Han Nee Gan

Interventional strategies associated with improvements in survival for out-of-hospital cardiac arrests in Singapore over 10 years

AIM We aim to study if there has been an improvement in survival for Out-of-Hospital Cardiac Arrest (OHCA) in Singapore, the effects of various interventional strategies over the past 10 years, and identify strategies that contributed to improved survival. METHODS Rates of OHCA survival were compared between 2001-2004 and 2010-2012, using nationwide data for all OHCA presenting to EMS and public hospitals. A multivariate logistic regression model for survival to discharge was constructed to identify strategies with significant impact. RESULTS A total of 5453 cases were included, 2428 cases from 2001 to 2004 and 3025 cases from 2010 to 2012. There was significant improvement in Utstein (witnessed, shockable) survival to discharge from 2001-2004 (2.5%) to 2010-2012 (11.0%), adjusted odds ratio (OR) 9.6 [95% CI: 2.2-41.9]). Overall survival to discharge increased from 1.6% to 3.2% (adjusted OR 2.2 [1.5-3.3]). Bystander CPR rates increased from 19.7% to 22.4% (p=0.02). The multivariate regression model (adjusted for important non-modifiable risk factors) showed that response time <8min (OR 1.5 [1.0-2.3]), bystander AED (OR 5.8 [2.0-16.2]), and post-resuscitation hypothermia (OR 30.0 [11.5-78.0]) were significantly associated with survival to hospital discharge. Conversely, pre-hospital epinephrine (OR 0.6 [0.4-0.9]) was associated negatively with survival. CONCLUSIONS OHCA survival has improved in Singapore over the past 10 years. Improvement in response time, public AEDs and post-resuscitation hypothermia appear to have contributed to the increase in survival. Singapores experience might suggest that developing EMS systems should focus on reducing times to basic life support, including bystander defibrillation and post-resuscitation care.

A before-after interventional trial of dispatcher-assisted cardio-pulmonary resuscitation for out-of-hospital cardiac arrests in Singapore

AIM To evaluate the effects of a comprehensive dispatcher-assisted CPR (DACPR) training program on bystander CPR (BCPR) rate and the outcomes of out-of-hospital cardiac arrest (OHCA) in Singapore. METHODS This is an initial program evaluation of a national DACPR intervention. A before-after analysis was conducted using OHCA cases retrieved from a local registry and DACPR information derived from audio recordings and ambulance notes. The primary outcomes were survival to admission, survival at 30 days post-arrest and good functional recovery. RESULTS Data was collected before the intervention (April 2010 to December 2011), during the run-in period (January 2012 to June 2012) and after the intervention (July 2012 to February 2013). A total of 2968 cases were included in the study with a mean age of 65.6. Overall survival rate was 3.9% (116) with good functional recovery in 2.2% (66) of the patients. BCPR rate increased from 22.4% to 42.1% (p<0.001) with odds ratio (OR) of 2.52 (95% confidence interval [CI]: 2.09-3.04) and ROSC increased significantly from 26.5% to 31.2% (p=0.02) with OR of 1.26 (95%CI: 1.04-1.53) after the intervention. Significantly higher survival at 30 days was observed for patients who received BCPR from a trained person as compared to no BCPR (p=0.001, OR=2.07 [95%CI: 1.41-3.02]) and DACPR (p=0.04, OR=0.30 [95%CI: 0.04-2.18]). CONCLUSION A significant increase in BCPR and ROSC was observed after the intervention. There was a trend to suggest improved survival outcomes with the intervention pending further results from the trial.

Does Pre-hospital Endotracheal Intubation Improve Survival in Adults with Non-traumatic Out-of-hospital Cardiac Arrest? A Systematic Review

Introduction Endotracheal intubation (ETI) is currently considered superior to supraglottic airway devices (SGA) for survival and other outcomes among adults with non-traumatic out-of-hospital cardiac arrest (OHCA). We aimed to determine if the research supports this conclusion by conducting a systematic review. Methods We searched the MEDLINE, Scopus and CINAHL databases for studies published between January 1, 1980, and 30 April 30, 2013, which compared pre-hospital use of ETI with SGA for outcomes of return of spontaneous circulation (ROSC); survival to hospital admission; survival to hospital discharge; and favorable neurological or functional status. We selected studies using pre-specified criteria. Included studies were independently screened for quality using the Newcastle-Ottawa scale. We did not pool results because of study variability. Study outcomes were extracted and results presented as summed odds ratios with 95% CI. Results We identified five eligible studies: one quasi-randomized controlled trial and four cohort studies, involving 303,348 patients in total. Only three of the five studies reported a higher proportion of ROSC with ETI versus SGA with no difference reported in the remaining two. None found significant differences between ETI and SGA for survival to hospital admission or discharge. One study reported better functional status at discharge for ETI versus SGA. Two studies reported no significant difference for favorable neurological status between ETI and SGA. Conclusion Current evidence does not conclusively support the superiority of ETI over SGA for multiple outcomes among adults with OHCA.

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.

Termination of Resuscitation Rules to Predict Neurological Outcomes in Out-of-Hospital Cardiac Arrest for an Intermediate Life Support Prehospital System.

Abstract Aim: Futile resuscitation can lead to unnecessary transports for out-of-hospital cardiac arrest (OHCA). The Basic Life Support (BLS) and Advanced Life Support (ALS) termination of resuscitation (TOR) guidelines have been validated with good results in North America. This study aims to evaluate the performance of these two rules in predicting neurological outcomes of OHCA patients in Singapore, which has an intermediate life support Emergency Medical Services (EMS) system. Methods: A retrospective cohort study was carried out on Singapore OHCA data collected from April 2010 to May 2012 for the Pan-Asian Resuscitation Outcomes Study (PAROS). The outcomes of each rule were compared to the actual neurological outcomes of the patients. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and predicted transport rates of each test were evaluated. Results: A total of 2,193 patients had cardiac arrest of presumed cardiac etiology. TOR was recommended for 1,411 patients with the BLS-TOR rule, with a specificity of 100% (91.9, 100.0) for predicting poor neurological outcomes, PPV 100% (99.7, 100.0), sensitivity 65.7% (63.6, 67.7), NPV 5.6% (4.1, 7.5), and transportation rate 35.6%. Using the ALS-TOR rule, TOR was recommended for 587 patients, specificity 100% (91.9, 100.0) for predicting poor neurological outcomes, PPV 100% (99.4, 100.0), sensitivity 27.3% (25.4, 29.3), NPV 2.7% (2.0, 3.7), and transportation rate 73.2%. BLS-TOR predicted survival (any neurological outcome) with specificity 93.4% (95% CI 85.3, 97.8) versus ALS-TOR 98.7% (95% CI 92.9, 99.8). Conclusion: Both the BLS and ALS-TOR rules had high specificities and PPV values in predicting neurological outcomes, the BLS-TOR rule had a lower predicted transport rate while the ALS-TOR rule was more accurate in predicting futility of resuscitation. Further research into unique local cultural issues would be useful to evaluate the feasibility of any system-wide implementation of TOR.

Geographic factors are associated with increased risk for out-of hospital cardiac arrests and provision of bystander cardio-pulmonary resuscitation in Singapore

BACKGROUND Bystander Cardio-Pulmonary Resuscitation (BCPR) can improve survival for Out-of-Hospital Cardiac Arrest (OHCA). This study aimed to investigate the geographic variation of BCPR provision and survival to discharge outcomes among residential OHCA cases, evaluate this variation with individual and population characteristics and identify high-risk residential areas with low relative risk (RR) of BCPR and high RR of OHCA at the development guide plan (DGP) census tract levels in Singapore. METHODS This was a retrospective, secondary analysis of two prospectively-collected registries in Singapore from 2001 to 2011. We used Bayesian conditional autoregressive spatial models to examine predictors at the DGP level and calculate smoothed RR to identify high-risk areas. We used multi-level mixed-effects logistic regression models to examine the independent effects of individual and neighborhood factors. RESULTS We found a total of 3942 OHCA with a BCPR rate of 20.3% and a survival to discharge rate of 1.9% and 3578 cases eligible for BCPR. After adjusting for age, witnessed status, presumed cardiac etiology and longer response time, the risk of BCPR provision significantly increased by 0.02% for every 1% increase in the proportion of household size 5 and above in the DGP area (odds ratio 1.02, 95%CI=1.002-1.038, p<0.026). We identified 10 high-risk residential areas with low RR of BCPR and high RR of OHCA. CONCLUSION This study informed that neighborhood household size could have played a significant role in the provision of BCPR and occurrence of high-risk areas. It demonstrates the public health potential of combining geospatial and epidemiological analysis for improving health.

Implications for public access defibrillation placement by non-traumatic out-of-hospital cardiac arrest occurrence in Singapore

The American Heart Association recommends automated external defibrillator placement in public areas with a high probability (>1) of out‐of‐hospital cardiac arrest (OHCA) occurring in 5 years. We aimed to determine the incidence rate of OHCA for different location categories in Singapore.

39 Bystander CPR in out-of-hospital cardiac arrest in singapore: age and other predictive factors

Aim Multiple studies affirm that Bystander CPR (BCPR) improves outcomes in Out-of-hospital Cardiac Arrest (OHCA). This study investigates age and other factors in affecting BCPR rates in Singapore. Method Data was extracted from the national cardiac arrest registry. OHCA cases in Singapore conveyed via emergency medical services from April 2010–December 2015 were included. Zipcodes of arrest location, census data from 2010–2015 and planning areas were used for geospatial analysis. Multivariate logistic regression was performed to investigate the association between patient demographics and pre-hospital data with BCPR. Results 8955 cases were split into 3 groups: Paediatric (Age 0–10 years; n=107), Young (Age 11–65 years; n=3979), Old (Age>65 years; n=4869). Compared to the Old, Paediatric and Young patients had higher rates of BCPR (OR 3.997, 95% CI: 2.567 to 6.224; OR 1.133, 95% CI: 1.027 to 1.249). Non-traumatic arrest (OR 2.550, 95% CI: 1.743 to 3.731) and Witnessed arrest (OR 1.267, 95% CI: 1.157 to 1.387), positively associated with BCPR, while arrest in residential location (OR 0.655, 95% CI: 0.441 to 0.973) negatively associated with BCPR. Of the OHCA in residential locations, patients in neighbourhoods with younger population were more likely to receive BCPR (OR 1.242, 95% CI: 1.061 to 1.453) compared to older neighbourhoods. There was no association with gender and major race groups, and univariate analysis showed no difference in BCPR rates between family bystanders and other layperson bystanders. Conclusion Older patients, residential arrests and older neighbourhoods were associated with lower rates of BCPR. Public education and training programs can be targeted to these populations to improve BCPR rates. Conflict of interest None Funding This study was supported by grants from National Medical Research Council, Clinician Scientist Award, Singapore (NMRC/CSA/024/2010 and NMRC/CSA/0049/2013), Ministry of Health, Health Services Research Grant, Singapore (HSRG/0021/2012) and Duke-NUS Khoo Research Student Award (Duke-NUS-KRSA/2013/0001).

Diurnal variation in outcomes after out-of-hospital cardiac arrest in Asian communities: The Pan-Asian Resuscitation Outcomes Study

The present study aimed to determine whether the time of out‐of‐hospital cardiac arrest (OHCA) is associated with survival rate and neurological outcome after OHCA, as well as to compare the effect size of time of OHCA across six Asian regions.