Chih-Hao Lin

Comparison of Emergency Medical Services Systems Across Pan-Asian Countries: A Web-based Survey

Abstract Background. There are great variations in out-of-hospital cardiac arrest (OHCA) survival outcomes among different countries and different emergency medical services (EMS) systems. The impact of different systems and their contribution to enhanced survival are poorly understood. This paper compares the EMS systems of several Asian sites making up the Pan-Asian Resuscitation Outcomes Study (PAROS) network. Some preliminary cardiac arrest outcomes are also reported. Methods. This is a cross-sectional descriptive survey study addressing population demographics, service levels, provider characteristics, system operations, budget and finance, medical direction (leadership), and oversight. Results. Most of the systems are single-tiered. Fire-based EMS systems are predominant. Bangkok and Kuala Lumpur have hospital-based systems. Service level is relatively low, from basic to intermediate in most of the communities. Korea, Japan, Singapore, and Bangkok have intermediate emergency medical technician (EMT) service levels, while Taiwan and Dubai have paramedic service levels. Medical direction and oversight have not been systemically established, except in some communities. Systems are mostly dependent on public funding. We found variations in available resources in terms of ambulances and providers. The number of ambulances is 0.3 to 3.2 per 100,000 population, and most ambulances are basic life support (BLS) vehicles. The number of human resources ranges from 4.0 per 100,000 population in Singapore to 55.7 per 100,000 population in Taipei. Average response times vary between 5.1 minutes (Tainan) and 22.5 minutes (Kuala Lumpur). Conclusion. We found substantial variation in 11 communities across the PAROS EMS systems. This study will provide the foundation for understanding subsequent studies arising from the PAROS effort.

Comparison of emergency medical services systems in the pan-Asian resuscitation outcomes study countries: Report from a literature review and survey

Asia–Pacific countries have unique prehospital emergency care or emergency medical services (EMS) systems, which are different from European or Anglo‐American models. We aimed to compare the EMS systems of eight Asia–Pacific countries/regions as part of the Pan Asian Resuscitation Outcomes Study (PAROS), to provide a basis for future comparative studies across systems of care.

Managing emergency department overcrowding via ambulance diversion: A discrete event simulation model

BACKGROUND/PURPOSEnAmbulance diversion (AD) is considered one of the possible solutions to relieve emergency department (ED) overcrowding. Study of the effectiveness of various AD strategies is prerequisite for policy-making. Our aim is to develop a tool that quantitatively evaluates the effectiveness of various AD strategies.nnnMETHODSnA simulation model and a computer simulation program were developed. Three sets of simulations were executed to evaluate AD initiating criteria, patient-blocking rules, and AD intervals, respectively. The crowdedness index, the patient waiting time for service, and the percentage of adverse patients were assessed to determine the effect of various AD policies.nnnRESULTSnSimulation results suggest that, in a certain setting, the best timing for implementing AD is when the crowdedness index reaches the critical value, 1.0 - an indicator that ED is operating at its maximal capacity. The strategy to divert all patients transported by ambulance is more effective than to divert either high-acuity patients only or low-acuity patients only. Given a total allowable AD duration, implementing AD multiple times with short intervals generally has better effect than having a single AD with maximal allowable duration.nnnCONCLUSIONnAn input-throughput-output simulation model is proposed for simulating ED operation. Effectiveness of several AD strategies on relieving ED overcrowding was assessed via computer simulations based on this model. By appropriate parameter settings, the model can represent medical resource providers of different scales. It is also feasible to expand the simulations to evaluate the effect of AD strategies on a community basis. The results may offer insights for making effective AD policies.

Rationale, Methodology, and Implementation of a Dispatcher-assisted Cardiopulmonary Resuscitation Trial in the Asia-Pacific (Pan-Asian Resuscitation Outcomes Study Phase 2)

Abstract Background. Survival outcomes from out-of-hospital cardiac arrest (OHCA) in Asia are poor (2–11%). Bystander cardiopulmonary resuscitation (CPR) rates are relatively low in Asia. Dispatcher-assisted CPR (DA-CPR) has recently emerged as a potentially cost-effective intervention to increase bystander CPR and survival from OHCA. The Pan-Asian Resuscitation Outcomes Study (PAROS), an Asia-Pacific cardiac arrest registry, was set up in 2009, with the aim of understanding OHCA as a disease in Asia and improving OHCA survival. The network has adopted DA-CPR as part of its strategy to improve OHCA survival. Objective. This article aims to describe the conceptualization, study design, potential benefits, and difficulties for implementation of DA-CPR trial in the Asia-Pacific. Methods. Two levels of intervention, basic and comprehensive, will be offered to PAROS participating sites. The basic level consists of implementation of a DA-CPR protocol and training program, while the comprehensive level consists of implementation of the basic level, with the addition of a dispatch quality measurement tool, quality improvement program, and community education program. Sites that are not able to implement the package will contribute control data. The primary outcome of the study is survival to hospital discharge or survival to 30 days post cardiac arrest. DA-CPR and bystander CPR are secondary outcomes. Conclusion. Implementation of DA-CPR requires concerted efforts by EMS leaders and supervisors, dispatchers, hospital stakeholders, policy makers, and the general public. The DA-CPR trial implemented by the PAROS sites, if successful, can serve as a model for other countries considering such an intervention in their EMS systems.

Associations between gender and cardiac arrest outcomes in Pan-Asian out-of-hospital cardiac arrest patients☆

BACKGROUNDnThe incidence of out-of-hospital cardiac arrest (OHCA) in women is thought to be lower than that of men, with better outcomes in some Western studies.nnnOBJECTIVESnThis study aimed to investigate the effect of gender on OHCA outcomes in the Pan-Asian population.nnnMETHODOLOGYnThis was a retrospective, secondary analysis of the Pan Asian Resuscitation Outcomes Study (PAROS) data between 2009 and 2012. We included OHCA cases which were presumed cardiac etiology, aged 18 years and above and resuscitation attempted by emergency medical services (EMS) systems. We used multi-level mixed-effects logistic regression models to account for the clustering effect of individuals within the country. Primary outcome was survival to hospital discharge.nnnRESULTSnWe included a total of 40,159 OHCA cases, 40% of which were women. We found that women were more likely to be older and have an initial non-shockable arrest rhythm; they were more likely to receive bystander cardio-pulmonary resuscitation (CPR). The univariate analysis showed that women were significantly less likely to have return of spontaneous circulation (ROSC) at scene or in the emergency department (ED), and had lower rates of survival-to-admission and discharge, and poorer overall and cerebral performance outcomes. There was however, no significant gender difference on outcomes after adjustment of other confounders. Women in the reproductive age group (age 18-44 years) were significantly more likely to have ROSC at scene or in the ED, higher rates of survival-to-admission and discharge, and have better overall and cerebral performance outcomes after adjustment for differences in baseline and pre-hospital factors. Menopausal women (age 55 years and above) were less likely to survive to admission after adjusting for other pre-hospital characteristics but not after age adjustment.nnnCONCLUSIONnDifferences in survival outcomes between reproductive and menopausal women highlight a need for further investigations into the plausible social, pathologic or hormonal basis.

Recommendations on Ambulance Cardiopulmonary Resuscitation in Basic Life Support Systems

AbstractAim. Cardiopulmonary resuscitation (CPR) during ambulance transport can be a safety risk for providers and can affect CPR quality. In many Asian countries with basic life support (BLS) systems, patients experiencing out-of-hospital cardiac arrest (OHCA) are routinely transported in ambulances in which CPR is performed. This paper aims to make recommendations on best practices for CPR during ambulance transport in BLS systems. Methods. A panel consisting of 20 experts (including 4 North Americans) in emergency medical services (EMS) and resuscitation science was selected, and met over two days. We performed a literature review and selected 33 candidate issues in five core areas. Using Delphi methodology, the issues were classified into dichotomous (yes/no), multiple choice, and ranking questions. Primary consensus between experts was reached when there was more than 70% agreement. Questions with 60–69% agreement were made more specific and were submitted for a second round of voting. Results. The panel agreed upon 24 consensus statements with more than 70% agreement (2 rounds of voting). The recommendations cover the following: length of time on the scene; advanced airway at the scene; CPR prior to transport; rhythm analysis and defibrillation during transport; prehospital interventions; field termination of resuscitation (TOR); consent for TOR; destination hospital; transport protocol; number of staff members; restraint systems; mechanical CPR; turning off of the engine for rhythm analysis; alternative CPR; and feedback for CPR quality. Conclusion. Recommendations for CPR during ambulance transport were developed using the Delphi method. These recommendations should be validated in clinical settings.

Electrolyte abnormalities and laboratory findings in patients with out-of-hospital cardiac arrest who have kidney disease

PURPOSESnAlthough electrolyte abnormalities have been generally considered the major cause of out-of-hospital cardiac arrest (OHCA) in patients with kidney disease (KD), this association has never been prospectively validated.nnnMETHODSnA prospective, observational study was conducted in a tertiary university hospital between January 2008 and December 2009. The study sample consisted of consecutively admitted patients with nontraumatic OHCA. Based on the estimated glomerular filtration rate (eGFR, unit: milliliters per minute per 1.73 m(2)), the enrollees were divided into 3 groups: group A (normal kidney function or mild KD; eGFR, 60.0), group B (moderate KD; eGFR between 15.0 and 59.9), and group C (severe KD; eGFR<15.0 or on dialysis). The laboratory findings of the groups were compared. Two-tailed P values less than .005 were considered significant.nnnRESULTSnTwo hundred thirty-four enrollees (137 were male) were divided into 3 groups: group A (n = 51; 21.8%), group B (n = 128; 54.7%), and group C (n = 55; 23.5%). Compared with the other 2 groups, group C presented significantly higher serum potassium and magnesium and lower pH and hemoglobin level (all P < .005). After stratifications of the significant variables, a post hoc analysis revealed that group C presented significantly higher incidences of hypermagnesemia (Mg >2.5 mmol/L) and severe hyperkalemia (K >6.5 mmol/L) (both P < .005) than the other 2 groups. The odds ratios of the incidence of severe hyperkalemia in group C was 3.37 (95% confidence intervals, 1.46-7.77) compared with group A (50.9% vs 23.5%, P < .005).nnnCONCLUSIONSnSevere hyperkalemia is common in patients with OHCA who have severe KD and should be considered during resuscitation for these patients.

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.

Prognostic values of blood ammonia and partial pressure of ammonia on hospital arrival in out-of-hospital cardiac arrests

PURPOSESnOutcome prediction for out-of-hospital cardiac arrest (OHCA) is of medical, ethical, and socioeconomic importance. We hypothesized that blood ammonia may reflect tissue hypoxia in OHCA patients and conducted this study to evaluate the prognostic value of ammonia for the return of spontaneous circulation (ROSC).nnnMETHODSnThis prospective, observational study was conducted in a tertiary university hospital between January 2008 and December 2008. The subjects consisted of OHCA patients who were sent to the emergency department (ED). The primary outcome was ROSC. The prognostic values were calculated for ammonia levels and the partial pressure of ammonia (pNH(3)), and the results were depicted as a receiver operating characteristics curve with an area under the curve.nnnRESULTSnAmong 119 patients enrolled in this study, 28 patients (23.5%) achieved ROSC. Ammonia levels and pNH(3) in the non-ROSC group were significantly higher than those in the ROSC group (167.0 μmol/L vs 80.0 μmol/L, P < .05; 2.61 × 10(-5) vs 1.67 × 10(-5) mm Hg, P < .05, respectively). The predictive capacity of area under the curve for ammonia and pNH(3) for non-ROSC was 0.85 (95% confidence interval, 0.75-0.95) and 0.73 (95% confidence interval, 0.61-0.84), respectively. The multivariate analysis confirmed that ammonia and pNH(3) are independent predictors of non-ROSC. The prognostic value of ammonia was better than that of pNH(3). The cutoff level for ammonia of 84 μmol/L was 94.5% sensitive and 75.0% specific for predicting non-ROSC with a diagnostic accuracy of 89.9%.nnnCONCLUSIONSnHyperammonemia on ED arrival is independently predictive of non-ROSC for OHCA patients. The findings may offer useful information for clinical management.

Use of automated external defibrillators in patients with traumatic out-of-hospital cardiac arrest

BACKGROUNDnBecause out-of-hospital cardiac arrests (OHCAs) due to a major trauma rarely present with shockable rhythms, the potential benefits of using automated external defibrillators (AEDs) at the scene of traumatic OHCAs have not been examined.nnnMETHODSnWe conducted an observational, retrospective cohort study using an Utstein-style analysis in Tainan city, Taiwan. The enrollees were adult patients with traumatic OHCAs accessed by emergency medical technicians (EMTs) from January 1, 2004 to December 31, 2010. The exposure was the use or non-use of AEDs at the scene, as determined by the clinical judgment of the EMTs. The primary outcome evaluated was a sustained (≥2h) return of spontaneous circulation (ROSC), and the secondary outcomes were prehospital ROSC, overall ROSC, survival to hospital admission, survival at one month and favorable neurologic status at one month.nnnRESULTSnA total of 424 patients (313 males) were enrolled, of whom 280 had AEDs applied, and 144 did not. Only 25 (5.9%) patients had received bystander cardiopulmonary resuscitation (CPR), and merely 21 (7.5%) patients in the AED group presented with shockable rhythms. Compared to the non-AED group, the primary and secondary outcomes of the AED group were not significantly different, except for a significantly lower prehospital ROSC rate (1.1% vs. 4.9%, p<0.05). Multivariate analysis showed no significant interactions between the use of AEDs and other key variables. Use of the AED was not associated with sustained ROSC (OR 1.33; 95% CI 0.75-2.38, p=0.33).nnnCONCLUSIONSnIn a community with a low prevalence of shockable rhythms and administration of bystander CPR in patients with traumatic OHCA, we found no significant differences in the sustained ROSC between the AED and the non-AED groups. Considering scene safety and the possible interruption of CPR, we do not encourage the routine use of AEDs at the scene of traumatic OHCAs.