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

Discussion

This year we measured a decrease in OHCA, recording 3,115 worked arrests compared to 3,484 in 2017/18. Whilst this is a modest change, this may reflect an increasing emphasis across the healthcare system on anticipatory care planning and improved end of life care. Our ability to link ambulance service data to clinical outcomes via the Community Health Index was similar to the previous year with 86.2% of incidents linked. As with previous reporting, we have counted the unlinked incidents as deaths and added them to the denominator for the calculation of percentage survival (unless otherwise indicated). We did this in an attempt to be as transparent as possible, but recognise that this reduces our survival percentage slightly. We have also reported survival per million population in Scotland which avoids the confounding introduced by this type of issue.

The baseline characteristics of our OHCA patients remain stable with a mean patient age of 66 years and the male/female split of 64% vs 36%. The proportion of OHCA occurring in each of the SIMD quintiles has remained similar with 15% of arrests in SIMD 5 (least deprived) compared with 26% in SIMD 1 (most deprived).

Increasing bystander CPR rates has been a key priority for the OHCA strategy partners and it is gratifying to see that bystander CPR rates increased to 64.0% in 2018/19 compared with 55.5% in 2017/18. This improvement is a vindication of sustained effort by the Save a Life for Scotland partnership which has completed CPR familiarisation with over 519,800 face-to-face contacts with the Scottish public since its inception in October 2015. Continuation of this coordinated work will be essential to further improvement in clinical outcomes. This has been accompanied by a trend towards the increased use of public access defibrillators by bystanders during 2018/19.

The proportion of patients responding favourably to initial resuscitation efforts rose with a ‘Return of Spontaneous Circulation’ rate (all initial rhythms) of 30.3% in 2018/19, up from 23.3% the previous year. This was accompanied by an increase in 30 day survival which exceeded 10% for the first time at 10.2% of all worked arrests in 2018/19 compared to 8.3% the previous year. Expressed as the number of survivors per million of the Scottish population, this equates to 59 survivors/million which shows an increase from 53 survivors/million in 2017/18. In absolute terms this represents 318 individuals leaving hospital alive after OHCA in 2018/19, compared with an average of 209 per year in the 5 years leading up to the official launch of Scotland’s Strategy for OHCA (shown in figure 11). The number of individuals surviving OHCA each year in Scotland has doubled since coordinated national improvement work began in 2011/12.

Whilst there has been significant improvement in survival across the whole country the data also shows that improvement has not been as marked for those in our most deprived communities when compared to those living in more affluent circumstances. The area in which you live continues to have a significant relationship to survival. Those in the most deprived quintile (SIMD 1) are less likely to receive bystander CPR compared to those in the least deprived areas (SIMD 5) and this in turn impacts likelihood of emerging alive at the other end of the Chain of Survival. Those living in the most deprived areas of Scotland are almost 60% less likely to survive an OHCA compared to their more affluent counterparts. This is undoubtedly a multifactorial issue, and reducing this specific manifestation of health inequality is a key priority.

Initiatives such as the Scottish Ambulance Service’s national implementation of GoodSAM, adoption of the British Heart Foundation PAD database (The Circuit), innovative use of community cardiac responders (e.g. Grampian’s Sandpiper WILDCAT project) and the commitment by Scotland’s Local Authorities to teach CPR in schools will all further contribute to enhancing the vital early response to a person in sudden cardiac arrest. With wider engagement from Scotland’s communities and their leaders there is a clear opportunity to co-design further initiatives to save more lives.

In few other areas of healthcare is a whole system approach more necessary. Developing a Chain of Survival to deliver the best outcomes for patients after OHCA requires an excellent partnership. Close synergy between those coordinating and directly delivering high quality prehospital response, specialist in-hospital clinical care and the people of Scotland is necessary to improving outcomes. It takes a system to save a life.