Scottish Out-of-Hospital Cardiac Arrest data linkage project: 2018-2019 results

Out-of-Hospital Cardiac Arrest Data for 2018/19

Number of worked arrests

BOX 1

Worked Arrests

‘Worked arrests’ are those non-traumatic OHCA where resuscitation was attempted by the Scottish Ambulance Service (SAS). This number forms the denominator for all subsequent outcome calculations. There are a number of reasons why SAS may not attempt resuscitation including obvious death (i.e. the patient shows obvious signs of having been dead for some time) and/or the confirmation that resuscitation was not the patient’s wish - for example by the presence of a ‘do not attempt CPR’ order as part of an anticipatory care plan.Number of worked arrests

Figure 1 below shows the number of worked arrests has increased gradually from 2,692 patients in 2011/12 to 3,115 in 2018/19.

Data Linkage

The collection and preparation of data contained in this report follows the same methodology of our previous report: Initial Results of the Scottish Out-of-Hospital Cardiac Arrest Data Linkage Project 2. In brief, the SAS provided data on all OHCA incidents where resuscitation was attempted during the reporting period. Where possible the patients involved in each incident were linked to survival outcome data via their Community Health Index (CHI) number by the Information Services Division, NHS National Services Scotland. In addition, components such as the Scottish Index of Multiple Deprivation (SIMD)3 were applied to the dataset to allow further analysis.

The percentage of linked arrests has increased from 73.0% in 2011/12 to a peak of 88.7% in 2017/18. In the 2018/19 dataset, 86.2% of SAS incidents were linked to survival outcome data. The remainder were assumed to be deaths (a worst case assumption) and included in the denominator for the calculation of the percentage of survival.

Figure 1 below shows the gradual increase in the number of worked arrests each year. It also shows a gradual improvement in the number of these cases which have been linked to clinical outcomes via the CHI number.

Figure 1: Percentage of worked OHCA cases included in linked dataset

Figure 1: Bars show the number of worked OHCA cases, including the number linked to outcome data (blue shade) and the percentage of linked cases (blue line), 2011/12 and 2018/19.