The effects of colloid solutions on hemostasis

Can J Anaesth.
.Van der Linden P, Ickx BE.
Department of Anesthesiology, CHU Brugmann – HUDERF, 4 Place Van Gehuchten, B-1020 Brussels, Belgium.
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PURPOSE: Colloid solutions are widely used to prevent or to correct hypovolemia in surgical patients. Although more efficacious than crystalloids, they are more expensive and can be associated with adverse effects, in particular when they interfere with the hemostatic system. METHODS: This narrative review focuses on the effects of albumin and synthetic colloids on the biological markers of coagulation and their clinical consequences. RESULTS: All colloidal plasma substitutes interfere with the physiological mechanisms of hemostasis either through a non-specific effect correlated to the degree of hemodilution or through specific actions of these macromolecules on platelet function, coagulation proteins, and the fibrinolytic system. Albumin has the least effect, while high molecular weight (Mw) dextrans and hydroxyethyl starches (HES) have the most significant effects. Gelatins and medium Mw HES with a low molar substitution ratio have moderate and, probably, comparable effects. The use of dextrans and high in vivo Mw HES may be associated with increased bleeding, while gelatins and low in vivo Mw HES are unlikely to have such an effect. CONCLUSIONS: In most cases, the clinical consequences of the biological effects of colloids on hemostasis are limited, provided that safety considerations are observed (maximum daily dosage, duration of treatment, patient’s hemostatic status, clinical conditions). The implications may be different in patients with hemostatic disorders, either inherited or related to preoperative antiplatelet or anticoagulant treatment. In these patients, crystalloids, gelatins or even albumin solutions should be preferred when hemodilution exceeds 30% of the circulating blood volume.

Recombinant human erythropoietins and cancer patients: updated meta-analysis of 57 studies including 9353 patients.

Editorial: J Natl Cancer Inst
Fecha: 01/06/2006
Bohlius J, Wilson J, Seidenfeld J, Piper M, Schwarzer G, Sandercock J, Trelle S, Weingart O, Bayliss S, Djulbegovic B, Bennett CL, Langensiepen S, Hyde C, Engert A.

This is an updated systematic review of 57 trials and 9353 cancer patients from articles, abstracts, and reports published between January 1, 1985, and April 30, 2005, on the effects of epoetin alfa and beta (i.e., epoetin) and darbepoetin alfa (i.e., darbepoetin). We included randomized controlled trials comparing epoetin or darbepoetin plus red blood cell transfusion with red blood cell transfusion alone for prophylaxis or treatment of anemia in cancer patients with or without concurrent antineoplastic therapy. The Cochrane Library, MEDLINE, EMBASE, and conference proceedings were searched. Effect estimates and 95% confidence intervals (CIs) were calculated with fixed-effects models. Treatment with epoetin or darbepoetin statistically significantly reduced the risk for red blood cell transfusions (relative risk [RR] = 0.64, 95% CI = 0.60 to 0.68; 42 trials and 6510 patients) and improved hematologic response (RR = 3.43, 95% CI = 3.07 to 3.84; 22 trials and 4307 patients). Treatment with epoetin or darbepoetin increased the risk of thrombo-embolic events (RR = 1.67, 95% CI = 1.35 to 2.06; 35 trials and 6769 patients). Uncertainties remain as to whether and how epoetin or darbepoetin affects overall survival (hazard ratio = 1.08, 95% CI = 0.99 to 1.18; 42 trials and 8167 patients). Caution is advised when using epoetin or darbepoetin in combination with thrombogenic chemotherapeutic agents or for cancer patients who are at high risk for thrombo-embolic events

Pharmacological approaches to reducing blood loss and transfusions in the surgical patient

Editorial: Can J Anaesth
Fecha: 01/06/2006
Ozier Y, Schlumberger S.
Service d’Anesthesie-Reanimation Chirurgicale, France

PURPOSE: To review the efficacy, effectiveness and safety of hemostatic drugs to reduce surgical blood loss. METHODS: Analysis of randomized controlled trials and meta-analyses exploring the efficacy of desmopressin, aprotinin, lysine analogues and recombinant activated factor VII (rFVIIa) on clinically important endpoints. MAIN FINDINGS: Although potentially useful in surgical patients with mild hemophilia or type I von Willebrand’s disease, desmopressin has no proven benefit in patients without previous hemostatic defects. Aprotinin has been studied extensively in cardiopulmonary bypass surgery, with evidence of a blood sparing effect. Additional benefits are suggested. The drug is less consistently effective in liver transplantation and major orthopedic surgery. Although rare, hypersensitivity reactions to aprotinin may occur, especially on re-exposure. Tranexamic acid can reduce blood transfusion in cardiac surgery, liver transplantation and total knee arthroplasty surgery with a satisfactory safety profile. Epsilon aminocaproic acid has not been investigated adequately, despite its widespread use. While rFVIIa may be beneficial in controlling massive coagulopathic bleeding in trauma and surgical patients, there is currently no evidence to support its prophylactic use in elective surgical patients. CONCLUSION: Aprotinin and tranexamic acid are valuable pharmacologic options for reducing surgical bleeding. The expected benefit of these drugs is highly dependent on the actual blood usage for a given procedure at the institutional level. More studies using clinically significant endpoints are necessary to assess the relative efficacy and optimal dosing of these drugs

Massive transfusion practices around the globe and a suggestion for a common massive transfusion protocol.

j trauma
Malone DL, Hess JR, Fingerhut A.
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BACKGROUND: Massive transfusion, the administration of 10 to more than 100 units of red blood cells (RBC) in less than 24 hours, can be a life saving therapy in the treatment of severe injury. The rapid administration of large numbers of RBC, along with sufficient plasma and platelets to treat or prevent coagulopathy, is frequently a disorderly process. Patient care and collaborative research might be aided with a common protocol. METHODS: The authors polled trauma organizations and trauma centers to find examples of massive transfusion protocols. The goals and ease of use of these protocols were evaluated. RESULTS: Massive transfusion protocols exist at a relatively small number of large and well-organized trauma centers. Most of these protocols are designed to treat pre-existing and/or ongoing coagulopathy. CONCLUSIONS: The evidence would suggest that prevention of coagulopathy is superior to its treatment. Simple ratios such as 1:1:1 RBC:plasma:platelets have the benefit of ease of use and the relatively higher plasma and platelet doses appear to be associated with improved outcome. Such a standard protocol can foster multicenter research on resuscitation and hemorrhage control. The fixed volume ratios might allow the number and rate of administered units of RBC to be used as surrogates for blood loss and primary treatment effect.

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