Briefly discuss the information (including clinical features / investigations) that may help determine the prognosis of patients following cardiac arrest.
Answer and interpretation
Prognostication after cardiac arrest may be very difficult and involve a number of modalities.
It involves consideration of:
- Underlying cause of the arrest
- Use of therapeutic hypothermia
- Features of the arrest – down time, CPR, ROSC
- Timing:Neurological assessment timing will be determined by the use of therapeutic hypothermia and the duration and type of medication for sedation but is most reliably performed day 3 without therapeutic hypothermia – probably day 5 with TH. Suggestion is to wait 72 hours after return of normothermia.
With new TTM trial suggesting 36C then 72 hours post arrest may again be appropriate.
Clinical – off sedation and neuromuscular blocking agents
Cranial nerve abnormalities – absence of pupillary response and corneal reflexes are bad prognostic indicators.
Best Motor response at 72 hours with absent or extensor response associated with poor outcome.
Status / Generalised and repetitive myoclonus (as opposed to sporadic myoclonus)
- Nurone specific enolase >33mcg/L at days 1-3 indicates poor outcome
- S100, CSF CKBB not accurate enough for prognostication
- EEG: generalised suppression, burst suppression or generalised periodic complexes strongly associated with poor outcome.
- SSEPs: Bilateral absence of N20 component of SSEP with median nerve stimulation within 1-3 days is strongly associated with poor outcome.
- CT appearance – catastrophic changes with obvious pathology. Diffuse oedema has not been formally assessed as an indicator.
- MRI may be more sensitive
Predictors of better outcome are:
- Recovery of brainstem reflexes within 48 hours
- Return of purposeful response within 24 hours
- Hypothermia at the time of arrest
- Young age
Chris is an Intensivist and ECMO specialist at the Alfred ICU in Melbourne. He is also a Clinical Adjunct Associate Professor at Monash University. He is a co-founder of the Australia and New Zealand Clinician Educator Network (ANZCEN) and is the Lead for the ANZCEN Clinician Educator Incubator programme. He is on the Board of Directors for the Intensive Care Foundation and is a First Part Examiner for the College of Intensive Care Medicine. He is an internationally recognised Clinician Educator with a passion for helping clinicians learn and for improving the clinical performance of individuals and collectives.
After finishing his medical degree at the University of Auckland, he continued post-graduate training in New Zealand as well as Australia’s Northern Territory, Perth and Melbourne. He has completed fellowship training in both intensive care medicine and emergency medicine, as well as post-graduate training in biochemistry, clinical toxicology, clinical epidemiology, and health professional education.
He is actively involved in in using translational simulation to improve patient care and the design of processes and systems at Alfred Health. He coordinates the Alfred ICU’s education and simulation programmes and runs the unit’s education website, INTENSIVE. He created the ‘Critically Ill Airway’ course and teaches on numerous courses around the world. He is one of the founders of the FOAM movement (Free Open-Access Medical education) and is co-creator of litfl.com, the RAGE podcast, the Resuscitology course, and the SMACC conference.
His one great achievement is being the father of three amazing children.
On Twitter, he is @precordialthump.