Out-of-hospital cardiac arrest (OHCA) is a major public health issue worldwide. Emergency medical services (EMS)-treated OHCA incidence rates range from 19.2 to 150.1 per 100,000 person-years globally (1). Following OHCA, survival to discharge ranges from 0.6% to 25% in different parts of the world (1). Moreover, in the USA, it was found that only 8.5% of adults with EMS-treated nontraumatic OHCA survived with good neurological function (2).

Regional variations in epidemiological characteristics and outcomes of OHCA patients are well-reported in the literature (1, 3). These variations are possibly due to differences in definitions of OHCA used (1). However, unique demographic, medical, healthcare system, and EMS characteristics of these regions also play a role. Subsequently, each region must generate its own data to better characterize its OHCA population. This would be done as the first step towards exploring reasons for regional variation as well as identifying areas that are lacking in that particular region so that future interventions can be implemented to improve and optimize the care provided to OHCA patients.

Only two studies have examined the characteristics of OHCA patients in Saudi Arabia and were limited by small sample sizes and selection bias (4, 5). In 1999, Conroy and Jolin reported the characteristics of 66 OHCA cases who presented to a tertiary hospital over a 7-year period (4). A more recent study was conducted in 2015 and included 96 adult OHCA cases who presented to a university hospital in Riyadh (5). Both studies were single-center studies and included a small number of OHCA cases, which limits their generalizability. Therefore, the OHCA population in Saudi Arabia is yet to be appropriately characterized. This lack of OHCA characterization is hindering the improvement and optimization of OHCA care in Saudi Arabia. As such, we sought to describe the characteristics of OHCA patients attended by EMS in Riyadh province, Saudi Arabia, and identify predictors of bystander cardiopulmonary resuscitation (CPR).

This is a cross-sectional study of OHCA patients who were attended by EMS in Riyadh province, Saudi Arabia.

Our study is the first to examine the characteristics of OHCA and predictors of bystander CPR in Saudi Arabia using EMS data. We observed young age at presentation, low rate of bystander CPR, and long response time when compared with published literature from other countries (Supplementary Table S2). We hope that our findings will ignite interest and guide further research aiming at improving the suboptimal care of OHCA in Saudi Arabia.

The mean age of adult OHCA cases in our study was 59.6, which was similar to previous smaller studies performed in Saudi Arabia and the Gulf region (Supplementary Table S2) (4, 5, 7) However, this is significantly younger than the average age reported by western countries such as the USA (63.7) and England (68.6) (8, 9). The likely reason for this apparent younger age at presentation in Saudi Arabia is the young overall age of the Saudi population as compared to other countries. However, further research needs to ascertain if the high prevalence of cardiovascular risk factors such as diabetes mellitus and hypertension plays a role (10). This young age at presentation highlights the paramount importance of improving survival of OHCA in Saudi Arabia given the potential years of life lost and its effect on the community in general.

A small percentage of patients received bystander CPR in our study (12.7%). This is clearly in contrast to reported rates from other countries such as the USA (34.4%), Singapore (45.7%), England (55.2%), Victoria-Australia (58.5%), Norway (73%), and the Netherlands (81.2%) (8, 9, 11–13). It is well known that bystander CPR is associated with significant improvement in survival from OHCA, as this has been demonstrated by multiple studies over the years (9, 14–18). Therefore, it should be a priority target to improve the survival of OHCA patients especially since it is an inexpensive and readily available modifiable factor. Indeed, several nationwide initiatives aimed at increasing resuscitation by bystanders in Denmark were associated with doubling the rate of bystander CPR (from 21.1% in 2001 to 44.9% in 2010), which also were associated with improved overall survival (19).

Low bystander CPR rates have been explored previously in the literature (20–23). Multiple factors were found to be contributing such as lack of training, lack of confidence, fear of causing harm, fear of legal liability, and fear of acquiring infections (20–23). It has been hypothesized that middle eastern societies' set of values may provide a cultural barrier, particularly in the case of female patients (7). However, our study does not support this hypothesis given that the rate of bystander CPR was similar in both sexes [12.9% (46/356) in females as compared to 12.6% (84/667) in males]. Further studies need to examine causes of low bystander CPR rates in order to develop specific interventions aiming at improving it.

In our study, we found that being a child was an independent predictor of receiving bystander CPR (OR = 3.26, p = 0.02). This might be explained by the fact that children who are at risk of cardiac arrest are likely to have parents who are trained in performing CPR. The other independent predictor was the location of the arrest being in a healthcare institution (OR = 6.35, p = 0.001), which is expected as personnel in such settings are trained in CPR and are more confident in performing it.

A major finding of our study is the long EMS response time, which is double the acceptable international resuscitation benchmark of 8 min. One needs to study OHCA in other provinces in Saudi Arabia to determine whether this is specific to Riyadh province or a general feature of Saudi Arabia. This is especially important since Riyadh is known for its traffic congestion, large area, and rapid expansion which might render achieving the optimal EMS response time more difficult. EMS response time has been demonstrated to be inversely proportional to survival in OHCA in various studies (24–26). Smart solutions to achieve the acceptable response time have been proposed, such as the use of unmanned aerial vehicles (UAV), commonly known as drones. It was demonstrated by multiple studies that using UAVs can lead to faster delivery of automated external defibrillators as compared to EMS (27–31). In Stockholm County in Sweden, Claesson et al. performed a simulation study to test the effectiveness of UAVs' delivery of automated external defibrillators to OHCA cases and to determine whether their use can decrease response time (27). They used coordinates of previous OHCA cases in Stockholm County to determine the optimal placement of UAVs in urban and rural areas. Using Geographic Information System (GIS) models, they predicted that UAVs would arrive faster than EMS in 32% of urban OHCA cases (with a mean time saved of 1.5 min) and in 93% of rural OHCA cases (with a mean time saved of 19 min). Utilization of such innovations could potentially improve response time and subsequently OHCA survival, especially in an area such as Riyadh province where conventional methods can be challenging.

Our study has several limitations. First, we did not have access to in-hospital outcomes to determine the survival rate. Second, only limited data were available in the electronic patient care reports. Last, patients with OHCA who were brought to hospitals by means other than SRCA and those who did not receive CPR were not represented. Nonetheless, we believe our study provided important findings that can guide future research and initial interventional plans to improve the care of OHCA in Saudi Arabia.

This study identified key characteristics of OHCA in Riyadh province, Saudi Arabia. Young age at presentation, low rate of bystander CPR, and long EMS response time are the main characteristics that significantly differ from international standards. Additionally, we found being a child and having OHCA at a healthcare institution to be independent predictors of bystander CPR. More research is needed to identify factors that influence these characteristics and interventions that could improve them.