S-100B protein as a serum marker of secondary neurological complications in neurocritical care patients

Abstract

There is growing evidence that S-100B protein measured by a simple blood test can be used as a novel biochemical marker of brain cell damage. The objective of our study was to investigate the potential of S-100B measurements to diagnose an acute neurological complication in the analgo-sedated and intubated intensive care patient and the impact on patient management. Serum S-100B levels were serially investigated in 246 neurocritical care patients. Venous blood samples for S-100B determination were obtained as soon as possible after admission and every 24 hours thereafter, for the duration of the stay at the neurocritical care unit. Blood samples were taken every morning as part of the routine laboratory investigation for analysis of S-100B using the immunoluminometric assay (AB Sangtec Medical, Bromma, Sweden) and a fully automated LIAISON system (Byk-Sangtec-Diagnostica, Dietzenbach, Germany) with a short time to result. The primary endpoint of our study was the occurrence of a severe neurological complication. Patients were admitted to the neurosurgical intensive care unit after routine major intracranial surgery in 116 cases (47%) and after a neurological or neurosurgical emergency in 130 cases (53%). Of the latter group, 79 patients (32%) underwent emergency surgery for evacuation or decompression of a space-occupying lesion before ICU admission. A severe neurological complication was defined as a new infarction, new hemorrhage or a newly developed progressive disease despite maximum therapy with a radiologically confirmed increase of mass lesion and midline shift. In 33 patients (13%) a complication with neurological deterioration occurred. All patients showed pathologically increased serum S-100B values (mean 2.00 microg/l, standard deviation 2.61 microg/l, range 0.31-9.66 microg/l). Twenty-eight of these patients (85%) showed S-100B increases >0.5 microg/l. In five cases (16%), the increase in S-100B was the first sign of neurological complication and prompted emergency computed tomography scanning. In another two cases, increasing S-100B values changed management decision towards a surgical intervention. The major finding of our study was the influence of serial S-100B measurement on actual management of the patient in 21% of cases with neurological complications.