S-100B and neuron-specific enolase as predictors of neurological outcome in patients after cardiac arrest and return of spontaneous circulation: a systematic review.
BACKGROUND
Neurological prognostic factors after cardiopulmonary resuscitation (CPR) in patients with cardiac arrest (CA) as early and accurately as possible are urgently needed to determine therapeutic strategies after successful CPR. In particular, serum levels of protein neuron-specific enolase (NSE) and S-100B are considered promising candidates for neurological predictors, and many investigations on the clinical usefulness of these markers have been published. However, the design adopted varied from study to study, making a systematic literature review extremely difficult. The present review focuses on the following three respects for the study design: definitions of outcome, value of specificity and time points of blood sampling.


METHODS
A Medline search of literature published before August 2008 was performed using the following search terms: "NSE vs CA or CPR", "S100 vs CA or CPR". Publications examining the clinical usefulness of NSE or S-100B as a prognostic predictor in two outcome groups were reviewed. All publications met with inclusion criteria were classified into three groups with respect to the definitions of outcome; "dead or alive", "regained consciousness or remained comatose", and "return to independent daily life or not". The significance of differences between two outcome groups, cutoff values and predictive accuracy on each time points of blood sampling were investigated.


RESULTS
A total of 54 papers were retrieved by the initial text search, and 24 were finally selected. In the three classified groups, most of the studies showed the significance of differences and concluded these biomarkers were useful for neurological predictor. However, in view of blood sampling points, the significance was not always detected. Nevertheless, only five studies involved uniform application of a blood sampling schedule with sampling intervals specified based on a set starting point. Specificity was not always set to 100%, therefore it is difficult to indiscriminately assess the cut-off values and its predictive accuracy of these biomarkers in this meta analysis.


CONCLUSIONS
In such circumstances, the findings of the present study should aid future investigators in examining the clinical usefulness of these markers and determination of cut-off values.
Shinozaki
Koichiro
K
Department of Emergency and Critical Care Medicine, Graduate School of Medicine, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba City, 260-8677, Japan. shino@gk9.so-net.ne.jp
Oda
Shigeto
S
Sadahiro
Tomohito
T
Nakamura
Masataka
M
Hirayama
Yo
Y
Abe
Ryuzo
R
Tateishi
Yoshihisa
Y
Hattori
Noriyuki
N
Shimada
Tadanaga
T
Hirasawa
Hiroyuki
H
D016887:Cardiopulmonary Resuscitation; D002490:Central Nervous System / Q000503:physiopathology*; D015600:Glasgow Coma Scale; D006323:Heart Arrest / Q000201:enzymology / Q000503:physiopathology* / Q000628:therapy; D006801:Humans; D009414:Nerve Growth Factors / Q000097:blood*; D010751:Phosphopyruvate Hydratase / Q000097:blood*; D011379:Prognosis; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins / Q000097:blood*; D016896:Treatment Outcome
D009414:Nerve Growth Factors; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins; D010751:Phosphopyruvate Hydratase