Comparison between activated clotting time and anti-activated factor X activity for the monitoring of unfractionated heparin therapy in patients with aortic aneurysm undergoing an endovascular procedure.

OBJECTIVE: Current guidelines recommend administration of unfractionated heparin (UFH) and measurement of activated clotting time (ACT) during endovascular procedures. The aim of this study was to compare ACT and anti-activated factor X (anti-Xa) measurements for monitoring of UFH therapy during an aortic endograft procedure and to assess the association of peak ACT and peak anti-Xa activity with periprocedural bleeding. METHODS: We retrospectively studied 104 patients with aortic aneurysm undergoing endovascular procedures with repeated coagulation measurements. After a UFH bolus, further UFH doses were given according to ACT (target range, ≥250 seconds) in clinical routine, and in parallel to each ACT (Hemochron; Accriva Diagnostics, Newport Beach, Calif) measurement, we determined anti-Xa activity (HemosIL Liquid anti-Xa; Instrumentation Laboratory, Bedford, Mass). UFH redosing was solely based on the ACT measurements. We defined periprocedural bleeding as a drop in hemoglobin level ≥3 g/dL or red blood cell transfusion within 24 hours. RESULTS: After the initial UFH bolus (median, 67 IU/kg body weight), ACT and anti-Xa measurements showed a weak correlation (rs, 0.46; P < .001). Median ACT was 233 seconds (range, 127-374 seconds; interquartile range [IQR], 204-257 seconds); median anti-Xa activity was 1.0 IU/mL (range, 0.5-2.0 IU/mL; IQR, 0.9-1.2 IU/mL). Only 31% of the patients had an ACT value ≥250 seconds, whereas all patients had an anti-Xa activity ≥0.5 IU/mL. Accordingly, ACT triggered redosing of UFH frequently. Consequently, we saw a median total UFH use of 90 IU/kg during the procedure, a median peak ACT of 255 seconds (IQR, 234-273 seconds), and a median peak anti-Xa activity of 1.2 IU/mL (IQR, 1.0-1.4 IU/mL). Periprocedural bleeding occurred in 40 (38%) patients. Peak ACT ≥250 seconds was not associated with bleeding (odds ratio, 1.05; 95% confidence interval, 0.41-2.70; P = .952), whereas peak anti-Xa activity ≥1.2 IU/mL was independently associated with bleeding (odds ratio, 4.95; 95% confidence interval, 1.82-13.48; P = .002). Moreover, no periprocedural thromboembolic event occurred. CONCLUSIONS: In this retrospective study of patients with aortic aneurysm undergoing an endovascular procedure, ACT and anti-Xa measurements showed poor correlation; only increased peak anti-Xa activity was independently associated with periprocedural bleeding, not increased ACT. Our findings also suggest that monitoring of UFH therapy with anti-Xa during aortic endograft procedures may reduce total UFH use. We further speculate that this approach could reduce periprocedural bleeding.

[Definitions, decision-making and documentation in end of life situations in the intensive care unit]. / Therapiezieländerungen auf der Intensivstation - Definitionen, Entscheidungsfindung und Dokumentation.

The present work provides assistance for physicians concerning decision making in clinical borderline situations in the ICU. Based on a structured checklist the two fundamental aspects of any medical decision, the medical indication and the patient's preference are queried in a systematic way. Four possible steps of withholding and/or withdrawing therapy are discussed. Finally, recommendations regarding appropriate documentation of end of life decisions are provided.

[Coagulation management in trauma-related massive bleeding. - Recommendations of the Task Force for Coagulation (AGPG) of the Austrian Society of Anesthesiology, Resuscitation and Intensive Care Medicine (OGARI)]. / Gerinnungsmanagement bei traumatisch bedingter Massivblutung - Empfehlungen der Arbeitsgruppe für perioperative Gerinnung der OGARI.

Even nowadays and at specialized centers, one of the leading causes of death is exsanguination. Trauma-induced coagulopathy (TIC) occuring with massive blood loss primarily results from loss of coagualtion factors and platelets and is aggravated by hemodilution. In addition, hyperfibrinolysis, hypothermia, acidosis and hypocalcaemia also contribute to the development of severe haemostatic derangement. During the past few years new insights into the pathophysiology of TIC and the widespread use of viscoelastic coagulation monitoring provoked the development of alternative treatment concepts. As for the previously recommended standard therapy using fresh frozen plasma and platelet concentrates also for alternative strategies no data from large prospective randomized studies are available until now, however, the evidence is growing favoring the use of coagulation factor concentrates guided by viscoelastic measurements.

Implementation of a comprehensive unit-based safety program to reduce surgical site infections in cesarean delivery.

BACKGROUND: To evaluate whether using a comprehensive and multidisciplinary approach to implement an evidence-based bundle can reduce 30-day surgical site infection rates in women undergoing cesarean delivery. METHODS: This observational study with a preintervention and postintervention design included 2576 consecutive women undergoing cesarean delivery at our tertiary care hospital between January 1, 2013 and December 31, 2017. The primary outcome was 30-day surgical site infection rate after cesarean delivery defined according to the Centers for Disease Control and Prevention criteria. The preintervention period span from the January 1, 2013 to December 31, 2014. After initiation of a Comprehensive Unit-based Safety Program (ie, a continuous quality improvement program to improve patient safety using a comprehensive and multidisciplinary approach adapted on local demands), we introduced a bundle of evidence-based interventions (including preoperative shower, hair removal with clippers, correct antibiotic prophylaxis, maintaining normothermia, glycemic control, and strict compliance with hygiene standards as well as practice good hand hygiene) per January 1, 2015 into clinical routine. The postintervention period span from January 1, 2015 to December 31 2017. RESULTS: In the preintervention period the overall surgical site infection rate was 16 of 1,060 cesarean deliveries versus in the postintervention period the overall surgical site infection rate was 9 of 1,516 cesarean deliveries (1.50% vs 0.56%; P = .033). This corresponds to a relative risk reduction of over 60% after implementation of the evidence-based bundle (odds ratio 0.39, 95% confidence interval 0.17-0.89; P = .020). CONCLUSIONS: In the present study, we have adapted the Comprehensive Unit-based Safety Program strategy to implement an evidence based-bundle into clinical routine. Using this comprehensive and multidisciplinary approach, we could markedly reduce 30-day surgical site infections.

Airway stenosis-related increase of pulmonary pressure during high-frequency jet ventilation depends on injector's position.

BACKGROUND: High-frequency jet ventilation (HFJV) can lead to high-airway pressures under certain conditions. In this laboratory study, we evaluated the influence of the injector's position relative to a fixed airway obstruction on peak pressures in a tracheal-lung model. METHODS: We administered HFJV via a metal jet injector at varying distances from connectors simulating laryngotracheal airway stenosis. Peak pressures were measured inside the lung model. RESULTS: When the jet nozzle was near the simulated stenosis, peak pressure within the test lung increased and reached a maximum when the stenosis' lumen decreased despite unchanged parameters of jet gas flow. With the injector's tip placed 8-10 cm in front of the stenosis, reduction of airway diameter did not result in an increase of distal peak pressures. These observations were similar for all settings of gas flow (0.5-1.5 bar driving pressure) and frequencies. CONCLUSION: This study in a lung model suggests that placing an injector more than 8 cm proximal to a laryngotracheal stenosis will prevent changes in intrapulmonary pressure related to the degree of stenosis or driving pressure during HFJV. The location of the injector chosen for clinical care should balance the need for effective ventilation with the risk of barotrauma.

Acenocoumarol decreases tissue factor-dependent coagulation during systemic inflammation in humans.

BACKGROUND: Coumarin derivatives are still widely used for prophylaxis of thromboembolic events and therefore represent important comparator substances for new anticoagulants. Measurement of the efficacy of such novel compounds in a human coagulation model with adequate biomarkers could be useful for early-phase clinical drug development. To evaluate the applicability of a well-established model of tissue factor-dependent coagulation for defining anticoagulant potency, we investigated the effects of acenocoumarol in experimental human endotoxemia. METHODS: In a randomized, controlled, 2-by-2 factorial design, healthy volunteers received an infusion of 2 ng/kg endotoxin or placebo after 18 days of pretreatment with acenocoumarol or placebo. Prothrombin fragment 1+2 (F(1+2)), soluble fibrin, and D-dimer were used as markers of thrombin and fibrin formation. RESULTS: As expected, pretreatment with acenocoumarol decreased vitamin K-dependent coagulation factors, but it also decreased spontaneous thrombin formation. Acenocoumarol inhibited endotoxin-induced thrombin generation as measured by F(1+2) levels: endotoxin infusion increased F(1+2) levels 8-fold-from 0.5 to 4.1 nmol/L-in the placebo group, whereas peak F(1+2) levels reached only 1.0 nmol/L in subjects after acenocoumarol pretreatment. This inhibition was also reflected in decreased formation of soluble fibrin and decreased D-dimer levels, showing that depletion of endogenous coagulation factors limits the propagation of nonovert disseminated intravascular coagulation. CONCLUSIONS: Human endotoxemia is a suitable tool for measurement of the efficacy of oral anticoagulants and therefore may become a valuable addition for expeditious pharmacodynamic characterization of lead compounds with anticoagulant potency.

Point of care measurement of lepirudin and heparin anticoagulation during systemic inflammation.

BACKGROUND: The number of indications for recombinant human hirudin lepirudin therapy has increased in recent years, and now includes acute coronary syndromes and heparin-induced thrombocytopenia. Hence, point of care monitoring appears desirable for therapy with lepirudin. As CoaguChek Plus (CCP) provides a rapid bedside test to monitor therapy with other anticoagulants, we aimed to determine its suitability for lepirudin therapy. METHODS: Forty-four healthy volunteers received a 2 ng/kg endotoxin infusion (to induce coagulation) together with clinically relevant doses of lepirudin or heparin in a prospective, placebo-controlled, randomised fashion. Measurements of CCP-partial thromboplastin time (aPTT) were compared to laboratory STA-aPTT. RESULTS: As expected, baseline values of CCP-aPTT were shorter than STA-aPTT. Lepirudin increased CCP-aPTT 3-fold, and STA-aPTT 2-fold 1 h after bolus infusion. During lepirudin infusion, the correlation between CCP-aPTT and STA-aPTT was excellent (r=0.86-0.92). Both methods were equally sensitive to over-anticoagulation with heparin. Acute systemic inflammation had little effects on CCP-aPTT. CONCLUSION: CCP-aPTT is suitable for longitudinal point of care monitoring of lepirudin therapy. As baseline values of CCP-aPTT are shorter than STA-aPTT, it is recommended not to indiscriminately change between methods in the follow-up of individual patients.

Evaluation of antiinflammatory and antiadhesive effects of heparins in human endotoxemia.

OBJECTIVE: Cytokines and adhesion molecules have a decisive role in the development of early inflammatory response as well as the late sequelae of sepsis. Because L-selectin-deficient mice are protected from lethal endotoxemia, blockade of L-selectin may provide a useful therapeutic option in human sepsis. Heparin has immunomodulatory properties and effectively inhibits L- and P-selectin binding in vitro. We therefore investigated whether clinically applied doses of unfractionated or low-molecular-weight heparin affect early inflammatory response in human endotoxemia. DESIGN: The study was randomized, double-blinded, placebo-controlled, in three parallel groups consisting of 30 healthy male volunteers. SETTING: University medical center. INTERVENTIONS: All subjects received a 2-ng/kg intravenous bolus of lipopolysaccharide and 10 mins later unfractionated heparin, low-molecular-weight heparin, or placebo as bolus primed continuous infusion for 6 hrs. MEASUREMENTS AND MAIN RESULTS: Lipopolysaccharide infusion induced similar increases of tumor necrosis factor-alpha, interleukin-6, interleukin-8, C-reactive protein, and soluble E-selectin levels in all treatment groups. CD11b expression increased by approximately 400%, but L-selectin decreased by 41% in the placebo arm 6 hrs after lipopolysaccharide infusion. Interestingly, both heparins (in particular unfractionated heparin) decreased L-selectin down-regulation as compared with placebo. Similarly, the decrease in lymphocyte counts was significantly less in the unfractionated heparin group during the first 24 hrs (p <.05 vs. placebo) CONCLUSIONS: Heparins displayed little effects on cytokine production and endothelial cell activation in endotoxemia. Of note, however, unfractionated heparin reduced L-selectin down-regulation and lymphocytopenia. These could present novel mechanisms of action of unfractionated heparin.

Effect of factor X inhibition on coagulation activation and cytokine induction in human systemic inflammation.

Anticoagulants have gained increasing attention in the treatment of sepsis. This study used danaparoid to investigate the role of factor Xa in endotoxin-induced coagulation and inflammation and its effectiveness when coagulation activation has already occurred. Thirty healthy volunteers were enrolled in the randomized, placebo-controlled trial. Subjects received 2 ng/kg endotoxin and danaparoid 10 min or 3 h thereafter or placebo. Endotoxin increased prothrombin fragment 1+2 (F(1+2)) levels from 0.5 to 7.0 nmol/L at 5 h in the placebo group. Early danaparoid infusion inhibited endotoxin-induced thrombin formation: maximum F(1+2) levels reached only 1.8 nmol/L (P<.01, vs. baseline or placebo). Delayed danaparoid infusion effectively blocked further thrombin formation. However, danaparoid did not alter endotoxin-induced changes in the fibrinolytic system, cytokine levels, activation of leukocytes, or tissue factor expression on monocytes. Danaparoid therefore selectively attenuates endotoxin-induced coagulopathy, even with delayed administration when coagulation activation is well under way.