A Basic Data Collection Plan

Evaluation of OHCA survival can begin with tracking of just a few critical pieces of information. The most meaningful performance measurement is the rate of survival to hospital discharge for bystander witnessed, out-of-hospital cardiac arrests that occurred prior to the arrival of EMS, and for which the first recorded cardiac rhythm is ventricular fibrillation. This group of patients serves as the benchmark. They generally have well documented times of collapse and hearts with an opportunity to respond to rapid defibrillation. They are most likely to survive if the system is working optimally.

Minimum Data Elements Needed to Calculate Witnessed VF Survival Rates

• Cases of bystander witnessed sudden cardiac arrest, prior to EMS arrival
• Cases with the first recorded rhythm ventricular fibrillation (VF)
• Hospital outcome data to indicate survival at hospital discharge
• Patient care identifiers to allow linkage of prehospital data and hospital outcome: name, date of birth, EMS call identifier, date of incident, hospital name.

If your EMS system serves a population of 50,000 or less, there are likely fewer than 25 cardiac arrests per year in your system and fewer than 10 bystander-witnessed VF events.

In this case, it may be feasible to enter basic registry items in a downloadable spreadsheet format.

A Registry Plan for Larger Systems

Systems with resources available to assist in collection and evaluation of a moderate amount of data can include additional data elements in their registries. A more comprehensive data collection plan is suggested to enable evaluation of care and implementation of improvements to any system. The HeartRescue program has developed a list of data elements which is available here.

Hospital Information:

• Receiving hospitals should provide outcome information including survival to admission (yes or no), survival to hospital discharge (yes or no) and if discharged alive, an indication of neurologic status at discharge. The most commonly used scale for measuring neurologic outcome in this population is the cerebral performance category or CPC score (see box). It is widely used because it is relatively simple and can be calculated from information available in the medical record of the patient.
• Hospitals should also provide information about the patient. They should be asked if therapeutic hypothermia was used as well as if the patient received emergency heart catheterization and intervention. Obtaining these measures allows EMS to provide feedback to hospitals to ensure that they are providing optimal care for the patients they receive and to help them improve for future patients.