outcomes in out-of-hospital cardiac arrest (OHCA) patients as well as to assess the effect of the first-aid and basic characteristics in the EMS system.

Patients and Methods

This was a retrospective cohort study. The outcome was Cerebral Performance Categories grading on OHCA patients at hospital discharge. Decision tree-based models inclusive of C4.5 algorithm, classification and regression tree and random forest were built to determine an OHCA patient’s prognosis. Association rules mining was another data mining method which we used to find the combination of prognostic factors linked to the outcome.

Results

The total of 3520 patients were included in the final analysis. The mean age was 67.53 (±18.4) year-old and 63.4% were men. To overcome the imbalance outcome issue in machine learning, the random forest has a better predictive ability for OHCA patients in overall accuracy (91.19%), weighted precision (88.76%), weighted recall (91.20%) and F1 score (0.9) by oversampling adjustment. Under association rules mining, patients who had any witness on the spot when encountering OHCA or who had ever ROSC during first-aid would be highly correlated with good CPC prognosis.

Conclusion

The random forest has a better predictive ability for OHCA patients. This paper provides a role model applying several machine learning algorithms to the first-aid clinical assessment that will be promising combining with Artificial Intelligence for applying to emergency medical services.

Response Time and Causes of Delay in Prehospital Emergency Missions in Mashhad, 2015

Background: The response time is considered as one of the most important criteria for the quality of given care to the injured. This research aimed to investigate the frequency and causes of prehospital emergency delays in the 115 emergency center, in city of Mashhad, in 2015.

Methods: In this cross-sectional study, 21,142 missions performed in 2015 were investigated, from among which 640 missions with delays in systematic sampling were recognized. For data analysis purposes, descriptive statistics (frequency, mean and SD) in Excel 2013 software was implemented.

Results: Nearly 60% of the injured were men, 23% women, and the gender of 17% was not recorded in their profiles. The mean age of the injured was 29.8+15.9 years and 30% of the injured were in the age group of 16 to 25. The mean response time was 9:01+2:46. The most prevalent causes related to missions out of the operational zone (29.3%) and the second cause has been related to traffic groups (24.2%).

Conclusion: Establishing new bases and completing the number of ambulances and human recourses, intervention in traffic causing factors, and training the public about emergency cases can be effective in reducing the number of missions and the pace and quality of services provided to the injured.

A registry-based observational study comparing emergency calls assessed by emergency medical dispatchers with and without support by registered nurses

Background

The requirement concerning formal education for emergency medical dispatcher (EMD) is debated and varies, both nationally and internationally. There are few studies on the outcomes of emergency medical dispatching in relation to professional background. This study aimed to compare calls handled by an EMD with and without support by a registered nurse (RN), with respect to priority level, accuracy, and medical condition.

Methods

A retrospective observational study, performed on registry data from specific regions during 2015. The ambulance personnel’s first assessment of the priority level and medical condition was used as the reference standard. Outcomes were: the proportion of calls dispatched with a priority in concordance with the ambulance personnel’s assessment; over- and undertriage; the proportion of most adverse over- and undertriage; sensitivity, specificity and predictive values for each of the ambulance priorities; proportion of calls dispatched with a medical condition in concordance with the ambulance personnel’s assessment. Proportions were reported with 95% confidence intervals. χ²-test was used for comparisons. P-levels < 0.05 were regarded as significant.

Results

A total of 25,025 calls were included (EMD n = 23,723, EMD + RN n = 1302). Analyses relating to priority and medical condition were performed on 23,503 and 21,881 calls, respectively. A dispatched priority in concordance with the ambulance personnel’s assessment were: EMD n = 11,319 (50.7%) and EMD + RN n = 481 (41.5%) (p < 0.01). The proportion of overtriage was equal for both groups: EMD n = 5904, EMD + RN n = 306, (26.4%) p = 0.25). The proportion of undertriage for each group was: EMD n = 5122 (22.9%) and EMD + RN n = 371 (32.0%) (p < 0.01). Sensitivity for the most urgent priority was 54.6% for EMD, compared to 29.6% for EMD + RN (p < 0.01), and specificity was 67.3% and 84.8% (p < 0.01) respectively. A dispatched medical condition in concordance with the ambulance personnel’s assessment were: EMD n = 13,785 (66.4%) and EMD + RN n = 697 (62.2%) (p = 0.01).

Conclusions

A higher precision of emergency medical dispatching was not observed when the EMD was supported by an RN. How patient safety is affected by the observed divergence in dispatched priorities is an area for future research.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13049-021-00987-y.

Out-of-hospital cardiac arrests in the city of Cape Town, South Africa: a retrospective, descriptive analysis of prehospital patient records

OBJECTIVES

While prospective epidemiological data for out-of-hospital cardiac arrest (OHCA) exists in many high-income settings, there is a dearth of such data for the African continent. The aim of this study was to describe OHCA in the Cape Town metropole, South Africa.

DESIGN

Observational study with a retrospective descriptive design.

SETTING

Cape Town metropole, Western Cape province, South Africa.

PARTICIPANTS

All patients with OHCA for the period 1 January 2018-31 December 2018 were extracted from public and private emergency medical services (EMS) and described.

OUTCOME MEASURES

Description of patients with OHCA in terms of demographics, treatment and short-term outcome.

RESULTS

A total of 929 patients with OHCA received an EMS response in the Cape Town metropole, corresponding to an annual prevalence of 23.2 per 100 000 persons. Most patients were adult (n=885; 96.5%) and male (n=526; 56.6%) with a median (IQR) age of 63 (26) years. The majority of cardiac arrests occurred in private residences (n=740; 79.7%) and presented with asystole (n=322; 34.6%). EMS resuscitation was only attempted in 7.4% (n=69) of cases and return of spontaneous circulation (ROSC) occurred in 1.3% (n=13) of cases. Almost all patients (n=909; 97.8%) were declared dead on the scene.

CONCLUSION

To our knowledge, this was the largest study investigating OHCA ever undertaken in Africa. We found that while the incidence of OHCA in Cape Town was similar to the literature, resuscitation is attempted in very few patients and ROSC-rates are negligible. This may be as a consequence of protracted response times, poor patient prognosis or an underdeveloped and under-resourced Chain of Survival in low- to middle-income countries, like South Africa. The development of contextual guidelines given resources and disease burden is essential.

Association between prehospital prognostic factors on out-of-hospital cardiac arrest in different age groups

Background

The prognosis of out-of-hospital cardiac arrest (OHCA) is very poor. While several prehospital factors are known to be associated with improved survival, the impact of prehospital factors on different age groups is unclear. The objective of the study was to access the impact of prehospital factors and pre-existing comorbidities on OHCA outcomes in different age groups.

Methods

A retrospective observational analysis was conducted using the emergency medical service (EMS) database from January 2015 to December 2019. We collected information on prehospital factors, underlying diseases, and outcome of OHCAs in different age groups. Kaplan-Meier type survival curves and multivariable logistic regression were used to analyze the association between modifiable pre-hospital factors and outcomes.

Results

A total of 4188 witnessed adult OHCAs were analyzed. For the age group 1 (age ≦75 years old), after adjustment for confounding factors, EMS response time (odds ratio [OR] = 0.860, 95% confidence interval [CI]: 0.811–0.909, p < 0.001), public location (OR = 1.843, 95% CI: 1.179–1.761, p < 0.001), bystander CPR (OR = 1.329, 95% CI: 1.007–1.750, p = 0.045), attendance by an EMT-Paramedic (OR = 1.666, 95% CI: 1.277–2.168, p < 0.001), and prehospital defibrillation by automated external defibrillator (AED)(OR = 1.666, 95% CI: 1.277–2.168, p < 0.001) were prognostic factors for survival to hospital discharge in OHCA patients. For the age group 2 (age > 75 years old), age (OR = 0.924, CI:0.880–0.966, p = 0.001), EMS response time (OR = 0.833, 95% CI: 0.742–0.928, p = 0.001), public location (OR = 4.290, 95% CI: 2.450–7.343, p < 0.001), and attendance by an EMT-Paramedic (OR = 2.702, 95% CI: 1.704–4.279, p < 0.001) were independent prognostic factors for survival to hospital discharge in OHCA patients.

Conclusions

There were variations between younger and older OHCA patients. We found that bystander CPR and prehospital defibrillation by AED were independent prognostic factors for younger OHCA patients but not for the older group.

Evolution of Bystander Intention to Perform Resuscitation Since Last Training: Web-Based Survey

BACKGROUND

Victims of out-of-hospital cardiac arrest (OHCA) have higher survival rates and more favorable neurological outcomes when basic life support (BLS) maneuvers are initiated quickly after collapse. Although more than half of OHCAs are witnessed, BLS is infrequently provided, thereby worsening the survival and neurological prognoses of OHCA victims. According to the theory of planned behavior, the probability of executing an action is strongly linked to the intention of performing it. This intention is determined by three distinct dimensions: attitude, subjective normative beliefs, and control beliefs. We hypothesized that there could be a decrease in one or more of these dimensions even shortly after the last BLS training session.

OBJECTIVE

The aim of this study was to measure the variation of the three dimensions of the intention to perform resuscitation according to the time elapsed since the last first-aid course.

METHODS

Between January and April 2019, the two largest companies delivering first-aid courses in the region of Geneva, Switzerland sent invitation emails on our behalf to people who had followed a first-aid course between January 2014 and December 2018. Participants were asked to answer a set of 17 psychometric questions based on a 4-point Likert scale ("I don't agree," "I partially agree," "I agree," and "I totally agree") designed to assess the three dimensions of the intention to perform resuscitation. The primary outcome was the difference in each of these dimensions between participants who had followed a first-aid course less than 6 months before taking the questionnaire and those who took the questionnaire more than 6 months and up to 5 years after following such a course. Secondary outcomes were the change in each dimension using cutoffs at 1 year and 2 years, and the change regarding each individual question using cutoffs at 6 months, 1 year, and 2 years. Univariate and multivariable linear regression were used for analyses.

RESULTS

A total of 204 surveys (76%) were analyzed. After adjustment, control beliefs was the only dimension that was significantly lower in participants who took the questionnaire more than 6 months after their last BLS course (P<.001). Resisting diffusion of responsibility, a key element of subjective normative beliefs, was also less likely in this group (P=.001). By contrast, members of this group were less afraid of disease transmission (P=.03). However, fear of legal action was higher in this group (P=.02).

CONCLUSIONS

Control beliefs already show a significant decrease 6 months after the last first-aid course. Short interventions should be designed to restore this dimension to its immediate postcourse state. This could enhance the provision of BLS maneuvers in cases of OHCA.

Symptom-Based Dispatching in an Emergency Medical Communication Centre: Sensitivity, Specificity, and the Area under the ROC Curve

Measuring the performance of emergency medical dispatch tools used in paramedic-staffed emergency medical communication centres (EMCCs) is rarely performed. The objectives of our study were, therefore, to measure the performance and accuracy of Geneva's dispatch system based on symptom assessment, in particular, the performance of ambulance dispatching with lights and sirens (L&S) and to measure the effect of adding specific protocols for each symptom. Methods: We performed a prospective observational study including all emergency calls received at Geneva's EMCC (Switzerland) from 1 January 2014 to 1 July 2019. The risk levels selected during the emergency calls were compared to a reference standard, based on the National Advisory Committee for Aeronautics (NACA) scale, dichotomized to severe patient condition (NACA ≥ 4) or stable patient condition (NACA < 4) in the field. The symptom-based dispatch performance was assessed using a receiver operating characteristic (ROC) curve. Contingency tables and a Fagan nomogram were used to measure the performance of the dispatch with or without L&S. Measurements were carried out by symptom, and a group of symptoms with specific protocols was compared to a group without specific protocols. Results: We found an acceptable area under the ROC curve of 0.7474, 95%CI (0.7448-0.7503) for the 148,979 assessments included in the study. Where the severity prevalence was 21%, 95%CI (20.8-21.2). The sensitivity of the L&S dispatch was 87.5%, 95%CI (87.1-87.8); and the specificity was 47.3%, 95%CI (47.0-47.6). When symptom-specific assessment protocols were used, the accuracy of the assessments was slightly improved. Conclusions: Performance measurement of Geneva's symptom-based dispatch system using standard diagnostic test performance measurement tools was possible. The performance was found to be comparable to other emergency medical dispatch systems using the same reference standard. However, the implementation of specific assessment protocols for each symptom may improve the accuracy of symptom-based dispatch systems.

Association between prehospital prognostic factors and out-of-hospital cardiac arrest: Effect of rural-urban disparities

BACKGROUND

Out-of-hospital cardiac arrest (OHCA) is associated with a poor prognosis and a highly variable survival rate. Few studies have focused on outcomes in rural and urban groups while also evaluating underlying diseases and prehospital factors for OHCAs.

OBJECTIVE

To investigate the relationship between the patient's underlying disease and outcomes of OHCAs in urban areas versus those in rural areas.

METHODS

We reviewed the emergency medical service (EMS) database for information on OHCA patients treated between January 2015 and December 2019, and collected data on pre-hospital factors, underlying diseases, and outcomes of OHCAs. Univariate and multivariate logistic regression analyses were used to evaluate the prognostic factors for OHCA.

RESULTS

Data from 4225 OHCAs were analysed. EMS response time was shorter and the rate of attendance by EMS paramedics was higher in urban areas (p < 0.001 for both). Urban area was a prognostic factor for >24-h survival (odds ratio [OR] = 1.437, 95% confidence interval [CI]: 1.179-1.761). Age (OR = 0.986, 95% CI: 0.979-0.993). EMS response time (OR = 0.854, 95% CI: 0.811-0.898), cardiac arrest location (OR = 2.187, 95% CI: 1.707-2.795), attendance by paramedics (OR = 1.867, 95% CI: 1.483-2.347), and prehospital defibrillation (OR = 2.771, 95% CI: 2.154-3.556) were independent risk factors for survival to hospital discharge, although the influence of an urban area was not significant (OR = 1.211, 95% CI: 0.918-1.584).

CONCLUSIONS

Compared with rural areas, OHCA in urban areas are associated with a higher 24-h survival rate. Shorter EMS response time and a higher probability of being attended by paramedics were noted in urban areas. Although shorter EMS response time, younger age, public location, defibrillation by an automated external defibrillator, and attendance by Emergency Medical Technician-paramedics were associated with a higher rate of survival to hospital discharge, urban area was not an independent prognostic factor for survival to hospital discharge in OHCA patients.

The association of scene-access delay and survival with favourable neurological status in patients with out-of-hospital cardiac arrest

BACKGROUND

Rapid emergency medical service (EMS) response after out-of-hospital cardiac arrest (OHCA) is a major determinant of survival, however this is typically measured until EMS vehicle arrival. We sought to investigate whether the interval from EMS vehicle arrival to patient attendance (curb-to-care interval [CTC]) was associated with patient outcomes.

METHODS

We performed a secondary analysis of the "CCC Trial" dataset, which includes EMS-treated adult non-traumatic OHCA. We fit an adjusted logistic regression model to estimate the association between CTC interval (divided into quartiles) and the primary outcome (survival with favourable neurologic status at hospital discharge; mRS ≤ 3). We described the CTC interval distribution among enrolling clusters.

RESULTS

We included 24,685 patients: median age was 68 (IQR 56-81), 23% had initial shockable rhythms, and 7.6% survived with favourable neurological status. Compared to the first quartile (≤62 s), longer CTC quartiles (63-115, 116-180, and ≥181 s) demonstrated the following associations with survival with favourable neurological status: adjusted odds ratios 0.95, 95% CI 0.83-1.09; 0.77, 95% CI 0.66-0.89; 0.66, 95% CI 0.56-0.77, respectively. Of the 49 study clusters, median CTC intervals ranged from 86 (IQR 58-130) to 179 s (IQR 112-256).

CONCLUSION

A lower CTC interval was associated with improved patient outcomes. These results demonstrate a wide range of access metrics within North America, and provide a rationale to create protocols to mitigate access obstacles. A 2-min CTC threshold may represent an appropriate target for quality improvement.

Does second EMS unit response time affect outcomes of OHCA in multi-tiered system? A nationwide observational study

OBJECTIVES

The time dependence of a multi-tier response for out-of-hospital cardiac arrest (OHCA) is unclear. The aim of this study was to evaluate the time-dependent effect of EMS response type in a multi-tiered system on the clinical outcomes of OHCA.

METHODS

Adult EMS-treated OHCA of presumed cardiac etiology who were not witnessed by EMS between January 2015 and December 2017 were included. The main exposure was EMS response type: single-tier response, early multi-tier response (0-18 min from call to second EMS arrival), and late multi-tier response (19 min from call to second EMS arrival). The primary outcome was good neurologic recovery at the time of discharge from the hospital. Multivariate logistic regression analysis was performed, adjusting for patient-community and prehospital variables.

RESULTS

Among 54,436 patients, 29,995 patients (55.1%), 21,552 patients (39.6%), and 2889 patients (5.3%) were treated by single-tiered EMS, early multi-tiered EMS, and late multi-tiered EMS, respectively. Good neurological recovery and survival to discharge were more frequent in the early multi-tiered response group (6.4% and 9.7%) than in the single-tiered response group (4.8% and 7.5%) or late multi-tiered response group (3.1% and 5.8%). Compared to the single-tiered response group, the early multi-tiered response group was more likely to have good neurological recovery (adjusted OR, 95% CI: 1.15 [1.06-1.26]), but the late multi-tiered response group was less likely to have good neurological recovery (adjusted OR, 95% CI: 0.76 [0.61-0.96]).

CONCLUSION

In our basic to intermediate-tiered EMS system, early multi-tier response was associated with improved survival and good neurological recovery.

Evaluation of the quality of cardiopulmonary resuscitation according to vehicle driving pattern, using a virtual reality ambulance driving system: a prospective, cross-over, randomised study

OBJECTIVES

To analyse changes in the quality of cardiopulmonary resuscitation (CPR) according to driving patterns encountered during ambulance transport, using a virtual reality simulator.

DESIGN

Prospective, cross-over, randomised study.

SETTING

This study was conducted at the National Fire Service Academy, Cheonan-si, Korea.

PARTICIPANTS

Emergency medical technicians (39 men and 9 women) attending the National Fire Service Academy for clinical training with ≥6 months field experience or having performed ≥10 CPR. Individuals who withdrew consent were excluded.

OUTCOME MEASURES

CPR quality parameters (eg, chest compression depth and its variability).

RESULTS

Chest compressions were performed for 8 min each in a stationary and driving state. The mean chest compression depths were 54.8 mm and 55.3 mm during these two states, respectively (p=0.41). The SD of the chest compression depth was significantly higher while in the driving (7.6 mm) than in the stationary state (6.5 mm; p=0.04). The compression depths in the speed bump and sudden stop sections were 51.5 mm and 50.6 mm, respectively, which was shallower than those in all other sections (p<0.001). The correct hand position rate was low in the speed bump, sudden stop and right-hand cornering sections (65.4%, 71.5% and 72.5%, respectively; p=0.001) CONCLUSIONS: Although we found no differences in chest compression quality parameters between the stationary and driving states, the variability in the chest compression depth increased in the driving state. When comparing CPR quality parameters according to driving patterns, we noted a shallower compression depth, increased variability and decreased correct hand position rate in the speed bump, sudden stop and right-hand cornering sections. The clinical significance of these changes in CPR quality during ambulance transport remains to be determined. Future studies on how to reduce changes in the quality of CPR (including research on equipment development) are needed.

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.

Medical facilities in the neighborhood and incidence of sudden cardiac arrest

BACKGROUND

Medical establishments in the neighborhood, such as pharmacies and primary care clinics, may play a role in improving access to preventive care and treatment and could explain previously reported neighborhood variations in sudden cardiac arrest (SCA) incidence and survival.

METHODS

The Cardiac Arrest Blood Study Repository is a population-based repository of data from adult cardiac arrest patients and population-based controls residing in King County, Washington. We examined the association between the availability of medical facilities near home with SCA risk, using adult (age 18-80) Seattle residents experiencing cardiac arrest (n = 446) and matched controls (n = 208) without a history of heart disease. We also analyzed the association of major medical centers near the event location with emergency medical service (EMS) response time and survival among adult cases (age 18+) presenting with ventricular fibrillation from throughout King County (n = 1537). The number of medical facilities per census tract was determined by geocoding business locations from the National Establishment Time-Series longitudinal database 1990-2010.

RESULTS

More pharmacies in the home census tract was unexpectedly associated with higher odds of SCA (OR:1.28, 95% CI: 1.03, 1.59), and similar associations were observed for other medical facility types. The presence of a major medical center in the event census tract was associated with a faster EMS response time (-53 s, 95% CI: -84, -22), but not with short-term survival.

CONCLUSIONS

We did not observe a protective association between medical facilities in the home census tract and SCA risk, orbetween major medical centers in the event census tract and survival.

A five-year retrospective study of out-of-hospital cardiac arrest in a north-east Italian urban area

BACKGROUND

The reporting and analysing of data of out-of-hospital cardiac arrests encourages the quality improvement of the emergency medical services. For this reason, the establishment of a sufficiently large patient database is intended to allow analysis of resuscitation treatments for out-of-hospital cardiac arrests and performances of different emergency medical services.

AIMS

The aim of this study was to describe the demographics, characteristics, outcomes and determinant factors of survival for patients who suffered an out-of-hospital cardiac arrest.

METHODS

this was a retrospective study including all out-of-hospital cardiac arrest cases treated by the emergency medical service in the district of Udine (Italy) from 1 January 2010-31 December 2014.

RESULTS

A total of 1105 out-of-hospital cardiac arrest patients were attended by the emergency medical service. Of these, 489 (44.2%) underwent cardiopulmonary resuscitation, and return of spontaneous circulation was achieved in 142 patients (29%). There was a male predominance overall, and the main age was 72.6 years (standard deviation 17.9). Cardiopulmonary resuscitation before emergency medical service arrival was performed on 62 cases (44%) in the return of spontaneous circulation group, and on 115 cases (33%) in the no return of spontaneous circulation group ( p<0.024). Among the 142 cases of return of spontaneous circulation, 29 (5.9%) survived to hospital discharge. There was a smaller likelihood of return of spontaneous circulation when patients were female (odds ratio 0.61, 0.40-0.93). Patients who had an out-of-hospital cardiac arrest with an initial shockable rhythm (odds ratio 6.33, 3.86-10.39) or an age <60 years (odds ratio 2.91, 1.86-4.57) had a greater likelihood of return of spontaneous circulation. In addition, bystander cardiopulmonary resuscitation (odds ratio 1.56, 1.04-2.33) was associated with an increased chance of return of spontaneous circulation.

CONCLUSION

The incidence of out-of-hospital cardiac arrest and survival rate lies within the known range. A wider database is necessary to achieve a better knowledge of out-of-hospital cardiac arrest and to drive future investments in the healthcare system.

Out-of-Hospital Cardiac Arrest Resuscitation Systems of Care: A Scientific Statement From the American Heart Association

The American Heart Association previously recommended implementation of cardiac resuscitation systems of care that consist of interconnected community, emergency medical services, and hospital efforts to measure and improve the process of care and outcome for patients with cardiac arrest. In addition, the American Heart Association proposed a national process to develop and implement evidence-based guidelines for cardiac resuscitation systems of care. Significant experience has been gained with implementing these systems, and new evidence has accumulated. This update describes recent advances in the science of cardiac resuscitation systems and evidence of their effectiveness, as well as recent progress in dissemination and implementation throughout the United States. Emphasis is placed on evidence published since the original recommendations (ie, including and since 2010).

Relationship Between Emergency Medical Services Response Time and Bystander Intervention in Patients With Out-of-Hospital Cardiac Arrest

Background

The response time of emergency medical services (EMS) is an important determinant of survival after out‐of‐hospital cardiac arrest. We sought to identify upper limits of EMS response times and bystander interventions associated with neurologically intact survival.

Methods and Results

We analyzed the records of 553 426 patients with out‐of‐hospital cardiac arrest in a Japanese registry between 2010 and 2014. The primary study end point was 1‐month neurologically intact survival (Cerebral Performance Category scale 1 or 2). Increased EMS response time was associated with significantly decreased adjusted odds of 1‐month neurologically intact survival (adjusted odds ratio [aOR] for each 1‐minute increase, 0.89; 95% confidence interval [CI], 0.89–0.90), although this relationship was modified by bystander interventions. The bystander interventions and the ranges of EMS response times that were associated with increased adjusted 1‐month neurologically intact survival were as follows: bystander defibrillation, from ≤2 minutes (aOR, 3.10 [95% CI, 1.25–7.31]) to 13 minutes (aOR, 5.55 [95% CI, 2.66–11.2]); bystander conventional cardiopulmonary resuscitation, from 3 minutes (aOR 1.48 [95% CI, 1.02–2.12]) to 11 minutes (aOR 2.41 [95% CI, 1.61–3.56]); and bystander chest‐compression‐only cardiopulmonary resuscitation, from ≤2 minutes (aOR 1.57 [95% CI, 1.01–2.25]) to 11 minutes (aOR 1.92 [95% CI, 1.45–2.56]). However, the increase in neurologically intact survival of those receiving bystander interventions became statistically insignificant compared with no bystander interventions when the EMS response time was outside these ranges.

Conclusions

The upper limits of the EMS response times associated with improved 1‐month neurologically intact survival were 13 minutes when bystanders provided defibrillation (typically with cardiopulmonary resuscitation) and 11 minutes when bystanders provided cardiopulmonary resuscitation without defibrillation.

The Relationship between Emergency Response Time and Out-Of-Hospital Cardiac Arrest Prognosis: A Meta-Analysis

Objective

To assess the relationship between emergency response time and prognosis of patients with out-of-hospital cardiac arrest.

Design

Systematic review.

Methods

Relevant observational studies were identified by a search of PubMed and ISI databases to 30 January 2014. Primary outcome was survival to discharge. The weighted mean differences (WMD) for response time were calculated for those survivals to discharge and death in hospital. We also carried out a dose response meta-analysis for assessing summary odds ratio (OR) of survival by response time.

Results

A total of 13 studies with 804,998 patients included in the meta-analysis. The WMD of response time between survivals to discharge group and death in hospital group was 1.976 (95% confidence interval [CI] = 1.161-2.792; p<0.001). Sensitivity analyses by only included prospective cohorts showed the WMD of response time between two groups was 1.115 (95% CI=0.508-1.723; p<0.001). Dose-response relationship between response time and survival to discharge risk was observed statistically significant (χ2=39.86, p<0.001). In linear model, the summary OR was 0.914 (95% CI=0.889-0.940) for every 1 minutes delay in response time. In spline model, the survival OR decreased along with the response time, especially when response time less than 7 minutes.

Conclusions

Emergency response time is an important risk factor for prognosis after OHCA in adults. The EMS team must arrive as soon as possible to the site of the event. (Hong Kong j.emerg.med. 2015;22:345-351)

Defibrillation for Ventricular Fibrillation: A Shocking Update

Cardiac arrest is defined as the termination of cardiac activity associated with loss of consciousness, of spontaneous breathing, and of circulation. Sudden cardiac arrest and sudden cardiac death (SCD) are terms often used interchangeably. Most patients with out-of-hospital cardiac arrest have shown coronary artery disease or symptoms during the hour before the event. Cardiac arrest is potentially reversible by cardiopulmonary resuscitation, defibrillation, cardioversion, cardiac pacing, or treatments targeted at the underlying disease (e.g., acute coronary occlusion). We restrict SCD hereafter to cardiac arrest due to ventricular fibrillation, including rhythms shockable by an automatic external defibrillator (AED), implantable cardioverter-defibrillator (ICD), or wearable cardioverter-defibrillator (WCD). We summarize the state of the art related to defibrillation in treating SCD, including a brief history of the evolution of defibrillation, technical characteristics of modern AEDs, strategies to improve AED access and increase survival, ancillary treatments, and use of ICDs or WCDs.

Prehospital Predictors of Initial Shockable Rhythm in Out-of-Hospital Cardiac Arrest: Findings From the Taichung Sudden Unexpected Death Registry (THUNDER)

OBJECTIVE

To identify the incidence and prehospital predictors of ventricular tachycardia/ventricular fibrillation (VT/VF) as the initial arrhythmia in patients with out-of-hospital cardiac arrest (OHCA) in central Taiwan.

PATIENTS AND METHODS

The Taichung Sudden Unexpected Death Registry program encompasses the Taichung metropolitan area in central Taiwan, with a population of 2.7 million and 17 destination hospitals for patients with OHCA. We performed a detailed analysis of demographic characteristics, circumstances of cardiac arrest, and emergency medical service records using the Utstein Style.

RESULTS

From May 1, 2013, through April 30, 2014, resuscitation was attempted in 2013 individuals with OHCA, of which 384 were excluded due to trauma and noncardiac etiologies. Of the 1629 patients with presumed cardiogenic OHCA, 7.9% (n=129) had initial shockable rhythm; this proportion increased to 18.8% (61 of 325) in the witnessed arrest subgroup. Male sex (odds ratio [OR], 2.45; 95% CI, 1.46-4.12; P<.001), age younger than 65 years (OR, 2.39, 95% CI, 1.58-3.62; P<.001), public location of arrest (OR, 4.61; 95% CI, 2.86-7.44; P<.001), and witnessed status (OR, 3.98; 95% CI, 2.62-6.05; P<.001) were independent predictors of VT/VF rhythm.

CONCLUSION

The proportion of patients with OHCA presenting with VT/VF was generally low in this East Asian population. Of the prehospital factors associated with VT/VF, public location of OHCA was the strongest predictor of VT/VF in this population, which may affect planning and deployment of emergency medical services in central Taiwan.

The response time threshold for predicting favourable neurological outcomes in patients with bystander-witnessed out-of-hospital cardiac arrest

OBJECTIVE

It is well established that the period of time between a call being made to emergency medical services (EMS) and the time at which the EMS arrive at the scene (i.e. the response time) affects survival outcomes in patients who experience out-of-hospital cardiac arrest (OHCA). However, the relationship between the response time and favourable neurological outcomes remains unclear. We therefore aimed to determine a response time threshold in patients with bystander-witnessed OHCA that is associated with positive neurological outcomes and to assess the relationship between the response time and neurological outcomes in patients with OHCA.

METHODS

This study was a retrospective, observational analysis of data from 204,277 episodes of bystander-witnessed OHCA between 2006 and 2012 in Japan. We used classification and regression trees (CARTs) and receiver operating characteristic (ROC) curve analyses to determine the threshold of response time associated with favourable neurological outcomes (Cerebral Performance Category 1 or 2) 1 month after cardiac arrest.

RESULTS

Both CARTs and ROC analyses indicated that a threshold of 6.5min was associated with improved neurological outcomes in all bystander-witnessed OHCA events of cardiac origin. Furthermore, bystander cardiopulmonary resuscitation (CPR) prolonged the threshold of response time by 1min (up to 7.5min). The adjusted odds ratio for favourable neurological outcomes in patients with OHCA who received care within ≤6.5min was 1.935 (95% confidential interval: 1.834-2.041, P<0.001).

CONCLUSIONS

A response time of ≤6.5min was closely associated with favourable neurological outcomes in all bystander-witnessed patients with OHCA. Bystander CPR prolonged the response time threshold by 1min.

Impact of a feedback device on chest compression quality during extended manikin CPR: a randomized crossover study

PURPOSES

Chest compressions require physical effort leading to increased fatigue and rapid degradation in the quality of cardiopulmonary resuscitation overtime. Despite harmful effect of interrupting chest compressions, current guidelines recommend that rescuers switch every 2 minutes. The impact on the quality of chest compressions during extended cardiopulmonary resuscitation has yet to be assessed.

BASIC PROCEDURES

We conducted randomized crossover study on manikin (ResusciAnne; Laerdal). After randomization, 60 professional emergency rescuers performed 2 × 10 minutes of continuous chest compressions with and without a feedback device (CPRmeter). Efficient compression rate (primary outcome) was defined as the frequency target reached along with depth and leaning at the same time (recorded continuously).

MAIN FINDINGS

The 10-minute mean efficient compression rate was significantly better in the feedback group: 42% vs 21% (P< .001). There was no significant difference between the first (43%) and the tenth minute (36%; P= .068) with feedback. Conversely, a significant difference was evident from the second minute without feedback (35% initially vs 27%; P< .001). The efficient compression rate difference with and without feedback was significant every minute, from the second minute onwards. CPRmeter feedback significantly improved chest compression depth from the first minute, leaning from the second minute and rate from the third minute.

PRINCIPAL CONCLUSIONS

A real-time feedback device delivers longer effective, steadier chest compressions over time. An extrapolation of these results from simulation may allow rescuer switches to be carried out beyond the currently recommended 2 minutes when a feedback device is used.

Spatial Variation and Resuscitation Process Affecting Survival after Out-of-Hospital Cardiac Arrests (OHCA)

BACKGROUND

Ambulance response times and resuscitation efforts are critical predictors of the survival rate after out-of-hospital cardiac arrests (OHCA). On the other hand, rural-urban differences in the OHCA survival rates are an important public health issue.

METHODS

We retrospectively reviewed the January 2011-December 2013 OHCA registry data of Kaohsiung City, Taiwan. With particular focus on geospatial variables, we aimed to unveil risk factors predicting the overall OHCA survival until hospital admission. Spatial analysis, network analysis, and the Kriging method by using geographic information systems were applied to analyze spatial variations and calculate the transport distance. Logistic regression was used to identify the risk factors for OHCA survival.

RESULTS

Among the 4,957 patients, the overall OHCA survival to hospital admission was 16.5%. In the multivariate analysis, female sex (adjusted odds ratio:, AOR, 1.24 [1.06-1.45]), events in public areas (AOR: 1.30 [1.05-1.61]), exposure to automated external defibrillator (AED) shock (AOR: 1.70 [1.30-2.23]), use of laryngeal mask airway (LMA) (AOR: 1.35 [1.16-1.58]), non-trauma patients (AOR: 1.41 [1.04-1.90]), ambulance bypassed the closest hospital (AOR: 1.28 [1.07-1.53]), and OHCA within the high population density areas (AOR: 1.89 [1.55-2.32]) were positively associated with improved OHCA survival. By contrast, a prolonged total emergency medical services (EMS) time interval was negatively associated with OHCA survival (AOR: 0.98 [0.96-0.99]).

CONCLUSIONS

Resuscitative efforts, such as AED or LMA use, and a short total EMS time interval improved OHCA outcomes in emergency departments. The spatial heterogeneity of emergency medical resources between rural and urban areas might affect survival rate.

Emergency medical service treated out-of-hospital cardiac arrest: Identification of weak links in the chain-of-survival through an epidemiological study

BACKGROUND

In-depth analysis of emergency medical services (EMSs) performances in out-of-hospital cardiac arrest (OHCA) promotes quality improvement.

AIMS

The purpose of this study was to identify the improvable factors of the EMS response to OHCA through the description and analysis of OHCA incidence, characteristics, management and outcome.

METHODS

This was a retrospective cohort study on all OHCA patients treated by the EMSs of the district of Trieste, Italy (236,556 inhabitants) in 2011.

RESULTS

A total of 678 OHCAs occurred and 142 (20.1%) underwent cardiopulmonary resuscitation (CPR), with a respective incidence of 287/100,000/year and 60/100,000/year. The incidence of shockable rhythms in the CPR group was 13/100,000. OHCAs occurred mainly during daytime, though the proportion of patients receiving CPR was significantly higher by night-time (p=0.01). Thirty-four CPR patients (23.9%) restored spontaneous circulation on scene; 12 (8.5%) survived to hospital discharge (11 with good neurological recovery). Survival was not correlated with age, while was significantly higher for patients with shockable rhythms (32.3%; p<0.001). Mean response time was 8 min. Direct intervention of physician-staffed units did not improve the outcome when compared with two-tiered activation. Patients immediately identified as OHCA by dispatch nurses and those undergoing therapeutic hypothermia showed a non-significant trend towards improved survival (p=0.09 and 0.07, respectively).

CONCLUSIONS

OHCA identification by dispatch nurses and reduction of response time were the factors most susceptible to improvement.

Impact of vehicular networks on emergency medical services in urban areas

The speed with which emergency personnel can provide emergency treatment is crucial to reducing death and disability among acute and critically ill patients. Unfortunately, the rapid development of cities and increased numbers of vehicles are preventing emergency vehicles from easily reaching locations where they are needed. A significant number of researchers are experimenting with vehicular networks to address this issue, but in most studies the focus has been on communication technologies and protocols, with few efforts to assess how network applications actually support emergency medical care. Our motivation was to search the literature for suggested methods for assisting emergency vehicles, and to use simulations to evaluate them. Our results and evidence-based studies were cross-referenced to assess each method in terms of cumulative survival ratio (CSR) gains for acute and critically ill patients. Simulation results indicate that traffic light preemption resulted in significant CSR increases of between 32.4% and 90.2%. Route guidance was found to increase CSRs from 14.1% to 57.8%, while path clearing increased CSRs by 15.5% or less. It is our hope that this data will support the efforts of emergency medical technicians, traffic managers, and policy makers.

[Survival of out-hospital cardiac arrests attended by a mobile intensive care unit in Asturias (Spain) in 2010]

OBJECTIVE

To evaluate attendance timings, out- and in-hospital characteristics, and survival of cardiac arrests attended by an advanced life support unit in Asturias (Spain) in 2010. Factors related to survival upon admission and at discharge were also analyzed.

DESIGN

A retrospective, observational trial was carried out involving a cohort of out-hospital cardiac arrests (OHCA) occurring between 1 January 2010 and 31 December 2010, with one year of follow-up from OHCA.

SETTING

Health Care Area IV of the Principality of Asturias, with a population of 342,020 in 2010.

PATIENTS

All patients with OHCA and attended by an advanced life support unit were considered.

MAIN VARIABLES

Demographic data, the etiology of cardiac arrest, bystander cardiopulmonary resuscitation (CPR), attendance timings and survival upon admission, at discharge and after one year.

RESULTS

A total of 177 OHCA were included. Of these, 120 underwent CPR by the advanced life support team. Sixty-six of these cases (55%) were caused by presumed heart disease. A total of 63 patients (52.5%) recovered spontaneous circulation, and 51 (42.5%) maintained circulation upon admission to hospital. Thirteen patients (10.8%) were discharged alive. After one year, 11 patients were still alive (9.2%) - 9 of them (7.5%) with a Cerebral Performance Category (CPC) score of 1. Ventricular fibrillation and short attendance timings were related to increased survival.

CONCLUSIONS

The survival rate upon admission was better than in other series and similar at discharge. Initial rhythm and attendance timings were related. Public automated external defibrillators (AED) were not used, and bystander CPR was infrequent.

Chest injury following cardiopulmonary resuscitation: a prospective computed tomography evaluation

INTRODUCTION

Traumatic chest injuries may occur following cardiopulmonary resuscitation (CPR). The aim of this study was to address the frequency of injuries, especially rib and sternal fractures, and also to identify factors that contribute to post-CPR trauma.

METHODS

This study was a prospective cross-sectional study conducted in the emergency departments (ED) of eight academic tertiary care centers. To evaluate injuries secondary to CPR, we performed chest computed tomography (CT) in patients who were successfully resuscitated from cardiac arrest. Contributing factors that might be related to injuries were also investigated.

RESULTS

We enrolled 71 patients between 1 January 2011 and 30 June 2011. Rib and sternal fractures were diagnosed in 22 and 3 patients, respectively. Females were more susceptible to rib fracture (p=0.036). When non-physicians participated as chest compressors in the ED, more ribs were fractured (p=0.048). The duration of CPR and number of compressors were not contributing factors to trauma secondary to CPR. There was a wide variation in the frequency of rib fractures from hospital to hospital (0-83.3%). In high-risk hospitals (in which more than 50% of patients had rib fractures), the average age of the patients was higher, and non-physicians took part in ED CPR more often than they did at low-risk hospitals.

CONCLUSION

The incidence of rib fracture following CPR was different in various hospitals. The presence of non-physician chest compressors in the ED was one of the contributing factors to rib fracture. Further studies on the influence of resuscitators and relation between quality of chest compression and CPR-induced injuries are warranted to reduce complications following CPR.

Impact of physical fitness and biometric data on the quality of external chest compression: a randomised, crossover trial

Background

During circulatory arrest, effective external chest compression (ECC) is a key element for patient survival. In 2005, international emergency medical organisations changed their recommended compression-ventilation ratio (CVR) from 15:2 to 30:2 to acknowledge the vital importance of ECC. We hypothesised that physical fitness, biometric data and gender can influence the quality of ECC. Furthermore, we aimed to determine objective parameters of physical fitness that can reliably predict the quality of ECC.

Methods

The physical fitness of 30 male and 10 female healthcare professionals was assessed by cycling and rowing ergometry (focussing on lower and upper body, respectively). During ergometry, continuous breath-by-breath ergospirometric measurements and heart rate (HR) were recorded. All participants performed two nine-minute sequences of ECC on a manikin using CVRs of 30:2 and 15:2. We measured the compression and decompression depths, compression rates and assessed the participants' perception of exhaustion and comfort. The median body mass index (BMI; male 25.4 kg/m² and female 20.4 kg/m²) was used as the threshold for subgroup analyses of participants with higher and lower BMI.

Results

HR during rowing ergometry at 75 watts (HR₇₅) correlated best with the quality of ECC (r = -0.57, p < 0.05). Participants with a higher BMI and better physical fitness performed better and showed less fatigue during ECC. These results are valid for the entire cohort, as well as for the gender-based subgroups. The compressions of female participants were too shallow and more rapid (mean compression depth was 32 mm and rate was 117/min with a CVR of 30:2). For participants with a lower BMI and higher HR₇₅, the compression depth decreased over time, beginning after four minutes for the 15:2 CVR and after three minutes for the 30:2 CVR. Although found to be more exhausting, a CVR of 30:2 was rated as being more comfortable.

Conclusion

The quality of the ECC and fatigue can both be predicted by BMI and physical fitness. An evaluation focussing on the upper body may be a more valid predictor of ECC quality than cycling based tests. Our data strongly support the recommendation to relieve ECC providers after two minutes.