No abstract

Disturbance of fibrinogen/fibrin polymerization is the primary problem triggering dilutional coagulopathy during major orthopedic surgery. The magnitude of clot firmness reduction is determined by the type of fluid used, with hydroxyethyl starch showing the most pronounced effects. These undesirable effects of intravascular volume therapy can be reversed by increasing fibrinogen concentration by administering fibrinogen concentrate, even during continuing blood loss and intravascular volume replacement.

Prothrombin complex concentrates (PCCs) are used mainly for emergency reversal of vitamin K antagonist therapy. Historically, the major drawback with PCCs has been the risk of thrombotic complications. The aims of the present review are to examine thrombotic complications reported with PCCs, and to compare the safety of PCCs with human fresh frozen plasma. The risk of thrombotic complications may be increased by underlying disease, high or frequent PCC dosing, and poorly balanced PCC constituents. The causes of PCC thrombogenicity remain uncertain but accumulating evidence indicates the importance of factor II (prothrombin). With the inclusion of coagulation inhibitors and other manufacturing improvements, today's PCCs may be considered safer than earlier products. PCCs may be considered preferable to fresh frozen plasma for emergency anticoagulant reversal, and this is reflected in the latest British and American guidelines. Care should be taken to avoid excessive substitution with prothrombin, however, and accurate monitoring of patients' coagulation status may allow thrombotic risk to be reduced. The risk of a thrombotic complication due to treatment with PCCs should be weighed against the need for rapid and effective correction of coagulopathy.

Our data enlarge the body of evidence showing that ROTEM(®) assays are useful in trauma patients. Treatment concepts should focus on maintaining fibrin polymerization and treating hyperfibrinolysis.

Key points † Monitoring whole-blood coagulation using viscoelasticity assays is useful in managing perioperative bleeding. † This observational study compared thromboelastometry [ROTEM w ] assays with standard coagulation tests in 359 children in six age groups. † Age-dependent differences identified in both standard and ROTEM w assays provide important reference ranges for monitoring paediatric surgical patients.Background. The small sample volume needed and the prompt availability of results make viscoelastic methods like rotational thromboelastometry (ROTEM w ) attractive for monitoring coagulation in small children. However, data on reference ranges for ROTEM w parameters in children are scarce.Methods. Four hundred and seven children (ASA I and II) undergoing elective surgery were recruited for this prospective, two-centre, observational study. Subjects were grouped as follows: 0-3, 4 -12, 13 -24 months, 2-5, 6-10, and 11-16 yr. Study objectives were to establish age-dependent reference ranges for ROTEM w assays, analyse age dependence of parameters, and compare ROTEM w data with standard coagulation tests.Results. Data from 359 subjects remained for final analysis. Except for extrinsically activated clot strength and lysis, parameters for ROTEM w assays were significantly different among all age groups. The most striking finding was that subjects aged 0-3 months exhibited accelerated initiation (ExTEM coagulation time: median 48 s, Q1-Q3 38 -65 s; P¼0.001) and propagation of coagulation (a angle: median 78 o , Q1-Q3 69-84 o ; P,0.001) and maximum clot firmness (median 62 mm, Q1-Q3 54-74 mm), although standard plasma coagulation test results were prolonged (prothrombin time: median 13.2 s, Q1-Q3 12.6 -13.6 s; activated partial thromboplastin time: median 42 s, Q1-Q3 40-46 s). Lysis indices of ,85% were observed in nearly one-third of all children without increased bleeding tendency. Platelet count and fibrinogen levels correlated significantly with clot strength, and fibrinogen levels correlated with fibrin polymerization.Conclusions. Reference ranges for ROTEM w assays were determined for all paediatric age groups. These values will be helpful when monitoring paediatric patients and in studies of perioperative coagulation in children.Viscoelastic coagulation tests have gained a renewed interest in the safe management of surgery-or trauma-induced coagulopathy in adult and paediatric patients. 1 -4 Viscoelastic whole-blood analyses, such as thromboelastography (TEG w ) and thromboelastometry (ROTEM w ), reflect initiation and propagation of coagulation, fibrinogen/fibrin -platelet interaction, and clot lysis. In 1997, the ROTEM w device was introduced into clinical routine at our institution. A multicentre study published by Lang and colleagues 5 presented reference ranges for ROTEM w assays for adults aged 17-85 yr. With the exception of some data referring to preterm neonates, newborns, and children exhibiting cardiac failure, reference data are scarce for paediatric patients. 6 -10 The main objective of ...

Replacing 65% of the estimated blood volume with gelatin in swine resulted in dilutional coagulopathy; subsequent fibrinogen administration improved clot formation and reduced blood loss significantly.

Differences in postoperative infection rates between allogeneic and autologous recipients are still observable, although universal WBC filtration has been introduced into clinical practice.

Colloids and crystalloids are usually administered as treatment for hypovolemia in severely injured patients. However, dilution of clotting factors and platelets together with impaired fibrinogen polymerization are associated with fluid therapy and may aggravate hemorrhage, thus worsening final outcome of these patients. We investigated, in an in vitro model, whether the addition of fibrinogen to diluted blood samples can reverse dilutional coagulopathy. Blood from 5 healthy male volunteers was diluted by 60% using lactated Ringer's solution, 4% modified gelatin solution, or 6% hydroxyethyl starch 130/0.4, as well as the combination of lactated Ringer's solution with either of the 2 colloid solutions. Thereafter, aliquots of diluted blood samples were incubated with 3 different concentrations of fibrinogen (0.75, 1.5, and 3.0 mg/mL). Measurements were performed by modified thrombelastography (ROTEM; Pentapharm, Munich, Germany). After 60% dilution, clotting times increased, whereas clot firmness and fibrin polymerization decreased significantly. After administration of fibrinogen, clotting times decreased and clot firmness, as well as fibrin polymerization, increased in all diluted blood samples. The effect of in vitro fibrinogen substitution on ROTEM variables was dependent on the fibrinogen dosage and the type of solution used to dilute the blood samples.