Early sepsis care with the National Early Warning Score 2-guided Sepsis Hour-1 Bundle in the emergency department: hybrid type 1 effectiveness-implementation pilot stepped wedge randomised controlled trial (NEWS-1 TRIPS) protocol.

INTRODUCTION: Early sepsis treatment in the emergency department (ED) is crucial to improve patient survival. Despite international promulgation, the uptake of the Surviving Sepsis Campaign (SSC) Hour-1 Bundle (lactate measurement, blood culture, broad-spectrum antibiotics, 30 mL/kg crystalloid for hypotension/lactate ≥4 mmol/L and vasopressors for hypotension during/after fluid resuscitation within 1 hour of sepsis recognition) is low across healthcare settings. Delays in sepsis recognition and a lack of high-quality evidence hinder its implementation. We propose a novel sepsis care model (National Early Warning Score, NEWS-1 care), in which the SSC Hour-1 Bundle is triggered objectively by a high NEWS-2 (≥5). This study aims to determine the feasibility of a full-scale type 1 hybrid effectiveness-implementation trial on the NEWS-1 care in multiple EDs. METHODS AND ANALYSIS: We will conduct a pilot type 1 hybrid trial and prospectively recruit 200 patients from 4 public EDs in Hong Kong cluster randomised in a stepped wedge design over 10 months. All study sites will start with an initial period of standard care and switch in random order at 2-month intervals to the NEWS-1 care unidirectionally. The implementation evaluation will employ mixed methods guided by the Reach, Effectiveness, Adoption, Implementation and Maintenance framework, which includes qualitative and quantitative data from focus group interviews, staff survey and clinical record reviews. We will analyse the 14 feasibility outcomes as progression criteria to a full-scale trial, including trial acceptability to patients and staff, patient and staff recruitment rates, accuracy of sepsis screening, protocol adherence, accessibility to follow-up data, safety and preliminary clinical impacts of the NEWS1 care, using descriptive statistics. ETHICS AND DISSEMINATION: The institutional review boards of all study sites approved this study. This study will establish the feasibility of a full-scale hybrid trial. We will disseminate the findings through peer-reviewed publications, conference presentations and educational activities. TRIAL REGISTRATION NUMBER: NCT05731349.

Exposure-response relationship between COVID-19 incidence rate and incidence and survival of out-of-hospital cardiac arrest (OHCA).

Aim: We aimed to report the epidemiology of OHCA, bystander CPR pattern and other Utstein factors in a region in Hong Kong during the COVID-19 pandemic. In particular, we studied the relationship between COVID-19 incidence, OHCA incidence and survival outcome. Methods: This was a retrospective cohort study that used data from our registry to compare features of OHCA during pre-pandemic (Jan 2018 to Dec 2019), low-incidence pandemic (Jan 2020 to Dec 2021) and high-incidence pandemic (Jan to Mar 2022). We used multivariable logistic regression to identify survival predictors. Results: Incidence of OHCA increased dramatically with surging COVID-19 incidence (65.9 vs 74.2 vs 159.2 per 100,000 population per year, p < 0.001). During the pandemic, there were more indoor OHCA (89.3% vs 92.6% vs 97.4%, p < 0.001), fewer witnessed arrest (38.5% vs 38.3% vs 29.6%, p = 0.001), and longer median time to basic life support upon receiving call (9 min vs 10 min vs 14 min, p < 0.001). There was a higher proportion of OHCA cases with bystander-CPR (26.1% vs 31.3% vs 35.3%, p < 0.001). The proportion of cases with survival to admission (STA) (30.8% vs 22.2% vs 15.4%, p < 0.001) and survival to discharge (STD) (2.2% vs 1.0% vs 0.2%, p = 0.001) were lowered. After controlling for confounders, the odds of STA was reduced by 33% and 55% during the low-incidence and high-incidence pandemic respectively. Conclusion: The increase in COVID-19 incidence had an exposure-response relationship with an increased incidence of OHCA and worsened survival outcomes.

Return to work after injury in Hong Kong: prospective multi-center cohort study.

PURPOSE: Trauma remains a major cause of morbidity and disability worldwide; however, reliable data on the health status of an urban Asian population after injury are scarce. The aim was to evaluate 1-year post-trauma return to work (RTW) status in Hong Kong. METHODS: This was a prospective, multi-center cohort study involving four regional trauma centers from 2017 to 2019 in Hong Kong. Participants included adult patients entered into the trauma registry who were working or seeking employment at the time of injury. The primary outcome was the RTW status up to 1 year. The Extended Glasgow Outcome Scale, 12-item Short Form (SF-12) survey and EQ5D were also obtained during 1-, 3-, 6-, 9-, and 12-month follow-ups. Multivariable Cox proportional hazards regression analysis was used for analysis. RESULTS: Six hundred and seven of the 1115 (54%) recruited patients had RTW during the first year after injury. Lower physical requirements (p = 0.003, HR 1.51) in pre-injury job nature, higher educational levels (p < 0.001, HR 1.95), non-work-related injuries (p < 0.001, HR 1.85), shorter hospital length of stay (p = 0.007, HR 0.98), no requirement for surgery (p = 0.006, HR 1.34), and patients who could be discharged home (p = 0.006, HR 1.43) were associated with RTW within 12 months post-injury. In addition, 1-month outcomes including extended Glasgow Outcome Scale ≥ 6 (p = 0.001, HR 7.34), higher mean SF-12 physical component summary (p = 0.002, HR 1.02) and mental component summary (p < 0.001, HR 1.03), and higher EQ5D health index (p = 0.018, HR 2.14) were strongly associated with RTW. CONCLUSIONS: We have identified factors associated with failure to RTW during the first year following in Hong Kong including socioeconomic factors, injury factors and treatment-related factors and 1-month outcomes. Future studies should focus on the interventions that can impact on RTW outcomes. TRIAL REGISTRATION: ClinicalTrials.gov Identifier NCT03219424.

Clinical prediction rule of termination of resuscitation for out-of-hospital cardiac arrest patient with pre-hospital defibrillation given.

OBJECTIVE: To derive a clinical prediction rule of termination of resuscitation (TOR) for out-of-hospital cardiac arrest (OHCA) with pre-hospital defibrillation given. METHOD: This was a retrospective multicenter cohort study performed in three emergency departments (EDs) of three regional hospitals from 1/1/2012 to 31/12/2018. Patients of OHCA aged ≥18 years old were included. Those with post-mortem changes, return of spontaneous circulation and receiving no resuscitation in EDs were excluded. A TOR rule was derived by logistic regression analysis based on demographics and end-tidal carbon dioxide level of included subjects with pre-hospital defibrillation given. RESULTS: There were 447 included patients had received pre-hospital defibrillation, in which 148 had return of spontaneous circulation (ROSC), with 22 survived to discharge (STD). Independent predictors for death on or before ED arrival (no ROSC) included EMS call to ED time >20 min and ETCO2 level <20 mmHg from first three sets. A 2-criteria rule predicting death on or before ED arrival by fulfilling both of the independent predictors had a specificity of 0.95 (95% CI 0.90-0.98) and positive predictive value (PPV) of 0.95 (95% CI 0.90-0.98), if 2nd set of ETCO2 was used. The positive likelihood ratio was 10.04 (95% CI 4.83-20.89). CONCLUSION: The 2-criteria TOR rule for OHCA patients with pre-hospital defibrillation had a high specificity and PPV for predicting death on or before ED arrival.

Intramuscular midazolam, olanzapine, or haloperidol for the management of acute agitation: A multi-centre, double-blind, randomised clinical trial.

BACKGROUND: The safety and effectiveness of intramuscular olanzapine or haloperidol compared to midazolam as the initial pharmacological treatment for acute agitation in emergency departments (EDs) has not been evaluated. METHODS: A pragmatic, randomised, double-blind, active-controlled trial was conducted from December 2014 to September 2019, in six Hong Kong EDs. Patients (aged 18-75 years) with undifferentiated acute agitation requiring parenteral sedation were randomised to 5 mg intramuscular midazolam (n = 56), olanzapine (n = 54), or haloperidol (n = 57). Primary outcomes were time to adequate sedation and proportion of patients who achieved adequate sedation at each follow-up interval. Sedation levels were measured on a 6-level validated scale (ClinicalTrials.gov Identifier: NCT02380118). FINDINGS: Of 206 patients randomised, 167 (mean age, 42 years; 98 [58·7%] male) were analysed. Median time to sedation for IM midazolam, olanzapine, and haloperidol was 8·5 (IQR 8·0), 11·5 (IQR 30·0), and 23·0 (IQR 21·0) min, respectively. At 60 min, similar proportions of patients were adequately sedated (98%, 87%, and 97%). There were statistically significant differences for time to sedation with midazolam compared to olanzapine (p = 0·03) and haloperidol (p = 0·002). Adverse event rates were similar across the three arms. Dystonia (n = 1) and cardiac arrest (n = 1) were reported in the haloperidol group. INTERPRETATION: Midazolam resulted in faster sedation in patients with undifferentiated agitation in the emergency setting compared to olanzapine and haloperidol. Midazolam and olanzapine are preferred over haloperidol's slower time to sedation and potential for cardiovascular and extrapyramidal side effects. FUNDING: Research Grants Council, Hong Kong.

Clinical, laboratory, and radiological features indicative of novel coronavirus disease (COVID-19) in emergency departments: a multicenter case-control study in Hong Kong.

Objectives: Little is known about the value of routine clinical assessment in identifying patients with coronavirus disease 2019 (COVID-19) in the emergency department (ED). We aimed to compare the exposure history, signs and symptoms, laboratory, and radiographic features of ED patients who tested positive and negative for COVID-19. Methods: This was a case-control study in 7 EDs in Hong Kong from 20 January to 29 February 2020. Thirty-seven patients with laboratory-confirmed COVID-19 were age- and sex-matched to 111 controls. We compared the groups with univariate analysis and calculated the odds ratio (OR) of having COVID-19 for each characteristic that was significantly different between the groups with adjustment for age and presumed location of acquiring the infection. Results: There were no significant differences in patient characteristics and reported symptoms between the groups. A positive contact history within 14 days (adjusted OR 37.61, 95% CI: 10.86-130.19), bilateral chest radiograph shadow (adjusted OR 13.19, 95% CI: 4.66-37.35), having prior medical consultation (adjusted OR 7.43, 95% 2.89-19.09), a lower white blood cell count (adjusted OR 1.30, 95% CI: 1.11-1.51), and a lower platelet count (adjusted OR 1.07, 95% CI: 1.01-1.12) were associated with a higher odds of COVID-19 separately. A higher neutrophil count was associated with a lower odds of COVID-19 (adjusted OR 0.77, 95% CI: 0.65-0.91). Conclusion: This study highlights a number of clinical features that may be useful in identifying high-risk patients for early testing and isolation while waiting for the test result. Further studies are warranted to verify the findings.

Clinical prediction rule to predict pneumonia in adult presented with acute febrile respiratory illness.

OBJECTIVE: To derive a clinical prediction rule to predict pneumonia in patients with acute febrile respiratory illness to emergency departments. METHOD: This was a prospective multicentre study. 537 adults were recruited. Those requiring resuscitation or were hypoxaemic on presentation were excluded. Pneumonia was defined as new onset infiltrates on chest X-ray (CXR), or re-attendance within 7 days and diagnosed clinically as having pneumonia. A predictive model, the Acute Febrile Respiratory Illness (AFRI) rule was derived by logistic regression analysis based on clinical parameters. The AFRI rule was internally validated with bootstrap resampling and was compared with the Diehr and Heckerling rule. RESULTS: In the 363 patients who underwent CXR, 100 had CXR confirmed pneumonia. There were 7 weighted factors within the ARFI rule, which on summation, gave the AFRI score: age ≥ 65 (1 point), peak temperature within 24 h ≥ 40 °C (2 points), fever duration ≥3 days (2 points), sore throat (-2 points), abnormal breath sounds (1 point), history of pneumonia (1 point) and SpO2 ≤ 96% (1 point). With the bootstrap resampling, the AFRI rule was found to be more accurate than the Diehr and Heckerling rule (area under ROC curve 0.816, 0.721 and 0.566 respectively, p < 0.001). At a cut-off of AFRI≥0, the rule was found to have 95% sensitivity, with a negative predictive value of 97.2%. Using the AFRI score, we found CXR could be avoided for patients having a score of <0. CONCLUSION: AFRI score could assist emergency physicians in identifying pneumonia patients among all adult patients presented to ED for acute febrile respiratory illness.

Predictive model integrating dynamic parameters for massive blood transfusion in major trauma patients: The Dynamic MBT score.

BACKGROUND: Currently existing predictive models for massive blood transfusion in major trauma patients had limitations for sequential evaluation of patients and lack of dynamic parameters. OBJECTIVE: To establish a predictive model for predicting the need of massive blood transfusion major trauma patients, integrating dynamic parameters. DESIGN: Multi-center retrospective cohort study. SETTING: Four designated trauma centers in Hong Kong. METHODS: Trauma patients aged >12years were recruited from the trauma registries from 2005 to 2012. MBT was defined as delivery of ≥10units of packed red cells within 24h. Split sampling method was adopted for model building and validation. Multivariate logistic regression was adopted for model building, with weight assigned based on logarithmic of adjusted odds ratios. The performance of the dynamic MBT score (DMBT) was compared with the PWH score and the Trauma Associated Severe Hemorrhage (TASH) score in the validation data set. RESULTS: 4991 patients were included in the study. The DMBT was established with 8 parameters: systolic blood pressure, heart rate, hemoglobin, hemoglobin drop within the first 2h, INR, base deficit, unstable pelvic fracture and hemoperitoneum in radiological imaging. At cut-off score of 6 the DMBT achieved sensitivity of 78.2% and specificity of 89.2%. In the validation set, the AUCs of the DMBT, PWH score, and TASH score were 0.907, 0.844, and 0.867 respectively. CONCLUSIONS: The DMBT score allows both snapshot and sequential activation along the trauma care pathway and has better performance than the PWH score and TASH score.

Prognosticating Clinical Prediction Scores Without Clinical Gestalt for Patients With Chest Pain in the Emergency Department.

BACKGROUND: Assessment of patients with chest pain is a regular challenge in the emergency department (ED). Recent guidelines recommended quantitative assessment of ischemic risk by means of risk scores. OBJECTIVE: Our aim was to assess the performance of Thrombosis in Myocardial Infarction (TIMI); Global Registry of Acute Coronary Events (GRACE); history, electrocardiogram, age, risk factors, and troponin (HEART) scores; and the North America Chest Pain Rule (NACPR) without components of clinical gestalt in predicting 30-day major adverse cardiac events (MACE). METHODS: We performed a prospective cohort study in adult patients who attended the ED with undifferentiated chest pain. Clinical prediction rules were applied and calculated. The clinical prediction rules were modified from the original ones, excluding components requiring judgment by clinical gestalt. The primary outcome was MACE. Performance of the tests were evaluated by receive operating characteristic curves and the area under curves (AUC). RESULTS: There were 1081 patients included in the study. Thirty-day MACE occurred in 164 (15.2%) patients. The AUC of the GRACE score was 0.756, which was inferior to the TIMI score (AUC 0.809) and the HEART score (AUC 0.845). A TIMI score ≥ 1 had a sensitivity of 97% and a specificity of 45.7%. A GRACE score ≥ 50 had a sensitivity of 99.4% and a specificity of 7.5%. A HEART score ≥ 1 had a sensitivity of 98.8% and a specificity of 11.7%. The NACPR had a sensitivity of 93.3% and a specificity of 51.5%. CONCLUSIONS: Without clinical gestalt, the modified HEART score had the best discriminative capacity in predicting 30-day MACE.

Impact of hypotension after return of spontaneous circulation on survival in patients of out-of-hospital cardiac arrest.

OBJECTIVE: To investigate the relationship between hypotension in the first 3h after return of spontaneous circulation (ROSC) in patients with out-of-hospital cardiac arrest. METHOD: This retrospective cohort study occurred at two regional hospitals and included adult OHCA patients who experienced ROSC from July 1, 2014 to December 31, 2015. Hemodynamic and inotrope administration data were retrieved for 3h after ROSC. We calculated the hypotensive exposure index (HEI) as the surrogate marker of the exposure of hypotension. The area under the ROC curve and multivariate logistic regression models were performed to analyze the effect of HEI on survival. Mean arterial pressure (MAP) was explored in the surviving and non-surviving patient groups using repeated measures MANCOVA, adjusted for the use of inotropes and down time. RESULTS: A total of 289 patients were included in the study, and 29 survived. The median 1-hour HEI and 3-hour HEI were significantly lower in the survival group (p<0.001). The area under the ROC curve for 3-hour HEI was 0.861. The repeated measures MANCOVA indicated that an interaction existed between post-ROSC time and downtime [F(5,197)=2.31, p=0.046]. No significant change in the MAP was observed in the 3h after ROSC, except in the group with a prolonged down time. According to the tests examining the effects of the use of inotropes on the survival outcomes of the different subjects, the MAP was significantly higher in the surviving group [F(1,201)=4.11; p=0.044; ηp2=0.020]. CONCLUSION: Among the patients who experienced ROSC after OHCA, post-ROSC hypotension was an independent predictor of survival.

Prescription practice of antihistamines for acute upper respiratory tract infections in pediatric patients in a local emergency department in Hong Kong.

BACKGROUND: Currently there is very limited data in the literature assessing the prevalence of antihistamine prescription, and there is no local prevalence data about the prescription of antihistamine agents among primary practitioner and emergency physicians. The objectives are 1) to report the prevalence of antihistamine prescription for children less than 6 years old with acute upper respiratory infection and 2) to explore the associated factors for the prescription practice. METHODS: This is a cross-sectional study. All consecutive cases of paediatric patients aged 6 or below who presented to the emergency department during a study period of one week from April 1 to July 4, 2009 with diagnosis of acute upper respiratory infection were included. Totally 162 patients were included. RESULTS: Among the 162 cases, 141 (87%) patients were prescribed one antihistamine of any group. Sixty (37%) patients were prescribed two or more antihistamines. In multivariate logistic regression model, age was found to be significantly (P<0.001) associated with multiple antihistamine prescription (OR=1.042, 95%CI=1.02 to 1.06). Years of graduation of attending physician for more than 5 years was also a strong predictor of multiple antihistamine prescription (OR=4.654, 95%CI=2.20 to 9.84, P<0.001). CONCLUSION: In the local emergency department, patients' age and the years of graduation from medical school of the attending physician were predictors of multiple antihistamine prescription for acute upper respiratory infections for children aged less than 6.

Abrupt rise of end tidal carbon dioxide level was a specific but non-sensitive marker of return of spontaneous circulation in patient with out-of-hospital cardiac arrest.

OBJECTIVE: To evaluate the diagnostic accuracy of an abrupt and sustained increase in end-tidal carbon dioxide (ETCO2) to indicate return of spontaneous circulation (ROSC) during resuscitation of patient with out-of-hospital cardiac arrest. DESIGN: Cross-sectional study. SETTING: Emergency department of two regional hospitals. METHODS: Patients with age ≥18 years old, suffered non-traumatic out-of-hospital cardiac arrest with active resuscitation and endotracheal intubation performed in emergency department, were included. ETCO2 value was charted throughout resuscitation. Time of ROSC was remarked. ETCO2 levels before and after ROSC were compared. Diagnostic accuracy of ETCO2 rise ≥10mmHg, ETCO2 rise ≥20mmHg, and ETCO2 rise to the level ≥40mmHg were evaluated for indicating ROSC. RESULTS: ETCO2 level immediately after ROSC was higher as compared to the value before return of circulation (median ETCO2 was 32mmHg and 41mmHg respectively, p=0.033). With ETCO2 rise ≥10mmHg, the sensitivity was low (33%, 95% CI 22-47%), while specificity was 97% (95% CI 91-99%). Positive and negative predictive values were 83% (95% CI 62-95%) and 74% (95% CI 66-81%) respectively. The diagnostic accuracy was higher in cardiac arrest with presumed non-cardiac etiology (sensitivity 45%, specificity 100%) as compared to those with cardiac etiology (sensitivity 18%, specificity 97%). CONCLUSIONS: The feature of an abrupt rise of ETCO2 was a specific but non-sensitive marker of ROSC in patient with out-of-hospital cardiac arrest.

Presenting hydrothorax predicts failure of needle aspiration in primary spontaneous pneumothorax.

OBJECTIVE: The objective was to evaluate if existence of hydrothorax in initial chest radiograph predicts treatment outcome in patients with primary spontaneous pneumothorax who received needle thoracostomy. METHODS: This is a retrospective cohort study carried out from January 2011 to August 2014 in 1 public hospital in Hong Kong. All consecutive adult patients aged 18years or above who attended the emergency department with the diagnosis of primary spontaneous pneumothorax with needle aspiration performed as primary treatment were included. Age, smoking status, size of pneumothorax, previous history of pneumothorax, aspirated gas volume and presence of hydropneumothorax in initial radiograph were included in the analysis. The outcome was success or failure of the needle aspiration. Logistic regression was used to identify the predicting factors of failure of needle aspiration. RESULT: There were a total of 127 patients included. Seventy-three patients (57.5%) were successfully treated with no recurrence upon discharge. Among 54 failure cases, 13 patients (10.2%) failed immediately after procedure as evident by chest radiograph and required second treatment. Forty-one patients (32.3%) failed upon subsequent chest radiographs. Multivariate logistic regression showed factors independently associated with the failure of needle aspiration, which included hydropneumothorax in the initial radiograph (odds ratio [OR]=4.47 [1.56i12.83], P=.005), previous history of pneumothorax (OR=3.92 [1.57-9.79], P=.003), and large size of pneumothorax defined as apex-to-cupola distance ≥5cm (OR=2.75 [1.21-6.26], P=.016). CONCLUSIONS: Hydropneumothorax, previous history of pneumothorax, and large size were independent predictors of failure of needle aspiration in treatment of primary spontaneous pneumothorax.

Prognostication of out-of-hospital cardiac arrest patients by 3-min end-tidal capnometry level in emergency department.

OBJECTIVE: To evaluate the role of initial ETCO2 value in prognostication of OHCA patients in an Asian-Chinese cohort. DESIGN: Prospective cohort study. SETTING: Emergency departments of two regional hospitals in a cluster of Hong Kong. PATIENTS: Patients were recruited prospectively from the local cardiac arrest registry from July 2012 to June 2013. Patients of non traumatic OHCA aged ≥18 years old were included. Patients of OHCA presented with postmortem changes, those who decided for Do Not Resuscitate (DNR), regained pulse before arrival, or those without proper documentation of ETCO2 would be excluded. OUTCOME: Primary outcome was return of spontaneous circulation (ROSC). RESULTS: A 3-min ETCO2 >10mmHg was a predictor of ROSC with OR 18.16 (95% CI 4.79-51.32, p<0.001). The diagnostic accuracy of 3-min ETCO2 >10mmHg to predict ROSC: sensitivity was 0.95 (95% CI 0.89-0.98) while the specificity was 0.27 (95% CI 0.21-0.33). Positive predictive value was 0.40 (95% CI 0.34-0.46) while negative predictive value (NPV) was 0.92 (95% CI 0.82-0.97). Area under ROC curve of 3-min ETCO2 predicting ROSC was 0.80 (95% CI 0.71-0.91). CONCLUSIONS: A 3-min ETCO2 ≤10mmHg was associated with poor prognosis and low chance of ROSC. Low ETCO2 level may have a role to reduce prolonged medically futile resuscitation.

Utilization of the Accident & Emergency Departments by Chinese elderly in Hong Kong.

BACKGROUND: The epidemiological data on elderly patients attending Accident and Emergency Departments (AEDs) in Hong Kong is lacking. The study aimed to examine the epidemiology of geriatric patient visits to AEDs in Hong Kong, including demographic data and predictors of life-saving interventions (LSI) and admission. METHODS: A retrospective cross-sectional study of geriatric patients older than 64 years old attending three AEDs during the year 2012, with a sample of 1 200 patient visits recruited. The data were retrieved from the medical records of the respective hospitals. Descriptive characteristics of the visits were provided. Multivariate logistic regression was performed to evaluate the predictors of LSI and hospital admission. RESULTS: The mean age of the patients was 79.1 years. Totally 49.7% of the patients were male. "Diseases of the respiratory system" was the commonest diagnosis in AEDs as well as that required admission. The admission rate was 56.8%. Logistic regression demonstrated that dependent activity of daily living (ADL), arrival by ambulance, and the higher number of co-morbidities were predictors of LSI, while advanced age, dependent ADL, institutionalized patients, arrival by ambulance, and higher number of co-morbidities were predictors of hospital admission. CONCLUSIONS: Ageing population is creating an imminent burden on the emergency service in Hong Kong. Previously unavailable epidemiological information about geriatric attendance to AEDs was described. This forms the basis for development of future studies concerning the medical services on this specific group of patients.

Role of copeptin in dual-cardiac marker strategy for patients with chest pain presented to ED.

OBJECTIVE: The objective of the study is to evaluate the role of copeptin in the diagnosis of acute coronary syndrome (ACS) and its role in dual-cardiac marker diagnostic strategy with troponin. DESIGN: A prospective cohort study was carried out from May 2012 to October 2012. SETTING: The study was conducted at the emergency department (ED) of a public hospital in a cluster of Hong Kong. METHODS: Patients aged at least 18 years presented with chest pain to ED who have intermediate or high likelihood of ACS were included. All patients had blood taken in the ED for copeptin and troponin I. The adjudicated diagnoses of ACS were made by 2 independent physicians based on the universal definition. Diagnostic characteristics were calculated. Receiver operating characteristic curves were created. Areas under the curves were compared for copeptin, troponin I, and dual-marker strategy with copeptin and troponin I. RESULTS: A total of 637 patients were recruited. Seventy-eight had been diagnosed to be ACS. The negative predictive value of copeptin for ACS was 0.881 (0.849-0.907) compared with troponin I, 0.937 (0.913-0.956). The areas under the receiver operating characteristic curves of copeptin, troponin I, and dual-marker strategy were 0.68, 0.859, and 0.880, respectively. CONCLUSIONS: Addition of copeptin to troponin does not have significant improvement of the diagnostic accuracy of ACS in patients presented with chest pain.