In our protocol we aimed to include additional endpoints like the six months and final CPC score, long‐term mortality, quality of life at six months, long‐term dependency, and cost‐effectiveness. The retrieved studies did not provide any information on long‐term mortality and dependency, quality of life, or cost effectiveness.

All studies that were included in the individual patient analysis provided data on both best and final neurologic outcome (Bernard 2002; HACA 2002; Hachimi‐Idrissi 2001). In our opinion the "best neurological score during hospital stay" is superior to the final score as the final score may be influenced by other factors like worsening of body functions or re‐arrests.

Bernard 2002 and Hachimi‐Idrissi 2001gave information on survival to hospital discharge, HACA 2002 additionally on the six‐months survival, Laurent 2005 only gave information on the six‐months survival. As the study by Laurent was not included in the individual patients analysis we chose survival to hospital discharge as a secondary endpoint for the individual patient analysis.

The documentation of adverse effects were overlooked in the original protocol. As they form a vital part of every review we included them in the data extraction sheet before we performed the literature search.

In accordance with our reviewers to better explain the reasons for dual analysis and the way it was carried out we have changed the wording of the objectives from:

"The aim of this study is to present a systematic review of the literature and, if applicable, a meta‐analysis, concerning the neuroprotective effect of induced hypothermia in primary cardiac arrest survivors. We plan to use data at the aggregate (study) level and the individual (patient) level."

to:

"We aimed to perform a systematic review and meta‐analysis to assess the effectiveness of therapeutic hypothermia in patients after cardiac arrest. Neurologic outcome, survival and adverse events were our main outcome parameters. We aimed to perform individual patient data analysis if data were available. We intended to form subgroups according to the cardiac arrest situation."

The title has been changed from "Hypothermia for neuroprotection after cardiopulmonary resuscitation" to "Hypothermia for neuroprotection in adults after cardiopulmonary resuscitation".