Epidemiology and emergency cardiac care services for out-of-hospital cardiac arrest in Qatar

Abstract

Background: Out-of-hospital cardiac arrest (OHCA) is a common cause of cardiac emergency and death. Worldwide, there is wide variation in epidemiology and survival of OHCA. Racial and ethnic disparities are important contributors towards such variation. OHCA is mostly cardiac in origin, however there are several other non-cardiac etiologies of OHCA including trauma, submersion, drugs intoxication, asphyxia, conflagration, electrocution. With increasing trauma burden, traumatic cardiac arrest (TCA) is becoming more common. There are limited population-based studies on OHCA in the Asian region.

Aim: The aims were to establish a national OHCA registry and determine the epidemiology, prehospital interventions, emergency management and outcomes of OHCA of cardiac and noncardiac origin, with focus on TCA. Since Qatar, has a high trauma burden, TCA studies are feasible, important for public health and serve as important benchmarking indicators for EMS, cardiac and trauma services.

Methods: Utstein based guidelines were followed for data collection on prospectively enrolled OHCA patients resuscitated by EMS for establishment of OHCA registry, in Qatar, from June 2012 to May 2015. Study I and II, utilized data from the OHCA registry, while Study III and IV also utilized data from the Trauma registry, in Qatar. Study I was a nationwide population-based study that analyzed OHCA registry patients to describe epidemiology, cardiac arrest features, emergency management, health services delivery and outcomes. Study II was a retrospective cohort study that compared epidemiology, clinical presentation, emergency management, health services delivery and outcomes between Middle Eastern Gulf Cooperation Council (GCC) Arab ethnic and North African ethnic OHCA patients. Study III was a nationwide population-based observational study that analyzed out-of-hospital traumatic cardiac arrest (OHTCA) patients utilizing the OHCA registry and Trauma registry. Study IV was a retrospective cohort study that redefined TCA in two distinct categories and compared in-hospital traumatic cardiac arrest (IHTCA) patients with OHTCA patients.

Results: In Study I, the age-sex incidence of cardiac origin OHCA resuscitated by EMS was 87.8 per 100,000 population. Of the 447 OHCA patients analyzed, bystander cardiopulmonary resuscitation (CPR) rate was 20.6% and survival rate was 8.1%. In multivariable regression analysis, survival was associated with initial shockable rhythm (OR 13.4, 95% CI 5.4–33.3), male gender (OR 0.27, 95% CI 0.1–0.8) and advanced cardiac life support (ACLS) (OR 0.15, 95% CI 0.04–0.5). In Study II, there were 285 Middle Eastern GCC Arab ethnicity OHCA patients compared with 112 North African ethnicity OHCA patients, in Qatar. Multivariable regression analysis model showed that North African OHCA patients were associated with initial shockable rhythm (OR 2.86, 95% CI 1.30-6.33), greater scene time (OR 1.02 95% CI 1.0-1.04) and diabetes (OR 0.48, 95% CI 0.25-0.91). In Study III, the mean annual crude incidence rate of OHTCA patients was 4.0 per 100,000 population, in Qatar. Of 410 OHTCA patients, majority had blunt injuries (94.3%) with survival rate of 2.4%. Multivariable regression analysis for return of spontaneous circulation (ROSC) showed association with initial shockable rhythm (OR 6.4, 95% CI 1.3-30.7), external hemorrhage control (OR 5.9, 95% CI 1.9-18.0), and prehospital needle thoracostomy (OR 5.3, 95% CI 1.3-21.7). Univariate analysis for survival to hospital discharge showed association with initial shockable rhythm (OR 10.12, CI 0.97–105.23), Adrenaline (OR 0.045, CI 0.006–0.358), external hemorrhage control (OR 4.2, CI 1.03–16.8), blood transfusion (OR 9.22, CI 2.5–33.7) and surgery (OR 32.1, CI 7.54 136.6) In Study IV, there were 410 OHTCA patients compared with 199 IHTCA patients, in Qatar. The mean annual crude incidence of IHTCA was 2.0 per 100,000 population with a survival rate of 7.5%. In multivariable regression analysis, IHTCA was associated with cardiac re-arrest (OR 6.0, 95% CI 3.3-10.8, p <0.00), abdominal injury (OR 2.0, 95% CI 1.0-3.8), spinal injury (OR 3.5, 95% CI 1.5-8.3), higher prehospital GCS (OR 1.4, 95% CI 1.4-1.6) and survival (OR 6.3, 95% CI 1.3-31.2).

Conclusions: Standardized OHCA incidence and survival rates were comparable to industrialized countries but bystander CPR and defibrillation rates can be improved with tailored public education and training programs. North African OHCA patients were younger, associated with less risk factors, greater shockable rhythm, and received greater ACLS interventions with higher median EMS scene time compared to GCC Arab OHCA patients. Incidence of OHTCA was comparatively less than international rates and disproportionately low, relative to the trauma burden, in Qatar. Prehospital and emergency department (ED) management; hemorrhage control, needle thoracostomy, blood transfusion and surgery, were beneficial for survival and intervention studies are required to further guide management. IHTCA was a new sub-category of traumatic cardiac arrest that was defined and was associated with greater cardiac re-arrest, mean GCS score, initial shockable rhythm, and survival rates compared to OHTCA.