Sue metabolism, this has not yet been sufficiently studied during CPR. To resolve Rosiglitazone the tissue oxygen debt during cardiac arrest, blood circulation must be secured by high-quality and less-interrupted chest compressions [7]. In our study, a significant relation was found between oxy-Hb levels and arterial pH, suggesting that increasing oxy-Hb levels during CPR may attenuate metabolic acidosis by appropriate chest compression. Because rSO2 may reflect the balance between oxygen delivery and regional (frontal) cerebral metabolism, the product of blood Hb levels and cerebral oxygen saturation could parallel oxygen delivery during resuscitation. Therefore, rSO2 measured during CPR attempts could indicate whether the ongoing attempt is likely to sustain adequate oxygen delivery to cerebral tissues [31]. The clinical experience of cardiac-arrest resuscitation demonstrates that circulatory recovery does not always coincide with cerebral recovery. The high morbidity of neurologic dysfunction in patients with ROSC after OHCA has led to several clinical studies attempting to optimize neurologic outcomes through therapeutic efforts that include targeted temperature management or administration ofneuroprotective medications [32-34]. Our data are consistent with this clinical experience: although a standard CPR method may deliver adequate coronary perfusion to reverse cardiac arrest, it may deliver inadequate oxy-Hb to the central nervous system and contribute to cellular damage in cerebral tissue. The ability to predict outcomes early is an important aspect of postresuscitation care in patients with PCAS. A multimodal prediction approach has been evaluated for outcome prognostication after cardiac arrest and therapeutic hypothermia [35]. This incorporates neurologic examination [36,37], electroencephalography [37,38], somatosensory evoked potentials [39,40], neuron-specific enolase [41,42], and magnetic resonance imaging [43-45]. Multimodal scores that combine both clinical and laboratory variables have also been developed for outcome prediction. The OHCA score presented by Adrie et al. [46] predicts good neurologic outcomes for patients with AUC of 0.79 in a heterogeneous population of successfully resuscitated adult patients with OHCA. The advantage of prognostication using oxy-Hb is that prognostic assessment can be readily performed at hospital arrival. Moreover, modern multimodal severity-scale scores predict survival with an AUC of approximately 0.80 after further confounders are included [47,48], whereas oxy-Hb at hospital arrival has an AUC of 0.87. Thus, oxy-Hb has real potential as an indicator PubMed ID:https://www.ncbi.nlm.nih.gov/pubmed/16989806 of neuroprotection in patients with PCAS. Recently, Nielsen et al. [49] described that therapeutic hypothermia at a target temperature of 33 conferred no additional benefit compared with that at a targetedHayashida et al. Critical Care 2014, 18:500 http://ccforum.com/content/18/5/Page 9 oftemperature of 36 . One of several explanations for this absence of benefit is that illness severity varies greatly, and appropriate subgroups of patients may benefit from induced hypothermia. In particular, when the degree or duration of hypothermia must be adjusted to match injury severity, the benefits to a subgroup may be masked if appropriate subgroups are not defined [50]. Our results provide the possibility for estimated cerebral oxy-Hb levels to define subgroups that may benefit from individual therapies and to clarify how to adjust temperature targets to p.