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U Schött

Publications and source records attributed to U Schött.

15 recordsLinked to original sources
PubMed2002

The effects of platelet apheresis in total hip replacement surgery on platelet activation.

BACKGROUND: Autologous platelet rich plasma (PRP) harvest with autotransfusion devices has been used for 10 years in cardiac surgery and recently in orthopedics as a blood saving method. The quality of the harvested platelets has not been adequately examined, in part because of methodological difficulties in studying platelet function during surgery. METHODS: Twenty patients undergoing primary total hip replacement (THR) were studied. Ten patients underwent an immediate preoperative platelet apheresis to obtain concentrated platelet rich plasma (c-PRP). The other 10 patients not undergoing apheresis were allocated to a control group. Platelet activation was evaluated as the population expressing P-selectin on the surface of platelets in the c-PRP and in blood samples collected pre-, per- and postoperatively. The method used was flow cytometry. RESULTS AND CONCLUSIONS: A minor population of activated platelets was found to be circulating in the patients' blood, with a highly significant difference between patients (P = 0.005), and with a range of 1-23% in peroperative activation. PRP harvest did not significantly alter platelet activity. The platelet apheresis procedure did not inhibit platelet function in the c-PRP, as judged by a high proportion of platelets that could be activated in ADP stimulation experiments (mean value +/- SD 86% +/- 7.5%).

Adenosine Diphosphate↗
PubMed2000

Preoperative platelet-rich plasmapheresis and hemodilution with an autotransfusion device in total hip replacement surgery.

The effectiveness of both preoperative autologous donation (PAD) and intraoperative autotransfusion (IAT) with an autotransfusion device has recently been questioned. Preoperative apheresis, with separation of concentrated platelet rich-plasma (c-PRP) and erythrocyte concentrate (ERC), represents an aggressive use of the autotransfusion device. Can such a procedure replace PAD in total hip replacement surgery (THR)? Eighty patients undergoing THR were investigated in a prospective and randomized study. Forty patients underwent PAD, and 2 units of ERC + plasma were retrieved within 4 weeks preoperatively. Another 40 patients underwent an immediately preoperative apheresis with a concomitant hemodilution with 4% albumin, retrieving c-PRP (30% of the platelet pool) and 2 units of ERC. Both groups used IAT up to 2 hours postoperatively, with 3% dextran-60 as a plasma substitute according to our standard of care. There were no differences in blood loss, B-hemoglobin or allogeneic transfusions between the groups: 85% of the patients did not receive allogeneic blood. Both apheresis and reinfusion of c-PRP had minor impact on the coagulation parameters. Platelet count increased slightly but significantly (P<0.05) from 154 to 179 x 10(9)/L after the c-PRP at wound closure. Preoperative apheresis with an autotransfusion device, separating platelet-rich plasma and erythrocyte concentrate, is a useful alternative for patients who are unable to utilize the PAD technique for either religious or practical reasons.

Aged↗
PubMed2000

Tranexamic acid reduces blood loss in total hip replacement surgery.

UNLABELLED: Intraoperatively administered, tranexamic acid (TA) does not reduce bleeding in total hip replacement (THR). Therefore, its prophylactic use was attempted in the present study because this has been shown to be more effective in cardiac surgery. We investigated 40 patients undergoing THR in a prospective, randomized, double-blinded study. Twenty patients received TA given in two bolus doses of 10 mg/kg each, the first just before surgical incision and the second 3 h later. In addition, a continuous infusion of TA, 1.0 mg. kg(-1). h(-1) for 10 h, was given after the first bolus dose. The remaining 20 patients formed a control group. Both groups used preoperative autologous blood donation and intraoperative autotransfusion. Intraoperative bleeding was significantly less (P: = 0.001) in the TA group compared with the control group (630 +/- 220 mL vs 850 +/- 260 mL). Postoperative drainage bleeding was correspondingly less (P: = 0.001) (520 +/- 280 vs 920 +/- 410 mL). Up to 10 h postoperatively, plasma D-dimer concentration was halved in the TA group compared with the control group. One patient in each group had an ultrasound-verified late deep vein thrombosis. In conclusion, we found TA, administrated before surgical incision, to be efficient in reducing bleeding during THR. IMPLICATIONS: In a prospective, double-blinded study of 40 patients undergoing total hip replacement, the preoperative administration of tranexamic acid reduced bleeding by 35%, probably by decreasing induced fibrinolysis. Whether tranexamic acid therapy can replace predonation of autologous blood or intraoperative autotransfusion requires further study.

Aged↗
PubMed1999

Sonoclot coagulation analysis: a study of test variability.

OBJECTIVE: To test the reproducibility of Sonoclot coagulation analysis (SCA; Sienco Inc, Morrison, CO). The authors wished to determine if the mix/release of the preloaded celite activator in standard Sono-cuvettes could be responsible for the high variation coefficients for SCA parameters with citrated whole blood and if citrated whole blood is optimal for SCA. DESIGN: A prospective trial. SETTING: A large academic teaching medical center. PARTICIPANTS: Eight healthy volunteers. INTERVENTIONS: Repeated blood sampling was performed through indwelling radial artery catheters. Seven different Sonoclot analyzers were used to test seven different types of analysis procedures in the volunteers, involving activators of different types and amounts and in different forms, and the use of citrated or native whole blood. MEASUREMENTS AND MAIN RESULTS: Two-way and one-way ANOVA, variance, variance analysis, and Tukey's test were used to evaluate differences in SCA methods and volunteer influence. A high variance, with SDs up to 200% of the median values of the SCA parameters with recalcified citrated blood and the standard Sono-cuvette, was confirmed. SCA with native blood and/or the use of other types of preloaded activators, ie, kaolin, significantly (p < 0.05) reduced this variance. Repeated SCAs further reduced the variance to 10% to 35% of the variance for a single analysis (standard cuvette and native blood). CONCLUSION: Improvement of the activator in the Sonocuvette, use of native whole blood, and repeated Sonoclot analyses reduced the previously reported high variability of this instrument.

Adult↗
PubMed1995

Sonoclot coagulation analysis and plasma exchange in a case of meningococcal septicaemia.

On the basis of a patient with fulminant meningococcaemia and severe disseminated intravascular coagulation (DIC) syndrome, the diagnostic potential of a clot impedance test - Sonoclot coagulation analysis - was used to evaluate plasma exchange. A 17-yr-old girl was treated for a fulminant infection with Neisseria meningitidis in our intensive care unit. She developed severe DIC. Whereas platelet administration caused immediate arterial oxygen desaturation necessitating ventilatory support, plasma exchange improved pulmonary and mental function. Three separate exchanges all improved haemostasis. Sonoclot analysis was used together with routine coagulation analyses to evaluate this DIC treatment. Sonoclot signs, such as lack of the shoulder and peak, prolonged shoulder-peak interval and peak time predicted clinical bleeding manifestations (haematuria, haemoptysis, epistaxis) and were improved by platelet transfusion and plasma exchange. Plasma exchange was successful even at a very low platelet count of < 23 x 10(9).L-1. Sonoclot coagulation analyses were normalised several days before routine coagulation analyses. The Sonoclot gave additional information to routine coagulation studies, correctly indicated insufficient haemostasis and predicted a positive outcome. Also, plasma exchanges and platelet transfusions could be controlled in the management of DIC.

Adolescent↗
PubMed1995

Perioperative autotransfusion and functional coagulation analysis in total hip replacement.

Functional coagulation analyses like Sonoclot and thromboelastography have not been evaluated during perioperative autotransfusion. We have prospectively studied three different transfusion regimes in 45 patients undergoing total hip arthroplasty. Blood losses were replaced either with heterologous erythrocyte concentrate (group I), intra- and postoperative autotransfusion of blood salvaged with cellsaver technique (group II) or predonated autologous erythrocyte concentrates together with salvaged blood (group III). Routine and functional coagulation analyses with a Sonoclot were performed preoperatively, 6 hours postoperatively (6 h), day 1-5 and 10. An early postoperative hypo- and late postoperative hypercoagulative phase could be detected with Sonoclot signs of platelet function and fibrin deposition in all groups. Sonoclot coagulation analyses better correlated to both blood loss and dextran dosage than APTT and platelet count in the routine coagulation analyses. Functional coagulation analysis has a potential use in individualizing plasmasubstitution and thromboprophylaxis regimes during autotransfusion in THR.

Blood Coagulation↗
PubMed1995

Desmopressin acetate does not reduce blood loss during total hip replacement in patients receiving dextran.

The blood loss-reducing effect of desmopressin during dextran therapy was studied in a double-blind fashion in 79 elderly but otherwise healthy patients with preoperative normal bleeding time undergoing total hip replacement for primary coxarthrosis. An infusion of desmopressin (0.3 microgram/kg body weight) or placebo was randomly administered immediately after administration of spinal anaesthesia and six hours later. Haemostasis was evaluated on the basis of vWF: ristocetin cofactor activity, FVIII: C activity, human tissue plasminogen activator (tPA) plasminogen activator inhibitor type (PAI), beta-thromboglobuline (beta TG) and a clot impedance test (Sonoclot). There were no statistically significant differences (P > 0.05) in mean blood loss or transfusion requirements between the placebo and the desmopressin group. There was a significantly increase (P < 0.01) both in vWF: ristocetin cofactor and in FVIII: C activity after both infusions of desmopressin compared with placebo. There was no significant difference in beta TG, tPA, PAI or Sonoclot analysis between the groups. In conclusion, desmopressin did not reduce blood loss in patients undergoing total hip replacement.

Aged↗
PubMed1988

Hemodynamic effects of colloid concentration in experimental hemorrhage: a comparison of Ringer's acetate, 3% dextran-60, and 6% dextran-70.

Hemodynamic effects of iso-oncotic 3% dextran-60, 6% dextran-70, and Ringer's acetate were compared in 28 male pigs (25 to 30 kg) subjected to experimental trauma and hemorrhage. The animals were kept anesthetized with 75% N2O/25% O2, 0.8% halothane. Hemodynamic and respiratory conditions were allowed to stabilize for one hour preoperatively (baseline data). After surgical trauma (arthroplasty), three 0.5 L of arterial blood samples were withdrawn and replaced with autologous red cells mixed with one liter of 3% dextran-60 in one group 1 (n = 9), one liter of 6% dextran-70 in group 2 (n = 10), and 3 L of Ringer's acetate in group 3 (n = 9). Pulmonary capillary wedge pressure (WP) was kept at baseline level for a further 10 h with infusion of the respective fluid; for this purpose, groups 1 through 3 needed additional infusions of 0.8 +/- 0.3, 0.5 +/- 0.4, and 5.3 +/- 3 (SD) L, respectively. Group 1 showed the highest jejunal capillary blood flow at 10 h and the lowest intragroup variations in hemodynamic and respiratory data. Group 2 had the highest pulmonary arterial pressures and group 3 had the lowest colloid oncotic and arterial BP and left ventricular volume indices. In group 3, the Hct and serum albumin indicated insufficient plasma volume replacement. This group had a significantly larger (p less than .05) amount of tissue water in skin, skeletal muscle, and jejunum than the other groups; no significant difference in lung or heart muscle water was found between the groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

In vivo production of thromboxane and prostacyclin in patients following total hip arthroplasty.

The in vivo production of thromboxane and prostacyclin was studied by measurements of their major urinary metabolites in eight patients undergoing total hip arthroplasty. Specific methods based on gas chromatography-mass spectrometry were used to measure the urinary excretion of 2,3-dinor-TxB2 and 2,3-dinor-6-keto-PGF1 alpha. The excretion of these metabolites increased about 10-fold during the intra and immediate postoperative period and 4 days after surgery was still higher than during the preoperative period. The increased thromboxane formation reflects probable activation of platelets whereas the increased prostacyclin could be part of a vascular defense against induced thrombotic activity. These findings may have pathophysiological implications.

6-Ketoprostaglandin F1 alpha↗
PubMed1987

Blood substitution and complement activation.

Complement activation was studied in 45 patients undergoing total hip arthroplasty under epidural anesthesia. The patients were randomly allocated to three groups. In Group I blood loss was replaced with microaggregate-poor erythrocyte concentrate (SAGM-ERC) plus 3% dextran-60 as plasma substitute, and postoperative analgesia was maintained with intramuscular ketobemidone. In Group II blood loss was replaced as in Group I, but epidural anesthesia was prolonged 12 h postoperatively and kept at a level of T4 with 0.5% bupivacaine. In Group III blood loss was replaced with non-frozen stored plasma plus SAGM-ERC, and postoperative analgesia was maintained with ketobemidone as in Group I. All groups received pre- and postoperative thrombo-prophylaxis with dextran. The plasma concentration of C3a-des-arginine (C3a-desArg) was measured by radioimmunoassay preoperatively, immediately after operation and 3, 6 and 18 h postoperatively. No significant differences in plasma C3 and C4 were found between the groups. C3a-desArg was significantly (P less than 0.01) increased up to 6 h postoperatively in Group III compared with both the preoperative value and Groups I and II. It is demonstrated that infusion of plasma can enhance or initiate endogenous complement activation. Blood component therapy with SAGM-ERC and 3% dextran-60, on the other hand, did not significantly increase the plasma level of C3a-desArg irrespective of the type of postoperative analgesia.

Aged↗
PubMed1986

Influence of naloxone infusion on analgesia and respiratory depression following epidural morphine.

The influence of two different concentrations of iv naloxone infusion on the analgesia and adverse effects of epidural morphine were compared in a double-blind, placebo-controlled study. Forty-five patients undergoing gallbladder surgery were provided postoperative analgesia by 4 mg epidural morphine; they then received an iv infusion over a 12-h period consisting of either 5 micrograms X kg-1 X h-1 naloxone, 10 micrograms X kg-1 X h-1 naloxone, or saline. Pain relief was assessed by hourly visual analog scoring (VAS) and by direct questioning of the patient. Requirement of additional analgesia was noted. Respiratory frequency was monitored every 15 min and arterial blood gases were analyzed every 2 h for 24 h. Peak expiratory flow (PEF) was recorded 6 and 24 h postoperatively. Steady-state kinetics of naloxone were determined by a modified radioimmunoassay (RIA) method. All patients had good to excellent postoperative pain relief. Naloxone, 5 micrograms X kg-1 X h-1, did not appear to have any effect on epidural morphine analgesia. However, naloxone infusion at the rate of 10 micrograms X kg-1 X h-1 reduced the duration of analgesia by about 25%, and more frequent injections of epidural morphine were required to give effective analgesia. Complete reversal of analgesia was not seen in any patient. A dose-related stimulatory effect on respiratory frequency was noted in the groups receiving naloxone. PaCO2 values also were better in these groups as compared to values in the placebo group.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Three per cent dextran-60 as a plasma substitute in blood component therapy. I. An alternative in surgical blood loss replacement.

Microaggregate-poor erythrocyte concentrate with 3% dextran-60 as a plasma substitute was compared with microaggregate-poor whole blood for replacement of intra-operative and immediately postoperative blood loss. Sixty patients undergoing total hip arthroplasty randomly received either of these two forms of therapy. In accordance with the clinical routine of our orthopedic department, an infusion of 500 ml of 6% dextran-70 (Macrodex) was given as thrombo-prophylaxis in both groups. Use of 3% dextran-60 as a plasma substitute in blood component therapy for surgical hemorrhage of up to 50% of the calculated blood volume caused no increase in bleeding tendency or frequency of postoperative hematoma compared with whole blood replacement. Plasma protein levels were low immediately postoperatively in patients given the dextran, but from the 4th postoperative day onward there was no difference between the groups. Applied in clinical practice, this would be efficient in saving plasma for other urgent purposes.

Aged↗
PubMed1985

Three per cent dextran-60 as a plasma substitute in blood component therapy. II. Comparative studies on pre- and postoperative blood volume.

Microaggregate-poor erythrocyte concentrate with 3% dextran-60 as a plasma substitute was compared with microaggregate-poor whole blood for replacement of intra-operative blood loss. Their blood volume-conserving effects were studied by sequential blood volume determination with radioactive technetium (99mTc) in 19 patients undergoing total hip arthroplasty. Pre-operatively there was no difference in blood volume between the groups. Immediately after surgery and on the 2nd postoperative day there was no difference in total blood volume. Blood component therapy with 3% dextran as a plasma substitute is an efficient principle for intra-operative blood loss replacement at hip operations.

Aged↗