Objective: Systemic effects of carbon dioxide (CO2) insufflation during left-sided cardiac surgery were evaluated in a prospective randomized study, with regard to acid-base status, gas exchange, cerebral hemodynamics, and red blood cell morphology.Methods: Twenty patients undergoing elective left-sided cardiac surgery were randomized to de-airing procedure either by CO2 insufflation technique (CO2 group, n = 10) or by Lund technique without CO2 insufflation (Lund group, n = 10). Groups underwent assessment of acid-base status by intermittent arterial blood gases and in-line blood gas monitoring. Capnography was used to determine volume of CO2 produced. Cerebral hemodynamics was measured by transcranial Doppler sonography and near-infrared spectroscopy. Red cell morphology from cardiotomy suction and vent tubing was studied by scanning electron microscopy.Results: Patients in the CO2 group consequently developed significantly higher levels of hypercapnia with a concomitant increase in the volume of CO2 produced despite significantly higher oxygenator gas flows compared with the Lund group. Effects on cerebral hemodynamics were observed in the CO2 group with significantly higher blood flow velocities in the middle cerebral artery and higher regional cerebral saturation. Red blood cell damage was observed in the CO2 group by scanning electron microscopy (97% in CO2 group vs 18% in Lund group).Conclusions: Insufflation of CO2 into the cardiothoracic wound cavity during left-sided cardiac surgery can induce hypercapnic acidosis and increased cerebral blood flow and local blood cell damage. These systemic effects should be monitored by in-line capnography and acid-base measurements for early and effective correction by increase in gas flows to the oxygenator.

Increased levels of cardio-enriched microRNAs (miRNAs) have been described in patients with myocardial infarction (MI). We wanted to evaluate the diagnostic and prognostic potential of cardio-enriched miRNAs in patients presenting with a suspected acute coronary syndrome (ACS).

The objective of the present study was to validate the presence and explore the characteristics of mitochondrial permeability transition (mPT) in isolated mitochondria from human heart tissue in order to investigate if previous findings in animal models of cardiac disorders are translatable to human disease. Mitochondria were rapidly isolated from fresh atrial tissue samples obtained from 14 patients undergoing Maze surgery due to atrial fibrillation. Human heart mitochondria exhibited typical mPT characteristics upon calcium overload such as swelling, evaluated by changes in light scattering, inhibition of respiration and loss of respiratory coupling. Swelling was a morphologically reversible event following transient calcium challenge. Calcium retention capacity (CRC), a quantitative measure of mPT sensitivity assayed by following extramitochondrial [Ca(2+)] and changes in respiration during a continuous calcium infusion, was significantly increased by cyclophilin D (CypD) inhibitors. The thiol-reactive oxidant phenylarsine oxide sensitized mitochondria to calcium-induced mPT. Release of the pro-apoptotic intermembrane protein cytochrome c was increased after, but not before, calcium discharge and respiratory inhibition in the CRC assay. From the present study, we conclude that adult viable heart mitochondria have a CypD- and oxidant-regulated mPT. The findings support that inhibition of mPT may be a relevant pharmacological target in human cardiac disease and may underlie the beneficial effect of cyclosporin A in reperfusion injury.

BackgroundPost-operative renal dysfunction after cardiac surgery is not uncommon and can lead to adverse outcome. The ability to accurately monitor renal function is therefore important. Cystatin C is known to be a sensitive marker of the glomerular filtration rate (GFR), but it has not been fully evaluated in cardiac surgery. Iohexol clearance is considered a reliable reference method for the determination of GFR. The aim of this study is to, for the first time, evaluate the diagnostic accuracy of plasma cystatin C compared with iohexol clearance in cardiac surgery.MethodsTwenty-one patients scheduled for elective coronary artery bypass grafting were prospectively enrolled in the study. Before surgery and on the second post-operative day, an iohexol clearance was performed. Plasma cystatin C, plasma creatinine and plasma C-reactive protein were determined before surgery and on the first, second, third and fifth post-operative day. Estimated creatinine and cystatin C clearances were determined.ResultsPost-operative cystatin C and 1/cystatin C correlated strongly to iohexol clearance (r=-0.90 and 0.86) and so did creatinine and 1/creatinine (r=-0.83 and 0.78). Estimated creatinine clearance differed from iohexol clearance (P < 0.01), whereas estimated cystatin C clearance did not differ from iohexol clearance (P=0.81). No correlation was found between C-reactive protein and cystatin C.ConclusionThis study indicates that clearance estimations based on cystatin C are more accurate compared with estimations based on creatinine in determining GFR in cardiac surgery. Cystatin C has, in this study population, a stronger correlation to iohexol clearance than creatinine.

OBJECTIVE:We have compared the effectiveness, time required for de-airing, and safety of a newly developed de-airing technique for open left heart surgery (Lund technique) with a standardized carbon dioxide insufflation technique. METHODS:Twenty patients undergoing elective open aortic valve surgery were randomized prospectively to the Lund technique (Lund group, n = 10) or the carbon dioxide insufflation technique (carbon dioxide group, n = 10). Both groups were monitored intraoperatively during de-airing and for 10 minutes after weaning from cardiopulmonary bypass by transesophageal echocardiography and online transcranial Doppler for the severity and the number of gas emboli, respectively. The systemic arterial partial pressure of carbon dioxide and pH were also monitored in both groups before, during, and after cardiopulmonary bypass. RESULTS:The severity of gas emboli observed on transesophageal echocardiography and the number of microembolic signals recorded by transcranial Doppler were significantly lower in the Lund group during the de-airing procedure (P = .00634) and in the first 10 minutes after weaning from cardiopulmonary bypass (P = .000377). Furthermore, the de-airing time was significantly shorter in the Lund group (9 vs 15 minutes, P = .001). The arterial pH during the cooling phase of cardiopulmonary bypass was significantly lower in the carbon dioxide group (P = .00351), corresponding to significantly higher arterial partial pressure of carbon dioxide (P = .005196) despite significantly higher gas flows (P = .0398) in the oxygenator throughout the entire period of cardiopulmonary bypass. CONCLUSIONS:The Lund de-airing technique is safer, simpler, and more effective compared with the carbon dioxide insufflation technique. The technique is also more cost-effective because the de-airing time is shorter and no extra expenses are incurred.

BACKGROUND: Septic shock may cause splanchnic hypoperfusion. We hypothesized that levosimendan would improve systemic and hepatosplanchnic perfusion during endotoxemic shock.METHODS: In 16 anesthetized pigs (31.4 +/- 3.4 kg), a jugular vein, a carotid artery, the Pulmonary artery (thermodilution), the portal vein, and a hepatic vein were cannulated for hemodynamic monitoring and blood sampling. Ultrasonic flow-probes were placed around the portal vein, the hepatic artery, and the superior mesenteric artery (SMA). In addition to 30 mL/kg of dextran 70 given before baseline, all animals received 1.0 mL . kg(-1) . h(-1) of IV fluids throughout the experiment. An endotoxin infusion (2 mu g . kg(-1) . h(-1)) was given for 300 min; 100 min after the start of endotoxin, the pigs were randomized to receive levosimendan (50 mu g . kg(-1) . h(-1), n = 8) or placebo (n = 8). To evaluate the isolated effects of endotoxemia, all data before randomization were pooled into one group. Data were analyzed by analysis of variance and presented as mean +/- SEM.RESULTS: Endotoxemia (t = 90 min, pooled data) decreased systemic vascular resistance (SVR, 2526 +/- 203 to 1946 +/- 122 dyn . s . cm(-5), P = 0.003) and mean arterial blood pressure (MAP, 109 +/- 6 to 84 +/- 3 mm Hg, P < 0.05), whereas heart rate (66 +/- 4 to 98 +/- 8 bpm), and mean pulmonary arterial pressure (MPAP, 20 +/- 1 to 38 +/- 2 mm Hg) increased (P < 0.001). Cardiac output (CO, 3.4 +/- 0.2 L/min) and systemic oxygen delivery (414 +/- 33 mL/min) were unchanged, but blood flows in the SMA (575 +/- 34 to 392 +/- 38 mL/min) and the portal vein (881 +/- 62 to 568 +/- 39 mL/min) decreased (P < 0.001). Although hepatic arterial blood flows increased (36 +/- 8 to 219 +/- 38 mL/min), gut (114 +/- 11 to 84 +/- 7 mL/min) and hepatic (94 +/- 11 to 67 +/- 8 mL/min) oxygen deliveries decreased (P < 0.05). At t = 300 min, the levosimendan group showed lower MPAP (39 +/- 3 vs 49 +/- 2 mm Hg, P = 0.025), lower SVR (2158 +/- 186 vs 3069 +/- 370 dyn . s . cm(-5), P = 0.052), and lower MAP (55 +/- 9 vs 87 +/- 9 mm Hg, P < 0.001) than the control group. In both groups, CO, portal vein, and hepatic arterial blood flows decreased (P < 0.001); the mean values for the levosimendan group at t = 300 min were 2.0 +/- 0.4 L/min, 390 +/- 83 mL/min, and 36 +/- 12 mL/min, respectively. SMA blood flow decreased only in the levosimendan group (432 +/- 40 to 320 +/- 78 mL/min, P < 0.001), whereas gut oxygen delivery decreased in the levosimendan (85 +/- 12 to 63 +/- 12 mL/min, P < 0.001) and in the control (83 +/- 6 to 59 +/- 3 mL/min, P = 0.03) groups.CONCLUSION: Levosimendan administered after the establishment of endotoxemic shock to pigs receiving moderate fluid resuscitation prevented further increases in MPAP and maintained a low SVR. There were, however, no improvements in CO, MAP decreased, and levosimendan neither prevented the development of circulatory shock nor improved hepatosplanchnic perfusion. (Anesth Analg 2009:109:1568-75)

Objective: We have evaluated a new technique of cardiac de-airing that is aimed at a) minimizing air from entering into the pulmonary veins by opening both pleurae and allowing lungs to collapse and b) flushing out residual air from the lungs by staged cardiac filling and lung ventilation. These air emboli are usually trapped in the pulmonary veins and may lead to ventricular dysfunction, life-threatening arrhythmias, and transient or permanent neurologic deficits.Methods: Twenty patients undergoing elective true left open surgery were prospectively and alternately enrolled in the study to the conventional de-airing technique (pleural cavities unopened, dead space ventilation during cardiopulmonary bypass [control group]) and the new de-airing technique (pleural cavities open, ventilator disconnected during cardiopulmonary bypass, staged perfusion, and ventilation of lungs during de-airing [study group]). Transesophageal echocardiography and transcranial Doppler continually monitored the air emboli during the de-airing period and for 10 minutes after termination of the cardiopulmonary bypass.Results: The amount of air embolism as observed on echocardiography and the number of microembolic signals as recorded by transcranial Doppler were significantly less in the study group during the de-airing time (P < .001) and the first 10 minutes after termination of cardiopulmonary bypass (P < .001). Further, the de-airing time was significantly shorter in the study group (10 vs 17 minutes, P < .001).Conclusion: The de-airing technique evaluated in this study is simple, reproducible, controlled, safe, and effective. Moreover, it is cost-effective because the de-airing time is short and no extra expenses are involved.

BACKGROUND:We compared the association of levosimendan or dobutamine with norepinephrine for the maintenance of systemic and hepatosplanchnic perfusion during early endotoxemic shock. METHODS:Twenty anesthetized pigs (26.8 +/- 0.5 kg) were instrumented with flow probes and catheters to monitor systemic and regional perfusion as described in our companion article in this issue of the journal. Two animals were excluded because of surgical complications. Oxygen consumption (VO(2)) was measured by indirect calorimetry. Starting 1 h after instrumentation, an endotoxin infusion (Escherichia coli lipopolysaccharide, 2 microg x kg(-1) x h(-1)) was administered for 300 min. Sixty minutes after the start of endotoxin, the animals were fluid resuscitated (20 mL/kg dextran 70); at 120 min, they were randomized into three groups of six animals each: levosimendan (25-50 microg x kg(-1) x h(-1)), dobutamine (10-20 microg x kg(-1) x min(-1)), and control. In the first two groups, norepinephrine (0.5-2 microg x kg(-1) x min(-1)) was added when mean arterial blood pressure (MAP) or= baseline. The data were divided into two subsets: before (0-120 min, all animals) and after (120-300 min, three groups) randomization, and analyzed by analysis of variance. P < 0.05 was considered significant. RESULTS:At 120 min, cardiac output was 15% higher (P < 0.001), systemic vascular resistance was 30% lower (P < 0.001), and MAP decreased 12.5% (P = 0.004); blood flow in the hepatic artery, superior mesenteric artery, and portal vein had increased by 100% (P = 0.004), 60% (P < 0.001), and 20% (P < 0.001), respectively. Between 120 and 300 min, cardiac output and systemic oxygen delivery decreased 50% in control animals (P < 0.05), remained unchanged in the levosimendan group, and increased 60% with dobutamine (P = 0.05). MAP (P = 0.043) and VO(2) (P = 0.001) decreased 20% in the control group. Portal vein flow decreased in the control (50%) and levosimendan (30%) groups (P < 0.001) and was therefore higher in the dobutamine group (P = 0.003) at 300 min. Hepatic and gut oxygen deliveries decreased in the levosimendan (50%, and 30%, respectively, P < 0.001) and control groups (70% and 45%, respectively, P < 0.05); thus, regional oxygen deliveries were greater in the dobutamine group (P < 0.05). In this group, mixed venous and hepatic vein oxygen saturation were maintained; the latter variable was higher than in the other groups (P < 0.05). Although unchanged with dobutamine, arterial (P = 0.020), portal (P = 0.020), and hepatic vein (P = 0.034) lactate concentrations increased twofold with levosimendan. CONCLUSION:In volume-resuscitated endotoxemic pigs, the association of either levosimendan or dobutamine with norepinephrine preserved systemic blood flow, oxygen delivery, and VO(2). However, only dobutamine-norepinephrine maintained portal blood flow, which was associated with preservation of splanchnic and hepatic oxygen homeostasis and stable lactate concentrations.

Endotoxaemia is thought to occur in cardiac surgery using extracorporeal circulation (ECC) and a positive correlation has been proposed between the magnitude of endotoxaemia and risk for postoperative complications. We studied the effects of a new endotoxin adsorber device (Alteco® LPS adsorber) in patients undergoing cardiac surgery with ECC, with special reference to safety and ease of use. Fifteen patients undergoing coronary artery bypass and/or valvular surgery were studied. In 9 patients, the LPS Adsorber was included in the bypass circuit between the arterial filter and the venous reservoir. Flow through the adsorber was started when the aorta was clamped and stopped at the end of perfusion. Flow rate was kept at 150 ml/min. Six patients served as controls with no adsorber in the circuit. Samples were taken for analysis of endotoxin, TNFα, IL-1ß and IL-6 as well as complement factors C3, C4 and C1q. Whole blood coagulation status was evaluated using thromboelastograpy (TEG) and platelet count. No adverse events were encountered when the adsorber was used in the circuit. Blood flow through the device was easily monitored and kept at the desired level. Platelet count decreased in both groups during surgery. TEG data revealed a decrease in whole blood clot strength in the control group while it was preserved in the adsorber group. Endotoxin was detected in only 2 patients and IL-1ß in 4 patients. IL-6 decreased in both groups whereas no change in TNF concentrations was found. C3 fell in both groups, but no changes wer found in C4 and C1q. The Alteco® LPS adsorber can be used safely and is easy to handle in the bypass circuit. No complications related to the use of the adsorber were noted. The intended effects of the adsorber, i.e. removal of endotoxin from the blood stream could not be evaluated in this study, presumably due to the small number of patients and the relatively short perfusion times.

Objective. To study the kinetics of lipid micro-emboli during cardiac surgery. Design. Eleven pigs were studied. Seven of these were put on extracorporeal circulation. A shed blood phantom consisted of blood, saline and radioactive triolein was added to the circuit. Both venous and arterial blood samples were taken at short intervals. Four animals were used to study renal kinetics without extracorporeal circulation. The same kind of shed blood phantom was infused into the ascending aorta. Samples were taken from the renal artery and vein. All samples were analyzed for radioactivity by scintillation counting. Results. A median 130-fold increase in radioactivity was seen in the blood and was quickly eliminated. Systemic first-pass wedging was found to be 62%. The first-pass elimination in the kidney was 77%. No radioactivity was found in urine. Conclusions. This study shows that the turnover of lipid micro-emboli is fast, and that the majority of the emboli are trapped on their first passage through the capillary system. No evidence was found of a renal excretion of these lipid emboli.

Sepsis-associated myocardial depression is associated with calcium desensitization and adrenergic uncoupling. We conducted a prospective randomized investigation on the effects of the calcium sensitizer, levosimendan, on hemodynamics, myocardial blood flow, and myocardial lactate metabolism during porcine endotoxemia. Twelve pigs were studied. Oxygen consumption was measured by indirect calorimetry, and myocardial blood flow was measured by retrograde thermodilution. Pulmonary, arterial, and venous indwelling catheters allowed measurements of cardiac output, vascular pressures, and blood sampling. Fluids were given at an average of 15 mL · kg−1 · h−1. After baseline measurements (0 min), an infusion of Escherichia coli LPS (2 &mgr;g · kg−1 · min−1) was started in all animals. Beginning at 100 min, six animals received levosimendan (50 &mgr;g · kg−1 · h−1), whereas six control animals received placebo. The study lasted for 300 min. All animals responded to endotoxin with pulmonary hypertension, a transient decrease in cardiac output, tachycardia, and systemic hypotension. Levosimendan infusion decreased systemic vascular resistance (P = 0.001), coronary vascular resistance (P = 0.004), and mean arterial (P < 0.001) and coronary perfusion pressures (P < 0.001), whereas pulmonary hypertension was unaffected. Heart rate progressively increased in both groups and was significantly higher in the levosimendan group (P = 0.048). Myocardial blood flow remained unchanged in both groups; however, 80 min after the start of levosimendan infusion, left ventricular myocardial hypoxia ensued, as evidenced by a negative myocardial lactate gradient (P = 0.01). Two control and five levosimendan animals died before the end of the study. Early administration of levosimendan during porcine endotoxemia increased heart rate, caused arterial vasodilation, and decreased coronary perfusion pressure, resulting in myocardial hypoxia.

Background: The brain-derived protein S100B has been shown to be a useful marker of brain injury of different etiologies. Cognitive dysfunction after cardiac surgery using cardiopulmonary bypass has been reported to occur in up to 70% of patients. In this study we tried to evaluate S100B as a marker for cognitive dysfunction after coronary bypass surgery with cardiopulmonary bypass in a model where the inflow of S100B from shed mediastinal blood was corrected for.Methods: 56 patients scheduled for coronary artery bypass grafting underwent prospective neuropsychological testing. The test scores were standardized and an impairment index was constructed. S100B was sampled at the end of surgery, hourly for the first 6 hours, and then 8, 10, 15, 24 and 48 hours after surgery. None of the patients received autotransfusion.Results: In simple linear analysis, no significant relation was found between S100B levels and neuropsychological outcome. In a backwards stepwise regression analysis the three variables, S100B levels at the end of cardiopulmonary bypass, S100B levels 1 hour later and the age of the patients were found to explain part of the neuropsychological deterioration (r = 0.49, p < 0.005).Conclusions: In this study we found that S100B levels 1 hour after surgery seem to be the most informative. Our attempt to control the increased levels of S100B caused by contamination from the surgical field did not yield different results. We conclude that the clinical value of S100B as a predictive measurement of postoperative cognitive dysfunction after cardiac surgery is limited.

BACKGROUND:Deep sternal wound infection is a serious and potentially lethal complication of cardiac surgery when performed through a median sternotomy. We describe the outcome of a new treatment strategy with C-reactive protein level-guided vacuum-assisted closure used at our department.METHODS:Data from 16 consecutive adult patients who had deep sternal wound infections after cardiac surgery were reviewed. Patients with superficial infection or sterile dehiscence were not included. All patients with postoperative deep sternal wound infections were treated with first-line vacuum-assisted closure therapy, followed by direct surgical closure. A purpose-built vacuum-assisted closure system consisting of polyurethane foam pieces and a special pump unit was used. The foam was placed in the wound after debridement of foreign material and necrotic tissue. The wound was covered with adhesive drape and connected to the pump unit, which was programmed to create a continuous negative pressure of 125 mm Hg in the wound cavity. Intravenous antibiotics were given according to tissue-culture results. The patients were immediately extubated after the operation. When ingrowth of granulation tissue was observed in all parts of the wound and the plasma C-reactive protein level showed a steady decline to 30 to 70 mg/L or less without confounding factors, such as tissue injuries or concomitant infections, the sternotomy was rewired, and the wound was closed.RESULTS:All patients were alive and free from deep sternal wound infection 3 months after the operation. The median vacuum-assisted closure treatment time until surgical closure was 9 days (range, 3-34 days), and the median C-reactive protein level at closure was 45 mg/L (range, 20-173 mg/L). The median hospital stay was 22 days (range, 12-120 days).CONCLUSIONS:Early vacuum-assisted closure treatment, followed by surgical closure guided by the plasma C-reactive protein level, is a reliable and easily applied new strategy in patients with postoperative deep sternal wound infection.

BACKGROUND:Stroke after cardiac surgery is a clinical problem with often fatal or disabling outcome. To assess severity and probable outcome in affected patients only from clinical and radiological examinations is difficult. The glial-derived protein S100B has been suggested to be a marker of cerebral ischemia, and increased blood concentrations of S100B have been shown to correlate with size of lesion and prognosis after stroke. We studied the validity of S100B as a predictor of size of brain lesion and median term outcome in a consecutive group of patients suffering from stroke after cardiac surgery. METHODS:During a period of 17 months, 20 patients with clinical signs of postoperative stroke were investigated with S100B measurement, sampled at 5, 15 and 48 hours after surgery. All patients were examined with computed tomography or magnetic resonance imaging to confirm the diagnosis, and the size of cerebral infarction was estimated from the radiological examinations. The patients were followed up for survival 24 to 39 months after surgery. RESULTS:S100B concentration in blood 48 hours after surgery correlated with the size of infarcted brain tissue (r = 0.68, p < 0.001). Nine patients had S100B levels exceeding 0.5 microg/L and a 2-year mortality of 78%, whereas the 11 patients with S100B below 0.5 microg/L had a mortality of 18%. CONCLUSIONS:Increased S100B in patients with a stroke following cardiac surgery correlate with the size of infarcted brain tissue. High S100B levels 48 hours after surgery have a negative predictive value for median term survival.

Understanding of the elastic pressure/volume (Pel/V) curve is still limited in health and disease. The aim of the present study was to elucidate the Pel/V curve and elastance of the respiratory system (ERS) lung (EL) and chest wall (ECW) in healthy pigs. Six young (20.8 kg) and seven adult (58.9 kg), anaesthetized, paralysed and ventilated pigs were studied. Pel/V curves were recorded at zero end-expiratory pressure (ZEEP) and at positive end-expiratory pressure (PEEP) up to 40 cmH2O with a computer controlled ventilator during an insufflation at a low, constant flow. Pel/V curves of the respiratory system showed a complex pattern in both young and adult pigs. During the insufflation, ERS decreased, increased, fell, and increased again. A second Pel/V curve recorded immediately after the first one showed lower elastance and only one early fall in ERS. ECW fell over the initial segment and was then nearly stable. Difference between 1st and 2nd curves reflected changes in EL caused by recruitment during the 1st insufflation. At PEEP, such signs of collapse and recruitment were reduced. A strong tendency to lung collapse contributes to a complex pattern of elastic pressure/volume curves. At low volumes and distending pressures the chest wall contributes significantly to changes in respiratory system elastance.

Background. Minor cerebral complications are common after cardiac surgery. Several biochemical markers for brain injury are under research; one of these is neuron-specific enolase (NSE). The purpose of this study was to investigate the release of this enzyme into the blood during and immediately after extracorporeal circulation and to evaluate the effect of hemolysis on this release.Methods. Sixteen patients scheduled for elective heart surgery were included in the study. blood samples for analysis of NSE and free hemoglobin in plasma were drawn before, during, and up to 48 hours after the end of extracorporeal circulation. The release of NSE from erythrocytes and ifs correlation to the release of free hemoglobin was studied by serial dilution and hemolysis in vitro.Results. The peri- and postoperative course was uneventful in all patients. Extracorporeal circulation initiated a release of NSE that reached a maximum 6 hours after the end of perfusion. Thereafter, the levels declined with an estimated t(1/2) of 30 hours. The concentration of free hemoglobin increased during the perfusion, with maximum levels at the end ol: perfusion, after which they fell rapidly to normal values. The in vitro study showed a strong linearity between the release of NSE and free hemoglobin after induced hemolysis,Conclusions. The increased levels of enolase at the end of cardiopulmonary bypass can, to a major part; be explained by the release from hemolysed erythrocytes, The value of NSE as a marker for brain injury in these situations is therefore doubtful.(C) 2000 by The Society of Thoracic Surgeons.

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.