Comparison of Two Emergency Medical Services in Beijing and Hong Kong, China
Out-of-hospital cardiac arrest (OHCA) is a significant global health issue, with an estimated incidence of 50 to 60 cases per 100,000 people worldwide. Despite advancements in medical treatment and technology, survival rates following OHCA remain low. Various factors influence survival outcomes, including the type of emergency medical service (EMS) system in place. In Asia, EMS systems differ widely in terms of dispatch protocols, airway management, and medication administration. This study aimed to compare the survival outcomes of OHCA patients in Beijing and Hong Kong (HK), China, and to evaluate the impact of the EMS system type on these outcomes.
The study was a prospective analysis of OHCA cases in Beijing and HK, focusing on patients aged 18 years or older who experienced atraumatic OHCA and were treated by EMS between June 1, 2015, and August 31, 2015. Exclusions were made for OHCA cases caused by trauma or those where EMS did not initiate resuscitation in the prehospital phase. The primary outcome measured was survival to hospital discharge or at 30 days post-arrest, while the secondary outcome was neurological performance assessed using the cerebral performance categories scale. Data collection adhered to the Utstein template for prehospital data, with survival and neurological status information gathered from hospital records. Ethical approval was obtained from relevant bodies at both study sites. Statistical analyses included the Mann-Whitney test for continuous variables and the chi-square test for categorical variables.
Beijing and HK are both major metropolitan areas in China, but their EMS systems differ significantly. Beijing’s EMS is a one-tiered system operated by the Beijing Emergency Medical Center and the Beijing Red Cross Emergency Rescue Center. It is a physician-based system, with ambulance crews consisting of a paramedic driver, a physician, and a nurse. EMS dispatchers in Beijing do not provide cardiopulmonary resuscitation (CPR) instructions to callers. In cases of cardiac arrest, EMS crews perform advanced life support interventions, including intravenous (IV) fluid administration, IV medications, and advanced airway techniques such as tracheal intubation. Additionally, EMS crews in Beijing have the authority to withhold or withdraw CPR in the prehospital phase if deemed necessary.
In contrast, HK’s EMS is provided by the HK Fire Services Department and is also a one-tiered system. The ambulance crews in HK are trained at an intermediate level, similar to Emergency Medical Technicians. Like Beijing, EMS dispatchers in HK do not provide CPR instructions to callers. The EMS in HK primarily offers basic life support and defibrillation services. While a small number of EMS crews are trained to set up IV drips and insert laryngeal mask airways, these interventions are not commonly performed. EMS crews in HK are not permitted to withhold or withdraw CPR before the patient arrives at the emergency department (ED), unless the patient is obviously unsalvageable.
During the study period, there were 789 eligible OHCA cases in Beijing and 1204 in HK. Patients in HK were generally older than those in Beijing and were more likely to receive bystander CPR. Additionally, a higher proportion of HK patients presented with ventricular fibrillation or ventricular tachycardia. In both cities, the most common location of arrest was the patient’s home. The time intervals from the call to the patient’s side, recognition to CPR by EMS, and call to first defibrillation were all shorter in HK compared to Beijing. However, there were no significant differences in the rates of return of spontaneous circulation (ROSC) before ED arrival, survival to hospital discharge or at 30 days, and good neurological outcomes between the two cities before adjustment.
After propensity score adjustment, the rate of ROSC before ED arrival was higher in HK (8.9%) than in Beijing (7.6%). The rate of survival to hospital discharge or at 30 days was 3.3% in HK and 2.2% in Beijing. The percentage of survivors with a good neurological outcome was also higher in HK (2.6%) than in Beijing (2.2%). However, these differences did not reach statistical significance. Regression analysis identified the location of OHCA and the presence of a shockable rhythm on EMS arrival as predictors of survival to hospital discharge or at 30 days. Patients presenting with ventricular fibrillation or ventricular tachycardia had the highest probability of survival.
Despite having more cases of witnessed cardiac arrest, Beijing had a lower bystander CPR rate compared to HK. A survey in HK indicated that nearly 96% of respondents would assist a victim of OHCA. In contrast, public attitudes in Mainland China may be influenced by legal concerns, as there have been cases of malicious legal actions against bystander helpers. The implementation of Good Samaritan laws in more Chinese cities may improve this situation in the future.
The defibrillation rate in HK was lower than in Beijing, likely due to the high percentage of asystole among OHCA victims in HK. However, the call to defibrillation interval was longer in Beijing, possibly because almost all defibrillations were performed by EMS crews due to the public’s lack of knowledge about using automated external defibrillators. Similar to global findings, the location of arrest and the presence of a shockable ECG rhythm on EMS arrival were independent predictors of survival.
The study found no significant differences in the rates of ROSC before ED arrival, survival to hospital discharge or at 30 days, and neurological outcomes between Beijing and HK. Given that EMS in HK is not allowed to withhold or withdraw resuscitation at the scene, the calculated survival rate in HK may be negatively biased compared to Beijing. If patients who are unlikely to benefit from EMS resuscitation are excluded, the survival outcomes in HK are expected to be better than those in Beijing.
In conclusion, the study found no significant differences in the effects of the two EMS systems on survival from OHCA between Beijing and HK. Both systems have their strengths and limitations, and further research and improvements in public education and EMS protocols may enhance survival outcomes in both cities.
doi.org/10.1097/CM9.0000000000000252
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