Neuropsychological function in patients with increased serum levels of protein S-100 after minor head injury

Serum cleaved tau protein levels and clinical outcome in adult patients with closed head injury

STUDY OBJECTIVE

Intracranial injuries (ICI) are associated with high mortality and morbidity. Unfortunately, tools for diagnosis and risk stratification of ICIs are limited in the emergency department setting. We determine the relationship between the presence or absence of a detectable cleaved serum tau protein (tau(c)), ICI, and outcome at hospital discharge in adults with closed head injuries (CHI).

METHODS

This was a prospective pilot study of adult patients with CHI presenting to the ED of an urban Level I trauma center. Patients presenting within 10 hours of a CHI who underwent a head computed tomographic (CT) scan were eligible. A blood sample was collected at presentation and the tau(c) level was measured. Initial Glasgow Coma Scale scores and demographic information were recorded. A chart review was performed to determine outcome and final readings on the initial head CT scan.

RESULTS

Patients were dichotomized to 1 of 2 groups, those with an ICI (n=17) and those with an isolated skull fracture or no CT abnormality (NICI) (n=11). The 2 groups were similar in regard to demographic composition, mechanism of injury, and coexisting injuries. A tau(c) level of more than 0 was associated with an increased chance of an ICI on the initial head CT scan (odds ratio 11.25; 95% confidence interval [CI] 1.17 to 108.4) and a greater chance of poor outcome, defined as death while in hospital or transfer to a nursing home at hospital discharge (odds ratio 8.17; 95% CI 1.42 to 47).

CONCLUSION

A tau(c) level of more than 0 is associated with a greater chance of intracranial injury and poor outcome in patients with CHI.

Unchanged cerebral blood flow and oxidative metabolism after acclimatization to high altitude

The authors investigated the effect of acclimatization to high altitude on cerebral blood flow and oxidative metabolism at rest and during exercise. Nine healthy, native sea-level residents were studied 3 weeks after arrival at Chacaltaya, Bolivia (5,260 m) and after reacclimatization to sea level. Global cerebral blood flow at rest and during exercise on a bicycle ergometer was measured by the Kety-Schmidt technique. Cerebral metabolic rates of oxygen, glucose, and lactate were calculated by the Fick principle. Cerebral function was assessed by a computer-based measurement of reaction time. At high altitude at rest, arterial carbon dioxide tension, oxygen saturation, and oxygen tension were significantly reduced, and arterial oxygen content was increased because of an increase in hemoglobin concentration. Global cerebral blood flow was similar in the four conditions. Cerebral oxygen delivery and cerebral metabolic rates of oxygen and glucose also remained unchanged, whereas cerebral metabolic rates of lactate increased slightly but nonsignificantly at high altitude during exercise compared with high altitude at rest. Reaction time was unchanged. The data indicate that cerebral blood flow and oxidative metabolism are unaltered after high-altitude acclimatization from sea level, despite marked changes in breathing and other organ functions.

S-100 serum levels and outcome after severe head injury

S-100B a protein of astroglial cells is described as a marker for neuronal damage. Reliable outcome prediction from severe head injury is still unresolved. Clinical scores like the Glasgow Coma Score (GCS) and diagnostic scores like the Marshall CT Classification (MCTC) are well established and investigated, but there are still some concerns about these tools. The aim of this study was to investigate the predictive value of the initial serum level of S-100B. 44 patients with severe head injury (GCS < 9) were included. Blood samples were drawn within 1 to 6 hours of injury. After a period of 11 months their outcome was correlated using the Glasgow Outcome Scale. Patients with good outcome had significantly lower serum concentrations of S-100 on admission (0.96 microgram/l versus 5.5 micrograms/l mean, p < 0.0001). In addition patients with a S-100 serum level below 2 micrograms/l showed a significant better rating on the GOS at follow-up (4 points versus 1.8 points mean, p < 0.0001). With this cut-off line it was possible to predict longterm outcome with a sensitivity of 75% and specitivity of 82%. The serum level of S-100B calculated with one to six hours of a severe head injury is a useful additional outcome predictor.

S-100b as a screening marker of the severity of minor head trauma (MHT)--a pilot study

Due to its neural tissue specificity S-100b is considered as a screening marker of cerebral injury in head trauma patients. However, the occurrence and relevance of an increased S-100b serum level in minor head trauma (MHT) is still debated. Therefore, the purpose of our study was to evaluate the diagnostic utility of S-100b measurements in a level I trauma center emergency room (ER). Eighty patients presenting with clinical symptoms of MHT (GCS score of 13-15, transitory loss of consciousness, amnesia, nausea) were prospectively recruited. Blood samples were drawn at 0 h, 6 h and 24 h after admission, and a cerebral computed tomography (CT) was performed. The reference group consisted of 10 patients with severe head injury (GCS score < 8), the control group of 20 healthy volunteers. Concentrations of S-100b in serum were determined by an immunoluminometric assay. The results were compared with the plasma levels of polymorphonuclear (PMN) elastase as an established general trauma marker. In the MHT group, the S-100b serum level revealed 1.26 +/- 0.57 ng/ml at study entry (73.46 +/- 47.53 min after trauma). In comparison, the S-100b concentration was significantly elevated in patients with severe head trauma (5.26 +/- 1.65 ng/ml, p = 0.009), but no significant difference became evident in relation to the control group (0.05 +/- 0.01 ng/ml). Starting values of PMN elastase in plasma amounted to 66.40 +/- 14.92 ng/ml in severe trauma, and to 60.52 +/- 10.75 ng/ml in MHT showing significant differences only in relation to the control group (23.36 +/- 1.53 ng/ml). When correlated with the severity of the later clinical course, the first S-100b measurements exhibited steadily increasing values as demonstrated in MHT outpatients (0.29 +/- 0.11 ng/ml), MHT in-hospital patients (0.70 +/- 0.19 ng/ml) and MHT intensive care unit patients (5.03 +/- 3.18 ng/ml). PMN elastase levels revealed no significant differences concerning the three MHT subgroups. Thus, in contrast to the general trauma marker PMN elastase, assessment of the specific neuroprotein S-100b early after traumatic insult appears to be a promising laboratory marker for the prognosis of the severity of brain injury in MHT patients. Nevertheless, further investigations are required to better understand its predictive value.

Increased S100B blood levels in unmedicated and treated schizophrenic patients are correlated with negative symptomatology

S100B, a calcium-binding protein produced by astroglial cells, is a marker of astroglial cellular integrity. It has been shown to be increased in acute brain damage and neurodegeneration. A recent study showed increased S100B levels in medicated acutely psychotic patients with schizophrenia. The study presented here included 26 drug-free patients with acute schizophrenia and 26 matched healthy controls. S100B blood concentrations were determined using a quantitative immunoassay upon admission and after 6 weeks of neuroleptic treatment. The PANSS was used to investigate psychopathology. Unmedicated schizophrenic patients showed significantly increased S100B levels compared to matched healthy controls. After 6 weeks of treatment, 11 patients showed normal S100B levels while in 15 patients the levels remained increased. These patients showed significantly higher PANSS negative scores upon admission and after 6 weeks of treatment. Schizophrenic patients display a loss of astroglial integrity which is not caused by neuroleptic medication. Continuously increased S100B levels are associated with negative symptomatology.

Brain-specific NSE and S-100 proteins in umbilical blood after normal delivery

BACKGROUND

To determine normal blood levels of brain-specific proteins S-100 and neuron specific enolase (NSE) in healthy newborns and their mothers following uncomplicated birth.

METHODS

Umbilical artery and vein blood and maternal venous blood was collected at 112 consecutive uncomplicated deliveries. Venous blood samples were taken from 18 of the neonates 3 days after birth. S-100 and NSE were analyzed quantitatively by double antibody immunoluminometric assay (Sangtec Medical AB, Sweden).

RESULTS

Compared with adults, healthy neonates had higher levels of both S-100 and NSE. For S-100, median levels (range) were 1.10 microg/l (0.38-5.50 microg/l and 0.98 microg/l (0.43-2.70 microg/l) in umbilical artery and vein, respectively. For NSE, median levels (range) in umbilical artery blood and vein were 27 microg/l (10-140 microg/l) and 10.75 microg/l (8.80->/=200 microg/l) respectively. The maternal venous blood levels of both S-100 and NSE were significantly lower than in their infants. At 3 days of life, neonatal venous levels of the proteins were still high: S-100, 0.48-9.70 microg/l; NSE, 17->/=200 microg/l. In contrast to adults, haemolysis affected the S-100 levels in umbilical blood significantly.

CONCLUSION

Concentrations of both S-100 and NSE in blood are greater in newborns after normal birth than in healthy adults. The higher levels in umbilical artery blood than in umbilical vein blood are consistent with a fetal origin of these proteins. High levels in venous blood at 3 days of life suggest that the high levels at birth are not related to the birth process but reflect a high activity of these proteins during fetal development.

Release of biochemical markers of damage to neuronal and glial brain tissue is associated with short and long term neuropsychological outcome after traumatic brain injury

OBJECTIVES

The present study aimed at the analysis of release patterns of neurobiochemical markers of brain damage (neuron specific enolase (NSE) and protein S-100B) in patients with traumatic brain injury and their predictive value with respect to the short and long term neuropsychological outcome.

METHODS

Serial NSE and S-100B concentrations were analysed in blood samples taken at the first, second, and third day after traumatic brain injury. In 69 patients who fulfilled the inclusion criteria (no history of neurological or psychiatric disorder or alcohol or drug dependency, blood sampling according to the scheduled time scale, aged between 16 and 65 years) standardised neurological examinations and qualitative and quantitative evaluation of CT were performed. Comprehensive neuropsychological assessment was performed in 39 subjects 2 weeks after admission and in 29 subjects at a 6 month follow up examination.

RESULTS

Most patients presented with minor head injuries (GCS>/=13) at the time of admission. Six months later most patients were fully independent in activities of daily living. Two thirds of the patients, however, still had neuropsychological dysfunction. Patients with short and long term neuropsychological disorders had significantly higher NSE and S-100B serum concentrations and a significantly longer lasting release of both markers. A comparative analysis of the predictive value of clinical, neuroradiological, and biochemical data showed initial S-100B values above 140 ng/l to have the highest predictive power.

CONCLUSIONS

The analysis of post-traumatic release patterns of neurobiochemical markers of brain damage might help to identify patients with traumatic brain injury who run a risk of long term neuropsychological dysfunction.

Elimination of S100B and renal function after cardiac surgery

OBJECTIVES

To determine the biologic half-life of the S100B protein and to investigate if the elimination of S100B depends on glomerular filtration rate (GFR).

DESIGN

Prospective human study.

SETTING

University hospital.

PARTICIPANTS

Sixteen patients who underwent cardiac surgery with cardiopulmonary bypass.

INTERVENTIONS

Shed mediastinal blood (autotransfusion) was returned to the patients postoperatively and used to study the kinetics of S100B. Iohexol was infused simultaneously to estimate GFR. S100B was measured at 0, 20, 40, 60, and 180 minutes after infusion. Iohexol was measured at 180 and 240 minutes after infusion.

MEASUREMENTS AND MAIN RESULTS

S100B followed first-order kinetics, and the biologic half-life for S100B was determined to be 25.3 +/- 5.1 minutes. GFR was determined to be 63.8 +/- 34.4 mL/min. No correlation was found between GFR and S100B half-life.

CONCLUSIONS

The elimination of S100B after cardiac surgery is faster than reported earlier and not affected by a moderate decrease in GFR. This finding is important when evaluating S100B levels after cardiac surgery.

Comparison of serum S-100 protein levels following stroke and traumatic brain injury

Temporal changes in serum S-100 protein levels were compared between patients with ischemic stroke, transient ischemic attack (TIA) and traumatic brain injury (TBI). In addition, S-100 levels were correlated with clinical severity and outcome. Measurements were done with a LIA-mat((R)) Sangtec((R)) 100 using an automated immunoluminometric assay. Serum S-100 was measured in 21 stroke patients, 18 TIA patients and ten TBI patients on days 1 (0-24 h), 2, 3, 4, 5 or 6 and 8 or 9. In a control group of 28 healthy volunteers one measurement was done. For the stroke and TIA patients, National Institutes of Health Stroke Scale (NIHSS) scores were obtained on admission and on day 10. For the TBI patients, Glasgow Coma Scale (GCS) scores were obtained on admission and Glasgow Outcome Scale (GOS) scores were obtained after 6 months. Changes in serum S-100 levels over the first 3 days were significantly different between stroke and TBI patients (P=0.014) and between stroke and TIA patients (P=0.006). Peak concentrations of S-100 were most often observed on day 3 or 4 after stroke and on day 1 or 2 after TBI. In the stroke patients individual S-100 peak levels correlated well with the NIHSS score on admission (r=0.58 P=0.014) and the change in NIHSS score between day 10 and day 1 (r=0.65, P=0. 005). In the TBI patients a good correlation between individual peak levels of S-100 and the GCS score on admission (r=-0.81, P=0.010) and the GOS score 6 months after the trauma was found (r=-0.87, P=0. 004). We conclude that there is a significant difference in temporal changes of S-100 levels between ischemic stroke and TBI patients. This suggests different pathophysiological mechanisms. The results of this study further confirm that peak levels of serum S-100 correlate with neurological deficit resulting from either stroke or TBI.

The early fall in levels of S-100 beta in traumatic brain injury

Protein S-100 beta has been suggested as a prognostic marker in traumatic brain injury. However, little is known of its behaviour in the immediate post-injury period. With Ethics Committee approval, we recruited 30 patients with a history of head injury presenting to our Accident and Emergency Department. Blood was taken on arrival and at four hours post-injury. Serum S-100 beta was estimated using an immunoluminometric assay. Levels of S-100 beta were seen to fall rapidly with time. Half-time was distributed non-parametrically with a median of 198 minutes. Using the Mann-Whitney U test we found a statistically significant difference between non-desirable (Glasgow Outcome Score 1-3) and desirable (Glasgow Outcome Score 4-5) outcome on admission (p = 0.0155) but not at four hours (p = 0.1336). Levels of S-100 beta fell rapidly after its release following traumatic brain injury. Time after injury is therefore critical in assessing the significance of levels of S-100 beta, and sampling should be as early as possible to gain maximum information. If S-100 beta is to be assessed as a monitor of ongoing brain injury in the intensive therapy unit sampling must be frequent (e.g. every 4 hours) to be able to detect rises in serum levels before they have decayed to baseline.

Serum S100 protein as a marker of cerebral damage during cardiac surgery

The identification of a serum marker to assist in the diagnosis of cerebral injury after cardiac surgery is potentially useful. S100 protein is an early marker of cerebral damage. It is released after cardiac surgery performed under cardiopulmonary bypass (CPB). Its level is correlated with the duration of CPB, deep circulatory arrest and aortic cross-clamping. Increased levels of S100 protein are correlated with the age of the patient and the number of microemboli, especially during aortic cannulation. Perioperative cerebral complications such as stroke, delayed awakening and confusion are associated with increased levels of S100 protein directly after bypass and from 15 to 48 h after it. In addition, increased levels of S100 protein are related to neuropsychological dysfunction after cardiac surgery. S100 protein has early and late release patterns after CPB; the early pattern may be due to sub-clinical brain injury. The late release pattern may be due to perioperative cerebral complications. Patients undergoing intracardiac operations combined with coronary artery bypass surgery are more susceptible to brain injury and have higher levels of S100 after CPB. Furthermore, adults and children undergoing deep circulatory arrest are more susceptible to brain injury, in terms of higher S100 protein release after CPB. Serum S100 protein levels are reduced after using arterial line filtration and covalent-bonded heparin to coat the inner surface of the CPB circuit.

Nerve tissue protein S-100 and neurone-specific enolase concentrations in cerebrospinal fluid and blood during carotid endarterectomy

Nerve tissue protein S-100 and neurone-specific enolase levels in serum were studied in 10 patients before, during and for 2 days after elective carotid endarterectomy performed under general anaesthesia and using a Javid Shunt. In six patients, simultaneous cerebrospinal fluid samples were also obtained. Serum nerve tissue protein S-100 was normal throughout the operation, but in one patient with severe hypertension, levels increased to 1.38 microg. l-1 at 1 h postoperatively. Two patients showed an increase in cerebrospinal fluid nerve tissue protein S-100 during clamping: these patients also had neurological deficits at 6 months. Serum neurone-specific enolase increased from 5.8 to 9.3 microg.l-1 during shunting while cerebrospinal fluid neurone-specific enolase did not change. Uncomplicated carotid endarterectomy does not produce cerebral damage as measured by serum nerve tissue protein S-100; cerebrospinal fluid nerve tissue protein S-100 may be more sensitive for minor cerebral damage. Neurone-specific enolase appeared to be nonspecific. The lack of correlation between the neuroproteins may need to be explained before relying on these simple assays as diagnostic indicators of cerebral ischaemia.

Traumatic brain damage: serum S-100 protein measurements related to neuroradiological findings

This study was designed to investigate the correlation between S-100 protein serum measurements and neuroradiological findings in patients with head injury. We studied 278 patients with minor, moderate, and severe head injuries and 110 controls with no history of neurological disease. The study recruited patients from three Scandinavian neurotrauma centers. Serum levels of S-100 protein were measured at admittance, and computed tomographic scans of the brain were obtained within 24 h postinjury in all patients. In a subgroup of 45 patients with minor head injuries, magnetic resonance imaging was also performed. Increased serum level of S-100 protein was detected in 108 (39%) patients, and CT scan demonstrated intracranial pathology in 25 (9%) (brain contusion n = 13, subdural hematoma n = 6, epidural hematoma n = 2, traumatic subarachnoid hemorrhage n = 2, and brain edema n = 2). The proportion of patients with detectable serum level was significantly (p < 0.01) higher among those with intracranial pathology (92%) compared to those without (34%). The negative predictive value of an undetectable S-100 serum level was 0.99. Undetectable serum level of S-100 protein predicts normal intracranial findings on CT scan. Determination of S-100 protein in serum may be used to select patients for CT scanning.

Temporal profile of release of neurobiochemical markers of brain damage after traumatic brain injury is associated with intracranial pathology as demonstrated in cranial computerized tomography

This study aimed at the investigation of release patterns of neuron specific enolase (NSE) and protein S-100B after traumatic brain injury (TBI) and their association with intracranial pathologic changes as demonstrated in computerized tomography (CT). We analyzed NSE and S-100B concentrations in serial venous blood samples taken one to three days after TBI in 66 patients by the use of immunoluminometric assays. These markers are considered to be specific neurobiochemical indicators of damage to glial (S-100B) or neuronal (NSE) brain tissue. Standardized neurological examination and plani- and volumetric evaluation of computerized tomography scans were performed in all patients. Patients with medium severe to severe TBI [Glasgow Coma Scale (GCS) score at the site of accident < or =12] exhibited significantly higher NSE and S-100B concentrations and a significantly longer release compared to patients with minor head injury (GCS: 13-15). Both, patients with and without visible intracerebral pathology in CT scans exhibited elevated concentrations of NSE and S-100B after TBI and a significant decrease in the follow-up blood samples. Release patterns of S-100B and NSE differed in patients with primary cortical contusions, diffuse axonal injury (DAI), and signs of cerebral edema (ICP) without focal mass lesions. All serum concentrations of NSE and S-100B were significantly correlated with the volume of contusions. The data of the present study indicate that the early release patterns of NSE and S-100 may mirror different pathophysiological consequences of traumatic brain injury.

Elevated serum levels of astroglial S100beta in patients with liver cirrhosis indicate early and subclinical portal-systemic encephalopathy

Portal-systemic encephalopathy is the prototype among the neuropsychiatric disorders that fall under the term Hepatic Encephalopathies. Ammonia toxicity is central to the pathophysiology of Portal-systemic encephalopathy, and neuronal ammonia toxicity is modulated by activated astrocytes. The calcium-binding astroglial key protein S100beta is released in response to glial activation, and its measurement in serum only recently became possible. Serum S100beta was determined by an ultrasensitive ELISA in patients (n=36) with liver cirrhosis and transjugular intrahepatic portosystemic stent-shunt. Subclinical portal-systemic encephalopathy and overt portal-systemic encephalopathy were determined by age-adjusted psychometric tests and clinical staging, respectively. Serum S100beta, was specifically elevated in the presence of subclinical or early portal-systemic encephalopathy, but not arterial ammonia. S100 levels elevated above a reference value (S100beta < or = 110pg/ml) or the cut off value determined in our group of patients (112pg/ml) predicted subclinical portal-systemic encephalopathy with a specificity and sensitivity of 100 and 56.5%, respectively. Serum S100beta was significantly dependent on liver dysfunction (Child-Pugh score), but was more closely related to cognitive impairments than the score. Serum S100beta seems to be a promising biochemical surrogate marker for mild cognitive impairments due to portal-systemic encephalopathy.

Comparison of clinical, radiologic, and serum marker as prognostic factors after severe head injury

BACKGROUND

S-1OOB, a protein of astroglial cells, is described as a marker for neuronal damage. Reliable outcome prediction from severe head injury is still unresolved. Clinical scores such as the Glasgow Coma Scale score (GCS) and diagnostic scores such as the Marshall Computed Tomographic Classification are well established and investigated, but there are still some concerns about these tools. The aim of this study was to investigate the predictive value of the initial serum level of S-100B compared with the predictive value of the GCS score and the Marshall Computed Tomographic Classification to outcome after severe head injury.

METHODS

Forty-four patients with severe head injury (GCS score < 9) were included. Blood samples were drawn within 1 to 6 hours of injury. After a period of 11 months, their outcome was correlated by using the Glasgow Outcome Scale. Patients with an S-100B serum level above 2 microg/L, a GCS score between 3 and 5, and a computed tomographic scan in the categories 4 to 6 are predicted to have an unfavorable outcome. The predictive values of these tools were calculated according to these definitions.

RESULTS

The protein S-100B had with 17% the lowest total misclassification rate. When compared with the GCS score and Marshall Computed Tomographic Classification the S-100B serum level calculated on admission had the highest positive predictive value (87%) and negative predictive value (77%).

CONCLUSION

The serum level of S-100B calculated within 1 to 6 hours of a severe head injury is a useful additional outcome predictor.

Neurophysiologic monitoring and outcomes in cardiovascular surgery

The first step to make in improving neurologic outcome is to recognize and accept neurologic injury occurs in all patient groups undergoing CPB. Fortunately, that stage has now been passed. Accurate detection and documentation of the incidence of brain injury is the next progression. At the same time, the cause of the injury needs to be established. Since the introduction of CPB, numerous improvements and refinements have been achieved, making it the acceptable, everyday clinical tool that has enabled the development of cardiac surgery. Despite these improvements, CPB-related morbidity persists. The advent of new technologic advances drives the quest for new techniques. New protective strategies for many end organs, including the heart, kidney, and brain, are evolving. No organ system should be viewed in isolation; otherwise, organ-specific protective strategies may arise in conflict. A strategy that confers absolute myocardial protection would be ideal, but at what cost to the protection of the kidneys, intestines, and brain? A neuroprotective strategy would ideally eliminate brain injury and be beneficial for all organs. The only way to continue to make progress is by the scientific evaluation of new techniques. The use of appropriate monitoring and outcome measures is fundamental to this process.

Traumatic brain damage in minor head injury: relation of serum S-100 protein measurements to magnetic resonance imaging and neurobehavioral outcome

OBJECTIVE

The present study was conducted to validate S-100 protein as a marker of brain damage after minor head injury.

METHODS

We studied 50 patients with minor head injuries and Glasgow Coma Scale scores of 13 to 15 in whom computed tomographic scans of the brain revealed no abnormalities. Serum levels of S-100 protein were measured at admittance and hourly thereafter until 12 hours after injury. Magnetic resonance imaging and baseline neuropsychological examinations were performed within 48 hours, and neuropsychological follow-up was conducted at 3 months postinjury.

RESULTS

Fourteen patients (28%) had detectable serum levels of S-100 protein (mean peak value, 0.4 microg/L [standard deviation, +/- 0.3]). The S-100 protein levels were highest immediately after the trauma, and they declined each hour thereafter. At 6 hours postinjury, the serum level was below the detection limit (0.2 microg/L) in five (36%) of the patients with initially detectable levels. Magnetic resonance imaging revealed brain contusions in five patients, four of whom demonstrated detectable levels of S-100 protein in serum. The proportion of patients with detectable serum levels was significantly higher when magnetic resonance imaging revealed a brain contusion. In patients with detectable serum levels, we observed a trend toward impaired neuropsychological functioning on measures of attention, memory, and information processing speed.

CONCLUSION

Determination of S-100 protein levels in serum provides a valid measure of the presence and severity of traumatic brain damage if performed within the first hours after minor head injury.

Release of S100B during coronary artery bypass grafting is reduced by off-pump surgery

BACKGROUND

S100B, a plasma marker of brain injury, was compared after coronary artery bypass grafting with and without cardiopulmonary bypass (CPB).

METHODS

Fourteen patients with off-pump operations and 18 patients with CPB were compared. Seven patients in the off-pump group underwent a minithoracotomy and received only an arterial graft, whereas 7 patients underwent sternotomy and received both an arterial and one or two vein grafts. S100B was measured in arterial plasma using an immunoassay with enhanced sensitivity.

RESULTS

S100B before the operation was 0.03 microg/L. At wound closure, S100B in patients of the off-pump and CPB groups reached a maximum level of 0.22 +/- 0.07 and 2.4 +/- 1.5 microg/L, respectively (p < 0.001). No strokes occurred. Patients without CPB receiving arterial and vein grafts released slightly more S100B (p < 0.05) than patients with only arterial grafting. In patients undergoing CPB, S100B increased slightly before aortic cannulation (p < 0.001), to the same level as the maximum reached for the non-CPB group.

CONCLUSIONS

Coronary artery bypass grafting with CPB caused a 10-fold greater increase in S100B than off-pump grafting. S100B release after off-pump sternotomy with vein grafting was slightly greater than in arterial grafting through a minithoracotomy.

Neurobehavioural sequelae of cardiopulmonary bypass

The development of coronary artery bypass grafting (CABG) and its effect on angina is the product of a series of technical and scientific advances. Despite these advances, however, adverse neurobehavioural outcomes continue to occur. Stroke is the most serious complication of CABG, but studies that have identified demographic and medical risk factors available before surgery are an important advance. Short-term cognitive deficits are common after CABG, but may not be specific to this procedure. However, deficits in some cognitive areas such as visuoconstruction persist over time, and may reflect parieto-occipital watershed area injury secondary to hypoperfusion or embolic factors. Risk factors for cognitive decline may be time dependent, with short-term studies identifying factors that differ from those of long-term studies. Patients with depression before surgery are likely to have persistent depression afterwards. However, depression does not account for the cognitive decline after CABG. Since CABG is increasingly done in older patients with more comorbidity, the challenge is to identify patients at risk of adverse neurocognitive outcomes and to protect them by modification of the surgical procedure or by effective medical therapy.

S-100 serum levels after minor and major head injury

BACKGROUND

S-100, a protein of astroglial cells, is described as a marker for central nervous system damage. The aim of this study was to evaluate whether the marker could give information about the severity and possibility of functional recovery after minor and severe head injury.

METHODS

Thirty patients after severe head injury (Glasgow Coma Scale score < 9) and 11 patients after minor head injury (Glasgow Coma Scale score > 12) were included. In each case, blood samples were drawn within 6 hours after injury. Outcome was estimated at hospital discharge using the Glasgow Outcome Scale.

RESULTS

All patients who sustained minor head injury had reached a favorable outcome by the time they were discharged from the hospital. Their mean S-100 serum level was 0.35 microg/L. Patients who sustained severe head injury and were classified as having an unfavorable outcome (31%) showed a mean serum concentration of 4.9 microg/L, whereas patients classified as having a favorable outcome (69%) had a mean S-100 level of 1.2 microg/L. All groups differed significantly (p < 0.05).

CONCLUSION

S-100 appears to be a promising marker for the severity of head injury and neuronal damage.