Early thrombocytopenia is associated with an increased risk of mortality in patients with traumatic brain injury treated in the intensive care unit: a Finnish Intensive Care Consortium study.

BACKGROUND: Coagulopathy after traumatic brain injury (TBI) is associated with poor prognosis. PURPOSE: To assess the prevalence and association with outcomes of early thrombocytopenia in patients with TBI treated in the intensive care unit (ICU). METHODS: This is a retrospective multicenter study of adult TBI patients admitted to ICUs during 2003-2019. Thrombocytopenia was defined as a platelet count < 100 × 109/L during the first day. The association between thrombocytopenia and hospital and 12-month mortality was tested using multivariable logistic regression, adjusting for markers of injury severity. RESULTS: Of 4419 patients, 530 (12%) had early thrombocytopenia. In patients with thrombocytopenia, hospital and 12-month mortality were 26% and 48%, respectively; in patients with a platelet count > 100 × 109/L, they were 9% and 22%, respectively. After adjusting for injury severity, a higher platelet count was associated with decreased odds of hospital mortality (OR 0.998 per unit, 95% CI 0.996-0.999) and 12-month mortality (OR 0.998 per unit, 95% CI 0.997-0.999) in patients with moderate-to-severe TBI. Compared to patients with a normal platelet count, patients with thrombocytopenia not receiving platelet transfusion had an increased risk of 12-month mortality (OR 2.2, 95% CI 1.6-3.0), whereas patients with thrombocytopenia receiving platelet transfusion did not (OR 1.0, 95% CI 0.6-1.7). CONCLUSION: Early thrombocytopenia occurs in approximately one-tenth of patients with TBI treated in the ICU, and it is an independent risk factor for mortality in patients with moderate-to-severe TBI. Further research is necessary to determine whether this is modifiable by platelet transfusion.

Glycocalyx Degradation and Inflammation in Cardiac Surgery.

OBJECTIVE: Experimental inflammation induces degradation of glycocalyx. The authors hypothesized that inflammation is an important determinant of glycocalyx degradation in patients undergoing cardiac surgery with cardiopulmonary bypass (CPB). DESIGN: A prospective observational study. SETTING: Operation theater and intensive care unit of a university hospital. PARTICIPANTS: Two separate prospective patient cohorts. INTERVENTIONS: Blood samples were collected at 5 perioperative time points in the trial cohort (30 patients) and only preoperatively in the preoperative cohort (35 patients). Plasma syndecan-1 (biomarker of glycocalyx degradation), interleukin-6 (IL-6), IL-8, and IL-10 were measured. MEASUREMENTS AND MAIN RESULTS: In the trial cohort, preoperative ranges were as follows: 0.8-198 ng/mL for syndecan-1; 0-902 pg/mL for IL-6; 0-314.9 pg/mL for IL-8, and 0-2,909 pg/mL for IL-10. Seven out of 30 patients were outliers in terms of plasma concentrations of syndecan-1 and all cytokines preoperatively. The increase of syndecan-1 was 2.7-fold, and those of IL-6 and IL-8 were both 2.5-fold. The increase of IL-10 was modest. Plasma syndecan-1 correlated with all cytokines preoperatively (IL-6: R = 0.66, p < 0.001; IL-8: R = 0.67, p = 0.001; IL-10: R = 0.73, p < 0.001) as well as at 6 hours postoperatively (IL-6: R = 0.49, p = 0.006; IL-8: R = 0.43, p = 0.02; IL-10: R = 0.41, p = 0.03) and on the postoperative morning (IL-6: R = 0.57, p = 0.001; IL-8: R = 0.37, p = 0.06; IL-10: R = 0.51, p = 0.005) but not intraoperatively. The preoperative findings of the trial cohort could be confirmed in the preoperative cohort. CONCLUSIONS: In patients undergoing cardiac surgery with CPB, inflammation in terms of proinflammatory cytokines IL-6 and IL-8 and anti-inflammatory cytokine IL-10 is associated with glycocalyx degradation measured as plasma syndecan-1 concentrations.

The focus of temperature monitoring with zero-heat-flux technology (3M Bair-Hugger): a clinical study with patients undergoing craniotomy.

In the noninvasive zero-heat-flux (ZHF) method, deep body temperature is brought to the skin surface when an insulated temperature probe with servo-controlled heating on the skin creates a region of ZHF from the core to the skin. The sensor of the commercial Bair-Hugger ZHF device is placed on the forehead. According to the manufacturer, the sensor reaches a depth of 1-2 cm below the skin. In this observational study, the anatomical focus of the Bair-Hugger ZHF sensor was assessed in pre- and postoperative CT or MRI images of 29 patients undergoing elective craniotomy. Assuming the 2-cm depth from the forehead skin surface, the temperature measurement point preoperatively reached the brain cortex in all except one patient. Assuming the 1-cm depth, the preoperative temperature measurement point did not reach the brain parenchyma in any of the patients and was at the cortical surface in two patients. Corresponding results were obtained postoperatively, although either sub-arachnoid fluid or air was observed in all CT/MRI images. Craniotomy did not have a detectable effect on the course of the ZHF temperatures. In Bland-Altman analysis, the agreement of ZHF temperature with the nasopharyngeal temperature was 0.11 (95% confidence interval - 0.54 to 0.75) °C and with the bladder temperature - 0.14 (- 0.81 to 0.52) °C. As conclusions, within the reported range of the Bair-Hugger ZHF measurement depth, the anatomical focus of the sensor cannot be determined. Craniotomy did not have a detectable effect on the course of the ZHF temperatures that showed good agreement with the nasopharyngeal and bladder temperatures.

Transfusion Threshold of Hemoglobin 80 g/L Is Comparable to 100 g/L in Terms of Bleeding in Cardiac Surgery: A Prospective Randomized Study.

OBJECTIVE: Anemia is common after cardiac surgery and, according to some suggestive evidence, may be associated with increased bleeding, other morbidity, and mortality. However, transfusion of red blood cells (RBC) may cause adverse effects and increase cost. The authors hypothesized that the restrictive hemoglobin threshold (Hb of 80 g/L) may aggravate bleeding more than the higher Hb threshold (Hb 100 g/L). DESIGN: Prospective randomized trial. TYPE OF HOSPITAL: University Hospital of Helsinki, Finland. PARTICIPANTS: Eighty patients with written informed consent, scheduled for elective open-heart surgery were randomized in 2 groups. INTERVENTIONS: Two study groups had RBC transfusion threshold of either Hb 80 g/L or 100 g/L. These triggers were followed for a 24-hour period postoperatively. A medical follow-up was carried out for 7 days after surgery. MEASUREMENTS AND MAIN RESULTS: Rotational thromboelastometry (ROTEM) and conventional laboratory tests were performed to evaluate coagulation. There was no significant difference in bleeding or ROTEM parameters between the groups. Complication rate and Hb concentration after 7-day follow-up were not different between the groups, but Group 100 g/L had received twice the amount of RBC transfusions. CONCLUSION: Hb threshold of 80 g/L for RBC transfusion in cardiac surgery is comparable to 100 g/L in terms of bleeding and possibly short-term complications.

Decreased maximum clot firmness in rotational thromboelastometry (ROTEM®) is associated with bleeding during extracorporeal mechanical circulatory support.

BACKGROUND:: We aimed to characterize the coagulation disturbances which may increase the risk of bleeding, thrombosis or death shortly after implantation of an extracorporeal membrane oxygenation (ECMO) or ventricular assist (VAD) device. METHODS:: Antithrombotic treatment was started in 23 VAD and 24 ECMO patients according to the hospital protocol. Additionally, conventional laboratory testing, rotational thromboelastometry (ROTEM®) and platelet function analysis (Multiplate®) were performed at predetermined intervals. RESULTS:: Four out of twenty-four (16.7%) of ECMO patients and 6/23 (26.1%) of VAD patients had severe bleeding after the procedure. When all the patients were analyzed together, low maximum clot firmness (MCF) in ExTEM and FibTEM analyses was associated with severe bleeding (p<0.05) and low MCF in FibTEM with 30-day mortality. Low platelet count and hematocrit levels were also associated with severe bleeding. When VAD and ECMO patients were separated into different groups, the association between ROTEM® parameters, bleeding and survival was found only in limited time points. Four patients with VAD had cerebral ischemia indicative of thromboembolism. However, this had no significant correlation with ROTEM® or Multiplate® parameters. CONCLUSION:: Hypocoagulation shown by ROTEM® was associated with bleeding complications in patients with mechanical circulatory support. In contrast, hypercoagulation did not correlate with clinical thrombosis.

Stroke volume-directed administration of hydroxyethyl starch (HES 130/0.4) and Ringer's acetate in prone position during neurosurgery: a randomized controlled trial.

PURPOSE: General anesthesia in the prone position is associated with hypotension. We studied stroke volume (SV)-directed administration of hydroxyethyl starch (HES 130 kDa/0.4) and Ringer's acetate (RAC) in neurosurgical patients operated on in a prone position to determine the volumes required for stable hemodynamics and possible coagulatory effects. METHODS: Thirty elective neurosurgical patients received either HES (n = 15) or RAC (n = 15). Before positioning, SV measured by arterial pressure waveform analysis was maximized by fluid boluses until SV did not increase more than 10 %. SV was maintained by repeated administration of fluid. RAC 3 ml/kg/h was infused in both groups. Thromboelastometry assessed coagulation. Mann­Whitney U test, Wilcoxon signed-rank test, ANOVA on ranks, and a linear mixed model were applied. RESULTS: Comparable hemodynamics were achieved with the mean cumulative (SD) boluses of HES or RAC 240 (51) or 267 (62) ml (P = 0.207) before positioning, 340 (124) or 453 (160) ml (P = 0.039) 30 min after positioning, and 440 (229) or 653 (368) ml at the end of surgery (P = 0.067). The mean dose of basal RAC infusion was 813 (235) and 868 (354) ml (P = 0.620) in the HES and RAC group, respectively. Formation and maximum strength of the fibrin clot were decreased in the HES group. Intraoperative blood loss was comparable between groups (P = 0.861). CONCLUSION: The amount of RAC needed in the prone position was 25 % greater. The cumulative dose of 440 ml HES induced a slight disturbance in fibrin formation and clot strength. We suggest cautious administration of HES during neurosurgery.

Thromboelastometry during intraoperative transfusion of fresh frozen plasma in pediatric neurosurgery.

Normal blood coagulation is essential in pediatric neurosurgery because of the risk of abundant bleeding, and therefore it is important to avoid transfusion of fluids that might interfere negatively with the coagulation process. There is a lack of transfusion guidelines in massive bleeding with pediatric neurosurgical patients, and early use of blood compounds is partly controversial. We describe two pediatric patients for whom fresh frozen plasma (FFP) infusion was started at the early phase of brain tumor surgery to prevent intraoperative coagulopathy and hypovolemia. In addition to the traditional laboratory testing, modified thromboelastometry analyses were used to detect possible disturbances in coagulation. Early transfusion of FFP and red blood cells preserved the whole blood coagulation capacity. Even with continuous FFP infusion, fibrin clot firmness was near to critical value at the end of surgery despite increased preoperative values. By using FFP instead of large amounts of crystalloids and colloids when major blood loss is expected, blood coagulation is probably less likely to be impaired. Our results indicate, however, that the capacity of FFP to correct fibrinogen deficit is limited.

Comparison of hypertonic saline and mannitol on whole blood coagulation in vitro assessed by thromboelastometry.

BACKGROUND: Hypertonic saline (HS) is an alternative to mannitol for decreasing intracranial pressure in traumatic brain injury and before craniotomy. Both HS and mannitol may interfere with blood coagulation but their influence on coagulation has not been compared in controlled situations. Therefore, we evaluated different strengths of HS and 15% mannitol on blood coagulation in vitro. METHODS: Citrated fresh whole blood, withdrawn from 10 volunteers, was diluted with 0.9%, 2.5%, or 3.5% HS or 15% mannitol to make 10 vol.% and 20 vol.% hemodilution in vitro. The diluted blood and undiluted control samples were analyzed with thromboelastometry (ROTEM(®)) using two activators, tissue thromboplastin without (ExTEM(®)) or with cytochalasin (FibTEM(®)). RESULTS: In the FibTEM(®) analysis, maximum clot firmness (MCF) was stronger in the 2.5% HS group than in the mannitol group after both dilutions (P < 0.05). In the ExTEM(®) analysis, clot formation time (CFT) was more delayed in the mannitol group than in the 0.9%, 2.5%, or 3.5% HS groups in 20 vol.% hemodilution (P < 0.05). MCF was weaker in the mannitol group than in the other groups after 20 vol.% dilution (P < 0.05). MCF was also weaker in the 3.5% than in the 0.9% saline group after 20 vol.% dilution (P < 0.05). CONCLUSIONS: Blood coagulation is disturbed more by 15% mannitol than by equiosmolar 2.5% saline. This disturbance seems to be attributed to overall clot formation and strength but also to pure fibrin clot firmness. This saline solution might be more favorable than mannitol before craniotomy in patients with a high risk of bleeding.

Comparison of the effect of 6% hydroxyethyl starch and gelatine on cardiac and stroke volume index: a randomized, controlled trial after cardiac surgery.

BACKGROUND AND AIMS: The objective of this study was to find out the effect of various doses of hydroxyethyl starch (HES), gelatine or Ringer's acetate on cardiac and stroke volume index after cardiac surgery. MATERIAL AND METHODS: Three consecutive boluses (each 7 mL·kg(-1)) of either 6% HES 130/0.4, 4% gelatine, or Ringer's acetate solutions were administered to 45 patients postoperatively. The rate of infusions was adjusted according to haemodynamic measurements. Thereafter, infusion of the study solution (7 mL·kg(-1)) was continued for the following 12 hours. The total dose of study solution was 28 mL·kg(-1). RESULTS AND CONCLUSION: Mean (SD) cardiac and stroke volume indices were greater in the HES group [2.8 L·min(-1)·m(-2) (0.7), 34.1 (6.7) ml·m( -2)] than in the gelatine group [2.2 L·min(-1)·m( -2) (0.6), 25.8 (7.2) ml·m(-2)] after completion of 7 mL·kg(-1) of study solution. At this stage, the effect of gelatine did not differ from Ringer's acetate. After completion of 14 mL·kg(-1) and 21 mL·kg(-1) of colloids, similar cardiac and stroke volume indices were observed and the haemodynamic response was better in both colloid groups than in the Ringer's acetate group. No differences between groups were detected on the first postoperative morning. In the early postoperative phase after cardiac surgery, the effect of a single dose of HES solution on the haemodynamics was superior to the effect of gelatine or Ringer's acetate. However, after repeated administration of the study solutions, the haemodynamics in the two colloid groups appeared to be similar, but superior to the Ringer's acetate group.

Colloid solutions: a clinical update.

Albumin, dextran, gelatin, and hydroxyethyl starch (HES) solutions are colloids that efficiently expand the circulating blood volume. The administration of colloids restores the intravascular volume with minimal risk of tissue edema in comparison with crystalloid solutions alone. However, colloids are always given for surgical and critically ill patients. The type of the colloid, volumes applied, aggressiveness of fluid resuscitation, and the volume status at the initial phase of administration determine their clinical responses. The outcome after fluid resuscitation with various colloids in critically ill patients seems to be comparable according to systematic reviews. A randomized, adequately powered clinical trial comparing modern nonprotein colloid to albumin is still lacking. Rapidly degradable HES solutions have good hemodynamic effects, and the risk of adverse renal and coagulation effects, as well as allergic reactions, is minimal. The current investigation has also shown the beneficial effect of HES solution (especially HES 130/0.4) on inflammatory response, postoperative nausea and vomiting, and postoperative outcome. The indication of colloids with an assessment of the degree of hypovolemia and safety profiles should thus be taken into consideration before colloid administration.

Thromboprophylactic management in the neurosurgical patient with high risk for both thrombosis and intracranial bleeding.

PURPOSE OF REVIEW: Pharmacologic thromboprophylaxis is indicated in neurosurgery patients having high risk for venous or arterial thrombosis. The pharmacologic thromboprophylaxis, as well as temporary interruption of antithrombotic drugs because of surgery, and possible use of substitutive medication ('bridging therapy') are reviewed. RECENT FINDINGS: Pharmacologic thromboprophylaxis is used for most neurosurgical patients, but clinical practices vary a lot. There are only few reports of the management of neurosurgery patients having mechanical prosthetic heart valves, atrial fibrillation with comorbidities, history of deep venous thrombosis, thrombophilia, or coronary artery stent. These patients present a high risk for both thrombosis and bleeding as temporary interruption of antithrombotic medication as well as a substitutive medication would be indicated. Generally, the bridging therapy with low-molecular-weight heparin (LMWH) is a feasible approach in patients needing interruption of vitamin K antagonists. Experiences in neurosurgery patients emphasize carefully secured hemostasis and tailored dose as well as timing of LMWH. In patients with a recent coronary artery stent scheduled for neurosurgery, an individualized plan is needed. Bridging therapy for antiplatelet agents or novel oral anticoagulants is not yet settled. SUMMARY: Pharmacologic thromboprophylaxis, or bridging therapy, should be tailored according to the individual risks and the type of neurosurgery. The bleeding risk is likely minimized by allowing coagulation capacity to normalize preoperatively and by using reduced doses of LMWH starting relatively late after neurosurgery.

An evaluation of the epidural catheter position by epidural nerve stimulation in conjunction with continuous epidural analgesia in adult surgical patients.

BACKGROUND: The epidural stimulation test to confirm epidural catheter position has been described as being simple, fast, and reliable. We evaluated the feasibility of the epidural stimulation test and its potential in contributing to effective postoperative continuous epidural analgesia. METHODS: Thirty adult patients (ASA I-III) undergoing major abdominal surgery or thoracotomy were to receive continuous epidural analgesia at a thoracic level postoperatively. The epidural stimulation test was performed after catheter placement, after local anesthetic boluses, and during epidural analgesia, up to six times in each patient. Catheter positions were verified by epidurography (before start of epidural analgesia and again on the second postoperative day). RESULTS: Several technical issues (e.g., need to flush catheter with saline in order to maintain adequate stimulation during >25% of all measurements) and interpretation problems (e.g., interference of respiratory activity [n = 6]) made the implementation of the epidural stimulation test rather time consuming, both at the time of catheter placement and during epidural analgesia. Immediately after catheter placement (before test dose) the epidural stimulation test did not identify four of four catheters positioned outside the spinal canal. In addition, the initial epidural stimulation test indicated a possible intrathecal or paravertebral placement in 3 of 25 catheters correctly positioned in the epidural space. During 107 of 122 (88%) measurements with the catheter tip situated epidurally and with preceding or simultaneous administration of epidural local anesthetic, the epidural stimulation test elicited a motor response. Continuous epidural analgesia provided adequate pain relief in all 25 patients having positive epidurography. CONCLUSIONS: The epidural stimulation test was often associated with technical difficulties and interpretation problems. The role of the repeated use of the epidural stimulation test for quality assurance in patients undergoing postoperative continuous epidural analgesia remains undetermined.

Rapidly degradable hydroxyethyl starch solutions impair blood coagulation after cardiac surgery: a prospective randomized trial.

BACKGROUND: There is continuing concern about the effect of hydroxyethyl starch (HES) solutions on blood coagulation. Rapidly degradable HES solutions with more favorable effects on clot strength have therefore been developed. Because the risk of bleeding is increased after cardiopulmonary bypass, we examined whether these types of HES solutions could be administered after cardiac surgery without an alteration of coagulation. METHODS: Two new rapidly degradable HES solutions were compared with human albumin in 45 patients scheduled for elective primary cardiac surgery. After admission to the cardiac surgical intensive care unit, the patients were allocated in random order to receive either 15 mL/kg of HES solution with low molecular weight and low molar substitution (either 6% HES200/0.5 or 6% HES130/0.4) or 4% human albumin solution as a short-time (70-240 min) infusion. RESULTS: Clot formation time was prolonged and maximum clot firmness was decreased in thromboelastometry tracings after infusion of both HES solutions. This impairment in thromboelastometry tracings partly recovered (using InTEM and ExTEM coagulation activators) at 2 h after the completion of the study infusion. Platelet contribution to maximum clot firmness remained unaffected in all of the study groups. HES did not induce fibrinolysis. No changes in thromboelastometry tracings were observed after human albumin infusion. Chest tube drainage was comparable in the study groups. CONCLUSIONS: We conclude that a short-time infusion of rapidly degradable HES solutions after cardiac surgery produces impairment in fibrin formation and clot strength in thromboelastometry tracings. In this clinical setting, human albumin does not impair hemostasis.

The Janus face of thromboprophylaxis in patients with high risk for both thrombosis and bleeding during intracranial surgery: report of five exemplary cases.

BACKGROUND: The antithrombotic agents are usually interrupted in fear of bleeding complications before neurosurgery. However, the optimal schematic regimen of substitutive medication to prevent thromboembolic events after surgery is unsettled. METHODS: We report five complex neurosurgical cases with high risk for thromboembolism requiring thromboprophylaxis during craniotomy. CLINICAL FEATURE: In one patient with coronary bare metal stent and antiplatelet therapy, acetylsalicylic acid and clopidogrel was discontinued 5 and 11 days prior to surgery, respectively. Four other patients were on regular warfarin therapy due to previous deep venous thrombosis, pulmonary embolism, or mechanical aortic valve. Adjusted bridging therapy with low-molecular-weight heparin was applied in all cases. The patient with the coronary stent who was managed with reduced-dose dalteparin developed postoperative intracranial hemorrhage despite having platelet and fresh-frozen plasma transfusions, and the patient did not survive. Another patient with a history of lower-extremity deep venous thrombosis developed a postoperative intracranial hematoma but also a recurrence of left lower extremity deep venous thrombosis and had a delayed recovery. The other two patients with history of pulmonary embolism, and one patient having mechanical aortic valve and atrial fibrillation, recovered uneventfully when reduced doses of low molecular weight heparin bridging therapy were administered. CONCLUSION: Our observations confirm the complexity of balancing the risks of bleeding and thrombosis in neurosurgical patients on antithrombotic medication. In these patients, the individual bleeding risk is likely minimized by the administration of reduced doses of LMWH relatively late after craniotomy and by delaying the start of warfarin after surgery.

[Antithrombotic medication of cardiac patient in connection with surgery and minor operations]. / Sydänpotilaan antitromboottinen lääkitys leikkausten ja pientoimenpiteiden yhteydessä.

A major proportion of cardiac patients use long-time antithromobitic medication. It is not uncommon that these patients require surgery and operations. Discontinuation of antithrombotic therapy may be used to decrease risk of hemorrhage, but on the other hand the medication break will make the patient susceptible to thrombotic and thromboembolic complications. The attending physician must decide which is safer: to break the medication or to continue it. Often the best choice is a compromise of the above, i.e. application of a somewhat reduced compensatory antithrombotic therapy.

Effect of Albumin in Combination With Mannitol on Whole-blood Coagulation In Vitro Assessed by Thromboelastometry.

BACKGROUND: Albumin and mannitol may interfere with hemostasis, but their coinfluence is unclear. We aimed to determine the effects of albumin alone and in combination with mannitol or Ringer acetate (RAC) on hemostasis in crossover in vitro study. MATERIALS AND METHODS: From citrated fresh whole blood withdrawn from 10 volunteers, we prepared 2.5, 5, 10, 15, and 20 vol% dilutions of 4% albumin (Alb group). Each sample was thereafter diluted by 15% mannitol (Alb/Man group) or RAC (Alb/RAC group) at a ratio of 9:1. Using thromboelastometry, FibTEM (fibrinogen ROTEM) and ExTEM (extrinsic ROTEM) tests were performed. RESULTS: A 20 vol%, but not 2.5 to 15 vol% dilution of albumin caused a prolonged clot formation time, α-angle decrease, and maximum clot firmness (MCF) weakening compared with undiluted sample (P<0.05). Clot formation time prolonged more in Alb5/Man than in Alb5 and Alb5/RAC dilution (P<0.05). In Alb2.5/Man, Alb10/Man, and Alb15/Man, dilution α-angle was lower than in corresponding Alb/RAC and Alb-group dilutions (P<0.05). In ExTEM, MCF decreased similarly in every dilution of Alb/Man and Alb/RAC compared with Alb group (P<0.05). In FibTEM, MCF decreased more in Alb10/Man than in Alb10/RAC dilution (P<0.05). CONCLUSIONS: In up to 15 vol% dilutions, albumin alone did not impair hemostasis in vitro, but in combination with mannitol or RAC coagulation was disturbed similarly at most concentrations. There was some significant additional effect with mannitol at certain concentrations. Our results indicate that coadministration of mannitol and albumin needs further study in vivo.

Single-injection brachial plexus anesthesia for arteriovenous fistula surgery of the forearm: a comparison of infraclavicular coracoid and axillary approach.

BACKGROUND AND OBJECTIVES: The surgical site for the creation of an arteriovenous fistula at the lateral aspect of the distal forearm may be faster and more effectively blocked with the infraclavicular coracoid approach than with the axillary approach for brachial plexus block. METHODS: Sixty uremic patients scheduled for the creation of an arteriovenous fistula at the forearm were randomized to receive a single-injection brachial plexus block with 35 to 50 mL mepivacaine 0.95% with epinephrine using the infraclavicular coracoid approach (IC group) or the perivascular axillary approach (AX group). A distal muscular contraction elicited by a nerve stimulator at current <0.5 mA was used in all patients. RESULTS: At 30 and 45 minutes, complete loss of sensation was observed more often in group IC than AX in the cutaneous distribution of musculocutaneous nerve (62% v 30% [P < .05] and 69% v 40%, respectively [P < .05]), but at 60 minutes the difference was not statistically significant. In other areas, analgesia and motor block were achieved at a similar rate. In 3 patients surgery could not be performed under the block due to changes in schedule or the use of a brachial tourniquet. Patient satisfaction was equally high in both groups. CONCLUSIONS: Blockade of the musculocutaneous nerve developed faster with the infraclavicular coracoid approach than with the axillary approach. The infraclavicular coracoid approach may be preferable in patients scheduled for the creation of an arteriovenous fistula at the forearm.

Prone Versus Sitting Position in Neurosurgery-Differences in Patients' Hemodynamic Management.

OBJECTIVE: Neurosurgery in general anesthesia exposes patients to hemodynamic alterations in both the prone and the sitting position. We aimed to evaluate the hemodynamic profile during stroke volume-directed fluid administration in patients undergoing neurosurgery either in the sitting or the prone position. METHODS: In 2 separate prospective trials, 30 patients in prone and 28 patients in sitting position were randomly assigned to receive either Ringer acetate (RAC) or hydroxyethyl starch (HES; 130 kDa/0.4) for optimization of stroke volume. After combining data from these 2 trials, 2-way analysis of variance was performed to compare patients' hemodynamic profile between the 2 positions and to evaluate differences between RAC and HES consumption. RESULTS: To achieve comparable hemodynamics during surgery, a higher mean cumulative dose of RAC than HES was needed (679 mL ± 390 vs. 455 mL ± 253; P < 0.05). When fluid consumption was adjusted with weight, statistical difference was lost. Fluid administration did not differ between the prone and sitting position. Mean arterial pressure was lower and cardiac index and stroke volume index were higher over time in patients in the sitting position. CONCLUSIONS: The sitting position does not require excess fluid treatment compared with the prone position. HES is slightly more effective than RAC in achieving comparable hemodynamics, but the difference might be explained by patient weight. With goal-directed fluid administration and moderate use of vasoactive drugs, it is possible to achieve stable hemodynamics in both positions.