Gavin Perkins is a clinical academic with interests in intensive care medicine and pre-hospital care doctor. He co-chairs the International Liaison Committee on Resuscitation which evaluates resuscitation science to produce international consensus guidelines for cardiac arrest (www.ilcor.org). He led the PARAMEDIC2 trial of adrenaline (epinephrine) in out of hospital cardiac arrest and looks forwards to sharing some insights about the conduct and interpretation of the trial findings.
Adrenaline in cardiac arrest is dead, what next?
RESEARCH DARK ARTS
Adrenaline (epinephrine to some people) has been used as a treatment for cardiac arrest for decades despite equivocal evidence about its safety and effectiveness. The PARAMEDIC2 trial, (www.warwick.ac.uk/paramedic2 and https://www.nejm.org/doi/full/10.1056/NEJMoa1806842) enrolled 8014 patients with out of hospital cardiac arrest in the UK. Patients were randomised to receive standard dose adrenaline (1mg every 3-5 minutes) or placebo. The trial showed that adrenaline was effective at restarting the heart and more patients were admitted to hospital. Overall survival was low consistent with other studies and registry data. Outcomes were worse the longer the patient was in cardiac arrest. 0.8% more patients were alive at 30 days in the adrenaline group (number needed to treat (NNT) 112). The trial did not find evidence that long term neurological outcomes improved. Our 2019 Cochrane review reports that other vasopressor strategies were no more effective for improving long term outcomes (high dose adrenaline or vasopressin improved short term survival but not longer term outcomes).
So how should we interpret these trials and what are the implications for clinical practice?
My first take home message is that these trials highlight the importance of the community response to cardiac arrest and the first parts of the chain of survival. Much better outcomes occur with early access (NNT 11), early CPR (NNT 15) and early defibrillation (NNT 5).
For patients who do not respond to these initial treatments, my second take home message is that those responsible for healthcare policy should engage with the communities they serve to consider the balance the benefits and burdens of treatment with vasoactive drugs.
Finally, the trials highlight the overall poor outcomes from cardiac arrest and emphasise the need for further research â€“ particularly for patients who do not respond to initial treatment with CPR and defibrillation. Attention should focus not only on how to restart the heart but how to preserve the brain and improve patient centred outcomes.
Cutting Edge Cardiac Arrest – Scott Weingart interviews Bob Neumar and Gavin Perkins
A Panel with the Chairs of ILCOR with their 2 newest protocols: vasopressors for cardiac arrest and airway management during cardiac arrest. The goal of this session is to solicit input on these 2 protocols and set up the foundation for a social media input stream for all future protocols.