Out-of-hospital cardiac arrest in Karachi, Pakistan; burden and association of type of transportation (EMS vs. Non-EMS) with survival- a multicentre study

Date of Award


Document Type


Degree Name

Master of Science in Epidemiology & Biostatistics (MSc Epidemiology & Biostats)


Community Health Sciences


Abstract: Out-of-hospital cardiac arrest (OHCA) is one of the leading causes of death and disability worldwide. A substantial number to the burden of cardio vascular diseases globally is being contributed by developing countries like Pakistan. It is anticipated that this might be leading to a higher number of out-of-hospital cardiac arrests as well, which has never been explored in this population. Survival from OHCA has been reported to be variable from studies conducted in different regions. In Pakistan there is a scarcity of data in this field. Survival outcomes for cardiac arrest were reported in two single center studies; where outcomes from out-of-hospital cardiac arrest were reported in contrast with inhospital cardiac arrest. Pre-hospital care is a major determinant of survival and thus type of pre-hospital transportation plays an important part in survival from out of hospital cardiac arrest. Research conducted in different parts of the world to find out which system of life support interventions is associated with better survival, have been inconclusive. Objectives: This study aims to assess the burden of out of hospital cardiac arrest in Karachi Pakistan. It also aims to look at the association of type of transportation to hospital with survival after an out-of-hospital cardiac arrest. Methodology: We conducted a multicenter study from January 2013 to April 2013 in Karachi Pakistan. A cross sectional design and capture-recapture technique was used to estimate burden of OHCA from the analysis of records of 3 months from two sources; hospitals and emergency medical services (EMS). A prospective cohort study was conducted at emergency departments of five public and private sector hospitals to assess the association between type of transportation and survival after an OHCA. Twenty-four hour data collection was performed by trained data collectors. All patients > 18 year of age, diagnosed as having an event of out-of-hospital cardiac arrest which is defined as an event of unresponsiveness and absence of breathing outside of hospital setting and confirmed by either emergency depar lent (ED) or EMS physician, were included in the study. Patients with Do-not-resuscitate status, brought as a part of mass casualty and referred from other hospitals were excluded. A structured questionnaire was used to interview hospital staff, EMS staff and patient's relatives. Patients who survived to emergency department discharge were followed till discharge from the hospital and then after two months to check survival. Survival analysis was performed to identify factors for survival. Results: The annual incidence of non-traumatic out-of-hospital cardiac arrests was calculated to be 194 cases/100,000 population (95% CI: 177.8, 211.5). During three months period, data was obtained on 589 OHCA patients. Survival from an OHCA at hospital discharge was only 1% in this study. In a multivariable model being treated by EMS was found 35% protective from death as compared to being treated by a Non-EMS (aHR: 0.65, 95% CI: 0.54,0.77) while adjusting for CPR (cardiopulmonary resuscitation) and location of arrest. CPR in hospital as compared to No-CPR was associated with 54% protective effect (aHR, 0.46, 95% CI: .35, 0.62). Location of arrest being public was associated with 42% higher chances of death after an OHCA (aHR: 1.42, 95% CI: 1.19, 1.69) as compared to residence. Conclusion: The burden of Out-of-hospital cardiac arrest in the population of Karachi, Pakistan is higher as compared to the burden in Western countries, whereas survival is poor due to lack of bystander CPR and time delays in' providing life support interventions. This underline the importance of population based interventions such as public training to provide CPR, improving pre-hospital care and investing resources on developing EMS services, particularly EMS services with life support interventions which was found to have protective effect from death after an OHCA.

This document is available in the relevant AKU library