Perception of Telephone-assisted Cardiopulmonary Resuscitation Among Emergency Medical Personnel in China: a Web-based Survey

Background: To investigate the perception of telephone-assisted cardiopulmonary resuscitation (T-CPR) after out-of-hospital cardiac arrest (OHCA) among emergency medical service (EMS) providers in China. Methods: A multicentre, cross-sectional, descriptive, online questionnaire survey study was conducted on the perception among emergency centres in various regions across China from December 2018 to June 2019. Answers to questions concerning baseline characteristics of survey respondents, cognition and implementation of T-CPR, and use of automated external debrillators were surveyed. Results: Of 1,191 questionnaires obtained from 15 provinces in China, 1,187 were valid. Among the 1,187 respondents, the mean age was 38.0±1.1 (20–60) years; 436 (36.7%) were male and 751 (63.3%) female; there were 256 dispatchers, 494 emergency doctors, 400 emergency nurses, and 37 medical emergency assistants; 960 (80.9%) had previously learned T-CPR and 227 (19.1%) had not. Of the 960 participants who knew T-CPR, 796 (82.9%) recognised CA, 714 of whom (89.7%) would further implement T-CPR. The difference in the cognition rate of T-CPR was statistically signicant among EMS providers (chi-square test, 38.1; P<.001). In multivariate analysis, dispatchers had a signicantly improved knowledge of T-CPR as their workload increased (P<.001; OR=1.002; 95%CI, 1.001–1.003). Conclusion: Substantial and important differences in the perception and implementation of T-CPR among EMS personnel were observed throughout China. Further professional training in T-CPR is urgently required for improvement in outcomes of OHCA countrywide. Trial registration: not applicable. This study reports for the rst time the results of nationwide implementation of a detailed questionnaire survey among EMS personnel on the perception of T-CPR after the occurrence of OHCA. For the current comprehensive and systematic implementation of T-CPR, further improvement in the prognosis of patients with OHCA has fundamental importance. The survey addressed EMS personnel's awareness of T-CPR, its implementation, and the current state of the implementation of CPR by bystanders and telephone instruction for AED use.

Therefore, there may be other questions to be asked that have not been considered in this survey. Though, we have largely reduce the bias by selecting 15 provinces across China.

Background
Out-of-hospital cardiac arrest (OHCA) is a leading cause of mortality worldwide, although the incidence and mortality of OHCA treated by emergency medical services (EMS) is uncertain, with variations in uencing the exact nature of the global burden. 1 Every year more than 350,000 people fall victim to sudden, unexplained OHCA in the United States, and reports from 35 communities suggested an incidence of 55 per 100,000 person-years. Unfortunately, only about 10% of victims survived this dramatic event. 2 In Europe, it is estimated that 275,000 people have all-rhythm OHCA, with incidence of about 37.2/100,000 and only 10.55% surviving to hospital discharge. 3 OHCA affects 110,000 individuals in Japan annually 4 with a survival rate of 7.6%. In China, the incidence is 48.1/100,000, 5 i.e. 583,000 victims in a total population of 1.4 billion, while the survival rate in Beijing is a dismal 1.3%. 6 OHCA is a time-critical disease, and early cardiopulmonary resuscitation (CPR) is associated with a favourable prognosis. The emergency medical dispatcher is an essential link in the chain of survival, 7 and many countries have implemented telephone-assisted CPR (T-CPR) and related training programmes.
T-CPR is an effective means for the rst witness to perform CPR in timely fashion, which not only improves the CPR ratio of the rst witnesses 8 but can also improve the effectiveness of CPR and improve the prognosis. 9,10 The European Resuscitation Council Guidelines for Resuscitation 2010 rst indicated that a protocol for suspected CA should be devised for dispatchers. 11 In 2015, the International Guide issued by the American Heart Association emphasised the importance of T-CPR 12 under the moniker "dispatch-assisted CPR", which involves dispatchers providing CPR instruction to callers or bystanders by telephone. 13 Because little is known about T-CPR in China, we investigated the cognition of T-CPR among EMS staff by means of an online questionnaire survey 14

Methods
China has an area of ≈ 9,600,000 km 2 and its population in 2019 was ≈ 1,395 million, covering 34 provincial administrative units. The free emergency number 120 is used to call for an ambulance in most areas of China. Emergency services are provided 24 hours every day. An ambulance is dispatched from the nearest emergency station when called. EMS systems are single-tiered and government-fundedsome are independent emergency stations, some are hospital-based stations, and others are mixed. At least one emergency driver and one emergency doctor are deployed in an ambulance, with an accompanying nurse and/or rst-aid assistant in some areas.

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The survey respondents were EMS staff including emergency doctors, emergency nurses, emergency dispatchers and rst-aid assistants in 15 provinces, representative across China. To be eligible for inclusion in the study, each EMS system had to be an independently operated EMS unit, meaning the unit must have its own dispatch system.
After three rounds of expert consultation of the questionnaire, we presented it from site registration forms and an electronic Internet-based survey of all participating EMS systems in the study. A standardised survey form was constructed online (wjx.cn), delivered by the WeChat App and lled out via android/iOS smartphone or the website. Respondents to the survey were eligible if speci ed as EMS providers in the 15 provinces.

Patient and Public Involvement
No patient involved.

Survey Content and Administration
A cross-sectional descriptive study was conducted from December 2018 to January 2019 using a Webbased system. A survey of perception of T-CPR among EMS providers in China was lled out by personnel from emergency centres. Each EMS involved had a designated local principal investigator who was responsible for verifying data. In addition, the completed questionnaires were re-veri ed by statisticians, and uncompleted or logistically wrong questionnaires were excluded.

Data Analysis
Data collation, statistical description, and statistical analysis were performed using IBM SPSS Statistics 22 software (IBM, Armonk, NY, USA). Continuous variables were summarised by mean ± standard deviation; the composition distribution and rate were used to describe the basic distribution characteristics of the research objects. We assessed the differences in the perception of T-CPR among responding EMS providers in China by either chi-square test or Fisher exact test. Multivariable analysis was used to assess factors associated with the cognition of T-CPR among EMS respondents by using logistic regression models; odds ratios (OR) and their 95% con dence intervals (CI) were calculated. All tests were two-tailed, and P values of < .05 were considered statistically signi cant.
The authors had full access to, and take responsibility for, the integrity of the data.

Characteristics of survey respondents
A total of 1,191 questionnaires were collected. Four invalid questionnaires were eliminated, leaving 1,187 valid completed questionnaires. The survey covered 15 provincial administrative units from Beijing, Qinghai, Jiangxi, Ningxia, Xinjiang, Chongqing, Guangdong, Zhejiang, Guizhou, Shanghai, Hainan, Jiangsu, Shanxi, Inner Mongolia, and Hebei. The distribution of questionnaires in each province is shown in Fig. 1 Distribution of questionnaires in provinces that participated in the survey (The map in Fig. 1 is made from the website, http://c.dituhui.com/apps.).
Workload of emergency personnel and recognised OHCA via telephone in 12 hours
Among the 256 dispatchers, the number of sudden CAs that could be recognised by telephone among the emergency calls received within 24 hours was the highest in 1-3 cases (95 respondents, 37.1%), followed by 0 cases (79, 30.9%), 4-10 cases (60, 23.4%), and more than 10 cases (16, 6.3%). The other six dispatchers were unsure in determining the number of cases recognised to be CA in a 12-hour period.
Before arriving at the scene, 512 (55.0%) of the 931 emergency personnel never recognised whether the patient had a CA by phone; 261 (28.0%) could recognise 1-3 CA patients, 90 (9.7%) were able to recognise 4-10 cases, and 24 (2.6%) recognised more than 10 people with CA. In addition, 44 (4.7%) rescuers were unsure of the number of CA patients.

Knowledge of T-CPR
Among the 352 respondents who believed that the implementation of T-CPR should include the quality of CPR by bystanders, the top three operations to detect the quality of CPR conducted by bystanders were the frequency of chest compression (337, 95.7%), position of hands when compressing (324, 92.0%), and compression duration and number of compression interruptions (298, 84.7%), followed by depth of chest compression (290, 82.4%), frequency of ventilation (if any) (278, 79.0%), whether the chest rebounded during compression (266, 75.6%), and ventilation time (if any) (253, 71.9%).
Differences among respondents' characteristics concerning knowledge about T-CPR Baseline characteristics of respondents showed differences among various aspects of knowledge about T-CPR (Table 3), for which chi-square test values were calculated. Among the 960 (80.9%) respondents who know about T-CPR, the knowledge rate varies among EMS providers (chi-square = 38.1, P < .001). Level of EMS (chi-square = 27.4, P < .001), education background of EMS providers, vocation (chi-square = 47.9, P < .001), and professional title (chi-square = 13.7, P = 0.032) differed in respect of the medical priority dispatch system (MPDS). Gender (chi-square = 9.6, P = 0.008) and vocation (chi-square test = 82.6, P < .001) varied with regard to monitoring the quality of bystander CPR among 428 out of 1,187 (59.9%) respondents.

EMS provider factors associated with knowledge of T-CPR in China
In the multivariate analysis (Table 4) In the implementation of T-CPR, the most commonly recommended treatment method for bystanders is chest compression + arti cial breathing (310 respondents, 43.4%), followed by simple chest compression (216, 30.3%) and chest compression + arti cial respiration + AED (140, 19.6%).

Discussion
This study reports for the rst time the results of nationwide implementation of a detailed questionnaire survey among EMS personnel on the perception of T-CPR after the occurrence of OHCA. For the current comprehensive and systematic implementation of T-CPR, further improvement in the prognosis of patients with OHCA has fundamental importance. The survey addressed EMS personnel's awareness of T-CPR, its implementation, and the current state of the implementation of CPR by bystanders and telephone instruction for AED use.
Globally it is estimated that, on average, less than 10% of all patients with OHCA will survive. 15 T-CPR can effectively improve bystander CPR, pre-hospital return of spontaneous circulation (ROSC), and even the prognosis of OHCA patients. A before-and-after interventional trial of dispatcher-assisted CPR for out-ofhospital CA in Singapore showed a signi cant increase in bystander CPR and ROSC after the intervention. 16 Implementation of a regional T-CPR programme and outcomes after out-of-hospital CA indicated that implementation of a guideline-based T-CPR bundle of care was independently associated with signi cant improvements in the provision and timeliness of T-CPR, survival to hospital discharge, and survival with favourable functional outcome. 17 In a study of the effect of a dispatcher-assisted CPR programme and location of out-of-hospital CA on survival and neurological outcomes for out-of-hospital CA cases in private settings, bystander CPR was associated with improved neurological recovery only when dispatcher assistance was provided. 10 The results of our questionnaire survey showed that there are some regional differences among the 15 provinces surveyed. Knowledge of T-CPR varied among vocation of EMS providers (dispatcher, doctor, nurse, and others). Whether the use of MPDS was signi cant differed in terms of the level of EMS unit, vocation, and professional title. Monitoring the quality of bystander CPR was also distinguished by gender and vocation. According to the survey, the increased workload of dispatchers may improve their knowledge of T-CPR, whereas male gender and a junior professional title appear to suggest lack of knowledge of T-CPR.
Of particular note is the in uence of mobile phone technology on the process of T-CPR. With the development of communication technology, the communication method of T-CPR can now involve traditional telephone voice guidance or remote video telephone online guidance. Video communication has been widely used in social software such as Facebook, WeChat, and QQ. In the future, 5G communication technology will provide T-CPR with wider application prospects. It has been reported that CPR under video guidance is higher in quality and better overall than traditional telephone voice guidance. Chest compressions are signi cantly faster, the compression position and depth are more accurate, and the time to rst ventilation is faster in comparison with audio guidance. 18 Some additional aspects should be acknowledged as part of these considerations. The survival rate of OHCA patients is still very low globally. Early calls for emergency rescue, early rst-witness CPR, and early AED de brillation are the most important measures to improve OHCA. However, owing to the low prevalence of CPR in China and insu cient availability of AEDs in public places, the outcome of OHCA patients is still poor, so it will take a long time to implement commonplace T-CPR. The suitability of international CPR guidelines is still an open question, and the degree of implementation is not promising. The CPR process under the guidance of MPDS is also not satisfactory. There is a lack of systematic research on CPR in China, and clinical research on T-CPR is also inadequate. It is necessary to study current guidelines and formulate new ones suitable for China's national circumstances.