Machine learning prediction of refractory ventricular fibrillation in out-of-hospital cardiac arrest using features available to EMS

Background

Shock-refractory ventricular fibrillation (VF) or ventricular tachycardia (VT) is a treatment challenge in out-of-hospital cardiac arrest (OHCA). This study aimed to develop and validate machine learning models that could be implemented by emergency medical services (EMS) to predict refractory VF/VT in OHCA patients.

Methods

This was a retrospective study examining adult non-traumatic OHCA patients brought into the emergency department by Singapore EMS from the Pan-Asian Resuscitation Outcomes Study (PAROS) registry. Data from April 2010 to March 2020 were extracted for this study. Refractory VF/VT was defined as VF/VT persisting or recurring after at least one shock. Features were selected based on expert clinical opinion and availability to dispatch prior to arrival at scene. Multivariable logistic regression (MVR), LASSO and random forest (RF) models were investigated. Model performance was evaluated using receiver operator characteristic (ROC) area under curve (AUC) analysis and calibration plots.

Results

20,713 patients were included in this study, of which 860 (4.1%) fulfilled the criteria for refractory VF/VT. All models performed comparably and were moderately well-calibrated. ROC-AUC were 0.732 (95% CI, 0.695 - 0.769) for MVR, 0.738 (95% CI, 0.701 - 0.774) for LASSO, and 0.731 (95% CI, 0.690 - 0.773) for RF. The shared important predictors across all models included male gender and public location.

Conclusion

The machine learning models developed have potential clinical utility to improve outcomes in cases of refractory VF/VT OHCA. Prediction of refractory VF/VT prior to arrival at patient's side may allow for increased options for intervention both by EMS and tertiary care centres.

Inter hospital external validation of interpretable machine learning based triage score for the emergency department using common data model

Emergency departments (ED) are complex, triage is a main task in the ED to prioritize patient with limited medical resources who need them most. Machine learning (ML) based ED triage tool, Score for Emergency Risk Prediction (SERP), was previously developed using an interpretable ML framework with single center. We aimed to develop SERP with 3 Korean multicenter cohorts based on common data model (CDM) without data sharing and compare performance with inter-hospital validation design. This retrospective cohort study included all adult emergency visit patients of 3 hospitals in Korea from 2016 to 2017. We adopted CDM for the standardized multicenter research. The outcome of interest was 2-day mortality after the patients' ED visit. We developed each hospital SERP using interpretable ML framework and validated inter-hospital wisely. We accessed the performance of each hospital's score based on some metrics considering data imbalance strategy. The study population for each hospital included 87,670, 83,363 and 54,423 ED visits from 2016 to 2017. The 2-day mortality rate were 0.51%, 0.56% and 0.65%. Validation results showed accurate for inter hospital validation which has at least AUROC of 0.899 (0.858-0.940). We developed multicenter based Interpretable ML model using CDM for 2-day mortality prediction and executed Inter-hospital external validation which showed enough high accuracy.

Wolf creek XVII part 4: Amplifying lay-rescuer response

Introduction

Amplifying lay-rescuer response is a key priority to increase survival from out-of-hospital cardiac arrest (OHCA). We describe the current state of lay-rescuer response, how we envision the future, and the gaps, barriers, and research priorities that will amplify response to OHCA.

Methods

'Amplifying Lay-Rescuer Response' was one of six focus topics for the Wolf Creek XVII Conference held on June 14-17, 2023, in Ann Arbor, Michigan, USA. Conference invitees included international thought leaders and scientists in the field of cardiac arrest resuscitation from academia and industry. Participants submitted via online survey knowledge gaps, barriers to translation and research priorities for each focus topic. Expert panels used the survey results and their own perspectives and insights to create and present a preliminary unranked list for each category that was debated, revised and ranked by all attendees to identify the top 5 for each category.

Results

The top five knowledge gaps as ranked by the panel, reflected a recognition of the need to better understand the psycho-social aspects of lay response. The top five barriers to translation reflected issues at the individual, community, societal, structural, and governmental levels. The top five research priorities were focused on understanding the social/psychological and emotional barriers to action, finding the most effective/cost-effective strategies to educate lay persons and implement community life-saving interventions, evaluation of new technological solutions and how to enhance the role of dispatch working with lay-rescuers.

Conclusion

Future research in lay rescuer response should incorporate technology innovations, understand the "humanity" of the situation, leverage implementation science and systems thinking to save lives. This will require the field of resuscitation to engage with scholars outside our traditional ranks and to be open to new ways of thinking about old problems.

Corrigendum to "Development and Asian-wide validation of the Grade for Interpretable Field Triage (GIFT) for predicting mortality in pre-hospital patients using the Pan-Asian Trauma Outcomes Study (PATOS)" [The Lancet Regional Health - Western Pacific 34 (2023) 100733]

[This corrects the article DOI: 10.1016/j.lanwpc.2023.100733.].

Increasing neurologically intact survival after out-of-hospital cardiac arrest among elderly: Singapore Experience

Objectives

With more elderly presenting with Out-of-Hospital Cardiac Arrests (OHCAs) globally, neurologically intact survival (NIS) should be the aim of resuscitation. We aimed to study the trend of OHCA amongst elderly in a large Asian registry to identify if age is independently associated with NIS and factors associated with NIS.

Methods

All adult OHCAs aged ≥18 years attended by emergency medical services (EMS) from April 2010 to December 2019 in Singapore was extracted from the Pan-Asian Resuscitation Outcomes Study (PAROS) registry. Cases pronounced dead at scene, non-EMS transported, traumatic OHCAs and OHCAs in ambulances were excluded. Patient characteristics and outcomes were compared across four age categories (18-64, 65-79, 80-89, ≥90). Multivariable logistic regression analysis determined the factors associated with NIS.

Results

19,519 eligible cases were analyzed. OHCA incidence increased with age almost doubling in octogenarians (from 312/100,000 in 2011 to 652/100,000 in 2019) and tripling in those ≥90 years (from 458/100,000 in 2011 to 1271/100,000 in 2019). The proportion of patients with NIS improved over time for the 18-64, 65-79- and 80-89-years age groups, with the greatest improvement in the youngest group. NIS decreased with each increasing year of age and minute of response time. NIS increased in the arrests of presumed cardiac etiology, witnessed and bystander CPR.

Conclusions

Survival with good outcomes has increased even amongst the elderly. Regardless of age, NIS is possible with good-quality CPR, highlighting its importance. End-of-life planning is a complex yet necessary decision that requires qualitative exploration with elderly, their families and care providers.

Comparing outcomes of out-of-hospital cardiac arrest patients with initial shockable rhythm in Singapore and Osaka using population-based databases

BACKGROUND

Previous research indicated outcomes among refractory out-of-hospital cardiac arrest (OHCA) patients with initial shockable rhythm were different in Singapore and Osaka, Japan, possibly due to the differences in access to extracorporeal cardiopulmonary resuscitation. However, this previous study had a risk of selection bias. To address this concern, this study aimed to evaluate the outcomes between Singapore and Osaka for OHCA patients with initial shockable rhythm using only population-based databases.

METHODS

This was a secondary analysis of two OHCA population-based databases in Osaka and Singapore, including adult OHCA patients with initial shockable rhythm. A machine-learning-based prediction model was derived from the Osaka data (n = 3088) and applied to the PAROS-SG data (n = 2905). We calculated the observed-expected ratio (OE ratio) for good neurological outcomes observed in Singapore and the expected derived from the data in Osaka by dividing subgroups with or without prehospital ROSC.

RESULTS

The one-month good neurological outcomes in Osaka and Singapore among patients with prehospital ROSC were 70% (791/1,125) and 57% (440/773), and among patients without prehospital ROSC were 10% (196/1963) and 2.8% (60/2,132). After adjusting patient characteristics, the outcome in Singapore was slightly better than expected from Osaka in patients with ROSC (OE ratio, 1.067 [95%CI 1.012 to 1.125]), conversely, it was worse than expected in patients without prehospital ROSC (OE ratio, 0.238 [95%CI 0.173 to 0.294]).

CONCLUSION

This study showed the outcomes of OHCA patients without prehospital ROSC in Singapore were worse than expected derived from Osaka data even using population-based databases. (249/250 words).

Technology activated community first responders in Singapore: Real-world care delivery & outcome trends

BACKGROUND

Community first responders (CFRs) strengthen the Chain of Survival for out-of-hospital cardiac arrest (OHCA) care. Considerable efforts have been invested in Singapore's CFR program, during the years 2016-2020, by developing an app-based activation system called myResponder. This paper reports on national CFR response indicators to evaluate the real-world impact of these efforts.

METHODS

We matched data from the Singapore Civil Defence Force's CFR registry with the Pan Asian Resuscitation Outcomes Study (PAROS) registry data to calculate performance indicators. These included the number of CFRs receiving and accepting an issued alert per OHCA event. Also calculated were the fraction of OHCA events where CFRs received an issued alert, or accepted the alert, and arrived at the scene either before or after EMS. We also present trends of these indicators and compare the prevalence of these fractions between the CFR-attended and CFR-unattended OHCA events.

RESULTS

Of 6577 alerted OHCA events, 42.7% accepted an alert, 50% of these arrived at the scene and 71% of them arrived before EMS. Almost all CFR response indicators improved over time even for the pandemic year (2020). The fraction of OHCA events where >2 CFRs received an alert increased from 62% to 96%; the same figure for accepting an alert did not change much but >2 CFRs arriving at the scene increased from 0% to 7.5%. The fraction of OHCA events with an automated external defibrillator applied and defibrillation performed by CFR increased from 4.2% to 10.3% and 1.6% to 3%, respectively. Statistically significant differences were observed in these indicators when CFR-attended and CFR-unattended OHCA events were compared.

CONCLUSION

This real-world study shows that activating CFRs using mobile technology can improve community response to OHCA and are bearing fruit in Singapore at a national level. Some targets for improvement and future research are highlighted in this report.

Intensity-Modulated Proton Therapy (IMPT) Offered Advantageous Dosimetry Compared to Volumetric Arc Therapy (VMAT) or Helical Tomotherapy (HT) in Patients with Synchronous Bilateral Breast Cancer

PURPOSE/OBJECTIVE(S)

Radiotherapy of synchronous bilateral breast cancer poses some technical challenges with regards to dose coverage and sparing of organs at risk (OAR). In this study, we aimed to evaluate dosimetric characteristics of 3 different techniques, IMPT vs photon (VMAT and HT). We hypothesized that IMPT would result in lower doses to organs at risk, as compared to the other 2 techniques.

MATERIALS/METHODS

A total of 10 patients with synchronous bilateral breast cancer who were treated with VMAT at our institution were retrospectively analyzed. Clinical target volume (CTV) included chest wall and regional nodes (supraclavicular fossa and internal mammary chain) and prescription dose was 40.05 Gy in 15 daily fractions. HT and IMPT plans were generated for each patient. Dose-volume statistics, including planning target volume (PTV) coverage and dose to OAR: lungs, heart, thyroid, spinal cord, brachial plexus and esophagus, were compared between modalities using a paired T-test.

RESULTS

Mean age of patients was 61 years (43-84). Majority of the patients (80%) were ER+ PR+ and HER2-. 40% of patients underwent breast reconstruction following surgery. All 3 techniques provided adequate target volume distribution and OAR sparing. Compared to VMAT and HT plans, IMPT had better heart and lung sparing effects, resulting in lower mean and V25 Gy heart dose; mean, V20 Gy and V5 Gy lung dose (p<0.0001). There was no significant difference in VMAT and HT plans for mean heart and lung dose. VMAT plans showed significantly lower V25 Gy heart dose on average (p = 0.04). V5 Gy lung dose was slightly lower in HT compared to VMAT plans, approaching statistical significance (p = 0.08). PTV coverage was adequate for all 3 techniques. All techniques fulfilled cord, esophagus, thyroid and brachial plexus constraints.

CONCLUSION

IMPT plans showed significantly better OAR sparing compared to photon techniques. All 3 techniques met OAR constraints, and resulted in adequate target volume coverage. As IMPT is significantly more costly than VMAT or HT techniques, appropriate patient selection is important to deliver treatment in the most resource-effective manner for patients who would derive the most benefit, for example those with young age or existing heart or lung comorbidities.

Outcome assessment for out-of-hospital cardiac arrest patients in Singapore and Japan with initial shockable rhythm

BACKGROUND

Singapore and Osaka in Japan have comparable population sizes and prehospital management; however, the frequency of ECPR differs greatly for out-of-hospital cardiac arrest (OHCA) patients with initial shockable rhythm. Given this disparity, we hypothesized that the outcomes among the OHCA patients with initial shockable rhythm in Singapore were different from those in Osaka. The aim of this study was to evaluate the outcomes of OHCA patients with initial shockable rhythm in Singapore compared to the expected outcomes derived from Osaka data using machine learning-based prediction models.

METHODS

This was a secondary analysis of two OHCA databases: the Singapore PAROS database (SG-PAROS) and the Osaka-CRITICAL database from Osaka, Japan. This study included adult (18-74 years) OHCA patients with initial shockable rhythm. A machine learning-based prediction model was derived and validated using data from the Osaka-CRITICAL database (derivation data 2012-2017, validation data 2018-2019), and applied to the SG-PAROS database (2010-2016 data), to predict the risk-adjusted probability of favorable neurological outcomes. The observed and expected outcomes were compared using the observed-expected ratio (OE ratio) with 95% confidence intervals (CI).

RESULTS

From the SG-PAROS database, 1,789 patients were included in the analysis. For OHCA patients who achieved return of spontaneous circulation (ROSC) on hospital arrival, the observed favorable neurological outcome was at the same level as expected (OE ratio: 0.905 [95%CI: 0.784-1.036]). On the other hand, for those who had continued cardiac arrest on hospital arrival, the outcomes were lower than expected (shockable rhythm on hospital arrival, OE ratio: 0.369 [95%CI: 0.258-0.499], and nonshockable rhythm, OE ratio: 0.137 [95%CI: 0.065-0.235]).

CONCLUSION

This observational study found that the outcomes for patients with initial shockable rhythm but who did not obtain ROSC on hospital arrival in Singapore were lower than expected from Osaka. We hypothesize this is mainly due to differences in the use of ECPR.

Does witness type affect the chance of receiving bystander CPR in out-of-hospital cardiac arrest?

OBJECTIVES

The relationship between the bystander witness type and receipt of bystander CPR (BCPR) is not well understood. Herein we compared BCPR administration between family and non-family witnessed out-of-hospital cardiac arrest (OHCA).

BACKGROUND

In many communities, interventions in the past decade have contributed to an increased receipt of BCPR, for example in Singapore from 15% to 60%. However, BCPR rates have plateaued despite sustained and ongoing community-based interventions, which may be related to gaps in education or training for various witness types. The purpose of this study was to investigate the association between witness type and BCPR administration.

METHODS

Singapore data from 2010 - 2020 was extracted from the Pan-Asian Resuscitation Outcomes Study (PAROS) network registry (n = 25,024). All adult, layperson witnessed, non-traumatic OHCAs were included in this study.

RESULTS

Of 10,016 eligible OHCA cases, 6,895 were family witnessed and 3,121 were non-family witnessed. After adjustment for potential confounders, BCPR administration was less likely for non-family witnessed OHCA (OR 0.83, 95% CI 0.75, 0.93). After location stratification, non-family witnessed OHCAs were less likely to receive BCPR in residential settings (OR 0.75, 95% CI 0.66, 0.85). In non-residential settings, there was no statistically significant association between witness type and BCPR administration (OR 1.11, 95% CI 0.88, 1.39). Details regarding witness type and bystander CPR were limited.

CONCLUSION

This study found differences in BCPR administration between family and non-family witnessed OHCA cases. Elucidation of witness characteristics may be useful to determine populations that would benefit most from CPR education and training.

Development and Asian-wide validation of the Grade for Interpretable Field Triage (GIFT) for predicting mortality in pre-hospital patients using the Pan-Asian Trauma Outcomes Study (PATOS)

Background

Field triage is critical in injury patients as the appropriate transport of patients to trauma centers is directly associated with clinical outcomes. Several prehospital triage scores have been developed in Western and European cohorts; however, their validity and applicability in Asia remains unclear. Therefore, we aimed to develop and validate an interpretable field triage scoring systems based on a multinational trauma registry in Asia.

Methods

This retrospective and multinational cohort study included all adult transferred injury patients from Korea, Malaysia, Vietnam, and Taiwan between 2016 and 2018. The outcome of interest was a death in the emergency department (ED) after the patients' ED visit. Using these results, we developed the interpretable field triage score with the Korea registry using an interpretable machine learning framework and validated the score externally. The performance of each country's score was assessed using the area under the receiver operating characteristic curve (AUROC). Furthermore, a website for real-world application was developed using R Shiny.

Findings

The study population included 26,294, 9404, 673 and 826 transferred injury patients between 2016 and 2018 from Korea, Malaysia, Vietnam, and Taiwan, respectively. The corresponding rates of a death in the ED were 0.30%, 0.60%, 4.0%, and 4.6% respectively. Age and vital sign were found to be the significant variables for predicting mortality. External validation showed the accuracy of the model with an AUROC of 0.756-0.850.

Interpretation

The Grade for Interpretable Field Triage (GIFT) score is an interpretable and practical tool to predict mortality in field triage for trauma.

Funding

This research was supported by a grant of the Korea Health Technology R&D Project through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health & Welfare, Republic of Korea (Grant Number: HI19C1328).

Evaluation of telephone-assisted cardiopulmonary resuscitation recommendations for out-of-hospital cardiac arrest

AIM OF THE STUDY

While out-of-hospital cardiac arrest (OHCA) is associated with poor survival, early bystander CPR (B-CPR) and telephone CPR (T-CPR) improves survival from OHCA. American Heart Association (AHA) Scientific Statements outline recommendations for T-CPR. We assessed these recommendations and hypothesized that meeting performance standards is associated with increased likelihood of survival. Additional variables were analyzed to identify future performance measurements.

METHODS

We conducted a retrospective cohort study of non-traumatic, adult, OHCA using the Singapore Pan-Asian Resuscitation Outcomes Study. The primary outcome was likelihood of survival; secondary outcomes were pre-hospital Return of Spontaneous Circulation (ROSC) and B-CPR.

RESULTS

From 2012 to 2016, 2,574 arrests met inclusion criteria. Mean age was 68 ± 15; of 2,574, 1,125 (44%) received T-CPR with 5% (135/2574) survival. T-CPR cases that met the Lerner et al. performance metrics analyzed, demonstrated no statistically significant association with survival. Cases which met the Kurz et al. criteria, "Time for Dispatch to Recognize Need for CPR" and "Time to First Compression," had adjusted odds ratios of survival of 1.01 (95% CI:1.00, 1.02; p = <0.01) and 0.99 (95% CI:0.99, 0.99; p = <0.01), respectively. Identified barriers to CPR decreased the odds of T-CPR and B-CPR being performed. Patients with prehospital ROSC had higher odds of B-CPR being performed. EMS response time < 8 minutes was associated with increased survival among patients receiving T-CPR.

CONCLUSION

AHA scientific statements on T-CPR programs serve as ideal starting points for increasing the quality of T-CPR systems and patient outcomes. More work is needed to identify other system performance measures.

Clinical course and mortality in older patients with COVID-19: a cluster-based study in Hong Kong

INTRODUCTION

Compared with previous waves of the coronavirus disease 2019 (COVID-19) pandemic in Hong Kong, the third wave involved a greater number of frail older patients. Because local healthcare policy required hospitalisation for all older adults with COVID-19, we aimed to investigate the clinical course and outcomes in such patients.

METHODS

This retrospective observational study included all patients aged ≥65 years who were admitted to Tuen Mun Hospital for management of COVID-19 between 1 July 2020 and 31 August 2020. We reviewed baseline characteristics, clinical presentation, laboratory results, complications, and outcomes. We also investigated the associations of age and Clinical Frailty Scale (CFS) score with in-patient mortality.

RESULTS

In total, 101 patients were included (median age, 73 years); 52.5% were men and 85% had at least co-morbid chronic disease. The most common symptoms were fever (80.2%) and cough (63.4%). Fifty-two patients (51.5%) developed hypoxia, generally on day 8 (interquartile range, 5-11) after symptom onset. Of the 16 patients who required intensive care unit support, 13 required mechanical ventilation. The overall mortality rate was 16.8%. Patients aged 65-69, 70-79, 80-89, and ≥90 years had mortality rates of 9.1%, 10%, 30%, and 25%, respectively. Patients with CFS scores of 1-2, 3-4, 5-6, and ≥7 had mortality rates of 5.7%, 14.7%, 23.5%, and 40%, respectively. A linear relationship was confirmed between the two mortality trends.

CONCLUSION

Clinical deterioration was common in older patients with COVID-19; their overall mortality rate was 16.8%. Mortality increased linearly with both age and CFS score.

Inter-hospital trends of post-resuscitation interventions and outcomes of out-of-hospital cardiac arrest in Singapore

INTRODUCTION

Hospital-based resuscitation interventions, such as therapeutic temperature management (TTM), emergency percutaneous coronary intervention (PCI) and extracorporeal membrane oxygenation (ECMO) can improve outcomes in out-of-hospital cardiac arrest (OHCA). We investigated post-resuscitation interventions and hospital characteristics on OHCA outcomes across public hospitals in Singapore over a 9-year period.

METHODS

This was a prospective cohort study of all OHCA cases that presented to 6 hospitals in Singapore from 2010 to 2018. Data were extracted from the Pan-Asian Resuscitation Outcomes Study Clinical Research Network (PAROS CRN) registry. We excluded patients younger than 18 years or were dead on arrival at the emergency department. The outcomes were 30-day survival post-arrest, survival to admission, and neurological outcome.

RESULTS

The study analysed 17,735 cases. There was an increasing rate of provision of TTM, emergency PCI and ECMO (P<0.001) in hospitals, and a positive trend of survival outcomes (P<0.001). Relative to hospital F, hospitals B and C had lower provision rates of TTM (≤5.2%). ECMO rate was consistently <1% in all hospitals except hospital F. Hospitals A, B, C, E had <6.5% rates of provision of emergency PCI. Relative to hospital F, OHCA cases from hospitals A, B and C had lower odds of 30-day survival (adjusted odds ratio [aOR]<1; P<0.05 for hospitals A-C) and lower odds of good neurological outcomes (aOR<1; P<0.05 for hospitals A-C). OHCA cases from academic hospitals had higher odds ratio (OR) of 30-day survival (OR 1.3, 95% CI 1.1-1.5) than cases from hospitals without an academic status.

CONCLUSION

Post-resuscitation interventions for OHCA increased across all hospitals in Singapore from 2010 to 2018, correlating with survival rates. The academic status of hospitals was associated with improved survival.

Clinicopathological correlates of out‐of‐hospital cardiac arrests

Background

Methods

Results

Conclusion

Early Coronary Angiography Is Associated with Improved 30-Day Outcomes among Patients with Out-of-Hospital Cardiac Arrest

We evaluated the association between early coronary angiography (CAG) and outcomes in resuscitated out-of-hospital cardiac arrest (OHCA) patients, by linking data from the Singapore Pan-Asian Resuscitation Outcomes Study, with a national registry of cardiac procedures. The 30-day survival and neurological outcome were compared between patients undergoing early CAG (within 1-calender day), versus patients not undergoing early CAG. Inverse probability weighted estimates (IPWE) adjusted for non-randomized CAG. Of 976 resuscitated OHCA patients of cardiac etiology between 2011–2015 (mean(SD) age 64(13) years, 73.7% males), 337 (34.5%) underwent early CAG, of whom, 230 (68.2%) underwent PCI. Those who underwent early CAG were significantly younger (60(12) vs. 66(14) years old), healthier (42% vs. 59% with heart disease; 29% vs. 44% with diabetes), more likely males (86% vs. 67%), and presented with shockable rhythms (69% vs. 36%), compared with those who did not. Early CAG with PCI was associated with better survival and neurological outcome (adjusted odds ratio 1.91 and 1.82 respectively), findings robust to IPWE adjustment. The rates of bleeding and stroke were similar. CAG with PCI within 24 h was associated with improved clinical outcomes after OHCA, without increasing complications. Further studies are required to identify the characteristics of patients who would benefit most from this invasive strategy.

Incidence, characteristics and complications of dispatcher-assisted cardiopulmonary resuscitation initiated in patients not in cardiac arrest

AIM

Dispatcher-assisted cardiopulmonary resuscitation (DA-CPR) can increase bystander CPR rates and improve outcomes in out-of-hospital cardiac arrest (OHCA). Despite the use of protocols, dispatchers may falsely recognise some cases to be in cardiac arrest. Hence, this study aimed to find the incidence of DA-CPR initiated for non-OHCA cases, its characteristics and clinical outcomes in the Singapore population.

METHODS

This was a multi-centre, observational study of all dispatcher-recognised cardiac arrests cases between January to December 2017 involving three tertiary hospitals in Singapore. Data was obtained from the Pan-Asian Resuscitation Outcomes Study cohort. Audio review of dispatch calls from the national emergency ambulance service were conducted and information about patients' clinical outcomes were prospectively collected from health records. Univariate analysis was performed to determine factors associated with in-hospital mortality among non-OHCA patients who received DA-CPR.

RESULTS

Of the 821 patients recognised as having OHCA 328 (40.0%) were not in cardiac arrest and 173 (52.7%) of these received DA-CPR. No complications from chest compressions were found from hospital records. The top diagnoses of non-OHCA patients were cerebrovascular accidents (CVA), syncope and infection. Only final diagnoses of CVA (aOR 20.68), infection (aOR 17.34) and myocardial infarction (aOR 32.19) were significantly associated with in-hospital mortality.

CONCLUSION

In this study, chest compressions initiated on patients not in cardiac arrest by dispatchers did not result in any reported complications and was not associated with in-hospital mortality. This provides reassurance for the continued implementation of DA-CPR.

An evaluation of concordance between head and neck advanced practice radiation therapist and radiation oncologists in toxicity assessment for nasopharyngeal carcinoma patients

•

Show concordance in toxicity assessment between Head and Neck Advanced Practice Radiation Therapist (APRT) and Radiation Oncologist (RO) for Nasopharyngeal Carcinoma (NPC) patients.

•

Describe the importance of timely treatment for NPC patients.

•

Underline the important role development of APRT in complementing the RO.

•

Different ways of data analysis to support the concordance study.

Background

Weekly toxicity assessments for patients undergoing head and neck (HN) radiotherapy are essential to ensure that acute side effects are appropriately managed in order for patients to complete their treatment in a safe and timely manner. The incorporation of Advanced Practice Radiation Therapist (APRT) led treatment reviews has been reported for various subsites, but there is currently a lack of published literature regarding this role for patients with HN cancer. The purpose of this study is to assess the concordance of toxicity assessments performed during weekly radiotherapy treatment reviews for patients undergoing HN radiotherapy between the HN APRT and Radiation Oncologist (RO).

Methods

Twenty-three patients with nasopharyngeal cancer (NPC) under the care of 3 ROs were recruited from June to December 2018; weekly assessments were independently performed by HN APRT and ROs. The HN toxicity assessment was graded according to the Common Terminology Criteria for Advanced Events v4.0. Both assessors were blinded to each other’s assessments. The percentage agreement of concordance and agreement level were interpreted by Cohen’s Kappa statistic (κ), with the ROs’ assessments deemed as the ‘gold standard’.

Results

The overall concordance for all graded toxicity assessments between HN APRT and ROs was 78.4%. Xerostomia, dysgeusia, pharyngeal pain and dermatitis assessment were evaluated as ‘Good’ with agreement ranging from κ = 0.608–0.640 between the HN APRT and ROs while dysphagia scored an ‘Almost Perfect’ agreement of κ = 0.834. ‘Moderate’ agreement between the HN APRT and ROs was observed for oral pain and mucositis assessment. A scoring discrepancy of 1 and 2 grades was observed in 21.2% and 0.4% for these two toxicities.

Conclusion

 There was high concordance in scoring of acute toxicity between the HN APRT and ROs. The results support the continuing involvement of HN APRT in weekly assessments for NPC patients.

An essential review of Singapore's response to out-of-hospital cardiac arrests: improvements over a ten-year period

Care for patients who experience out-of-hospital cardiac arrest (OHCA) has rapidly evolved in the past decade. Increased sophistication of care in the community, emergency medical services (EMS) and hospital setting is associated with improved patient-centred outcomes. Notably, Utstein survival doubled from 11.6% to 23.1% between 2011 and 2016. These achievements involved collaboration between policymakers, clinicians and researchers, and were made possible by a strategic interplay of policy, research and implementation. We review the development and current state of OHCA in Singapore using primary population-based data from the Pan-Asian Resuscitation Outcomes Study and an unstructured search of research databases. We discuss the roles of important milestones in policy, community, dispatch, EMS and hospital interventions. Finally, we relate these interventions to relevant processes and outcomes, such as the relationship between the strategic implementation of bystander cardiopulmonary resuscitation and placement of automated external defibrillator with return of spontaneous circulation, survival to discharge and survival with favourable neurological outcomes.

Assessing unrealised potential for organ donation after out-of-hospital cardiac arrest

Background

Organ donation after brain death is the standard practice in many countries. Rates are low globally. This study explores the potential national number of candidates for uncontrolled donations after cardiac death (uDCD) amongst out-of-hospital cardiac arrest (OHCA) patients and the influence of extracorporeal cardiopulmonary resuscitation (ECPR) on the candidacy of these potential organ donors using Singapore as a case study.

Methods

Using Singapore data from the Pan-Asian Resuscitation Outcomes Study, we identified all non-traumatic OHCA cases from 2010 to 2016. Four established criteria for identifying uDCD candidates (Madrid, San Carlos Madrid, Maastricht and Paris) were retrospectively applied onto the population. Within these four groups, a condensed ECPR eligibility criteria was employed and thereafter, an estimated ECPR survival rate was applied, extrapolating for possible neurologically intact survivors had ECPR been administered.

Results

12,546 OHCA cases (64.8% male, mean age 65.2 years old) qualified for analysis. The estimated number of OHCA patients who were eligible for uDCD ranged from 4.3 to 19.6%. The final projected percentage of potential uDCD donors readjusted for ECPR survivors was 4.2% (Paris criteria worst-case scenario, n = 532) to 19.4% of all OHCA cases (Maastricht criteria best-case scenario, n = 2428), for an estimated 14.3 to 65.4 uDCD donors per million population per year (pmp/year).

Conclusions

In Singapore case study, we demonstrated the potential numbers of candidates for uDCD among resuscitated OHCA cases. This sizeable pool of potential donors demonstrates the potential for an uDCD program to expand the organ donor pool. A small proportion of these patients might however survive had they been administered ECPR. Further research into the factors influencing local organ and patient outcomes following uDCD and ECPR is indicated.

Impact of dispatcher-assisted cardiopulmonary resuscitation and myResponder mobile app on bystander resuscitation

INTRODUCTION

Bystander cardiopulmonary resuscitation (B-CPR) is associated with improved out-of hospital cardiac arrest survival. Community-level interventions including dispatcher-assisted CPR (DA-CPR) and myResponder were implemented to increase B-CPR. We sought to assess whether these interventions increased B-CPR.

METHODS

The Singapore out-of-hospital cardiac arrest registry captured cases that occurred between 2010 and 2017. Outcomes occurring in 3 time periods (Baseline, DA-CPR, and DA-CPR plus myResponder) were compared. Segmented regression of time-series data was conducted to investigate our intervention impact on the temporal changes in B-CPR.

RESULTS

A total of 13,829 out-of-hospital cardiac arrest cases were included from April 2010 to December 2017. Higher B-CPR rates (24.8% versus 50.8% vs 64.4%) were observed across the 3 time periods. B-CPR rates showed an increasing but plateauing trend. DA-CPR implementation was significantly associated with an increased B-CPR (level odds ratio [OR] 2.26, 95% confidence interval [CI] 1.79-2.88; trend OR 1.03, 95% CI 1.01-1.04), while no positive change was detected with myResponder (level OR 0.95, 95% CI 0.82-1.11; trend OR 0.99, 95% CI 0.98-1.00).

CONCLUSION

B-CPR rates in Singapore have been increasing alongside the implementation of community-level interventions such as DA-CPR and myResponder. DA-CPR was associated with improved odds of receiving B-CPR over time while the impact of myResponder was less clear.

Clinical evaluation of intravenous alone versus intravenous or intraosseous access for treatment of out-of-hospital cardiac arrest

OBJECTIVE

Obtaining vascular access during out-of-hospital cardiac arrest (OHCA) is challenging. The aim of this study was to determine if using intraosseous (IO) access when intravenous (IV) access fails improves outcomes.

METHODS

This was a prospective, parallel-group, cluster-randomised study that compared 'IV only' against 'IV + IO' in OHCA patients, where if 2 IV attempts failed or took more than 90 s, paramedics had 2 further attempts of IO. Primary outcome was any return of spontaneous circulation (ROSC). Secondary outcomes were insertion success rate, adrenaline administration, time to adrenaline and survival outcome.

RESULTS

A total of 1007 patients were included in the analysis. An Intention To Treat analysis showed a significant difference in success rates of obtaining vascular access in the IV + IO arm compared to the IV arm (76.6% vs 61.1% p = 0.001). There were significantly more patients in the IV + IO arm than the IV arm being administered prehospital adrenaline (71.3% vs 55.4% p = 0.001). The IV + IO arm also received adrenaline faster compared to the IV arm in terms of median time from emergency call to adrenaline (23 min vs 25 min p = 0.001). There was no significant difference in ROSC (adjusted OR 0.99 95%CI: 0.75-1.29), survival to discharge or survival with CPC 2 or better in both groups. A Per Protocol analysis also showed there was higher success in obtaining vascular access in the IV + IO arm, but ROSC and survival outcomes were not statistically different.

CONCLUSION

Using IO when IV failed led to a higher rate of vascular access, prehospital adrenaline administration and faster adrenaline administration. However, it was not associated with higher ROSC, survival to discharge, or good neurological outcome.

Implementation of a National 5-Year Plan for Prehospital Emergency Care in Singapore and Impact on Out-of-Hospital Cardiac Arrest Outcomes From 2011 to 2016

Background

Outcomes of patients from out‐of‐hospital cardiac arrest (OHCA) vary widely globally because of differences in prehospital systems of emergency care. National efforts had gone into improving OHCA outcomes in Singapore in recent years including community and prehospital initiatives. We aimed to document the impact of implementation of a national 5‐year Plan for prehospital emergency care in Singapore on OHCA outcomes from 2011 to 2016.

Methods and Results

Prospective, population‐based data of OHCA brought to Emergency Departments were obtained from the Pan‐Asian Resuscitation Outcomes Study cohort. The primary outcome was Utstein (bystander witnessed, shockable rhythm) survival‐to‐discharge or 30‐day postarrest. Mid‐year population estimates were used to calculate age‐standardized incidence. Multivariable logistic regression was performed to identify prehospital characteristics associated with survival‐to‐discharge across time. A total of 11 465 cases qualified for analysis. Age‐standardized incidence increased from 26.1 per 100 000 in 2011 to 39.2 per 100 000 in 2016. From 2011 to 2016, Utstein survival rates nearly doubled from 11.6% to 23.1% (P=0.006). Overall survival rates improved from 3.6% to 6.5% (P<0.001). Bystander cardiopulmonary resuscitation rates more than doubled from 21.9% to 56.3% and bystander automated external defibrillation rates also increased from 1.8% to 4.6%. Age ≤65 years, nonresidential location, witnessed arrest, shockable rhythm, bystander automated external defibrillation, and year 2016 were independently associated with improved survival.

Conclusions

Implementation of a national prehospital strategy doubled OHCA survival in Singapore from 2011 to 2016, along with corresponding increases in bystander cardiopulmonary resuscitation and bystander automated external defibrillation. This can be an implementation model for other systems trying to improve OHCA outcomes.

Incidence and Outcomes of Out-of-Hospital Cardiac Arrest in Singapore and Victoria: A Collaborative Study

Background

Incidence and outcomes of out‐of‐hospital cardiac arrest (OHCA) vary between communities. We aimed to examine differences in patient characteristics, prehospital care, and outcomes in Singapore and Victoria.

Methods and Results

Using the prospective Singapore Pan‐Asian Resuscitation Outcomes Study and Victorian Ambulance Cardiac Arrest Registry, we identified 11 061 and 32 003 emergency medical services‐attended adult OHCAs between 2011 and 2016 respectively. Incidence and survival rates were directly age adjusted using the World Health Organization population. Survival was analyzed with logistic regression, with model selection via backward elimination. Of the 11 061 and 14 834 emergency medical services‐treated OHCAs (overall mean age±SD 65.5±17.2; 67.4% males) in Singapore and Victoria respectively, 11 054 (99.9%) and 5595 (37.7%) were transported, and 440 (4.0%) and 2009 (13.6%) survived. Compared with Victoria, people with OHCA in Singapore were older (66.7±16.5 versus 64.6±17.7), had less shockable rhythms (17.7% versus 30.3%), and received less bystander cardiopulmonary resuscitation (45.7% versus 58.5%) and defibrillation (1.3% versus 2.5%) (all P<0.001). Age‐adjusted OHCA incidence and survival rates increased in Singapore between 2011 and 2016 (P<0.01 for trend), but remained stable, though higher, in Victoria. Likelihood of survival increased significantly (P<0.001) with arrest in public locations (adjusted odds ratio [aOR] 1.81), witnessed arrest (aOR 2.14), bystander cardiopulmonary resuscitation (aOR 1.72), initial shockable rhythm (aOR 9.82), and bystander defibrillation (aOR 2.04) but decreased with increasing age (aOR 0.98) and emergency medical services response time (aOR 0.91).

Conclusions

Singapore reported increasing OHCA incidence and survival rates between 2011 and 2016, compared with stable, albeit higher, rates in Victoria. Survival differences might be related to different emergency medical services practices including patient selection for resuscitation and transport.

Clinical evaluation of the use of laryngeal tube verses laryngeal mask airway for out-of-hospital cardiac arrest by paramedics in Singapore

INTRODUCTION

It is unclear which advanced airway device has better placement success and fewer adverse events in out-of-hospital cardiac arrests (OHCAs). This study aimed to evaluate the efficacy of the VBM laryngeal tube (LT) against the laryngeal mask airway (LMA) in OHCAs managed by emergency ambulances in Singapore.

METHODS

This was a real-world, prospective, cluster-randomised crossover study. All OHCA patients above 13 years old who were suitable for resuscitation were randomised to receive either LT or LMA. The primary outcome was placement success. Per-protocol analysis was performed and association between outcomes and airway device group was compared using multivariate binomial logistic regression analysis.

RESULTS

Of 965 patients with OHCAs from March 2016 to January 2018, 905 met the inclusion criteria, of which 502 (55.5%) were randomised to receive LT while 403 (44.5%) were randomised to receive LMA. Only 174 patients in the LT group actually received the device due to noncompliance. Placement success for LT was lower than for LMA (adjusted odds ratio [OR] 0.52, 95% confidence interval [CI] 0.31-0.90). Complications were more likely when using LT (OR 2.82,0 95% CI 1.64-4.86). Adjusted OR for prehospital return of spontaneous circulation (ROSC) was similar in both groups. A modified intention-to-treat analysis showed similar outcomes to the per-protocol analysis between the groups.

CONCLUSION

LT was associated with poorer placement success and higher complication rates than LMA. The likelihood of prehospital ROSC was similar between the two groups. Familiarity bias and a low compliance rate to the LT were the main limitations of this study.

myResponder Smartphone Application to Crowdsource Basic Life Support for Out-of-Hospital Cardiac Arrest: The Singapore Experience

OBJECTIVE

The Singapore myResponder is a novel smartphone application developed by the Singapore Civil Defence Force (SCDF) that notifies volunteer first responders of a suspected out-of-hospital cardiac arrest (OHCA) case and locations of Automated External Defibrillators (AED) in the vicinity so that they can assist with resuscitation. We aimed to examine the performance of this application, challenges encountered, and future directions. Methods: We analyzed data from the myResponder app since its launch from April 2015 to July 2019. The number of installations, registered community first responders, suspected OHCA cases, notifications sent by the app, percentage of responders who accepted activation and arrived at scene were reviewed. A subgroup of taxi driving responders (within a 1.5-kilometer response radius) carrying an AED under a subsequent pilot program was also analyzed. Results: By July 2019, 46,689 responders were registered in the myResponder app. There were a total of 19,189 cases created for suspected OHCA, with a median of 358 cases per month (IQR 330-430), in which 10,073 responders accepted activation from myResponder and 4,955 arrived on-scene. A total of 135,599 notifications were sent for these cases, with a median of 7.1 notifications per case (IQR 4.3-8.7). In 2019, the percentages of responders who accepted notification and arrived on scene were 45.8% and 24.1%, respectively. 43% (1110/2581) of responders arrived before EMS crew. Conclusion: The myResponder mobile application is a feasible smart technology solution to improve community response to OHCA, and to increase bystander CPR and AED use. Future directions include increasing the number of active responders, improving response rates, app performance, and better data capture for quality improvement.

Gastrointestinal Manifestations of SARS-CoV-2 Infection and Virus Load in Fecal Samples From a Hong Kong Cohort: Systematic Review and Meta-analysis

BACKGROUND & AIMS

Infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes coronavirus disease 2019 (COVID-19), which has been characterized by fever, respiratory, and gastrointestinal symptoms as well as shedding of virus RNA into feces. We performed a systematic review and meta-analysis of published gastrointestinal symptoms and detection of virus in stool and also summarized data from a cohort of patients with COVID-19 in Hong Kong.

METHODS

We collected data from the cohort of patients with COVID-19 in Hong Kong (N = 59; diagnosis from February 2 through February 29, 2020),and searched PubMed, Embase, Cochrane, and 3 Chinese databases through March 11, 2020, according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. We analyzed pooled data on the prevalence of overall and individual gastrointestinal symptoms (loss of appetite, nausea, vomiting, diarrhea, and abdominal pain or discomfort) using a random effects model.

RESULTS

Among the 59 patients with COVID-19 in Hong Kong, 15 patients (25.4%) had gastrointestinal symptoms, and 9 patients (15.3%) had stool that tested positive for virus RNA. Stool viral RNA was detected in 38.5% and 8.7% among those with and without diarrhea, respectively (P = .02). The median fecal viral load was 5.1 log10 copies per milliliter in patients with diarrhea vs 3.9 log10 copies per milliliter in patients without diarrhea (P = .06). In a meta-analysis of 60 studies comprising 4243 patients, the pooled prevalence of all gastrointestinal symptoms was 17.6% (95% confidence interval [CI], 12.3-24.5); 11.8% of patients with nonsevere COVID-19 had gastrointestinal symptoms (95% CI, 4.1-29.1), and 17.1% of patients with severe COVID-19 had gastrointestinal symptoms (95% CI, 6.9-36.7). In the meta-analysis, the pooled prevalence of stool samples that were positive for virus RNA was 48.1% (95% CI, 38.3-57.9); of these samples, 70.3% of those collected after loss of virus from respiratory specimens tested positive for the virus (95% CI, 49.6-85.1).

CONCLUSIONS

In an analysis of data from the Hong Kong cohort of patients with COVID-19 and a meta-analysis of findings from publications, we found that 17.6% of patients with COVID-19 had gastrointestinal symptoms. Virus RNA was detected in stool samples from 48.1% patients, even in stool collected after respiratory samples had negative test results. Health care workers should therefore exercise caution in collecting fecal samples or performing endoscopic procedures in patients with COVID-19, even during patient recovery.

Leveraging Machine Learning Techniques and Engineering of Multi-Nature Features for National Daily Regional Ambulance Demand Prediction

The accurate prediction of ambulance demand provides great value to emergency service providers and people living within a city. It supports the rational and dynamic allocation of ambulances and hospital staffing, and ensures patients have timely access to such resources. However, this task has been challenging due to complex multi-nature dependencies and nonlinear dynamics within ambulance demand, such as spatial characteristics involving the region of the city at which the demand is estimated, short and long-term historical demands, as well as the demographics of a region. Machine learning techniques are thus useful to quantify these characteristics of ambulance demand. However, there is generally a lack of studies that use machine learning tools for a comprehensive modeling of the important demand dependencies to predict ambulance demands. In this paper, an original and novel approach that leverages machine learning tools and extraction of features based on the multi-nature insights of ambulance demands is proposed. We experimentally evaluate the performance of next-day demand prediction across several state-of-the-art machine learning techniques and ambulance demand prediction methods, using real-world ambulatory and demographical datasets obtained from Singapore. We also provide an analysis of this ambulatory dataset and demonstrate the accuracy in modeling dependencies of different natures using various machine learning techniques.

Nation-Wide Observational Study of Cardiac Arrests Occurring in Nursing Homes and Nursing Facilities in Singapore

Introduction: Nursing home (NH) residents with out-of-hospital cardiac arrests (OHCA) have unique resuscitation priorities. This study aimed to describe OHCA characteristics in NH residents and identify independent predictors of survival. Materials and Methods: OHCA cases between 2010–16 in the Pan-Asian Resuscitation Outcomes Study were retrospectively analysed. Patients aged <18 years old and non-emergency cases were excluded. Primary outcome was survival at discharge or 30 days. Good neurological outcome was defined as a cerebral performance score between 1–2. Results: A total of 12,112 cases were included. Of these, 449 (3.7%) were NH residents who were older (median age 79 years, range 69–87 years) and more likely to have a history of stroke, heart and respiratory diseases. Fewer NH OHCA had presumed cardiac aetiology (62% vs 70%, P <0.01) and initial shockable rhythm (8.9% vs 18%, P <0.01), but had higher incidence of bystander cardiopulmonary resuscitation (74% vs 43%, P <0.01) and defibrillator use (8.5% vs 2.8%, P <0.01). Non-NH (2.8%) residents had better neurological outcomes than NH (0.9%) residents (P <0.05). Factors associated with survival for cardiac aetiology included age <65 years old, witnessed arrest, bystander defibrillator use and initial shockable rhythm; for non-cardiac aetiology, these included witnessed arrest (adjusted odds ratio [AOR] 3.8, P <0.001) and initial shockable rhythm (AOR 5.7, P <0.001). Conclusion: Neurological outcomes were poorer in NH survivors of OHCA. These findings should inform health policies on termination of resuscitation, advance care directives and do-not-resuscitate orders in this population. Ann Acad Med Singapore 2020;49:285–93 Key words: Advance care directives, Do-not-resuscitate orders, Geriatrics, Out-of- hospital, Palliative care

Simplified instructional phrasing in dispatcher-assisted cardiopulmonary resuscitation - when 'less is more'

INTRODUCTION

In our national emergency dispatch centre, the standard protocol for dispatcher-assisted cardiopulmonary resuscitation (DACPR) in out-of-hospital cardiac arrests (OHCAs) involves the instruction "push 100 times a minute 5 cm deep". As part of quality improvement, the instruction was simplified to "push hard and fast".

METHODS

We analysed all dispatcher-diagnosed OHCAs over four months in 2018: January to February ("push 100 times a minute 5 cm deep") and August to September ("push hard and fast"). We also performed secondary per-protocol analysis based on the protocol used: (a) standard (n = 48); (b) simplified (n = 227); and (c) own words (n = 231).

RESULTS

506 cases were included, 282 in the 'before' group and 224 in the 'after' group. Adherence to the protocol was 15.2% in the 'before' phase and 72.8% in the 'after' phase (p < 0.001). The mean time between instruction and first compression for the 'before' and 'after' groups was 34.36 seconds and 26.83 seconds, respectively (p < 0.001). Time to first compression was 238.62 seconds and 218.83 seconds in the 'before' and 'after' groups, respectively (p = 0.016). In the per-protocol analysis, the interval between instruction and compression was 37.19 seconds, 28.31 seconds and 32.40 seconds in the standard protocol, simplified protocol and 'own words' groups, respectively (p = 0.005). The need for paraphrasing was 60.4% in the standard protocol group and 81.5% in the simplified group (p < 0.001).

CONCLUSION

Simplified instructions were associated with a shorter interval between instruction and first compression. Efforts should be directed at simplifying DACPR instructions.

Nation-Wide Observational Study of Cardiac Arrests Occurring in Nursing Homes and Nursing Facilities in Singapore

INTRODUCTION

Nursing home (NH) residents with out-of-hospital cardiac arrests (OHCA) have unique resuscitation priorities. This study aimed to describe OHCA characteristics in NH residents and identify independent predictors of survival.

MATERIALS AND METHODS

OHCA cases between 2010-16 in the Pan-Asian Resuscitation Outcomes Study were retrospectively analysed. Patients aged <18 years old and non-emergency cases were excluded. Primary outcome was survival at discharge or 30 days. Good neurological outcome was defined as a cerebral performance score between 1-2.

RESULTS

A total of 12,112 cases were included. Of these, 449 (3.7%) were NH residents who were older (median age 79 years, range 69-87 years) and more likely to have a history of stroke, heart and respiratory diseases. Fewer NH OHCA had presumed cardiac aetiology (62% vs 70%, P <0.01) and initial shockable rhythm (8.9% vs 18%, P <0.01), but had higher incidence of bystander cardiopulmonary resuscitation (74% vs 43%, P <0.01) and defibrillator use (8.5% vs 2.8%, P <0.01). Non-NH (2.8%) residents had better neurological outcomes than NH (0.9%) residents (P <0.05). Factors associated with survival for cardiac aetiology included age <65 years old, witnessed arrest, bystander defibrillator use and initial shockable rhythm; for non-cardiac aetiology, these included witnessed arrest (adjusted odds ratio [AOR] 3.8, P <0.001) and initial shockable rhythm (AOR 5.7, P <0.001).

CONCLUSION

Neurological outcomes were poorer in NH survivors of OHCA. These findings should inform health policies on termination of resuscitation, advance care directives and do-not-resuscitate orders in this population.

Emergency medical services use and its association with acute ischaemic stroke evaluation and treatment in Singapore

Background

Emergency medical services (EMS) is a critical link in the chain of stroke survival. We aimed to assess EMS use for stroke in Singapore, identify characteristics associated with EMS use and the association of EMS use with stroke evaluation and treatment.

Methods

The Singapore Stroke Registry combines nationwide EMS and public hospital data for stroke cases in Singapore. Multivariate regressions with the generalised estimating equations were performed to examine the association between EMS use and timely stroke evaluation and treatment.

Results

Of 3555 acute ischaemic patients with symptom onset within 24 hours admitted to all five public hospitals between 2015 and 2016, 68% arrived via EMS. Patients who used EMS were older, were less likely to be female, had higher stroke severity by National Institute of Health Stroke Scale and had a higher prevalence of atrial fibrillation or peripheral arterial disease. Patients transported by EMS were more likely to receive rapid evaluation (door-to-imaging time ≤25 min 34.3% vs 11.1%, OR=2.74 (95% CI 1.40 to 5.38)) and were more likely to receive intravenous tissue plasminogen activator (tPA, 22.8% vs 4.6%, OR=4.61 (95% CI 3.52 to 6.03)). Among patients treated with tPA, patients who arrived via EMS were more likely to receive timely treatment than self-transported patients (door-to-needle time ≤60 min 52.6% vs 29.4%, OR=2.58 (95% CI 1.35 to 4.92)).

Conclusions

EMS use is associated with timely stroke evaluation and treatment in Singapore. Seamless EMS-Hospital stroke pathways and targeted public campaigns to advocate for appropriate EMS use have the potential to improve acute stroke care.

Nationwide trends in residential and non-residential out-of-hospital cardiac arrest and differences in bystander cardiopulmonary resuscitation

AIMS

Singapore is highly-urbanized, with >90% of the population living in high-rise apartments. She has implemented several city-wide interventions such as dispatcher-assisted CPR, community CPR training and smartphone activation of volunteers to increase bystander CPR (BCPR) rates for out-of-hospital cardiac arrest (OHCA). These may have different impact on residential and non-residential OHCA. We aimed to evaluate the characteristics, processes-of-care and outcome differences between residential and non-residential OHCA and study the differences in temporal trends of BCPR rates.

METHODS

This was a national, observational study in Singapore from 2010 to 2016, using data from the prospective Pan-Asian Resuscitation Outcomes Study. The primary outcome was survival (to-discharge or to-30-days). Multivariate logistic regression was performed to determine the effect of location-type on survival and a test of statistical interaction was performed to assess the difference in the temporal relationship of BCPR rates between location-type.

RESULTS

8397 cases qualified for analysis, of which 5990 (71.3%) were residential. BCPR and bystander automated external defibrillator (AED) rates were significantly lower in residential as compared to non-residential arrests (41.0% vs 53.6%, p < 0.01; 0.4% vs 10.8%, p < 0.01 respectively). Residential BCPR increased from 15.8% (2010) to 57.1% (2016). Residential cardiac arrests had lower survival-to-discharge (2.9% vs 10.1%, p < 0.01). Multivariate logistic regression analysis showed that location-type had an independent effect on survival, with residential arrests having poorer survival compared to non-residential cardiac arrests (adjusted OR 0.547 [0.435-0.688]). A test of statistical interaction showed a significant interaction effect between year and location-type for bystander CPR, with a narrowing of differences in bystander CPR between residential and non-residential cardiac arrests over the years.

CONCLUSION

Residential cardiac arrests had poorer bystander intervention and survival from 2010 to 2016 in Singapore. BCPR had improved more in residential arrests compared to non-residential arrests over a period of city-wide interventions to improve BCPR.

Comparison of inhalational methoxyflurane (Penthrox®) and intramuscular tramadol for prehospital analgesia

INTRODUCTION

Treatment of pain is an important component of prehospital care. Inhalational analgesia agents have attractive strengths, but there is a paucity of studies comparing these with more conventional agents. We aimed to compare inhalational methoxyflurane and intramuscular (IM) tramadol as first-contact analgesia in the Singapore national ambulance service.

METHODS

Ambulances were randomised to carry either methoxyflurane or IM tramadol for the first six months and crossed over to the other arm after six months. Patients aged ≥ 16 years, with acute pain arising from musculoskeletal trauma with Numerical Rating Scale (NRS) score ≥ 3 were enrolled. Variables included NRS reduction, time variables, adverse effects, Ramsay Sedation Scores, and patient and paramedic satisfaction scores on a Likert scale.

RESULTS

A total of 369 patients were enrolled into this study, but 26 patients were excluded due to missing data. The methoxyflurane arm had a shorter median time taken from arrival at the scene to drug administration (9.0 [interquartile range 6.0-14.0] minutes vs. 11.0 [interquartile range 8.0-15.0] minutes). For patients who achieved reduction in NRS ≥ 3 within 20 minutes, those in the methoxyflurane arm took a shorter time. However, the methoxyflurane (46.7%) arm experienced lower proportion of patients not achieving NRS reduction ≥ 3 when compared to the tramadol (71.6%) arm after over 20 minutes. The methoxyflurane arm had significantly higher paramedic and patient satisfaction scores.

CONCLUSION

For the doses of medication used in this implementation study, methoxyflurane was superior in efficacy, speed of onset and administration, but had more minor adverse effects when compared to IM tramadol.

Getting R-AEDI to save lives in Singapore

Early cardiopulmonary resuscitation (CPR) and defibrillation prior to the arrival of emergency medical services can improve survival from out-of-hospital cardiac arrest (OHCA) with good neurological outcome. However, the rate of local bystander CPR is only 24.3% and bystander defibrillation 2.1%. In 2015, the R-AEDI (Registry for AED Integration) initiative was started to improve OHCA survival rates. R-AEDI alerts volunteers to nearby OHCA cases via the myResponder mobile application. In 2015-2017, 7,682 AEDs were mapped and made accessible via this app. Comprehensive site inspections also resulted in fewer non-functional AEDs, as AED owners were educated on the importance of the maintenance of pads and batteries. The AED heat map allows us to identify areas that are lacking in or require improved public access AED coverage. The online AED registry found in the myResponder app is useful to locate AEDs rapidly during OHCAs. More community education would improve the rate of bystander defibrillation.

Emergency medical dispatch services across Pan-Asian countries: a web-based survey

Background

Dispatch services (DS’s) form an integral part of emergency medical service (EMS) systems. The role of a dispatcher has also evolved into a crucial link in patient care delivery, particularly in dispatcher assisted cardio-pulmonary resuscitation (DACPR) during out-of-hospital cardiac arrest (OHCA). Yet, there has been a paucity of research into the emerging area of dispatch science in Asia. This paper compares the characteristics of DS’s, and state of implementation of DACPR within the Pan-Asian Resuscitation Outcomes (PAROS) network.

Methods

A cross-sectional descriptive survey addressing population characteristics, DS structures and levels of service, state of DACPR implementation (including protocols and quality improvement programs) among PAROS DS’s.

Results

9 DS’s responded, representing a total of 23 dispatch centres from 9 countries that serve over 80 million people. Most PAROS DS’s operate a tiered dispatch response, have implemented medical oversight, and tend to be staffed by dispatchers with a predominantly medical background. Almost all PAROS DS’s have begun tracking key EMS indicators. 77.8% (n = 7) of PAROS DS’s have introduced DACPR. Of the DS’s that have rolled out DACPR, 71.4% (n = 5) provided instructions in over one language. All DS’s that implemented DACPR and provided feedback to dispatchers offered feedback on missed OHCA recognition. The majority of DS’s (83.3%; n = 5) that offered DACPR and provided feedback to dispatchers also implemented corrective feedback, while 66.7% (n = 4) offered positive feedback. Compression-only CPR was the standard instruction for PAROS DS’s. OHCA recognition sensitivity varied widely in PAROS DS’s, ranging from 32.6% (95% CI: 29.9–35.5%) to 79.2% (95% CI: 72.9–84.4%). Median time to first compression ranged from 120 s to 220 s.

Conclusions

We found notable variations in characteristics and state of DACPR implementation between PAROS DS’s. These findings will lay the groundwork for future DS and DACPR studies in the PAROS network.

Outcomes and modifiable resuscitative characteristics amongst pan-Asian out-of-hospital cardiac arrest occurring at night

Studies are divided on the effect of day-night temporal differences on clinical outcomes in out-of-hospital cardiac arrest (OHCA). This study aimed to elucidate any differences in OHCA survival between day and night occurrence, and the factors associated with differences in survival.This was a prospective, observational study of OHCA cases across multinational Pan-Asian sites. Cases were divided according to time call received by dispatch centers into day (0700H-1900H) and night (1900H-0659H). Primary outcome was 30-day survival. Secondary outcomes were prehospital and hospital modifiable resuscitative characteristics.About 22,501 out of 55,881 cases occurred at night. Night cases were less likely to be witnessed (40.2% vs. 43.1%, P < .001), more likely to occur at home (32.5% vs. 29%, P < .001), had non-shockable initial rhythms (90.8% vs. 89.4%, P < .001), lower bystander CPR rates (36.2 vs. 37.6%, P = .001), lower bystander AED application rate (0.3% vs. 0.7%, P < .001), lower rates of prehospital defibrillation (13% vs. 14.4%, P < .001), and were less likely to receive prehospital adrenaline (9.8% vs. 11%, P < .001). 30-day survival at night was lower with an adjusted odds ratio of 0.79 (95% CI 0.73-0.86, P < .001). On multivariate logistic regression, occurrence at night was associated with decreased provision of bystander CPR, bystander AED application, and prehospital adrenaline.30-day survival was worse in OHCA occurring at night. There were circadian patterns in incidence. Bystander CPR and bystander AED application were significantly lower at night in multivariate analysis. This would at least partially explain the decreased survival at night.

Comparison of Outcomes and Characteristics of Emergency Medical Services (EMS)-Witnessed, Bystander-Witnessed, and Unwitnessed Out-of-Hospital Cardiac Arrests in Singapore

Objectives: The objective was to compare the survival outcomes of emergency medical services (EMS)-witnessed to bystander-witnessed, and unwitnessed out-of-hospital cardiac arrests (OHCA) in Singapore. Secondary aims are to describe the 5-year trend in survival rates of EMS-witnessed arrests. Methods: This was a retrospective analysis of the Singapore's OHCA registry data from 2011 to 2015. Excluded from the analysis were patients younger than 18 years old, arrests of traumatic etiology, resuscitation not attempted, and cases not conveyed by EMS. The primary outcome was survival to hospital discharge or 30 days post-arrest. Secondary outcomes were return of spontaneous circulation (ROSC) and survival to hospital admission. Results: 8,394 cases were analyzed, with 650 (7.7%) EMS-witnessed arrests, 4480 (53.4%) bystander-witnessed arrests, and 3264 (38.9%) unwitnessed arrests. Among EMS-witnessed arrests, the majority were presumed to be of cardiac etiology (62.8%) and the most common presenting rhythm was pulseless electrical activity (PEA; 57.2%). Survival to discharge or 30^th day post-arrest was higher in EMS-witnessed arrests compared to bystander-witnessed and unwitnessed arrests (11.2% vs. 5.3% and 1.3%, p < 0.001). Survival to discharge for EMS-witnessed cases increased from 2011 (13.2%) to 2015 (18.9%). Conclusions: EMS-witnessed OHCAs were more likely to have favorable outcomes compared to bystander-witnessed and unwitnessed OHCAs. High PEA rates in EMS-witnessed arrests were associated with older patients with underlying preexisting medical conditions. Increasing public awareness on recognition of prodromal symptoms and early activation of EMS could improve post-arrest survival and neurological outcomes of OHCA.

Most impactful predictors for hyperoxaemia in exacerbation of chronic obstructive pulmonary disease managed by Emergency Medical Services and Emergency Department

INTRODUCTION

Hyperoxemia in acute exacerbation of chronic obstructive pulmonary disease (AECOPD) leads to adverse outcomes. It remains prevalent in the pre-hospital Emergency Medical Services (EMS) and Emergency Department (ED).

OBJECTIVE

To determine the key predictors for hyperoxemia in AECOPD in EMS and ED.

METHODS

This was a prospective observational study of AECOPD patients in EMS and two EDs. Hyperoxemia was defined as PaO₂ > 65 mm Hg (corresponds to SpO₂ > 92%). We determined apriori candidate factors in Patient, Organization and Staff domains. Primary outcomes were the key predictors for hyperoxemia. Secondary outcomes were in-hospital mortality and mechanical ventilation rates in hyperoxemic versus non-hyperoxemic groups. We generated a logistic regression model for each domain. We reported the adjusted odds ratios (AORs), 95% CIs and p values. We selected the output factors using AOR ≥2.0 and ≥2.5 for modifiable and non-modifiable factors, respectively. These selected factors were fed into a final model with eventual factors selected based on: threshold AORs as stated above and/or 95% CIs including these AORs.

RESULTS

Three hundred and twenty-six patients were analysed; 60.7% had hyperoxemia. We found three eventual modifiable factors; first, ED SpO₂ > 95% [AOR 2.62 (95% CIs: 1.61-4.33); P < 0.001], EMS non-rebreathing mask [AOR 2.01 (95% CIs: 1.06-3.97); P = 0.04]; and ED nasal cannula [AOR 1.69 (95% CIs: 1.05-2.72); P = 0.03]. Secondary outcomes did not differ between groups.

CONCLUSION

We identified three key modifiable predictors. We intend to conduct an interventional study using them to reduce hyperoxemia rate in AECOPD.

Ethnic and Neighborhood Socioeconomic Differences In Incidence and Survival From Out-Of-Hospital Cardiac Arrest In Singapore

Objective: We aimed to examine the association of ethnicity and socioeconomic status (SES) with Out-of-Hospital Cardiac Arrest (OHCA) incidence and 30-day survival in Singapore. Methods: We analyzed the Singapore cohort of Pan-Asia Resuscitation Outcome Study (PAROS), a multi-center, prospective OHCA registry between 2010 and 2015. The Singapore Socioeconomic Disadvantage Index (SEDI) score, obtained according to zip code, was used as surrogate for neighborhood SES. Age-adjusted OHCA incidence and Utstein survival were calculated by ethnicity and SES. Utstein survival was defined as the number of cardiac OHCA cases with initial rhythm of ventricular fibrillation witnessed by a bystander who survived 30-days or until hospital discharge. Logistic regression was used to investigate association of ethnicity with 30-day and Utstein survivals. Results: Our study population comprised 8,900 patients: 6,453 Chinese, 1,472 Malays, and 975 Indians. The overall age-adjusted incidence ratios (95% CI) for Malay/Chinese and Indian/Chinese were 1.93 (1.83-2.04) and 1.95 (1.83-2.08), respectively. The overall age-adjusted incidence ratios (95% CI) for average/low and high/low SEDI group were 1.12 (0.95-1.33) and 1.29 (1.08-1.53), respectively. Malay showed lesser Utstein survival of 8.1% compared to Chinese (14.6%) and Indian (20.4%) [p = 0.018]. Ethnicity did not reach statistical significance (p = 0.072) in forward selection model of Utstein survival, while SEDI score and category were not significant (p > 0.2 and p = 0.349). Conclusions: We found Malay and Indian communities to be at higher risks of OHCA compared to Chinese, and additionally, the Malay community is at higher risk of subsequent mortality than the Chinese and Indian communities. These disparities were not explained by neighborhood SES.

Evaluation of culture-specific popular music as a mental metronome for cardiopulmonary resuscitation: a randomised crossover trial

Introduction:

Bystander cardiopulmonary resuscitation (CPR) improves survival in out-of-hospital cardiac arrest. The use of certain songs as mental metronomes for CPR have been validated and recognised by contemporary guidelines. We hypothesise that the National Day song, Count on me Singapore (COMS CPR), is not inferior to standard ‘one-and-two-and-three-and-four’ counting (standard CPR) for timing CPR, in terms of the proportion of participants achieving the guideline compression rate of 100–120/minute.

Methods:

This was a prospective randomised crossover trial powered to demonstrate non-inferiority in the CPR rate. After a familiarisation session, volunteers were randomly assigned to two groups. Group A performed one cycle of standard CPR while group B performed one cycle of COMS CPR. Participants then crossed over to perform the other method. The Laerdal SkillReporter measured CPR quality. Four weeks later, participants attended a test scenario, using standard CPR or COMS CPR (randomly allocated).

Results:

Ninety subjects were recruited; 46 were randomly assigned to group A and 44 to group B. Baseline characteristics were similar; 41.1% of COMS CPR achieved 100–120/minute, versus 28.9% of standard CPR ( P=0.028). In mixed effects logistical regression, significantly more COMS CPR was performed at 100–120/minute compared to standard CPR (odds ratio 2.44, 95% confidence interval 1.01–5.9, P=0.047). The proportion of insufficient depth was higher in COMS CPR (80.59% vs. 68.01%, P<0.001). There were no differences in other aspects of CPR quality. There were no differences in CPR quality between standard CPR and COMS CPR during the follow-up.

Conclusion:

COMS CPR was not inferior in terms of the proportion of participants delivering a guideline-compliant rate of chest compression. COMS CPR may have applications to layman CPR education, such as in mass education events.

Characteristics of Frequent Users of Emergency Medical Services in Singapore

OBJECTIVES

This study aims to describe frequent users of Emergency Medical Services (EMS) conveyed to a Singapore tertiary hospital, focusing on a comparison between younger users (age <65) and older users in diagnoses and admission rates.

METHODS

All patients conveyed by EMS to a tertiary hospital 4 times or more over a 1-year period in 2015 had their EMS ambulance charts and Emergency Department (ED) electronic records retrospectively analyzed (n = 243), with admission the primary outcome.

RESULTS

The 243 frequent users were analyzed with a combined total of 1,705 visits, out of a total of 10,183 patients with 12,839 visits conveyed by EMS to Singapore General Hospital (SGH) in 2015. Younger frequent users (<65 years age) were found to be predominantly male (79.6%, p = 0.001) and were on average responsible for more visits than elderly frequent users (8.6 vs. 5.7, p = 0.004). Medical co-morbidities were significantly more prevalent in older users. Younger frequent users were more likely to be smokers (60.2% vs. 22.3%), heavy drinkers (51.3% vs. 8.5%), substance abusers (12.4% vs. 0.8%), and bad debtors (49.6% vs. 20.0%, p < 0.001). A larger proportion presented with altered mental states (11.7% vs. 5.4%, p < 0.001) and alcohol related diagnoses (34.7% vs. 5.3%, p < 0.001). Many were picked up from public areas (45.5% vs. 19.6%, p < 0.001), and had lower acuity triage scores at both EMS (p < 0.001) and ED (p = 0.001). They had lower admission rates (40.5% vs. 78.7%, p < 0.001) and shorter length of stay (4.3 vs. 5.9 days, p < 0.001). Univariable and multivariable analysis showed alcohol related diagnoses, history of alcohol abuse and lower triage scores were less likely to require admissions.

CONCLUSION

Frequent EMS users consume a disproportionate amount of healthcare resources. Two broad subgroups of patients were identified: younger patients with social issues and older patients with multiple medical conditions. EMS usage by older patients was significantly associated with higher rates of admission.