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At least 487 records · Page 27Linked to original sources
PubMed1985

Hemostasis in plastic surgical patients.

Every surgeon should be acutely cognizant of the importance of the evaluation and treatment of bleeding abnormalities. Dependence upon a normal platelet and clotting system is a requirement for surgery. Significant emphasis should always be placed on a detailed history and physical examination. Routine laboratory evaluations should be regarded as a screening method and be augmented by suspicion raised during the history and physical examination. The importance of a basic understanding of hemostasis and the correction of abnormalities in hemostasis is essential to the practicing surgeon.

Blood Coagulation↗
PubMed1984

Heparin elimination and hemostasis in hemodialysis.

The heparin concentrations at the end of dialysis and the post-dialysis hemostasis were studied in 16 patients in a chronic hemodialysis program. In 8 of the patients, the heparin half-life values after dialysis were determined as well. The heparin doses were calculated as 90 IU/kg body-weight, administered in a standardized way. The heparin concentrations and the half-life values varied between 0.12-0.94 IU/ml and 29-114 minutes respectively, indicating that the heparin administration must be individually modelled. The hemostasis, measured by the arterial pressure times, was positively correlated to the heparin concentrations. Heparin levels less than 0.3 IU/ml were regularly associated with pressure times less than 10 minutes and no remaining heparin activity two hours after dialysis. In order to minimize the risk of both bleeding and clotting complications at the end of and after dialysis, a heparin concentration of approximately 0.25 IU/ml should be aimed for.

Adult↗
PubMedDate not supplied

Tourniquet hemostasis. A clinical study.

A clinical study was undertaken to evaluate the pneumatic tourniquet setting required for adequate hemostasis in extremity surgery. After induction of anesthesia, the pneumatic tourniquet pressure at which the peripheral pulse disappeared was determined using a Doppler stethoscope. For upper-extremity procedures 50 mm Hg was added to this setting to allow for collateral circulation and blood pressure changes. An average pressure of 189.9 +/- 24.1 mm Hg was used for the upper-extremity group (44 patients), and an average of 231.0 +/- 26.5 mm Hg was used for the lower-extremity group (40 patients). Maximum pressures utilized were 255 mm Hg in the upper extremity and 305 mm Hg in the lower extremity. This simple, noninvasive technique uses tourniquet pressure settings well below those recommended in standard reference texts without sacrificing the adequacy of hemostasis to obtain a "bloodless field."

Adolescent↗
PubMed1983

The effect of serotonin inhibition on initial microvessel hemostasis and platelet aggregation in vivo.

The role of serotonin (5-HT) in initial microvascular hemostasis is not fully understood. This study was made to evaluate the effect on hemostatic plug formation and laser-induced arteriolar microembolism of different substances which counteract the effect of 5-HT. Hemostatic plug formation time and stability was measured in the rabbit mesenteric microcirculation and laser-induced embolism in the rabbit ear chamber. Ketanserine, a selective 5-HT2-receptor blocker shortened arteriolar hemostatic plug formation time. Dihydroergotamine, an unselective blocker (with 5-HT-and alpha-adrenergic receptor affinity) increased venular hemostatic plug formation time and also decreased the hemostatic plug stability. Laser-induced platelet embolism was unaltered after both ketanserine and dihydroergotamine administration. The magnitude of these changes seems to exclude an important effect of 5-HT in initial microvessel hemostasis or on platelet activity.

Animals↗
PubMed1982

The control of hemostasis. Role of endothelium in the regulation of inhibitory and catabolic pathways.

The role of the microvascular endothelium in the integration of inhibitory and catabolic pathways of hemostasis is discussed in light of recent findings of direct biochemical links between endothelium and regulatory plasma proteins. These findings include the following: (1) On the vascular endothelium, a cofactor for antithrombin III (with an activity comparable to stationary phase heparin) catalyzes thrombin inhibition in vivo. (2) A second cofactor on endothelium binds thrombin in a manner that enhances by several orders of magnitude the ability of thrombin to activate protein C. (3) Activated protein C has both anticoagulant and catabolic activities; anticoagulant activity results from the susceptibility of factors Va and VIIIa to inactivation by activated protein C, whereas catabolic activity arises from the stimulation by activated protein C of the release from endothelium of fibrin-dependent plasminogen activator. (4) Because it requires fibrin as a cofactor, the plasminogen activator lyses clots without provoking fibrinogenolysis. Location of these activities on endothelium separates coagulation in time and space from catabolic pathways, and provides for their expression after the initiation of hemostasis.

Antithrombins↗
PubMed1980

Tests for hemostasis and their relevance to venous thrombosis.

The authors have tried to determine which patients were at risk of venous thrombosis. They chose 10 tests for hemostasis that might be of value in predicting those patients who were at risk. The tests were used in two groups of patients: one group in a respiratory intensive care unit and another group of patients about to undergo a major spinal operation. The tests were those for measuring: platelet count, prothrombin time, activated partial thromboplastin time, platelet thromboplastic activity (platelet factor 3), plasma clotting time, and concentrations of fibrinogen, plasminogen, antithrombin-III, alpha-1-antitrypsin and platelet fibrin degradation products (FDP). A diagnosis of thrombosis was made by three techniques: radioactive fibrinogen accumulation in the developing thrombus, impedance plethysmograhpy and ascending venography. The only test for hemostasis that discriminated between patients with and without thrombosis was the level of circulatory FDP. Several of the tests showed pronounced changes within the normal range following development of thrombosis and even before its detection. Therefore, none of the tests was truly predictive. A detailed discussion of the performance and interpretation of impedance plethysmography is presented.

Adult↗
PubMed1978

Impairment of hemostasis in patients with severe hemophilia. Failure of diphenhydramine, chlorpromazine, and guaifenesin.

Twenty-three patients with severe hemophilia were given single or multiple doses of diphenhydramine hydrochloride, chlorpromazine hydrochloride, or guaifenesin to test their effects on hemostasis. In contrast with earlier studies with aspirin, bleeding times were not prolonged after ingestion of these three drugs. No patient had hemorrhage because of the drugs, and none recalled excessive bleeding following drug ingestion. These results greatly extend the clinical implications of prior observations carried out in normal subjects demonstrating that many antiplatelet drugs have no effects on in vivo hemostasis. We conclude that these drugs are probably safe for patients with bleeding disorders like hemophilia.

Adolescent↗
PubMedDate not supplied

[Spinal-epidural anesthesia: hemodynamics and hemostasis].

Combined spinal epidural anesthesia using an original Portex kit was carried out in 62 patients operated on for orthopaedic, urological, and gynecological disorders. Hemodynamics was examined by tetrapolar chest rheography, hemostasis by electrocoagulography. Satisfactory blocking was attained in 98% cases, in 1 patient an accidental puncture of the subarachnoidal space with Tuohy needle occurred. Development of spinal block was associated with a reduction of heart productivity and hypocoagulation changes in the hemostasis. The parameters examined remained within the normal range of values.

Adult↗
PubMed1976

[Changes in hemostasis during epilespy treatment using dipropyl acetate. Extended study].

The influence of Dipropyl-Acetate (DPA, Ergenyl) on hemostasis parameters was examined in 12 patients. In 8 cases there was a prolongation of bleeding time, in 2 cases thrombocytopenia, in 6 out of 10 cases the platelet adhesiveness was pathologically reduced. We therefore recommend hemostasis-examinations--with emphasis on the thrombocytic system--in patients taking DPA.

Adolescent↗
PubMed1993

[The seasonal dynamics of hemostasis and fibrinolysis in the central belt of Russia].

Upon evaluating seasonal shifts in hemostasis in healthy subjects (3200 examinees aged 18-40) it was established that coagulation rate is the highest in spring. This phenomenon occurred in association with activated fibrinolysis, reduced levels of antithrombin III and more marked paracoagulant tests. Natural lysis of the clot and euglobin fibrinolysis proved more intensive in spring, while least intensive in winter. Frequency of clot lysis inhibition varies with season of the year. In winter the inhibition is observed in 45%, in spring in 21.6%, in summer in 41% and autumn in 36.2% of the examinees. The facts allowed the conclusion on more active hemostasis in spring and less active fibrinolysis in winter, this making these seasons in the Middle Russia most risky as regards vascular accidents.

Blood Coagulation Tests↗
PubMed1993

[Effect of fragmin, a low-molecular heparin, on hemostasis in patients with alimentary-constitutional obesity].

The authors conducted comparative study of the hemostasis indices before and in the immediate period after operation for formation of a small stomach in 31 patients with stage III-IV alimentary-constitutional obesity, in 50 patients without obesity who underwent operation on the stomach, and in 15 volunteers. Nonspecific prevention of thrombogenesis was performed in all patients with normal weight and those with obesity. Patients with obesity were given in addition specific thrombogenesis prevention with nonfractionated heparin (group I) and fractionated low-molecular heparin-fragmin produced by KABI (groups II and III). Study of the parameters of the hemostasis system in the postoperative period showed nonspecific prevention of thrombogenesis to be sufficient to reduce the risk of pulmonary artery phlebothrombosis and embolism in most patients without obesity. In patients with obesity the probability of phlebothrombosis and thromboembolism is much higher, in view of which they must be given heparin in addition to nonspecific prevention. Fragmin, as an agent for thrombosis prevention, has certain advantages over nonfractionated heparin and should be used more frequently in clinical practice in patients of the risk group, e. g. with pathological obesity, in a dose no less than 100 U/kg. With the use of fragmin laboratory control before each injection is not needed. Administration of nonfractionated and fractionated heparins must be combined with bandaging of the lower limbs and other measures of nonspecific prevention of thrombogenesis.

Adult↗
PubMed1993

The pathologist as a clinical consultant for hemostasis in the community hospital.

Most of the clinically recognized disorders of hemostasis were described before the availability of today's sensitive and specific molecular assays. Even though many of these newer assays are not yet technically practical for the average community hospital, in certain situations they are indispensable to accurate diagnosis and treatment. The most significant advances, however, have come not from the tests themselves but from the new insights they have provided into the basic mechanisms of hemostasis, thereby extending the usefulness of the widely available older global clotting assays. Pathologists who are able to integrate this increased understanding of the pathophysiology of various disorders with the history and physical findings will be better able to assist their clinical counterparts in the most cost-effective approach to the care of their patients.

Blood Coagulation Disorders↗
PubMed1996

Platelet-dependent primary hemostasis promotes selectin- and integrin-mediated neutrophil adhesion to damaged endothelium under flow conditions.

Co-localization of blood platelets and granulocytes at sites of hemostasis and inflammation has triggered an intense interest in possible interactions between these cellular processes and induction of vessel wall injury. Leukocyte adhesion to endothelial cells decreases with increasing shear and is dependent on an initial rolling phase mediated by selectins. We hypothesized that flow-dependent platelet adhesion at an injured vessel wall will lead to P-selectin expression by platelets, thus mediating leukocyte co-localization. A perfusion chamber was used in which flowing whole blood induced platelet adhesion to a subendothelial matrix (ECM) of cultured human umbilical vein endothelial cells (HUVEC). We compared neutrophil (polymorphonuclear leukocyte [PMN]) interactions with HUVEC and their ECM with and without adhered platelets. PMNs adhered predominantly to ECM-adhered platelets and not to endothelial cells. ECM alone did not support PMN adhesion under flow conditions. PMN adhesion to unstimulated HUVEC was only substantial at low shear (up to 200 cells/mm2 at shear stress 80 mPa). In marked contrast, PMN adhesion to ECM-adhered platelets was dramatically increased, and adhesion was demonstrated at much higher shear stress (up to 640 mPa). Studies with specific antibodies showed that the platelet-dependent neutrophil adhesion was selectin-mediated. Inhibition of P-selectin caused a marked inhibition of adhesion at high shear stress, whereas the role of leukocyte L-selectin was less pronounced. beta2-Integrin-blocking antibodies inhibited static neutrophil adhesion. fMLP induced L-selectin shedding from leukocytes, resulting in decreased leukocyte adhesion. In conclusion, platelet-dependent hemostasis at the ECM appears to be a powerful intermediate in neutrophil-vessel wall interactions at shear stresses that normally do not allow neutrophil adhesion to intact endothelium.

Antibodies, Monoclonal↗
PubMed1995

Control and treatment of hemostasis in cardiovascular surgery. The experience of La Pitié Hospital with patients on total artificial heart.

The hemostasis protocol applied at the Cardiovascular Surgery Dept. of La Pitié Hospital has greatly reduced thromboembolic accidents and excessive bleeding, with consequent benefits for patients as well as cost reduction. Protocol also has been adopted for patients implanted with a circulatory assist device or a TAH. This paper presents our criteria on supervision and treatment of coagulation with such patients, who reflect all the acquired pathology in clinical hemostasis. From 04/86 to 07/94, 82 patients underwent TAH as a bridge to transplantation. Mean age: 38. Overall duration of mechanical support: 1930 days (mean: 23), of which 137 and 603 for 2 patients. Average duration of CPB: 150 min. Systematic approach to complex TAH-blood interaction and pre-operative multiple organ dysfunction used to control bleeding and/or thromboembolism after CPB. In addition to routine tests, specific regular testing was carried out at least once a day for platelet functions, for thrombin formation and its regulatory pathways, and for the fibrinolytic system. Patients were treated with small doses of Heparin, large doses of Dypyridamole, small doses of Aspirin, modulated doses of Aprotinin, Ticlopidine, Pentoxifylline, FFP, as well as Fibrinogen and AT III concentrates. Dosage was adapted to patient's clinical profile as well as to test interpretation criteria to provide personalized treatment. DIC, widely present in its different phases, was thus diagnosed and treated. All DIC bleeding was controlled, making it possible to detect other causes of post-operatory bleeding and use blood derivates rationally. There were no thromboembolic complications and no iatrogenic bleeding. TAH explanation shows no evidence of macroscopic clots in high risk sites, confirmed by microscopic analysis.

Adolescent↗
PubMed1996

Validation protocol of analytical hemostasis systems: measurement of anti-Xa activity of low-molecular-weight heparins.

A standard validation protocol adapted to the chromogenic assay of anti-Xa activity of low-molecular-weight heparins was used in a multicenter study to assess its suitability for comparing and evaluating analytical hemostasis systems. The protocol included: familiarization with the system (repeatability); assessment of limits of linearity, detection limits, and cross-contamination; and validation (reproducibility and accuracy of measurements of treated patients' plasmas). We calibrated the systems with the same range of lyophilized plasmas daily and evaluated repeatability and reproducibility by using a single batch of lyophilized plasmas at three anti-Xa activities. The two automated systems tested [SB 300 (Gilford) and ACL (IL)] and the two semiautomated systems [ST 888 (D. Stago) and Chromotimer (Behring)] gave similar mean values. Dispersion of results was lower with the automated systems than with the semiautomated ones, especially at low anti-Xa activities, a tendency that also was observed for reproducibility. Because each analytical system gave linear results for activities as great as 1000 IU/L, suitable sample dilution is advisable for higher anti-Xa activities. Accuracy was greater in the automated systems. We conclude that this protocol is feasible and is applicable to validation of other analytical hemostasis instruments, in particular the latest generation of fully automated instruments.

Autoanalysis↗
PubMedDate not supplied

Hemostasis-altering drugs and central neural block. A survey of anesthetic practice in Scotland and the United Kingdom.

BACKGROUND AND OBJECTIVES: There is debate regarding the use of central neural block in the presence of hemostasis-altering drugs. This study aims to examine current practice. METHODS: A survey was made of the members of the Scottish Society of Anaesthetists and the U.K. branch of the European Society of Regional Anaesthesia to determine the pattern of use of central neural block in patients who are receiving drugs known to alter hemostasis. RESULTS: Spinal anesthetics were considered safer than single epidural injections (P < .05) and single epidural injections safer than infusions via epidural catheters (P < .05). CONCLUSIONS: There is general agreement regarding contraindication of central neural block in the presence of full anticoagulation with either heparin or warfarin, but there is less consensus about the use of central neural block in the presence of low-dose subcutaneous heparin. There is some confusion about the role of aspirin and its duration of action.

Anesthesia, Epidural↗
PubMed1996

[Effect of postoperative retransfusion of autologous blood products on hemostasis in heart surgery].

In cardiac surgery a reduction of homologous blood products is mainly achieved by autologous blood salvage. Unprocessed retransfusion of autologous blood may induce changes in hemostasis. We assessed changes of activated clotting times (ACT) after retransfusion of unprocessed (1) oxygenator blood and (2) shed mediastinal blood. In 41 patients undergoing cardiac surgery (37 revascularization and 4 valve procedures) with a mean cardiopulmonary bypass time of 116.3 min, ACT was measured at the following time points: pre- and postoperatively, and before and after retransfusion of oxygenator blood and shed mediastinal blood. A significant prolongation of ACT values was only seen between pre- to postoperative blood (p < 0.003). Retransfusion of oxygenator blood changed ACT from 120 +/- 25 vs 116 +/- 17 sec and retransfusion of shed mediastinal blood showed a mean ACT of 118 +/- 14 vs 115 +/- 20 sec from before to after transfusion. There was a significant correlation between the ACT value in the unprocessed oxygenator blood and the ACT value measured in the patient after retransfusion (r = 0.41, p < 0.02). 6 patients receiving over 1 litre of unprocessed autologous blood (either from the oxygenator or the mediastinum) in less than 60 minutes showed a significant increase of ACT value after transfusion (p < 0.05). Hence, under normal conditions, retransfusion of unprocessed autologous blood will not significantly alter hemostasis measured by the ACT test in patients undergoing cardiac surgery.

Adult↗
PubMed1996

[Effect of treating glomerulonephritis with omega 3 fatty acids for selected parameters of hemostasis, blood platelet function and lipid metabolism].

Disturbances in serum lipids, hemostasis and platelet functions are frequent features in some kidney diseases and may contribute to the progression of atherosclerosis with its complications. Recently, an attention has been paid on beneficial effects of fish oil on serum lipids and hemostasis, and proteinuria. The purpose of this work was to assess platelet functions, some hemostatic parameters and serum lipids in patients with chronic glomerulonephritis treated with Trienyl. The study was performed on 7 patients with glomerulonephritis, before, 3 and 6 months following fish oil treatment. A small and nonsignificant rise in cholesterol, HDL and LDL was found, whereas triglycerides level fell significantly following 3 and 6 months of therapy Fibrinogen concentration was lowered significantly 6 months following fish oil administration. Platelet aggregation in platelet-rich plasma remained unaltered during therapy, whereas platelet responses to ADP and arachidonic acid in the whole blood were inhibited after 6 months of the therapy. Unsaturated omega 3 fatty acids in Trienyl alter lipid metabolism, platelet/vessel wall interactions and proteinuria and therefore might be beneficial in therapy of glomerulonephritis, particularly in combination treatment.

Adult↗