Changing Risk of In-Hospital Cardiac Arrest in Children Following Cardiac Surgery in Victoria, Australia, 2007-2016.

BACKGROUND: Reported incidence of in hospital cardiac arrest (IHCA) after paediatric cardiac surgery varies between 3-4% in high income countries and this risk may have changed over time. We sought to examine this trend in detail.

METHODS: A retrospective observational study of 3781 children who underwent 4938 cardiac surgeries between 1 January 2007 and 31 December 2016 in a tertiary children's hospital. IHCA was defined as cessation of cardiac mechanical activity requiring cardiac massage for ≥1minute. Surgical complexity was categorized using risk adjusted congenital heart surgery (RACHS-1) category. Poisson regression was used to analyse trends for every two-year period.

RESULTS: There were a total of 211 (4.3%) IHCA events after surgery. These patients were younger, more likely to have had a premature birth, have a chromosomal or genetic syndrome association and have a high surgical complexity. Overall, there was a 52% reduction in IHCA rate over ten years: reducing from 5.4 /100 surgeries in 2007-08 to 2.6/100 surgeries in 2015-16 (p-trend=<0.001). The reduction was mainly seen in low-to-moderate risk categories (RACHS-1 categories 1-4) and not in high risk categories (RACHS-1 category 5-6). Children in high risk categories were 13.6 times more likely to experience an IHCA (compared to low risk categories). Overall hospital mortality for children suffering IHCA decreased from 42.5/100 patients in 2007-08 to 11.1/100 patients in 2015-16 (p-trend=0.037).

CONCLUSIONS: The IHCA rate following cardiac surgery has more than halved over the last decade; children who experience IHCA also have lower mortality than in previous years. High risk procedures still have a substantial rate of IHCA and efforts are needed to minimise the burden further in this population.