Timing of neuroprognostication in postcardiac arrest therapeutic hypothermia*

Abstract

Objective: Early assessment of neurologic recovery is often challenging in survivors of cardiac arrest. Further, little is known about when to assess neurologic status in comatose, postarrest patients receiving therapeutic hypothermia. We sought to evaluate timing of prognostication in cardiac arrest survivors who received therapeutic hypothermia.

Design: A retrospective chart review of consecutive postarrest patients receiving therapeutic hypothermia (protocol: 24-hr maintenance at target temperature followed by rewarming over 8 hrs). Data were abstracted from the medical chart, including documentation during the first 96 hrs post arrest of "poor" prognosis, diagnostic tests for neuroprognostication, consultations used for determination of prognosis, and outcome at discharge.

Setting: Two academic urban emergency departments.

Patients: A total of 55 consecutive patients who underwent therapeutic hypothermia were reviewed between September 2005 and April 2009.

Intervention: None.

Results: Of our cohort of comatose postarrest patients, 59% (29 of 49) were male, and the mean age was 56 ± 16 yrs. Chart documentation of "poor" or "grave" prognosis occurred "early": during induction, maintenance of cooling, rewarming, or within 15 hrs after normothermia in 57% (28 of 49) of cases. Of patients with early documentation of poor prognosis, 25% (seven of 28) had care withdrawn within 72 hrs post arrest, and 21% (six of 28) survived to discharge with favorable neurologic recovery. In the first 96 hrs post arrest: 88% (43 of 49) of patients received a head computed tomography, 90% (44 of 49) received electroencephalography, 2% (one of 49) received somatosensory evoked potential testing, and 71% (35 of 49) received neurology consultation.

Conclusions: Documentation of "poor prognosis" occurred during therapeutic hypothermia in more than half of patients in our cohort. Premature documentation of poor prognosis may contribute to early decisions to withdraw care. Future guidelines should address when to best prognosticate in postarrest patients receiving therapeutic hypothermia.

Figure 1

Timeline of documentation of poor prognosis in relation to the phase within therapeutic hypothermia. The y-axis represents year of patient arrest and subsequent hypothermia. The x-axis represents phase within the hypothermia protocol. Each box represents an individual patient. The arrow indicates when patients had care withdrawn, if this occurred. The star indicates patients who had “poor” prognosis but survived to discharge. The number of patients who underwent therapeutic hypothermia is documented below each designated year.