The current status of CPR KAP of security guards
From our study results, we found that the security guards surveyed have a low level of CPR knowledge, and their grasp of CPR knowledge is not ideal. Compared with many domestic studies [24,25,26], For example, Mei , Li  and Tao  have consistent results on the domestic public and primary caregivers of coronary heart disease. The above-mentioned data may be due to the publicity of cardiopulmonary resuscitation and insufficient attention and limited channels for security guards to learn first aid knowledge, except for the lack of attention to CPR and incomplete knowledge of domestic security personnel. The training penetration rate of cardiopulmonary resuscitation is also an important indicator to measure the comprehensive strength of a country . Although the Chinese government and health departments have begun to pay attention to and promote the training and popularization of emergency care knowledge and skills, and have achieved gratifying results in the training of professional skills, the training and popularization of non-professionals urgently need to be strengthened.
According to the data presented in this study, the average CPR attitude score of the security guards surveyed was 31.99±3.94, and their attitude towards CPR implementation was relatively active. Compared with the study by Chen et al. , the results were inconsistent, which may be related to the willingness of different occupations to implement first aid. In an emergency, security guards are more willing to implement CPR than the general public. On the other hand, the average score of CPR behavior of the security guards under investigation is 20.89±4.54, and the behavior of implementing CPR is relatively weak. Compared with Li and other studies, the results are consistent. The results of another multi-center study show the average CPR implementation rate of witnesses outside hospitals in large and medium-sized cities in China is only 4.5% , which also validates this view. The reason for the above data may be that only a small part of the security guards participating in the investigation have participated in rescue experience, and the chance of doing CPR for real people is relatively small. The government should actively advocate the concept of "Healthy China, First Aid First", and advocate the social morality of "Take action when it's time to take action". Encourage citizens to take the initiative to rescue in emergencies, so as to increase the rate of witnesses' CPR implementation and rescue success rate.
Analysis of influencing factors of CPR for security guards
According to the data presented in this study, the different workplaces of security guards under investigation are the influencing factors of KAP. Among them, the score of KAP with security guards in hospitals is the highest, followed by airports, hypermarkets and communities, and the scored of KAP with security guards in commercial buildings is the lowest. The reason for the above data may be: security personnel's awareness of first aid in different places and their attitude towards CPR is different from behavior enthusiasm: hospitals, as an important venue for protecting human health, are responsible for the health and safety of human life. At the same time, this study also shows that although first aid is a key responsibility of the government's livelihood, security guards in different workplaces have different levels of awareness of first aid knowledge. Some scholars conducted an epidemiological survey on the location of CA and confirmed that CA mostly occurred in public places outside the hospitals. The high-incidence locations are mainly public sports venues, transportation hubs (such as airports, train stations and subway stations), large shopping centers, communities, etc. . Therefore, it is necessary to strengthen the training of first aid knowledge and skills of security guards in these places, and make full use of existing resources to build a "government-led, vertical and horizontal linkage of various departments (industry), medical personnel as the main trainer, and security guards for everyone to participate." The first aid training system enables training to be carried out regularly and stably, in order to improve the CPR knowledge and skills of security guards in public places.
According to the data presented in this study, the past occupations of the security guards under investigation have an impact on knowledge, trust, and behavior. security guards who have been engaged in fitness coaching, military service, and military work in the past have the highest scores for knowledge, belief and behavior, followed by firefighters, armed police, etc. The reasons for the above data may be related to the particularity of these jobs. Personnel engaged in these occupations must master a certain amount of first aid knowledge, and be able to put the lives of others in the first place when facing the dangers of others' lives, which reflects the good professional qualities of people who have engaged in the above occupations in the past. At the same time, among the personnel surveyed based on this research, the proportion of security guards with senior professional titles (security guard and senior security officer) is only 1.4%, while junior security guards account for the vast majority (89.7%). Therefore, according to the data presented in this research, the title level is not an influencing factor for the surveyed personnel knowledge, belief and behavior.
Participation in CPR training
According to the data presented in this research, whether you have heard of CPR and whether you have participated in CPR training has an impact on the knowledge, belief, and behavior of security personnel. It is consistent with the research results of Tao  and Liu . This may be related to the fact that they have known and understood part of CPR related knowledge through various channels, and realized that having CPR knowledge and skills can play a vital role in saving the lives of patients at critical times. At the same time, it further suggests that strengthening training is the focus of popularizing CPR. Research by Yan et al.  shows that the public’s first aid knowledge has been improved and enhanced through training such as PPT courseware, video demonstration, and scenario simulation. However, this survey found that 57.7% of security guards have never received training. In China, there is a lack of an assessment system on knowledge of CPR for securit guards ,and there is no unified pre-job training textbooks and training teacher standards in China, and there is still no domestic policy on first aid training and assessment for security guards.Without relevant laws requiring professional training, security guards have very limited knowledge of CPR ,and result in low rate of rescue success. However, the law in the United States stipulates that some people with special occupations, such as police and firefighters,and security guards must receive CPR training .Meanwhile , the United States is one of the most developed countries in the security service industry today,and Security guards in USA must receive at least 8 hours of professional CPR training before and after starting work, and after receiving 16 hours of on-the-job training, 8 hours of CPR training are required after working each year. The state and government departments in China should attach great importance to it, formulate corresponding policies and systems, increase publicity, encourage and require all types of security guards to participate in first aid training and assessment, and at the same time strengthen ideological and moral education and increase their attention to first aid. And it can add a strong sense of responsibility and responsibility to the security guards when they are encountering emergencies, and overcome obstacles to the implementation of CPR, and better implement on-site first aid in China.
CPR operation mastery
According to the data presented in this research, the CPR operation mastery has an impact on the knowledge, belief and behavior of security personnel. It is consistent with the research results of Wang. The reasons for the above data suggest that operations and drills are an important way to simulate emergency response and improve emergency management and handling capabilities. In addition, the presence or absence of CPR rescue experience is not an influencing factor that affects the investigators' knowledge, belief, and behavior. This is compared with Huang  research, and the results are inconsistent. This may be due to the low proportion of security guards who participated in the CPR rescue in this investigation. Only 4.7% of the security guards participated in the rescue, which affected the results of this investigation.
According to the data presented in this study, age is the main factor affecting knowledge, belief and behavior. At the same time, the results of single factor analysis showed that the security guards of the 20-39 and 40-49-year-old groups had a highest level of knowledge, belief and behavior, followed by the 50-59 years old, and the 60-70 years old group had the lowest score. This result is consistent with Tao  . This may be the same as that of the security guards under the age of 50 who are in the middle and adolescent period. Social communication is relatively active, and they are more receptive to new things. At the same time, they are better at using new media such as the Internet and mobile terminals to obtain the latest knowledge and have fairly good information acquisition skills so its knowledge and attitude score is higher. However, older security guards gradually degrade their ability to accept and use new things, and their memory gradually declines. Their willingness to learn actively is lower than that of young people, so the total score of knowledge, belief and behavior is lower. With the acceleration of population aging, potential rescuers are often in the elderly group. The 14th National Five-Year Plan has clearly emphasized and pointed out the important role of the elderly in society. Therefore, it should be used as appropriate among the elderly security personnel. Carry out training to enable capable elderly security guards to play an active role when they become "first witnesses."
According to the data of this study, education background is the main influencing factor of KAP. In this group, the security guards CPR junior high school, primary school and below are lower than other security personnel, which is consistent with the study  The reason of the above data may be due to the fact that the higher the education level, the higher the knowledge mastery, the higher the amount of information acquisition, and the higher the level of understanding of emergency knowledge. All factors should be taken into account in the CPR training of security personnel, especially the training methods of low-educated security personnel, and the training of security guards with lower education level should be strengthened.
Limitations of the study
There is a limitation in this study. The result in this study cannot be all generalized to all security guides, as the security guides in this study were from one city. More research needs to be done, specifically recruiting more security guides from more workplace in different cities in China to confirm the findings of this study.