Adrenaline
Adrenaline has been a mainstay of treatment in OHCA for half a century. Before PARAMEDIC2 its effects on OHCA had been evaluated predominantly by observational studies rather than randomised trials. PARAMEDIC2 was a pragmatic individually randomised double-blind controlled trial with an economic evaluation. Patients were randomised to receive either adrenaline or placebo.11-12
8014 patients were randomised. Survival to hospital admission was higher for those receiving adrenaline than for those receiving placebo (23.6% vs. 8.0%; adjusted odds ratio 3.83, 95% CI 3.304.43). The rate of favourable neurological outcome at hospital discharge was not significantly different between the arms (2.2% vs. 1.9%; adjusted odds ratio 1.19, 95% CI 0.851.68).
At 6-months 78 (2.0%) of the patients in the adrenaline group and 58 (1.5%) of patients in the placebo group had a favourable neurological outcome (adjusted odds ratio 1.35 (95% CI 0.931.97)). 117 (2.9%) patients were alive at 6-months in the adrenaline group compared with 86 (2.2%) in the placebo group (1.43 (95% CI 1.051.96), reducing to 107 (2.7%) and 80 (2.0%) respectively at 12-months (1.38 (95% CI 1.001.92)). This suggested that although there is improved survival with adrenaline this does not translate to improved neurological outcomes.11-12
A cost-effectiveness study published this year by the authors found the incremental cost-effectiveness ratio for adrenaline was estimated at 1,693,003 per quality-adjusted life-year gained over the first 6 months after the cardiac arrest event and 81,070 per quality-adjusted life-year gained over the lifetime of survivors. This value exceeds the threshold of 20,000-30,000 per quality-adjusted life-year usually supported by the NHS.13
A metanalysis of the PARAMEDIC2 and the PACA study found that relative to placebo, the effects of adrenaline ROSC are greater for patients with an initially non-shockable rhythm than those with a shockable rhythm.14