Prevalence and impact of abnormal ROTEM(R) assays in severe blunt trauma: results of the 'Diagnosis and Treatment of Trauma-Induced Coagulopathy (DIA-TRE-TIC) study'.

BACKGROUND: ROTEM(®)/TEG(®) (rotational thromboelastometry) assays appear to be useful for the treatment of bleeding trauma patients. However, data on the prevalence and impact of abnormal ROTEM(®) assays are scarce. METHODS: This is a prospective cohort study of blunt trauma patients (Injury Severity Score ≥15 or Glasgow Coma Score ≤14) admitted to Innsbruck Medical University Hospital between July 2005 and July 2008. Standard coagulation tests, antithrombin (AT), prothrombin fragments (F1+2), thrombin-antithrombin complex (TAT), and ROTEM(®) assays were measured after admission. Data on 334 patients remained for final analysis. RESULTS: ROTEM(®) parameters correlated with standard coagulation tests (all Spearman r>0.5), and significant differences in mortality were detected for defined ROTEM(®) thresholds [FIBTEM 7 mm (21% vs 9%, P=0.006), EXTEM MCF (maximum clot firmness) 45 mm (25.4% vs 9.4%, P=0.001)]. EXTEM MCF was independently associated with early mortality [odds ratio (OR) 0.94, 95% confidence interval (CI) 0.9-0.99] and MCF FIBTEM with need for red blood cell transfusion (OR 0.92, 95% CI 0.87-0.98). In polytrauma patients with or without head injury (n=274), the prevalence of low fibrinogen concentrations, impaired fibrin polymerization, and reduced clot firmness was 26%, 30%, and 22%, respectively, and thus higher than the prolonged international normalized ratio (14%). Hyperfibrinolysis increased fatality rates and occurred as frequently in isolated brain injury (n=60) as in polytrauma (n=274) (5%, 95% CI 1.04-13.92 vs 7.3%, 95% CI 4.52-11.05). All patients showed elevated F1+2 and TAT and low AT levels, indicating increased thrombin formation. CONCLUSIONS: 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.

Prothrombin complex concentrate and recombinant prothrombin alone or in combination with recombinant factor X and FVIIa in dilutional coagulopathy: a porcine model.

BACKGROUND: This study was conducted to assess whether newly developed recombinant clotting factor concentrates enable the reversal of dilutional coagulopathy. METHODS: In 50 anesthetized pigs, ~60% of the blood volume was withdrawn and replaced with hydroxyethyl starch. Pigs were randomized to receive either 200 mg kg(-1) fibrinogen (n = 10), fibrinogen and 35 IU kg(-1) prothrombin complex concentrate (PCC) (n = 10), fibrinogen and 4 mg kg(-1) recombinant human factor II (rhFII) concentrate (n = 10), fibrinogen and a three-factor combination (3F) of 4 mg kg(-1) rhFII, 0.006 mg kg(-1) recombinant human FVIIa and 0.32 mg kg(-1) recombinant human FX (n = 10), or saline (n = 10). Thereafter, a standardized liver laceration was performed to induce uncontrolled hemorrhage. Survival time and blood loss were determined, and standard coagulation tests and thrombelastometry were performed. RESULTS: Fibrinogen combined with rhFII or PCC improved survival. Blood loss was significantly decreased in all groups as compared with the animals receiving saline. Clotting time was significantly shortened in the animals treated with fibrinogen and PCC, as well as in those treated with fibrinogen and 3F. One animal died after administration of fibrinogen and PCC. CONCLUSION: Following hemodilution, a combination of fibrinogen and PCC, rhFII or 3F enhances coagulation and final clot strength. Mortality was reduced statistically significantly only in the animals treated with fibrinogen and rhFII or PCC, whereas administration of the combination of fibrinogen and PCC caused a fatal thromboembolic complication. The combination of fibrinogen and rhFII might be effective in reversing dilutional coagulopathy and may reduce blood loss in cases of dilutional coagulopathy.

Thromboelastometry (ROTEM) in children: age-related reference ranges and correlations with standard coagulation tests.

BACKGROUND: The small sample volume needed and the prompt availability of results make viscoelastic methods like rotational thromboelastometry (ROTEM) attractive for monitoring coagulation in small children. However, data on reference ranges for ROTEM 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 assays, analyse age dependence of parameters, and compare ROTEM 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 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; P=0.001) and propagation of coagulation (α 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 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.

Re-transfusion of salvaged washed red cells improves clot formation in pigs as measured by rotational thrombelastometry (ROTEM).

BACKGROUND AND OBJECTIVE: Patients exhibiting considerable blood loss are prone to develop dilutional coagulopathy following volume supply. In such patients, in addition to transfusing stored blood components, cell saver systems are used to minimize allogeneic transfusion. Since red cell transfusion might influence the haemostatic system by further dilution, we investigated the effects of re-transfusion of salvaged washed red blood cells on the haemostatic process in an animal model of controlled haemorrhage using rotational thrombelastometry (ROTEM; Pentapharm Co., Munich, Germany). METHODS: Anaesthetized pigs (n = 20) developed coagulopathy following haemorrhagic shock (withdrawal of 66% of estimated blood volume) and volume resuscitation with 6% hydroxyethyl starch 130/0.4. The shed blood was processed in a Cellsaver device (CATS; Fresenius AG, Bad Homburg, Germany), and the resulting salvaged red blood cells were re-transfused. ROTEM assays were performed at baseline, after blood loss, after volume resuscitation and following re-transfusion of salvaged red blood cells. RESULTS: As compared with baseline, blood loss and subsequent volume resuscitation resulted in significantly increased median values of clotting time (CT: 47.0, 5 .3 and 103.5 s), and clot formation time (CFT: 36.0, 40.0 and 186.0 s), whiggle maximum clot firmness decreased (MCF: 72.0, 68.5 and 39.5 mm). After re-transfusion of salvaged red blood cells (805 +/- 175 mL) all these parameters improved (CT: 80.5 s; P = 0.05, CFT: 144.0 s; P = 0.0008, MCF: 42.0 mm; P = 0.0019) although baseline values were not reached. CONCLUSION: In the case of extreme isovolaemic haemodilution, increasing the circulating red cell mass by re-transfusing salvaged red blood cells did not worsen the findings of dilutional coagulopathy but interestingly, at least partially, improves the clot formation process.

Comparison of high- and low-dose intrathecal morphine for spinal fusion in children.

BACKGROUND: The purpose of this prospective study was to assess the blood-sparing effect, the quality of analgesia, and the incidence of side-effects of a low-dose regime of intrathecal opioids (ITO) when compared with those of a high-dose regime in scoliosis surgery in children. METHODS: Forty-six children were randomly included into one of the three groups to receive morphine 5 microg kg(-1) plus sufentanil 1 microg kg(-1) [low-dose intrathecal opioid (LITO)], morphine 15 microg kg(-1) plus sufentanil 1 microg kg(-1) [high-dose intrathecal opioid (HITO)] intrathecally, or no intrathecal opioid. Postoperative analgesia was provided by i.v. opioids. Intraoperative blood loss, postoperative quality of analgesia, opioid requirements, and the incidence of side-effects were recorded for 3 days. RESULTS: Intraoperative blood loss was significantly reduced by ITOs [LITO: 41.4 (sd 18.8) ml kg(-1); HITO: 37.5 (6.9) ml kg(-1); control: 76.9 (15.3) ml kg(-1), P<0.001], with no difference between the two intrathecal opioid groups. Mean pain scores on the day of surgery were lower in both intrathecal opioid groups (LITO: 2.2 and HITO: 2.1) when compared with the control group (4.1, P<0.03) and opioid consumption was significantly decreased [LITO: 304.3 (65.0) microg kg(-1); HITO: 224.1 (51.8) microg kg(-1); control: 667.7 (89.5) microg kg(-1), P<0.002]. Side-effects of intrathecally administered opioids were similarly frequent in all groups. CONCLUSIONS: Intrathecal administration of opioids significantly reduces blood loss and postoperative opioid demand, thereby showing side-effects comparable with the control group. These effects were already seen with the low-dose regimen and high dose did not further improve efficacy.

Effects of colloid and crystalloid solutions on endogenous activation of fibrinolysis and resistance of polymerized fibrin to recombinant tissue plasminogen activator added ex vivo.

BACKGROUND: The study was conducted to explore the effects of colloid and crystalloid solutions on activation of fibrinolysis during orthopaedic surgery and to determine whether fluids facilitate clot dissolution at a particular fibrinolytic activity. METHODS: Tissue-type plasminogen activator (t-PA) and plasminogen activator inhibitor-1 (PAI-1) were measured in plasma samples of 66 orthopaedic patients randomly receiving gelatin solution, hydroxyethyl starch (HES) (130/0.4), or exclusively Ringer's lactate solution. Plasma obtained before induction of anaesthesia (undiluted) and at the end of surgery (diluted) was exposed to recombinant tissue plasminogen activator (r-tPA) in vitro and analysed by modified thrombelastography (ROTEM). RESULTS: There were similar changes in t-PA and PAI-1 concentrations in the gelatin, HES, and Ringer's lactate groups. When compared with the effect of r-tPA on undiluted plasma samples, the presence of colloids prompted faster clot dissolution than did Ringer's lactate solution. Lysis index at 30 min decreased significantly [median (min/max); P vs Ringer's lactate solution] to 43 (1/82)% (P=0.007), 14 (3/70)% (P<0.001), and 91 (34/97)%, lysis onset time decreased to 1269 (1054/1743) s (P=0.007), 972 (490/1565) s (P<0.001), and 1970 (1260/2165) s, and lysis time to 2469 (1586/3303) s (P=0.019), 2002 (1569/3600) s (P=0.006), and 3012 (2017/3600) s in the gelatin, HES, and Ringer's lactate groups, respectively. CONCLUSIONS: The type of i.v. fluid used does not influence endogenously occurring fibrinolytic activity in patients undergoing major orthopaedic surgery. However, during hyperfibrinolysis, the presence of HES or gelatin solution facilitates clot disintegration to a greater extent than Ringer's lactate solution, because the weaker clots formed with colloids dissolve faster.

Effects of albumin 5% and artificial colloids on clot formation in small infants.

Albumin is often cited in textbooks as the gold standard for fluid replacement in paediatrics, but in practice artificial colloids are more frequently used. Although one concern with the use of artificial colloids is their intrinsic action on haemostasis, the available data in children are inconclusive for 6% hydroxyethyl starch 130/0.4 (HES) and no data exist for gelatine solution with respect to coagulation. A total of 42 children (3-15 kg) undergoing surgery and needing colloid replacement were randomly assigned to receive 15 mlxkg(-1) of either albumin 5%, 4% modified gelatine solution or 6% hydroxyethyl starch 130/0.4 solution. Standard coagulation tests and modified thrombelastography (ROTEM) were performed. After colloid administration, routine coagulation test results changed significantly and comparably in all groups, although activated partial thromboplastin time values increased more with gelatine and HES. Coagulation time was unchanged in the children who received albumin or gelatine but other activated modified thrombelastography values were significantly impaired in all groups. After gelatine and after albumin the median clot firmness decreased significantly but remained within the normal range. Following HES, coagulation time increased significantly, and clot formation time, alpha angle, clot firmness, and fibrinogen/fibrin polymerisation were significantly more impaired than for albumin or gelatine, reaching median values below the normal range. From a haemostatic point of view it might be preferable to use gelatine solution as an alternative to albumin; HES showed the greatest effects on the overall coagulation process.

[Preoperative evaluation of the bleeding history. Recommendations of the working group on perioperative coagulation of the Austrian Society for Anaesthesia, Resuscitation and Intensive Care]. / Präoperative Blutungsanamnese. Empfehlungen der Arbeitsgruppe perioperative Gerinnung der Osterreichischen Gesellschaft für Anästhesiologie, Reanimation und Intensivmedizin.

Unexpected bleeding in the perioperative period is largely caused by impaired inherited or drug-induced primary haemostasis. Standard tests for plasma coagulation are predominantly employed to gauge the risk of bleeding. In accordance with several reports the subcommittee for perioperative coagulation (AGPG) of the Austrian Society of Anaesthesia, Resuscitation and Intensive Care (OGARI) recommends the use of a standardised questionnaire to detect an increased risk of bleeding. Accordingly, healthy patients of the American Society of Anesthesiologists (ASA) grades I and II without any suspicion of impaired haemostasis who are scheduled for procedures without expected transfusion requirements, need no standard tests for coagulation. In all other patients (including patients taking medication affecting coagulation, or patients who are unable to provide adequate information) platelet count, platelet function, aPTT, PT, and fibrinogen levels should be assessed.

The effect of fibrinogen concentrate on thrombocytopenia.

OBJECTIVES: The hypothesis that the administration of fibrinogen concentrate enables restoration of impaired clot formation and increased bleeding in severe thrombocytopenia was tested. METHODS: Thirty pigs were anesthetized, instrumented for blood sampling (routine coagulation tests, modified thrombelastography ROTEM, hemodynamic monitoring and platelet apheresis to a target below 30 x 10(9) L(-1) after splenectomy. Thereafter 10 each of the animals randomly received two apheresis platelet concentrates, 250 mg kg(-1) fibrinogen concentrate or normal saline solution. A standardized liver injury was subsequently inflicted to induce uncontrolled hemorrhage. RESULTS: Median (Q1, Q3) clot firmness increased significantly more in thrombocytopenic pigs after fibrinogen administration (42 mm (41, 43) to 60 mm (57, 63)) than following platelet transfusion (40 mm (37, 45) to 52 mm (48, 55), P = 0.0004) or placebo (45 mm (41, 48) to 45 mm (43, 46), P = 0.0002). Median blood loss velocity after liver injury was significantly less with fibrinogen (33 mL min(-1), P = 0.005) than with platelets (62 mL min(-1), P = 0.037) or saline (84 mL min(-1), P = 0.005), and median survival time after liver injury was 55 min in the fibrinogen, 26 min in the platelet (P = 0.035) and 19 min in the saline group (P = < 0.0001). CONCLUSIONS: These data show for the first time that impaired clot formation during thrombocytopenia improves with administration of fibrinogen concentrate, which results in a slowdown of blood loss and prolonged survival.

[Perioperative management of coagulation]. / Perioperatives Gerinnungsmanagement.

Guidelines of official societies for diagnosis and therapy of intraoperatively occurring hypocoagulability rely mainly on data of patients receiving whole blood transfusions. They recommend--provided that laboratory evaluation shows deficiency (values>1.5 fold normal)--administration of fresh frozen plasma, cryoprecipitate and platelet concentrates (platelet count<50,000 or <100,000/microl). This article describes the pathogenesis of coagulopathy in the light of the special intraoperative setting, emphasizes recent changes of blood component preparation, transfusion triggers, effects of volume therapy and challenges standard laboratory assays as reliable guide for intraoperative hemostatic therapy. The role of thrombelastographic monitoring is discussed as well as an alternative strategy to compensate deficiencies by the use of coagulation factor concentrates instead of or in addition to transfusion of FFP, a new concept which is illustrated by the presentation of an actual case report.

Efficacy of fibrinogen and prothrombin complex concentrate used to reverse dilutional coagulopathy--a porcine model.

BACKGROUND: This study was conducted to assess whether the combined administration of fibrinogen and prothrombin complex concentrate (PCC) enables the reversal of dilutional coagulopathy resulting from intended blood loss and fluid replacement, and whether this treatment reduces further blood loss and mortality. METHODS: In 20 anaesthetized pigs, approximately 65% of the estimated blood volume was withdrawn and replaced with the same amount of hydroxyethyl starch (6% HES 130/0.4) to mimic blood loss and to develop a dilutional coagulopathy. Pigs (randomized) received either fibrinogen (200 mg kg(-1)) and PCC (35 IU kg(-1)) (n=10), or placebo (n=10). Thereafter, a standard liver laceration was performed to induce uncontrolled haemorrhage. The subsequent blood loss and survival time were determined as primary outcome variables. Throughout the experiment serial blood samples were obtained to assess the competence of the haemostatic system using standard coagulation tests, modified Thrombelastograph measurements (ROTEM) and electron microscopy clot imaging. RESULTS: As compared with baseline, after haemodilution both groups showed statistically significant impairment of haemostasis as measured with standard coagulation tests and thrombelastography. These parameters significantly improved after administration of the study drugs while aPPT measurements remained unchanged. Blood loss after liver injury was significantly less in the treatment group as compared with placebo: 240 ml (50-830) vs 1800 ml (1500-2500) (P<0.0001). All treated animals survived, whereas 80% of the placebo group died (P<0.0001). CONCLUSION: During haemodilution, substitution of fibrinogen and PCC causes an enhancement of coagulation and final clot strength. This reversal of dilutional coagulopathy may reduce blood loss and mortality when large amounts of colloids are needed to maintain normovolaemia during huge blood losses.

Effects of protamine and heparin can be detected and easily differentiated by modified thrombelastography (Rotem): an in vitro study.

BACKGROUND: Precise coagulation monitoring might help prevent heparin-protamine mismatch and thus decrease postoperative blood loss. We therefore measured coagulation time (CT) by modified thrombelastography (Rotem) as a possible differential monitor of the effects of heparin and protamine. METHODS: Undiluted and diluted blood samples from 26 healthy volunteers were spiked with increasing concentrations of heparin (0.1, 0.2, 0.4, 0.8 and 1 U ml(-1)). In addition, undiluted blood was spiked with protamine hydrochloride (0.1, 0.2, 0.4, 0.8 and 1.6 U ml(-1)), and we tested the effect of protamine on the reversal of heparin 0.4 U ml(-1). Heparin-containing samples were analysed using the heparin-sensitive INTEM test and the heparinase-containing HEPTEM test; protamine series were also analysed with the EXTEM test (tissue factor activation). RESULTS: CT by the INTEM test [CT-INTEM; median (min/max)] increased significantly and dose-dependently with increasing concentrations of heparin [control, 175 s (146/226); heparin, 1.0 U ml(-1) 1320 s (559/2100); P<0.001] and protamine [control, 172 s (150/255); protamine, 1.6 U ml(-1) 527 s (300/1345); P<0.0001]. Up to heparin concentrations of 0.4 U ml(-1), results were similar in undiluted and diluted blood samples. As expected, CT-HEPTEM remained within the normal range for all tested heparin concentrations (median 180-183 s), but increased similarly to CT-INTEM for increasing protamine concentrations. CONCLUSION: CT measurement using the Rotem technique appears to be a valuable tool for heparin-protamine management. For detection of heparin alone, protamine alone and the two combined, the ratio of CT-INTEM:CT-HEPTEM can be used to distinguish the effects of heparin excess (CT-INTEM:CT-HEPTEM>1) from those of protamine excess (CT-INTEM:CT-HEPTEM=1).

Effect of fibrinogen on reversal of dilutional coagulopathy: a porcine model.

BACKGROUND: This study was conducted to determine whether replacement of fibrinogen is useful in reversing dilutional coagulopathy following severe haemorrhage and administration of colloids. METHODS: In 14 anaesthetized pigs, approximately 65% of the estimated blood volume was withdrawn and replaced with the same amount of gelatin solution to achieve dilutional coagulopathy. Animals were randomized to receive either 250 mg kg(-1) fibrinogen (n=7) or normal saline (n=7). A standardized liver injury was then inflicted to induce uncontrolled haemorrhage. Modified thrombelastography and standard coagulation tests were performed at baseline, after blood withdrawal, after dilution, after injection of the study drugs, and on conclusion of the protocol. Further, electron microscopy imaging of the blood clots was performed and blood loss after liver injury was determined. RESULTS: Severely impaired haemostasis was observed after haemodilution with gelatin substitution. With administration of fibrinogen, clot firmness and dynamics of clot formation reached baseline values. Median blood loss following liver injury was significantly less (P=0.018) in the fibrinogen-treated animals (1100 ml; 800-1400 ml) than in the placebo group (2010 ml; 1800-2200 ml). CONCLUSIONS: 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.

[Locoregional anesthesia and coagulation inhibitors. Recommendations of the Task Force on Perioperative Coagulation of the Austrian Society for Anesthesiology and Intensive Care Medicine]. / Lokoregionalanästhesien unter gerinnungshemmender Medikation. Empfehlungen der Arbeitsgruppe Perioperative Gerinnung (AGPG) der Osterreichischen Gesellschaft für Anästhesiologie und Intensivmedizin (OGARI).

More efficacious anticoagulant and antiplatelet agents have been introduced in vascular medicine and in the prevention of perioperative venous thromboembolisms. Patient management should be guided by familiarity with the pharmacology of coagulation-altering drugs and by consensus statements. The present paper reviews recommendations from the Austrian Task Force for Perioperative Coagulation which are based on thorough evaluation of the available pharmacological information and case reports. The consensus statement focuses on neuraxial and peripheral techniques and is designed to encourage safe and quality patient care.

[Management of coagulation after multiple trauma]. / Gerinnungsmanagement beim Polytrauma.

Hemorrhage after traumatic injury results in coagulopathy which only worsens the situation. This coagulopathy is caused by depletion and dilution of clotting factors and platelets, increased fibrinolytic activity, hypothermia, metabolic changes and anemia. The effect of synthetic colloids used for compensating the blood loss, further aggravates the situation through their specific action on the hemostatic system. Bedside coagulation monitoring permits relevant impairment of the coagulation system to be detected very early and the efficacy of the hemostatic therapy to be controlled directly. Administration of fresh frozen plasma (FFP), platelet concentrates and antifibrinolytic agents is essential for restoring the impaired coagulation system in trauma patients. Clotting factor concentrates should be administered if coagulopathy is based on diagnosed depletion of clotting factors, if FFP is not available and if transfusion of FFP is insufficient to treat the coagulopathy. Recombined FVIIa is frequently employed during severe bleeding which could not be treated by conventional methods but the results of on-going clinical trials are not yet available.

Employing vasopressin as an adjunct vasopressor in uncontrolled traumatic hemorrhagic shock. Three cases and a brief analysis of the literature.

Resuscitation of patients in hemorrhagic shock remains one of the most challenging aspects of trauma care. We showed in experimental studies that vasopressin, but not fluid resuscitation, enabled short-term and long-term survival in a porcine model of uncontrolled hemorrhagic shock after penetrating liver trauma. In this case report, we present two cases with temporarily successful cardiopulmonary resuscitation (CPR) using vasopressin and catecholamines in uncontrolled hemorrhagic shock with subsequent cardiac arrest that was refractory to catecholamines and fluid replacement. In a third patient, an infusion of vasopressin was started before cardiac arrest occurred; in this case, we were able to stabilize blood pressure thus allowing further therapy. The patient underwent multiple surgical procedures, developed multi-organ failure, but was finally discharged from the critical care unit without neurological damage.

[Monitoring of Perioperative Dilutional Coagulopathy Using the ROTEM Analyzer: Basic Principles and Clinical Examples]. / 3. Internationales Symposium: "Autologe Transfusion -- Von der Euphorie zur Ratio: Praktisches Handeln aus wissenschaftlicher Sicht" (Teil III).

Recent changes in quality of transfusion supply, transfusion triggers as well as fluid therapy promote the development of dilutional coagulopathy. Nevertheless, up to now guidelines generally assume presence of hypocoagulability when more than one individual circulating blood volume is lost. This might be true for some patients under some conditions but is not necessarily true for every patient. Routine coagulation tests are insufficient in predicting increased bleeding and, moreover, available after an unacceptable time delay. Therefore the occurrence of diffuse microvascular bleeding is often used as clinical sign to start hemostatic therapy. However, such severe derangement of hemostasis might lead to the development of secondary tissue damage and frequently is unresponsive to conventional treatment. Coagulopathy occurring during extensive surgery or after polytrauma can be detected and treated early when using the ROTEM monitoring. Recent data showing a direct beneficial effect of hemostatic therapy on blood loss and final outcome are scarce. However, evidence exists that the amount of blood loss, presence of coagulopathy and number of transfusions needed are associated with poor outcome in bleeding patients. Although manifold articles have been published already using thrombelastography for various indications (medline research "thrombelastography", 2022 articles), further data are needed to confirm the clinical experience that this technique is an excellent tool for safe patient management.

[Autologous transfusion -- from euphoria to reason: clinical practice based on scientific knowledge (Part II). Autologous transfusion in children -- blood saving techniques]. / 3. Internationales Symposium: "Autologe Transfusion -- Von der Euphorie zur Ratio: Praktisches Handeln aus wissenschaftlicher Sicht" (Teil II).

It is uncontested that blood-saving strategies should also be applied in children. However, in the past, blood-saving techniques saw limited use in children, although they are well-established in adults. This is due to technical and methodical problems, but also to the physiologically limited compensatory mechanisms for diminished oxygen delivery in this age group. For this reason, the various blood saving-techniques cannot be universally applied to all age groups. During the first year of life most perioperative techniques are of only limited benefit: even only a small amount of blood loss in relation to total blood volume makes a transfusion of allogeneic blood necessary, which is far before enough shed blood can be recovered for retransfusion. Preoperative autologous donation of blood calls for a high degree of cooperation by the child and the parents an is equally demanding in terms of organization and skills. Therefore, this procedure is used mainly in school-age children and in adolescents. Intraoperative blood salvage, by contrast, is already worthwhile in children from age one year with an expected blood loss of 20 % of blood volume. Acute normovolemic hemodilution and deliberate hypotension should be recommended only in an age group where cardiovascular compensatory mechanisms are given. Supporting procedures aimed at avoiding the need for allogeneic blood include perioperative administration of erythropoietin, iron supplementation, blood-saving surgical techniques and careful hemostasis. These prerequisites, the combination of various techniques, as well as the definition of an age-specific low transfusion trigger have contributed to a marked decrease in the need for allogeneic blood products in children in recent years.