Blog

This week sees the release of a review of clinical signs and their predictive significance in cardiac arrest in children (see the current paper in the journal club). This paper attempts to address the impact of the recent widespread adoption of therapeutic hypothermia on these clinical predictors. Prediction of neurological outcome remains a subject of frustration and conjecture for most intensivists. Guidelines have been released in recent years, though the widespread adoption of these have been lacking. Clinical signs remain the best studied prognostic indicators, though studies by and large are confounded by the issue of a "self fulfilling prophecy" - ie, the mere fact that someone has these clinical indicators of poor outcome means they're more likely to have treatment withdrawn, confirming them as a marker of a poor outcome! The absence of bilateral somatosensory evolked potentials a week after arrest is also reasonably well established, but access to this fairly specialised test is far from widespread. Many clinicians are then forced to make a decision - confronted with a patient who based on the clinical story and background comorbidities is likely, but not certain, to have a poor outcome, prognostication is often unclear, if not impossible and delays are inevitable. This is made even worse by the introduction of therapeutic hypothermia. Not only is decision making prolonged by the act of cooling, but the act of cooling may subsequently alter the clinical signs we now rely upon. A recent case of a false positive brain death clinical examination is a notable example of this (see our previous blog). Sudden cardiac death is far from unusual in modern day western ICUs. A sensitive and specific, immediate prognostic indicator that allows early identification of survivors, and implementation of comfort measures for non-survivors is sorely missed.