Inda0714@gmail.com 1 Department of Emergency and Critical Care Medicin…

Inda0714@gmail.com 1 Department of Emergency and Critical Care Medicine, Rosiglitazone School of Medicine, Keio University, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan Full list of author information is available at the end of the article?2014 Hayashida et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly credited. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.Hayashida et al. Critical Care 2014, 18:500 http://ccforum.com/content/18/5/Page 2 ofIntroduction Although neurologic sequelae are common among survivors of out-of-hospital cardiac arrest (OHCA), no early prognostic markers have been reliably established [1-4]. The main objective of neurologic assessment of survivors with post ardiac arrest syndrome (PCAS) in the acute postresuscitation period is not only to determine the ongoing injury but also to establish the patient's recovery from unresponsiveness [3]. Because the brain is highly susceptible to ischemia, global cerebral ischemia often results in neurologic impairment after OHCA, regardless of whether a return of spontaneous circulation (ROSC) occurs [5,6]. Immediate high-quality cardiopulmonary resuscitation (CPR) is crucial for optimal patient outcomes [7,8]. The purpose of CPR is to provide effective oxygenation to the vital organs, particularly the brain and heart, through the artificial circulation of oxyhemoglobin (oxy-Hb) until ROSC is achieved [7]. The intended effect is to stop the processes of ischemia/anoxia caused by inadequate circulation and oxygenation [9]. The restoration of blood perfusion to the cerebral tissue and the capacity for oxygen delivery are strongly associated with anoxic brain damage during and after cardiac arrest. Notably, oxy-Hb levels and cardiac output are essential determinants of oxygen delivery during ongoing CPR attempts. However, little is known about oxy-Hb levels in the cerebral tissue during the development of anoxic and ischemic brain injury. Recently, cerebral oximetry with near-infrared spectroscopy (NIRS) has been developed as a noninvasive technology that may be used for monitoring cerebral oxygen saturation during cardiac arrest [10-12]. Regional cerebral oxygen saturation (rSO2) can be continually measured by using the Beer ambert law [12,13], which describes the ratio [oxy-Hb/(oxy-Hb + deoxyhemoglobin)] ?100 [14]. The estimated cerebral oxy-Hb level, which is the product of blood hemoglobin (Hb) and rSO2, is described as [Hb (g/dl) ?rSO2 ( )]/100, and it can reflect the cerebral oxy-Hb level during and after resuscitation. We hypothesized that the estimated cerebral oxy-Hb level obtained on hospital arrival may reflect the level of neuroprotection in patients who are successfully resuscitated after OHCA. This study aimed to determine whether the estimated cerebral oxy-Hb level is a simple and effective predictor of 90-day neurologic outcomes in patients with PCAS. Materials and methodsStudy design and settingsPatient selectionPatients included in the J-POP registry were unresponsive during resuscitation on hospital PubMed ID:https://www.ncbi.nlm.nih.gov/pubmed/7500280 arrival after OHCA. To collect maximum clinical data from the real-world setting, we includ.