Prehospital electrocardiogram shortens ischaemic time in patients with ST-segment elevation myocardial infarction

INTRODUCTION

Total ischaemic time should be shortened as much as possible in patients with ST-segment elevation myocardial infarction (STEMI). This study evaluated whether prehospital 12-lead electrocardiogram (ECG) could shorten system delay in STEMI management.

METHODS

From November 2015 to November 2017, 15 ambulances equipped with X Series Monitor/ Defibrillator (Zoll Medical Corporation) were used in the catchment area of Queen Mary Hospital, Hong Kong. Prehospital ECG was performed for patients with chest pain; the data were tele-transmitted to attending emergency physicians at the Accident and Emergency Department (AED) for rapid assessment. Data from patients with STEMI who were transported by these 15 ambulances were compared with data from patients with STEMI who were transported by ambulances without prehospital ECG or who used self-arranged transport.

RESULTS

Data were analysed from 197 patients with STEMI. The median patient delay for activation of the emergency response system was 90 minutes; 12% of patients experienced a delay of >12 hours. There was a significant difference in delay between patients transported by ambulance and those who used self-arranged transport (P<0.001). For system delay, the use of prehospital ECG shortened the median time from ambulance on scene to first ECG (P<0.001). When performed upon ambulance on scene, prehospital ECG was available 5 minutes earlier than if performed in ambulance compartment before departure. Use of prehospital ECG significantly shortened AED door-to-triage time, AED door-to-first AED ECG time, AED door-to-physician consultation time, and length of stay in the AED (P<0.001 for all comparisons).

CONCLUSION

Prehospital ECG shortened ischaemic time prior to hospital admission.

Prehospital 12-lead electrocardiogram for patients with chest pain: a pilot study

INTRODUCTION

After ST-segment elevation myocardial infarction (STEMI), it is vital to shorten reperfusion time. This study examined data from a pilot project to shorten the door-to-balloon (D2B) time by using prehospital 12-lead electrocardiogram (ECG).

METHODS

Fifteen ambulances equipped with X Series^® Monitor/Defibrillator (Zoll Medical Corporation) were deployed to the catchment area of Queen Mary Hospital, Hong Kong, from November 2015 to December 2016. For patients with chest pain, prehospital 12-lead ECG was performed and tele-transmitted to attending physicians at the accident and emergency department for immediate interpretation. The on-call cardiologist was called before patient arrival if STEMI was suspected. Data from this group of patients with STEMI were compared with data from patients with STEMI who were transported by ambulances without prehospital ECG or by self-arranged transport.

RESULTS

From 841 patients with chest pain, 731 gave verbal consent and prehospital ECG was performed and transmitted. Of these, 25 patients with clinically diagnosed STEMI required emergency coronary angiogram with or without primary percutaneous coronary intervention. The mean D2B time for these 25 patients (93 minutes) was significantly shorter (P=0.003) than that for 58 patients with STEMI transported by ambulances without prehospital ECG (112 minutes) and that for 41 patients with STEMI with self-arranged transport (138 minutes). However, shorter reperfusion time was only recorded during daytime hours (08:00-17:59). No statistically significant difference in 30-day mortality was found.

CONCLUSION

Prehospital ECG is technologically feasible in Hong Kong and shortens the D2B time. However, shorter reperfusion time was only recorded during daytime hours.

Out-of-hospital cardiac arrest in Hong Kong: a territory-wide study

INTRODUCTION

Out-of-hospital cardiac arrest is a global health care problem. Like other cities in the world, Hong Kong faces the impact of such events. This study is the first territory-wide investigation of the epidemiology and outcomes of out-of-hospital cardiac arrest in Hong Kong. It is hoped that the findings can improve survival of patients with cardiac arrest.

METHODS

This study was a retrospective analysis of the prospectively collected data on out-of-hospital cardiac arrest managed by the emergency medical service from 1 August 2012 to 31 July 2013. The characteristics of patients and cardiac arrests, timeliness of emergency medical service attendance, and survival rates were reported with descriptive statistics. Predictors of 30-day survival were evaluated with logistic regression.

RESULTS

A total of 5154 cases of out-of-hospital cardiac arrest were analysed. The median age of patients was 80 years. Most arrests occurred at the patient's home. Ventricular fibrillation or ventricular tachycardia was identified in 8.7% of patients. The median time taken for the emergency services to reach the patient was 9 minutes. The median time to first defibrillation was 12 minutes. Of note, 2.3% of patients were alive at 30 days or survived to hospital discharge; 1.5% had a good neurological outcome. Location of arrest, initial electrocardiogram rhythm, and time to first defibrillation were independent predictors of survival at 30 days.

CONCLUSION

The survival rate of out-of-hospital cardiac arrest patients in Hong Kong is low. Territory-wide public access defibrillation programme and cardiopulmonary resuscitation training may help improve survival.

Evaluation of various POSSUM models for predicting mortality in patients undergoing elective oesophagectomy for carcinoma

Background

The aim of the study was to validate the use of the Physiological and Operative Severity Score for the enUmeration of Mortality and morbidity (POSSUM), Portsmouth (P) POSSUM and upper gastrointestinal (O) POSSUM models in patients undergoing elective thoracic oesophagectomy for carcinoma.

Methods

The observed in-hospital mortality rates in 545 patients undergoing elective thoracic oesophagectomy for squamous cell carcinoma of the oesophagus in all public hospitals in Hong Kong was compared with rates predicted by POSSUM, P-POSSUM and O-POSSUM. The discriminatory power of these models was assessed using receiver–operator characteristic (ROC) curve analysis.

Results

The observed mortality rate was 5·5 per cent, whereas rates predicted by POSSUM, P-POSSUM and O-POSSUM were 15·0, 4·7 and 10·9 per cent respectively. P-POSSUM showed no lack of fit (P = 0·814), but POSSUM (P &lt; 0·001) and O-POSSUM (P = 0·002) showed lack of fit against observed mortality. POSSUM overpredicted mortality across nearly all risk groups, whereas O-POSSUM overpredicted mortality in patients with low physiological scores and in older patients. POSSUM (area under ROC curve 0·776) and P-POSSUM (0·776) showed equally good discriminatory power but O-POSSUM (0·676) was inferior.

Conclusion

P-POSSUM provided the most accurate prediction of in-hospital mortality in this group of patients who had elective oesophagectomy.

Candidates for thrombolytic treatment in acute ischaemic stroke--where are our patients in Hong Kong?

OBJECTIVE

Tissue plasminogen activator (t-PA) has been approved by the Food and Drug Administration in the treatment of patients with acute ischaemic stroke presenting within three hours from onset of symptoms. This study aims to identify the potential number of stroke patients suitable for t-PA in Hong Kong.

METHODS

All patients with a clinical diagnosis of acute stroke were recruited. Data collected included demographics, vital signs, medical history, contraindications to thrombolysis, severity of stroke (Canadian neurological scale), time course from onset of symptoms to computed tomography, computed tomography results, and final diagnoses by physicians.

RESULTS

During the five month study period, 201 patients were recruited and nine were subsequently excluded from further analysis because computed tomography was not performed. Their mean age was 70.9 (range from 41-91) years. Eighty (41.7%) and 100 (52.1%) patients presented to our emergency department within two hours and three hours respectively from symptom onset. The mean severity score (Canadian neurological scale) was 7.83 (out of a maximum of 11.5). A total of 132 (68.8%) patients had acute ischaemic stroke confirmed by computed tomography. Mean delay in computed tomography was 4.91 hours. Fourteen (7.3%) and 52 (27.1%) of all patients had computed tomography of the brain done within one and two hours respectively. Only 20 patients (10.45%) could meet the three hour criteria as stated in the National Institute of Neurologic Disorders and Stroke rt-PA stroke study and seven (3.6%) of them were confirmed to have acute ischaemic stroke. Two patients were further excluded because of high systolic blood pressure and current warfarin medication.

CONCLUSION

At present very few patients could benefit from thrombolytic treatment. Delays in the chain of recovery in stroke management should be identified and corrected.