Friday, February 20, 2015

Outcome after resuscitation beyond 30 minutes in drowned children with cardiac arrest and hypothermia



Authors: J Kieboom, H Verkade,J Burgerhof, J Bierens, P van Rheenen, M Kneyber, M Albers
Journal: British Medical Journal,  Feb 2015

Hypothermia plays an important role in the pathophysiology and treatment of resuscitation... that is about as much as we know.  The degree to which it plays a role, and even whether its beneficial or detrimental, is not so clear.  What we are pretty sure of is that, in general, hypothermia is a poor prognostic factor; what complicates things are the multiple case reports of survival with good neurologic outcome following prolonged submersion and cardiac arrest in very cold water.  These are usually young patients with a rapid cooling due to fall in icy water, which differs greatly from some one who is hypothermic due to prolonged exposure in warmer water.

This article reports the findings from 20 years of retrospective analysis of pediatric patients in the Netherlands who were found to be hypothermic and in cardiac arrest due to drowning.  The authors sought to determine the outcome of those patients who undergo prolonged resuscitation.  Some current guidelines call for extending resuscitation in this patient population due to the possible neuroprotective properties of hypothermia and reports of survival after prolonged submersion.

Population: patients aged 16 and under, cardiac arrest due to drowning, hypothermic
Outcome measures: mortality, survival, neurologic outcome

Results
  • 160 total patient
  • 86% survived to ICU
  • 44 survived to discharge (27%)
    •  17 survived with no, mild, or moderate neuro insult (10% of total, 3% of survivors)
  • Prolonged CPR (> 30 min)
    • 89% death
    • 11% severe neuro insult or vegetative state
    • 0% good outcome
    • Max CPR time with good neuro outcome was 25 min
    • ECMO did not change outcome with prolonged CPR
  • Effect of season  (used as marker for water temp)
    • More died from drowning in summer and spring
    • Better survival rates with good neuro outcome in winter
  • Submersion time
    • Not known in most cases (3% witnessed)
    • Longest submersion with good neuro outcome was 25 minutes
  • Initial Cardiac rhythm
    • 86% asystole
    • 13% bradycardia
    • 2% Vent fib
I really like this study, if for no other reason than that fact that they analysed relatively good data following Utstein reporting to focus not just on survival, but survival with good neurologic outcome.  Also, it was performed in an almost ideal medical environment, where these patients get a repsonse from an ambulance and physician-lead helicopter, and protocols are in place for direct/rapid transfer to PICUs and ECMO-capable centers.  When it comes to pediatric drowning, especially in cold water, there is often a push in the literature and in practice for prolonged resuscitation.  In this study, despite achieving survival after CPR > 30 min, the neurologic outcomes were terrible.  Additionally, while true water temperatures were not collected, there was a trend towards improved survival in the winter months, which would possibly indicate a protective effect of very cold water, although the authors note that this sub-population was too small to draw any real conclusions. We need to keep collecting and reporting data like this to be able to make evidence-based recommendations, so that we don't do more harm than good resuscitating a child who will live out the rest of his/her life in a vegetative state.

Link to PubMed abstract