Poor performance of the modified early warning score for predicting mortality in critically ill patients presenting to an emergency department

BACKGROUND:This study was undertaken to validate the use of the modified early warning score(MEWS) as a predictor of patient mortality and intensive care unit(ICU)/ high dependency(HD)admission in an Asian population.METHODS:The MEWS was applied to a retrospective cohort of 1 024 critically ill patients presenting to a large Asian tertiary emergency department(ED) between November 2006 and December2007.Individual MEWS was calculated based on vital signs parameters on arrival at ED.Outcomes of mortality and ICU/HD admission were obtained from hospital records.The ability of the composite MEWS and its individual components to predict mortality within 30 days from ED visit was assessed.Sensitivity,specificity,positive and negative predictive values were derived and compared with values from other cohorts.A MEWS of ≥4 was chosen as the cut-off value for poor prognosis based on previous studies.RESULTS:A total of 311(30.4%) critically ill patients were presented with a MEWS ≥4.Their mean age was 61.4 years(SD 18.1) with a male to female ratio of 1.10.Of the 311 patients,53(17%)died within 30 days,64(20.6%) were admitted to ICU and 86(27.7%) were admitted to HD.The area under the receiver operating characteristic curve was 0.71 with a sensitivity of 53.0%and a specificity of 72.1%in addition to a positive predictive value(PPV) of 17.0%and a negative predictive value(NPV)of 93.4%(MEWS cut-off of ≥4) for predicting mortality.CONCLUSION:The composite MEWS did not perform well in predicting poor patient outcomes for critically ill patients presenting to an ED.

Prehospital system delay in patients with ST-segment elevation myocardial infarction in Singapore

BACKGROUND: Timely reperfusion in ST-segment elevation myocardial infarction(STEMI)improves outcomes. System delay is that between first medical contact and reperfusion therapy,comprising prehospital and hospital components. This study aimed to characterize prehospital system delay in Singapore.METHODS: A retrospective chart review was performed for 462 consecutive STEMI patients presenting to a tertiary hospital from December 2006 to April 2008. Patients with cardiac arrest secondarily presented were excluded. For those who received emergency medical services(EMS),ambulance records were reviewed. Time intervals in the hospital were collected prospectively. The patients were divided into two equal groups of high/low prehospital system delay using visual binning technique.RESULTS: Of 462 patients, 76 received EMS and 52 of the 76 patients were analyzed. The median system delay was 125.5 minutes and the median prehospital system delay was 33.5minutes(interquartile range [IQR]=27.0, 42.0). Delay between call-received-by-ambulance and ambulance-dispatched was 2.48 minutes(IQR=1.47, 16.55); between ambulance-dispatch and arrival-at-patient-location was 8.07 minutes(IQR=1.30, 22.13); between arrival-at- and departurefrom-patient-location was 13.12 minutes(IQR=3.12, 32.2); and between leaving-patient-location to ED-registration was 9.90 minutes(IQR=1.62, 32.92). Comparing patients with prehospital system delay of less than 35.5 minutes versus more showed that the median delay between ambulancedispatch and arrival-at-patient-location was shorter(5.75 vs. 9.37 minutes, P<0.01). The median delay between arrival-at-patient-location and leaving-patient-location was also shorter(10.78 vs.14.37 minutes, P<0.01).CONCLUSION: Prehospital system delay in our patients was suboptimal. This is the first attempt at characterizing prehospital system delay in Singapore and forms the basis for improving efficiency of STEMI care.

Association between the elderly frequent attender to the emergency department and 30-day mortality： A retrospective study over 10 years

BACKGROUND: To determine if elderly frequent attenders are associated with increased 30-day mortality, assess resource utilization by the elderly frequent attenders and identify associated characteristics that contribute to mortality. METHODS: Retrospective observational study of electronic clinical records of all emergency department(ED) visits over a 10-year period to an urban tertiary general hospital in Singapore. Patients aged 65 years and older, with 3 or more visits within a calendar year were identified. Outcomes measured include 30-day mortality, admission rate, admission diagnosis and duration spent at ED. Chi-square-tests were used to assess categorical factors and Student t-test was used to assess continuous variables on their association with being a frequent attender. Univariate and multivariate logistic regressions were conducted on all significant independent factors on to the outcome variable(30-day mortality), to determine factor independent odds ratios of being a frequent attender.RESULTS: 1.381 million attendance records were analyzed. Elderly patients accounted for 25.5% of all attendances, of which 31.3% are frequent attenders. Their 30-day mortality rate increased from 4.0% in the first visit, to 8.8% in the third visit, peaking at 10.2% in the sixth visit. Factors associated with mortality include patients with neoplasms, ambulance utilization, male gender and having attended the ED the previous year.CONCLUSION: Elderly attenders have a higher 30-day mortality risk compared to the overall ED population, with mortality risk more marked for frequent attenders. This study illustrates the importance and need for interventions to address frequent ED visits by the elderly, especially in an aging society.

Development of a heart rate variability and complexity model in predicting the need for life-saving interventions amongst trauma patients

Background:Triage trauma scores are utilised to determine patient disposition,interventions and prognostication in the care of trauma patients.Heart rate variability(HRV)and heart rate complexity(HRC)reflect the autonomic nervous system and are derived from electrocardiogram(ECG)analysis.In this study,we aimed to develop a model incorporating HRV and HRC,to predict the need for life-saving interventions(LSI)in trauma patients,within 24 h of emergency department presentation.Methods:We included adult trauma patients(≥18 years of age)presenting at the emergency department of Singapore General Hospital between October 2014 and October 2015.We excluded patients who had non-sinus rhythms and larger proportions of artefacts and/or ectopics in ECG analysis.We obtained patient demographics,laboratory results,vital signs and outcomes from electronic health records.We conducted univariate and multivariate analyses for predictive model building.Results:Two hundred and twenty-five patients met inclusion criteria,in which 49 patients required LSIs.The LSI group had a higher proportion of deaths(10,20.41%vs 1,0.57%,p<0.001).In the LSI group,the mean of detrended fluctuation analysis(DFA)-α1(1.24 vs 1.12,p=0.045)and the median of DFA-α2(1.09 vs 1.00,p=0.027)were significantly higher.Multivariate stepwise logistic regression analysis determined that a lower Glasgow Coma Scale,a higher DFA-α1 and higher DFA-α2 were independent predictors of requiring LSIs.The area under the curve(AUC)for our model(0.75,95%confidence interval,0.66–0.83)was higher than other scoring systems and selected vital signs.Conclusions:An HRV/HRC model outperforms other triage trauma scores and selected vital signs in predicting the need for LSIs but needs to be validated in larger patient populations.

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.