Pin Pin Pek

A randomised, double-blind, multi-centre trial comparing vasopressin and adrenaline in patients with cardiac arrest presenting to or in the Emergency Department

OBJECTIVE To compare vasopressin and adrenaline in the treatment of patients with cardiac arrest presenting to or in the Emergency Department (ED). DESIGN A randomised, double-blind, multi-centre, parallel-design clinical trial in four adult hospitals. METHOD Eligible cardiac arrest patients (confirmed by the absence of pulse, unresponsiveness and apnea) aged >16 (aged>21 for one hospital) were randomly assigned to intravenous adrenaline (1mg) or vasopressin (40 IU) at ED. Patients with traumatic cardiac arrest or contraindication for cardiopulmonary resuscitation (CPR) were excluded. Patients received additional open label doses of adrenaline as per current guidelines. Primary outcome was survival to hospital discharge (defined as participant discharged alive or survival to 30 days post-arrest). MAIN RESULTS The study recruited 727 participants (adrenaline = 353; vasopressin = 374). Baseline characteristics of the two groups were comparable. Eight participants (2.3%) from adrenaline and 11 (2.9%) from vasopressin group survived to hospital discharge with no significant difference between groups (p = 0.27, RR = 1.72, 95% CI = 0.65-4.51). After adjustment for race, medical history, bystander CPR and prior adrenaline given, more participants survived to hospital admission with vasopressin (22.2%) than with adrenaline (16.7%) (p = 0.05, RR = 1.43, 95% CI = 1.02-2.04). Sub-group analysis suggested improved outcomes for vasopressin in participants with prolonged arrest times. CONCLUSIONS Combination of vasopressin and adrenaline did not improve long term survival but seemed to improve survival to admission in patients with prolonged cardiac arrest. Further studies on the effect of vasopressin combined with therapeutic hypothermia on patients with prolonged cardiac arrest are needed.

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

BACKGROUND The 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. OBJECTIVES This study aimed to investigate the effect of gender on OHCA outcomes in the Pan-Asian population. METHODOLOGY This 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. RESULTS We 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. CONCLUSION Differences in survival outcomes between reproductive and menopausal women highlight a need for further investigations into the plausible social, pathologic or hormonal basis.

Prehospital Trauma Care in Singapore

Abstract Prehospital emergency care in Singapore has taken shape over almost a century. What began as a hospital-based ambulance service intended to ferry medical cases was later complemented by an ambulance service under the Singapore Fire Brigade to transport trauma cases. The two ambulance services would later combine and come under the Singapore Civil Defence Force. The development of prehospital care systems in island city–state Singapore faces unique challenges as a result of its land area and population density. This article defines aspects of prehospital trauma care in Singapore. It outlines key historical milestones and current initiatives in service, training, and research. It makes propositions for the future direction of trauma care in Singapore. The progress Singapore has made given her circumstances may serve as lessons for the future development of prehospital trauma systems in similar environments. Key words: Singapore; trauma; prehospital emergency care; emergency medical services

Risk stratification for prediction of adverse coronary events in emergency department chest pain patients with a machine learning score compared with the TIMI score

a Department of Emergency Medicine, Singapore General Hospital, Singapore b Centre for Quantitative Medicine, Duke-NUS Graduate Medical School, Singapore c SingHealth Emergency Medicine Residency Program, Singapore Health Services, Singapore d Department of Statistics and Applied Probability, National University of Singapore, Singapore e Division of Research, Singapore General Hospital, Singapore f Singapore Institute of Technology, Singapore g School of Electrical and Electronic Engineering, Nanyang Technological University, Singapore h Health Services and Systems Research, Duke-NUS Graduate Medical School, Singapore

Conversion to shockable rhythms during resuscitation and survival for out-of hospital cardiac arrest.

Background: In out of hospital cardiac arrest (OHCA), the prognostic influence of conversion to shockable rhythms during resuscitation for initially non‐shockable rhythms remains unknown. This study aimed to assess the relationship between initial and subsequent shockable rhythm and post‐arrest survival and neurological outcomes after OHCA. Methodology: This was a retrospective analysis of all OHCA cases collected from the Pan‐Asian Resuscitation Outcomes Study (PAROS) registry in 7 countries in Asia between 2009 and 2012. We included OHCA cases of presumed cardiac etiology, aged 18‐years and above and resuscitation attempted by EMS. We performed multivariate logistic regression analyses to assess the relationship between initial and subsequent shockable rhythm and survival and neurological outcomes. 2‐stage seemingly unrelated bivariate probit models were developed to jointly model the survival and neurological outcomes. We adjusted for the clustering effects of country variance in all models. Results: 40,160 OHCA cases met the inclusion criteria. There were 5356 OHCA cases (13.3%) with initial shockable rhythm and 33,974 (84.7%) with initial non‐shockable rhythm. After adjustment of baseline and prehospital characteristics, OHCA with initial shockable rhythm (odds ratio/OR = 6.10, 95% confidence interval/CI = 5.06–7.34) and subsequent conversion to shockable rhythm (OR = 2.00,95%CI = 1.10–3.65) independently predicted better survival‐to‐hospital‐discharge outcomes. Subsequent shockable rhythm conversion significantly improved survival‐to‐admission, discharge and post‐arrest overall and cerebral performance outcomes in the multivariate logistic regression and 2‐stage analyses. Conclusion: Initial shockable rhythm was the strongest predictor for survival. However, conversion to subsequent shockable rhythm significantly improved post‐arrest survival and neurological outcomes. This study suggests the importance of early resuscitation efforts even for initially non‐shockable rhythms which has prognostic implications and selection of subsequent post‐resuscitation therapy.

Evolutionary Voting-Based Extreme Learning Machines

Voting-based extreme learning machine (V-ELM) was proposed to improve learning efficiency where majority voting was employed. V-ELM assumes that all individual classifiers contribute equally to the decision ensemble. However, in many real-world scenarios, this assumption does not work well. In this paper, we aim to enhance V-ELM by introducing weights to distinguish the importance of each individual ELM classifier in decision making. Genetic algorithm is used for optimizing these weights. This evolutionary V-ELM is named as EV-ELM. Results on several benchmark databases show that EV-ELM achieves the highest classification accuracy compared with V-ELM and ELM.

Prehospital delay in patients presenting with acute ST-elevation myocardial infarction.

To characterize prehospital delays in patients presenting with acute ST-elevation myocardial infarction to the emergency department of a tertiary hospital in Asia. A retrospective review of 273 patients with diagnosis of ST-elevation myocardial infarction; symptom to door (S2D) time was described in two ways, time from first onset of symptoms; and time from the onset of the worst episode to presentation at emergency department. The median first onset S2D time was 173 min (interquartile range 80–350 min); and median worst episode S2D time was 131 min (interquartile range 70–261 min). Patients with prehospital delay tended to use their own transport compared with the no delay group (P=0.026, 95% confidence interval=0.02–0.24). There was no difference in S2D times for typical compared with atypical symptoms. A large proportion of patients experienced delay in seeking medical care after the onset of acute coronary symptoms. Self-transport was associated with delay.

Manifold ranking based scoring system with its application to cardiac arrest prediction

BACKGROUND The recently developed geometric distance scoring system has shown the effectiveness of scoring systems in predicting cardiac arrest within 72h and the potential to predict other clinical outcomes. However, the geometric distance scoring system predicts scores based on only local structure embedded by the data, thus leaving much room for improvement in terms of prediction accuracy. METHODS We developed a novel scoring system for predicting cardiac arrest within 72h. The scoring system was developed based on a semi-supervised learning algorithm, manifold ranking, which explores both the local and global consistency of the data. System evaluation was conducted on emergency department patients׳ data, including both vital signs and heart rate variability (HRV) parameters. Comparison of the proposed scoring system with previous work was given in terms of sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV). RESULTS Out of 1025 patients, 52 (5.1%) met the primary outcome. Experimental results show that the proposed scoring system was able to achieve higher area under the curve (AUC) on both the balanced dataset (0.907 vs. 0.824) and the imbalanced dataset (0.774 vs. 0.734) compared to the geometric distance scoring system. CONCLUSIONS The proposed scoring system improved the prediction accuracy by utilizing the global consistency of the training data. We foresee the potential of extending this scoring system, as well as manifold ranking algorithm, to other medical decision making problems. Furthermore, we will investigate the parameter selection process and other techniques to improve performance on the imbalanced dataset.

Pilot prospective study of therapeutic hypothermia for treatment of post-cardiac arrest patients

arrest patients☆,☆☆, Mingwei Ng , Aaron Sung Lung Wong , Huck Chin Chew , Nur Shahidah , Pin Pin Pek , Juliana Poh , Chee Tang Chin , Terrance Siang Jin Chua , Marcus Eng Hock Ong d,⁎ a Yong Loo Lin School of Medicine, National University Health System, Singapore, Singapore b Department of Cardiology, National Heart Centre, Singapore, Singapore c Department of Respiratory and Critical Care Medicine, Singapore General Hospital, Singapore, Singapore d Department of Emergency Medicine, Singapore General Hospital, Singapore, Singapore

Validation of the new Vancouver Chest Pain Rule in Asian chest pain patients presenting at the emergency department.

OBJECTIVES The new Vancouver Chest Pain (VCP) Rule recommends early discharge for chest pain patients who are at low risk of developing acute coronary syndrome (ACS), and thus can be discharged within 2 hours of arrival at the emergency department (ED). This study aimed to assess the performance of the new VCP Rule for Asian patients presenting with chest pain at the ED. METHODS This prospective cohort study involved patients attended to at the ED of a large urban centre. Patients of at least 25 years old, presenting with stable chest pain and a non-diagnostic ECG, and with no history of active coronary artery disease were included in the study. The main outcome measures were cardiac events, angioplasty, or coronary artery bypass within 30 days of enrolment. RESULTS The study included 1690 patients from 27 August 2000 to 1 May 2002, with 661 patients fulfilling the VCP criteria. Of those for early discharge, 24 had cardiac events and 13 had angioplasty or bypass at 30 days, compared to 91 and 41, respectively, for those unsuitable for discharge. This gave the rule a sensitivity of 78.1% for cardiac events, including angioplasty and bypass. Specificity was 41.0%, and negative predictive value (NPV) was 94.4%. CONCLUSION We found the new VCP Rule to have moderate sensitivity and poor specificity for adverse cardiac events in our population. With an NPV of less than 100%, this means that a small proportion of patients sent home with early discharge would still have adverse cardiac events.