This study is registered at http://www.umin.ac.jp/ctr/index.htm (UMIN000002224 and UMIN000008506).

Originally, the present study was financially supported by the Ministry of Health, Labour and Welfare of Japan and was intended to determine the effect of pharyngeal cooling on tympanic temperature. In July 2010, the institutional review board at Okayama University Medical School recommended discontinuation of this work because of the apparent decrease in tympanic temperature in the pharyngeal cooling group. In December 2011, after approval by the institutional review board, the research was resumed to examine the effect of pharyngeal cooling on survival with the same protocol and was supported by Daiken Medical Co. Although the sample size (108 cases) was much smaller than the size required to evaluate

survival (692 cases), the study was terminated owing to the end of the planned experimental PR-171 in vivo period. Written, informed consent was obtained before enrolment Selleckchem Pexidartinib when the family of the patient was present. However, if the family of the patient could not be located, the need for written, informed consent was waived, and consent was obtained as soon as possible. Randomization assignments were generated with block sizes of 4 in a 1:1 allocation to groups receiving standard care with or without pharyngeal cooling. The emergency physician in each participating centre checked the eligibility of patients and, when a patient was eligible, telephoned the allocation centre. The eligibility criteria included the following: aged 16–89 years and witnessed cardiogenic cardiac arrest or witnessed non-cardiogenic cardiac arrest with resuscitation by medical personnel, including emergency services, within 15 min after collapse. Both in-hospital and out-of-hospital cardiac arrests science were included. The exclusion criteria included the following: traumatic cardiac arrest, core body temperature <34 °C upon arrival at the emergency room, or pharyngeal

or oesophageal disorder. Patients were resuscitated according to the 2005 or 2010 American Heart Association (AHA) Guidelines, depending on the date of admission. Immediately after arriving at the emergency room, pharyngeal cooling was initiated during chest compression or immediately after ROSC, if ROSC was achieved before arrival, and continued for 2 h unless the tympanic temperature decreased to <32 °C. Although it was encouraged to initiate whole body cooling following 2 h of pharyngeal cooling, the decision regarding timing and the technique were up to each facility based on their current standard care practice, i.e. infusion of cold fluid, ice pack, body surface cooling, or percutaneous cardiopulmonary support. Resuscitation measures were continued for at least 30 min after arrival at the emergency room.