The bispectral index declines during neuromuscular block in fully awake persons.

UNLABELLED: Bispectral index (BIS) is an electroencephalographic variable promoted for measuring depth of anesthesia. Electromyographic activity influences surface electroencephalography and the calculation of BIS. In this study, we sought to determine the effect of spontaneous electromyographic activity on BIS. BIS was monitored in three volunteers by using an Aspect A-1000 monitor. The experiment was repeated in one volunteer. Electromyographic activity was recorded. Alcuronium and succinylcholine were administered. No other drugs were used. In parallel with spontaneous electromyographic activity of the facial muscles, BIS decreased in response to muscle relaxation to a minimum value of 33 and, in the repeated measurement, to a minimum value of 9 when total neuromuscular block was achieved. In two volunteers, no total block was achieved. BIS decreased to a minimal value of 64 and 57, respectively. In turn, recovery of BIS coincided with the reappearance of spontaneous electromyographic activity. During the entire experiment, the volunteers had full consciousness. BIS, assessed by software Version 3.31, correlates with spontaneous electromyographic activity of the facial muscles. BIS failed to detect awareness in completely paralyzed subjects. Thus, in paralyzed patients, BIS monitoring may not reliably indicate a decline in sedation and imminent awareness. IMPLICATIONS: The bispectral index (BIS) is an electroencephalographic variable intended for measuring depth of anesthesia. Electromyographic activity influences the calculation of BIS. We found that the administration of a muscle relaxant to unanesthetized volunteers decreases the bispectral index value. Thus, awareness in totally paralyzed patients cannot be excluded.

Early increase of procalcitonin after cardiovascular surgery in patients with postoperative complications.

OBJECTIVE: Type and frequency of postoperative abnormalities were registered after cardiovascular surgery to evaluate the aetiology and diagnostic value of increased concentrations of procalcitonin (PCT) and C-reactive protein (CRP) during the early postoperative period. DESIGN: Prospective, observational study. PATIENTS: Two hundred and eight patients undergoing coronary artery bypass grafting or valve replacement requiring cardiopulmonary bypass were monitored for 7 days postoperatively for various types of infectious or non-infectious complications. Plasma PCT and CRP levels were measured on day 1 and day 2 after surgery and, when increased, until day 7. RESULTS: More patients with PCT above 2 ng/ml on day 1 or 2 (n=55) had postoperative abnormalities (95%) than patients with lower PCT (59%). Specifically, the incidence of three or more criteria of the "systemic inflammatory response syndrome" was 45% versus 4% (area under the curve of the receiver operating characteristic 0.866); positive inotropic support was needed in 65% versus 9% (0.870); respiratory insufficiency (PaO(2)/FIO(2)<200) 38% versus 12% (0.704); proven and suspected bacterial infection 9% versus 1% (0.900) and 24% versus 1% (0.897), respectively. For CRP, the respective areas under the curve were all below 0.63, while all patients had elevated CRP levels, whether they had a complication or not. CONCLUSIONS: Elevated PCT, but not CRP, correlates with evidence of systemic inflammation and other complications early postoperatively after cardiac surgery. Although the PCT levels do not rise as quickly as the criteria of the systemic inflammatory response syndrome appear, they do reflect systemic inflammation. Early identification and quantification of a systemic inflammatory response may help reduce postoperative complications.

Serum procalcitonin monitoring for differential diagnosis of ventriculitis in adult intensive care patients.

The objective of our study was to assess the value of serum procalcitonin (PCT) monitoring in the differential diagnosis of ventriculitis in adult intensive care (ICU) patients. We analyzed 15 consecutive patients with ventriculitis in which a ventricular catheter had been inserted and contrasted these data with the observations in 10 patients with community-acquired bacterial meningitis. Cerebrospinal fluid (CSF) and blood samples were collected daily to assess serum PCT, C-reactive protein (CRP) and CSF leukocyte count. PCT levels were normal or slightly elevated in patients with ventriculitis with either positive or negative CSF bacterial culture but elevated in patients with bacterial meningitis. A PCT cut-off value of 1.0 ng/ml or more showed a specificity of 77% and a sensitivity of 68% for ventriculitis with positive CSF bacterial culture. Serum PCT levels reflected more accurately the time phases of disease during therapy. We conclude that the monitoring of serum PCT alone is not helpful for the differential diagnosis of ventriculitis, in contrast to that of bacterial meningitis. The value of PCT as an additional marker with which to assess the efficacy of therapy in ventriculitis is suggested, but requires further assessment.

The detrimental role of colloidal volume substitutes in severe ovarian hyperstimulation syndrome: a case report.

Although, the mechanisms for the development of ovarian hyperstimulation syndrome (OHSS) are still not clear, the symptoms usually correlate with the levels of serum estradiol and ovarian enlargement. We report a case, where the clinical course was unusually prolonged. When menstrual bleeding had already occurred, serum estradiol was less than 10 pg/ml and the ovaries were almost normal in size, the patient developed pleural effusion and a significant alteration in blood-coagulation. This was most likely caused by an over-infusion of hydroxyethyl starch (HES) over 10 days. The pleural effusion contained high levels of HES, reaching 74% of the plasma concentration as measured by a novel method after acidic hydrolysis of HES. Carbohydrates as dextran and HES are well known to interact with the blood-coagulation system. Increase capillary permeability, typical of OHSS, leads to loss of colloidal substances into the third space, where HES is slowly degraded and osmotic pressure is high. This might prolong and aggravate the urine of OHSS.

Randomized, placebo-controlled trial of the anti-tumor necrosis factor antibody fragment afelimomab in hyperinflammatory response during severe sepsis: The RAMSES Study.

OBJECTIVE: This study investigated whether treatment with the anti-tumor necrosis factor-alpha monoclonal antibody afelimomab would improve survival in septic patients with serum interleukin (IL)-6 concentrations of >1000 pg/mL. DESIGN: Multicenter, double-blind, randomized, placebo-controlled study. SETTING: Eighty-four intensive care units in academic medical centers in Europe and Israel. PATIENTS: A total of 944 septic patients were screened and stratified by the results of a rapid qualitative immunostrip test for serum IL-6 concentrations. Patients with a positive test kit result indicating IL-6 concentrations of >1000 pg/mL were randomized to receive either afelimomab (n = 224) or placebo (n = 222). Patients with a negative IL-6 test (n = 498) were not randomized and were followed up for 28 days. INTERVENTIONS: Treatment consisted of 15-min infusions of 1 mg/kg afelimomab or matching placebo every 8 hrs for 3 days. Standard surgical and intensive care therapy was otherwise delivered. MEASUREMENTS AND MAIN RESULTS: The study was terminated prematurely after an interim analysis estimated that the primary efficacy end points would not be met. The 28-day mortality rate in the nonrandomized patients (39.6%, 197 of 498) was significantly lower (p <.001) than that found in the randomized patients (55.8%, 249 of 446). The mortality rates in the IL-6 test kit positive patients randomized to afelimomab and placebo were similar, 54.0% (121 of 224) vs. 57.7% (128 of 222), respectively. Treatment with afelimomab was not associated with any particular adverse events. CONCLUSIONS: The IL-6 immunostrip test identified two distinct sepsis populations with significantly different mortality rates. A small (3.7%) absolute reduction in mortality rate was found in the afelimomab-treated patients. The treatment difference did not reach statistical significance.

Endothelin in septic patients: effects on cardiovascular and renal function and its relationship to proinflammatory cytokines.

OBJECTIVE: To determine the time course of big-endothelin (big-ET) and its relationship to proinflammatory cytokines and organ function in sepsis. DESIGN: Prospective analysis in patients meeting criteria of severe sepsis as part of a multicenter study (RAMSES) with an anti-tumor necrosis factor monoclonal antibody F(ab')2 fragment (afelimomab). SETTING: University hospital intensive care unit. PATIENTS: A total of 23 nontrauma patients with severe sepsis or septic shock and ten multiple trauma patients. Septic patients were randomized for additional experimental treatment when initial interleukin (IL)-6 serum level was above 1000 pg/mL. INTERVENTIONS: Randomized patients received 1.0 mg/kg afelimomab or placebo three times daily over 3 days in addition to standard treatment. In each patient, serial blood samples for plasma big-ET and cytokine determination as well as clinical data were collected over 28 days. MEASUREMENTS AND MAIN RESULTS: Significantly increased concentrations of circulating big-ET were found in patients with severe sepsis as compared with healthy subjects. In septic patients, big-ET plasma levels were higher than in multiple trauma patients, and were more elevated in randomized than in nonrandomized patients. At study entry (day 0), big-ET reached a peak concentration and significantly correlated with IL-6 (r2 = .43) and IL-8 (r2 = .44) in patients with severe sepsis. Moreover, big-ET levels in septic patients, pooled over all observation days, correlated positively with pressure-adjusted heart rate, central venous pressure, pulmonary artery pressure, and pulmonary vascular resistance and correlated inversely with creatinine clearance (r2 = .54, .54, .59, .40, and .51, respectively, p = .0001). In all randomized septic patients, pressure-adjusted heart rate decreased from day 0 to day 2 in parallel with big-ET; however, a significant decrease in big-ET (day 0 to day 2) was only found in patients additionally treated with afelimomab. CONCLUSIONS: In patients with severe sepsis, big-ET plasma levels are markedly increased, even above those of multiple trauma patients, in close relationship to IL-6 and IL-8, and with significant correlation to renal function and pulmonary vascular tone.

Fish oil-supplemented parenteral diets normalize splanchnic blood flow and improve killing of translocated bacteria in a low-dose endotoxin rat model.

OBJECTIVE: Intestinal ischemia decreases barrier function of the gut and enhances translocation of bacteria and toxins. Several studies indicate that fish oil can modulate prostaglandin formation and thus, regional blood flow and immune function. This study was performed to determine the effects of parenteral diets with omega-3 fatty acids on microcirculation and barrier function of the gut.0 DESIGN: Prospective, randomized, controlled animal study. SETTING: University laboratory. SUBJECTS: A total of 64 male Sprague-Dawley CD rats. INTERVENTIONS AND MEASUREMENTS: For 48 hrs, eight groups of eight rats each received total parenteral nutrition with four different types of lipids. The source of fat in group L was soybean oil only and in group L-M a mixture of soybean oil and medium-chain triglycerides. In groups FO-20 and FO-40, 20% or 40%, respectively, of the soybean oil in group L-M was replaced by fish oil. The other four groups received an additional continuous infusion of endotoxin (0.1 mg/100 g body weight per day) for the last 24 hrs. Blood flow was measured with microspheres, and translocation was determined by microbiological methods and instillation of radioactive-marked bacteria into the gut. MAIN RESULTS: In the animals without fish oil, the endotoxin application reduced the blood flow to the intestine approximately 25%. Animals with fish oil in their diets showed normal values. Translocation of gut bacteria was increased significantly in all endotoxin groups. However, less-viable bacteria could be detected in the animals with fish oil diets in their mesenteric lymph nodes and livers. CONCLUSIONS: In this model, diets enriched with fish oil abolish the endotoxin-induced decrease of nutritive blood flow to the gut and ameliorate the bactericidal defense of the splanchnic region. The lower count of viable bacteria in the fish oil groups is more related to an improved killing of translocated bacteria than a reduction of the translocation rate.

Changes in circulating blood volume after cardiac surgery measured by a novel method using hydroxyethyl starch.

OBJECTIVE: To determine the incidence and extent of postoperative blood volume (BV) changes in patients after elective cardiac surgery using a new method based on dilution of hydroxyethyl-starch. DESIGN: Prospective, clinical, and laboratory investigation. SETTING: University hospital intensive care unit. PATIENTS: A total of thirty-five patients undergoing cardiac surgery requiring cardiopulmonary bypass (CPB). INTERVENTIONS: Perioperative measurements of circulating BV, systemic hemodynamics, lactate, and collection of clinical data. MEASUREMENTS AND MAIN RESULTS: Measurements were made before and 1 to 72 hrs after CPB. The majority of patients undergoing cardiac surgery showed postoperative BV deficits compared with preoperative BV despite marked positive fluid balances after CPB. At 1 hr and 5 hrs after CPB, 18% and 33% of the patients, respectively, had BV deficits in the range of 0.5 L and 1.5 L, and in 3% to 10% of the cases, postoperative BV deficits exceeded 1.5 L. Concomitantly, at 5 hrs after CPB, mean arterial pressure was maximally reduced, and heart rate and lactate levels were maximally elevated. Thereafter, BV began to normalize, and at 24 hrs after CPB, pre- and postoperative mean BV were no longer significantly different. At 48 hrs and 72 hrs, even a BV surplus of more than 1 L could be observed in 6% and 14% of the patients, respectively. CONCLUSIONS: During the first hours after CPB, a high percentage of patients had significantly reduced BV and, concomitantly, showed cardiovascular dysfunction and hyperlactemia. Because hypovolemia is associated with increases of perioperative morbidity and mortality, rapid determination of BV is warranted to guide fluid therapy and optimize treatment in patients undergoing cardiac surgery.

Influence of pyrrolidine dithiocarbamate on the inflammatory response in macrophages and mouse endotoxin shock.

To analyze the immunomodulatory effect of pyrrolidine dithiocarbamate (PDTC) on the endotoxin (LPS) stimulated inflammatory response, we measured the LPS-stimulated cytokine and NO production in murine peritoneal macrophages, J774A.1 cells and human whole blood in the presence of PDTC (60 microM). PDTC significantly inhibited the production of nitrite, IL-1beta and IL-6 in these cells. TNFalpha release was stimulated in murine cells, but suppressed in human whole blood. We further investigated the influence of PDTC on mortality and cytokine release in mouse endotoxin shock. PDTC was i.p. injected 30 min prior to the induction of endotoxin shock in female NMRI-mice and survival was significantly improved as compared to controls (48% vs 20%, n=25 per group). Plasma concentrations of TNFalpha were slightly augmented while IL-6 levels were decreased in PDTC-treated animals as compared to controls, however, without reaching significance. We conclude that PDTC is a potent immunomodulatory substance that modulates the inflammatory response in vitro and reduces mortality in mouse endotoxin shock. The pathophysiological mechanisms of the protective effect of PDTC in vivo, however, appears to be pluripotent, comprising both antioxidative properties and the inhibition of NF-kB.

The natural elimination rate of procalcitonin in patients with normal and impaired renal function.

OBJECTIVE: Procalcitonin (PCT) plasma concentrations and its kinetic can be used as a diagnostic tool in critically ill patients and patients with sepsis. Since renal dysfunction is a frequent complication in these patients, and PCT is a protein with a low molecular weight, we have measured the half-life time of PCT after peak concentrations in patients with normal and impaired renal function. We also have analyzed the influence of patients age and gender on PCT elimination kinetics. DESIGN: Prospective clinical study. Renal dysfunction was assessed by plasma creatinine. The half-life time of PCT was evaluated 24 and 48 h after acute induction of PCT, when the focus of PCT induction has rapidly been eliminated. SETTING: Intensive care unit of our University hospital, a tertiary health care institution. PATIENTS: 69 patients were included into the study. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: The half-life-time of PCT was not significantly altered during renal dysfunction (26.1-33.1 h, 25-50 percentiles, creatinine clearance < 30 ml/min) when compared with normal renal function (22.3-28.9 h). It neither correlated with creatinine clearance (p=0.14), nor age (p=0.99) or gender (p=0.90, Pearson product-moment correlation). CONCLUSIONS: The data of the present study demonstrate that assessment of PCT kinetic can also be used for diagnostic and prognostic reasons in patients with renal dysfunction. It may, however, exceed 24 h also in patients with normal renal function. As to the present knowledge, renal secretion does not contribute as a main pathway to PCT elimination.

Volatile anesthetics differentially affect immunostimulated expression of inducible nitric oxide synthase: role of intracellular calcium.

BACKGROUND: Nitric oxide released by inducible nitric oxide synthase (iNOS) plays an important role in immune responses and systemic vasodilation in septic shock. Volatile anesthetics have been reported to interfere with signal transduction and gene expression. We studied the effect of volatile anesthetics on activity and expression of iNOS and potential mechanisms of action. METHODS: Nitrite release and iNOS expression were determined using the Griess reaction and Western and Northern blot techniques, respectively, in J774 murine macrophages stimulated with lipopolysaccharide and gamma-interferon in the absence and presence of various concentrations (0.25-2.0 minimum alveolar concentration [MAC]) of volatile anesthetics (i.e., halothane, enflurane, isoflurane, desflurane). Furthermore, potential interference of volatile anesthetics with specific signal transduction pathways was investigated. RESULTS: All volatile anesthetics, studied in a time- and dose-dependent manner, suppressed nitrite production and iNOS expression in J774 macrophages stimulated by lipopolysaccharide or gamma-interferon at clinically relevant concentrations. The inhibition was completely antagonized by ionomycin but unaffected by diacylglycerol, phorbol myristate acetate, and C2-ceramide. In contrast, in cells costimulated by lipopolysaccharide plus gamma-interferon, volatile anesthetics significantly increased nitrite production and iNOS expression independent of ionomycin and other mediators studied. CONCLUSIONS: Volatile anesthetics strongly reduced the mRNA and protein levels of iNOS and NOS activity after a single stimulation with lipopolysaccharide or gamma-interferon, most likely by attenuating intracellular calcium increase. Costimnulation with lipopolysaccharide plus gamma-interferon, however, results in maximum iNOS expression and activity, which are no longer inhibited but are potentiated by volatile anesthetics by unidentified mechanisms.

Comparison of procalcitonin (PCT) and C-reactive protein (CRP) plasma concentrations at different SOFA scores during the course of sepsis and MODS.

OBJECTIVES: The relation of procalcitonin (PCT) plasma concentrations compared with C-reactive protein (CRP) was analyzed in patients with different severity of multiple organ dysfunction syndrome (MODS) and systemic inflammation. PATIENTS AND METHODS: PCT, CRP, the sepsis-related organ failure assessment (SOFA) score, the Acute Physiology, Age, Chronic Health Evaluation (APACHE) II score and survival were evaluated in 40 patients with systemic inflammation and consecutive MODS over a period of 15 days. RESULTS: Higher SOFA score levels were associated with significantly higher PCT plasma concentrations (SOFA 7-12: PCT 2.62 ng/ml, SOFA 19-24: PCT 15.22 ng/ml) (median), whereas CRP was elevated irrespective of the scores observed (SOFT 7-12: CRP 131 mg/l, SOFT 19-24: CRP 135 mg/l). PCT of non-surviving patients was initially not different from that of survivors but significantly increased after the fourth day following onset of the disease, whereas CRP was not different between both groups throughout the whole observation period. CONCLUSIONS: Measurement of PCT concentrations during multiple organ dysfunction syndrome provides more information about the severity and the course of the disease than that of CRP. Regarding the strong association of PCT and the respective score systems in future studies we recommend evaluation also of the severity of inflammation and MODS when PCT concentrations were compared between different types of disease.

Postoperative plasma concentrations of procalcitonin after different types of surgery.

OBJECTIVE: Procalcitonin (PCT) and C-reactive protein (CRP) plasma concentrations were measured after different types of surgery to analyze a possible postoperative induction of procalcitonin (PCT), which might interfere with the diagnosis of bacterial infection or sepsis by PCT. DESIGN: PCT and CRP plasma levels as well as clinical symptoms of infection were prospectively registered preoperatively and 5 days postoperatively. SETTING: University hospital, in-patient postoperative care. PATIENTS: Hundred thirty patients were followed up; 117 patients with a normal postoperative course were statistically analyzed. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: PCT concentrations were moderately increased above the normal range in 32 % of patients after minor and aseptic surgery, in 59 % after cardiac and thoracic surgery, and in 95 % of patients after surgery of the intestine. In patients with an abnormal postoperative course, PCT was increased in 12 of 13 patients. CRP was increased in almost all patients. CONCLUSIONS: Postoperative induction of PCT largely depends on the type of surgery. Intestinal surgery and major operations more often increase PCT, whereas it is normal in the majority of patients after minor and primarily aseptic surgery. PCT can thus be used postoperatively for diagnostic means only when the range of PCT concentrations during the normal course of a certain type of surgery is considered and concentrations are followed up.

[Prothrombin time and thromboplastin time. On-site measurement of the prothrombin time and activated partial thromboplastin time of surgical patients with laser photometry]. / Prothrombinzeit und Thromboplastinzeit. On-site Messung der Prothrombinzeit und der Aktivierten Partiellen Thromboplastinzeit bei operativen Eingriffen mittels Laserphotometrie.

UNLABELLED: Turnaround time for analysis of prothrombin time (PT) and activated partial thromboplastin time (APTT) by standard laboratory methods ranges between 40 min and several hours. The delay in obtaining the test results limits their clinical utility for treatment of perioperative coagulation disorders and adequate anti-coagulation therapy. In this study, we compared on-site coagulation testing (OCT) of whole blood, which takes about 3 min, with standard laboratory plasma coagulation tests by our institutional laboratory (LAB) to assess the accuracy of the OCT in a clinical setting (abdominal and postcardiac surgery). METHODS: PT of 62 patients with abdominal surgery was measured intra- and postoperatively using both LAB (KC 40, Thromborel S, Centeon) and OCT (CoaguChek Plus, Boehringer Mannheim) systems. APTT was determined by LAB-(KC 40, Pathromtin, Centeon) and OCT-methods in 53 patients who underwent cardiac surgery requiring cardiopulmonary bypass. RESULTS: Linear regression demonstrated a strong and significant (p = 0.0001) correlation of OCT- and LAB-determinations both for PT (r = 0.92) and APTT (r = 0.91). For PT testing, bias analyses showed an agreement between OCT- and LAB-International Normalized Ratio (INR) (bias = 0.24; relative error = 14.6%) that was considered clinically acceptable, with 95% of the INR-differences lying between -0,26 and +0,74 (mean +/- 2 SD). Although commercial APTT-reagents usually differ in their sensitivity to heparin, we also found an acceptable agreement between OCT- and LAB-APTT values (bias = 6.7 s +/- 22 s; mean +/- 2 SD; relative error = 12%). CONCLUSION: On-site coagulation monitoring provides a rapid, convenient, and accurate assessment of coagulation that can both guide specific anti-coagulation therapy and optimize therapy control of coagulation disorders after cardiac and abdominal operations. As a consequence, OCT offers a valuable tool to reduce the inappropriate use of fresh frozen plasma and to improve cost-effectiveness.

Comparison of the effect of EMLA and semicircular subcutaneous anaesthesia in the prevention of tourniquet pain during plexus block anaesthesia of the arm.

In 54 patients who were to undergo surgery of the upper extremity in plexus block anaesthesia the effect of 5 g EMLA (group E) on tourniquet pain was examined and compared with the effect of a semicircular subcutaneous anaesthesia using 10 ml 0.25% bupivacaine (group B) or 10 ml 1% mepivacaine (group M). Among the patients with satisfactory brachial plexus analgesia allowing for surgery (n = 51), the incidence of tourniquet pain was not significantly different between groups E, M and B. Notably, there was no significant difference in the time of tourniquet application. We conclude that topical application of EMLA is as effective as a semicircular subcutaneous anaesthesia with mepivacaine or bupivacaine in the prevention of tourniquet pain during brachial plexus anaesthesia.

Modulation of mouse endotoxin shock by inhibition of phosphatidylcholine-specific phospholipase C.

During Gram-negative bacterial infections, lipopolysaccharide (LPS) interacts with monocyte/macrophage receptors, resulting in a host defense response. Activation of intracellular signal transduction pathways implicating various protein kinase and phospholipases is crucial in activating the transcription of genes encoding proinflammatory cytokines and inducible nitric oxide synthase (iNOS). In this article, we demonstrate that in mouse, endotoxin shock activation of phosphatidylcholine-specific phospholipase C (PC-PLC) plays a major role in controlling the inflammatory response. Inhibition of PC-PLC by the specific inhibitor tricyclodecan-9-yl-xanthogenate (D609) before LPS reduced the release of interleukin-1 beta, interleukin-6 and nitric oxide (NO) in vivo. In contrast, tumor necrosis factor-alpha serum levels were not altered by the pretreatment with D609. Consequently, survival from endotoxin shock of D609-treated animals was significantly improved compared with control animals (45% vs. 20%). Thus, inhibition of PC-PLC can reduce the inflammatory response to LPS and may serve as a novel approach to therapy of sepsis.

Procalcitonin--influence of temperature, storage, anticoagulation and arterial or venous asservation of blood samples on procalcitonin concentrations.

In this study we have analysed the influence of temperature and time of storage and of repeated freezing on procalcitonin plasma concentrations ex vivo. We have also analysed the difference of procalcitonin concentrations in arterial or venous blood samples and the influence of different anticoagulation techniques on procalcitonin concentrations (serum, EDTA-, lithium-heparin- or citrate plasma). At room temperature (25 degrees C) a loss of procalcitonin plasma concentrations of 6.4% +/- 2.6% (mean, 2 standard error of the mean) after 3 hours (4.6% +/- 5.2% at 4 degrees C) and 12.3% +/- 3.1% after 24 hours occurred (6.3% +/- 5.0% at 4 degrees C, n = 17 each). Comparing the procalcitonin concentrations of blood samples with different anticoagulants (n = 24 each), there was only a significant difference between procalcitonin concentrations in heparinized plasma and serum (+ 7.6%, difference of the mean). There was no significant influence of the blood sampling technique (arterial or venous line) and of repeated freezing/thawing cycles (up to 3 times) on the procalcitonin concentrations measured. Although the difference of sampling and storage of the blood on procalcitonin concentrations is not significant, multiple factors may act synergistically on the result of procalcitonin measurement. To keep variations of ex vivo conditions as minimal as possible, a standardized technique of anticoagulation, time and temperature of storage is recommended, e.g. the use of EDTA-plasma and storage at room temperature, when samples are measured within 4 hours after blood drawing.

Blood volume determination using hydroxyethyl starch: a rapid and simple intravenous injection method.

OBJECTIVE: To develop and evaluate a new method for blood volume measurements using hydroxyethyl starch as a dilution marker. DESIGN: Laboratory and clinical investigation. SETTING: Neurosurgical operating rooms and anesthesiological laboratories of a university hospital. PATIENTS: Twelve patients who underwent a neurosurgical operation. INTERVENTIONS: Anesthesia and operations were carried out by physicians who were not involved in the study. In addition, blood samples were drawn from 50 volunteers. MEASUREMENTS AND MAIN RESULTS: Blood volume measurements by the hydroxyethyl starch method were validated in vivo by comparison with a conventional carbon monoxide technique. Patients were intravenously injected with hydroxyethyl starch (100 mL) and received simultaneously an injection of carbon monoxide (50 mL) into a closed-circuit ventilation system. Blood samples obtained before and 5 mins after injection were analyzed for carboxyhemoglobin and glucose plasma concentrations after acidic hydrolysis of hydroxyethyl starch. Blood volume was calculated from the difference between glucose concentrations measured after hydrolysis in the plasma, before and after the addition of hydroxyethyl starch. In vitro, the hydroxyethyl starch method had an error and a precision of approximately 2%. In vivo, simultaneous measurements of blood volume using hydroxyethyl starch and carbon monoxide demonstrated a high correlation (r2 = .96, p < .001) between these methods. The mean difference between the two methods relative to their average value was 1.0 +/- 3.5%; the bias was 52.3 mL, and the 95% confidence interval was -64.0 to +168.7 mL. CONCLUSIONS: Blood volume determination by the hydroxyethyl starch method is accurate and rapid and may enhance perioperative monitoring of fluid and blood therapy.

Induction of nitric oxide synthase activity in phagocytic cells inhibited by tricyclodecan-9-yl-xanthogenate (D609).

1. The synthesis of nitric oxide (NO) by immune-stimulated murine phagocytic cells (J774) and the modulation of this synthesis by tricyclodecan-9-yl-xanthogenate (D609), a specific inhibitor of phosphatidylcholine-specific phospholipase C (PC-PLC), was investigated. D609 dose-dependently suppressed production of NO, as measured by the release of nitrite and nitrate, in response to lipopolysaccharide (LPS) and interferon-gamma (IFN-gamma) in intact cultured cells with an IC50 of approximately 20 micrograms ml-1. D609 at 40 micrograms ml-1 completely abrogated immune-stimulated nitrite production. 2. The inhibitory effects of D609 on nitrite production were time-dependent and restricted to the first 18 h post-stimulation. D609 did not inhibit nitrite production in the cytosol of immune-stimulated phagocytes. 3. These findings indicate that the xanthogenate, D609, is a potent inhibitor of the induction of NO-synthase activity in immune-stimulated phagocytes. Furthermore, since D609 has been demonstrated to inhibit PC-PLC specifically, our findings suggest that the activation of this enzyme by LPS and IFN-gamma is a proximal step in the signal transduction of inducible NO-synthase in phagocytic cells.