Evidence for the use of hypothermia after cardiac arrest.

In April 2004, the Canadian Association of Emergency Physicians (CAEP) Critical Care Committee committed to examine the evidence for therapeutic hypothermia after cardiac arrest and make recommendations on its use in the emergency department. The primary review committee (PRC) was made up of 5 members of the CAEP Critical Care Committee. All 5 members signed statements confirming that they had no potential or perceived conflictsof-interest. The PRC developed a set of questions to be addressed by the position statement. These questions focused on both the indications and the practical application of therapeutic hypothermia. (See Table 1 for key definitions used by the PRC.) A search of Medline and EMBASE, from 1996 to September 2004, using the terms “hypothermia” and “cardiac arrest,” yielded 79 relevant articles. These articles were circulated to the PRC and used to develop a series of statements in response to the questions. The committee evaluated and graded the support for each of the statements, using the Oxford Centre for Evidence-based Medicine Levels of Evidence, summarized in Table 2. The statements were collated along with summary background materials in to a draft position statement. The draft was circulated to 20 physician experts, including emergency physicians, cardiologists, neurologists, intensivists, anesthetists, community and tertiary care physicians from across Canada for critical review. Eighteen of these physicians submitted written reports. Their comments and suggestions were brought back to the PRC for incorporation and synthesis. The final draft was approved by the PRC on May 30, 2005, and forwarded to the CAEP Standards committee, who approved it in July 2005. On Aug. 29, 2005, the CAEP executive adopted the statement. This document reviews the postulated mechanism for therapeutic hypothermia, summarizes the existing literature, and outlines the rationale for the position statement and guidelines.