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Volod O, Wegner J. Viscoelastic Testing in the Management of Adult Patients on Mechanical Circulatory Support Devices with Focus on Extracorporeal Membrane Oxygenation. Semin Thromb Hemost 2022; 48:814-827. [DOI: 10.1055/s-0042-1756303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Abstract
AbstractThromboembolic and hemorrhagic complications continue to remain frequent complications that significantly impact the morbidity and mortality of patients implanted with mechanical circulatory support devices (MCSDs). The severe acute respiratory syndrome caused by coronavirus 2 (SARS-CoV-2) has resulted in a number of COVID-19 patients being supported by MCSDs, specifically extracorporeal membrane oxygenation (ECMO), which in turn has created a crucial need for rapid assessment of hemostatic status in these patients to avoid bleeding and thrombotic complications. Currently, conventional plasma-based coagulation assays such as prothrombin time and activated partial thromboplastin time (aPTT) are used to assess hemostasis, and the activated clotting time (ACT) and aPTT are the most common tests used to monitor heparin anticoagulation in patients on ECMO. Unfractionated heparin remains the mainstay anticoagulation therapy for patients on ECMO. Extracorporeal Life Support Organization (ELSO) offers little guidance on the subject but does state that each institution should create its internal anticoagulation protocols. Viscoelastic assays (VEAs) are increasingly recognized by ELSO and ECMO community for their potential to assess hemostatic derangements in patients implanted with MCSDs as well as guidance for appropriate hemostatic therapy. This review focuses on the evidence for the use of viscoelastic assays to assess overall hemostasis and to guide the treatment of adult patients connected to an ECMO circuit. Limitations of the use of conventional assays, ACT, and VEA are also discussed.
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Affiliation(s)
- Oksana Volod
- Department of Pathology and Laboratory Medicine, Cedars Sinai Medical Center, Los Angeles, California
| | - Julie Wegner
- College of Health Professions, South University Online, Savannah, Georgia
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Point-of-Care Measurement of Kaolin Activated Clotting Time during Cardiopulmonary Bypass: A Single Sample Comparison between ACT Plus and i-STAT. THE JOURNAL OF EXTRA-CORPOREAL TECHNOLOGY 2021; 53:57-61. [PMID: 33814607 DOI: 10.1182/ject-2000046] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 02/02/2021] [Indexed: 11/20/2022]
Abstract
Heparin anticoagulation monitoring by point-of-care activated clotting time (ACT) is essential for cardiopulmonary bypass (CPB) initiation, maintenance, and anticoagulant reversal. Concerns exist regarding the comparability of kaolin activated ACT devices. The current study, therefore, evaluated the agreement of ACT assays using parallel measurements performed on two commonly used devices. Measurements were conducted in a split-sample fashion on both the ACT Plus (Medtronic, Minneapolis, MN) and i-STAT (Abbott Point of Care, Princeton, NJ) analyzers. Blood samples from 100 adult patients undergoing elective cardiac surgery with CPB were assayed at specified time points: before heparinization, following systemic heparinization, after CPB initiation, every 30 minutes during CPB, and following protamine administration. A cutoff value of 400 seconds (s) was used as part of the local protocol. Measurements were compared using t tests or Wilcoxon signed-rank tests, linear regression, and Bland-Altman analyses. Parallel ACT measurements demonstrated a good linear correlation (r = .831, p < .001). The overall median difference between both measurements was significantly different from zero, amounting to 87 (14-189) (p < .001), with limits of agreement of -124 and 333s. The i-STAT-derived ACT values were systematically lower than the ACT Plus values, which was more pronounced during CPB. Fourteen patients received additional heparin during CPB at a median ACT Plus value of 414s, with a concomitant median i-STAT value of 316s. Assuming 308s as the theoretical i-STAT cutoff value based on the linear regression equation and an ACT Plus threshold of 400s, 29 patients would have received additional heparin. Based on these results, kaolin point-of-care ACT devices cannot be used interchangeably. Device-specific predefined target values are warranted to avert heparin overdosing during CPB.
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Wool GD. Benefits and Pitfalls of Point-of-Care Coagulation Testing for Anticoagulation Management: An ACLPS Critical Review. Am J Clin Pathol 2019; 151:1-17. [PMID: 30215666 DOI: 10.1093/ajcp/aqy087] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Objectives Point-of-care (POC) testing is generally less precise and has higher reagent costs per test than laboratory-based assays. However, POC hemostasis testing can offer significant advantages in particular situations: patient-managed warfarin therapy as well as rapid turnaround time heparin management for intraoperative patients. Of note, POC hemostasis testing is generally approved for the purposes of anticoagulation monitoring and is inferior to laboratory coagulation testing for the diagnosis of congenital or acquired coagulopathy. Methods The frequently used POC coagulation instruments for POC international normalized ratio and activated clotting time are reviewed, as well as their typical performance relative to central laboratory testing (where available). Results Several cases are discussed that highlight the benefits, as well as pitfalls, of POC coagulation testing. Conclusions POC coagulation testing for anticoagulation monitoring offers advantages in particular situations. Clear policies and protocols must be developed to guide proper use of POC versus central laboratory hemostasis testing.
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Affiliation(s)
- Geoffrey D Wool
- The Department of Pathology, University of Chicago, Chicago, IL
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Chang E, Gatling JW, Bode S, Herrmann PC, Bull BS, Applegate RL. Extreme Plasma Dilution Decreases Heparin and Protamine Cardiopulmonary Bypass Requirements: A Case Report on a Jehovah's Witness Patient. ACTA ACUST UNITED AC 2017; 8:291-293. [PMID: 28328588 DOI: 10.1213/xaa.0000000000000493] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The primary focus of cardiopulmonary bypass management in Jehovah's Witness patients is the need to conserve blood. A consequence of these strategies inevitably results in hemodilution that is frequently extreme enough to dilute clotting factors and potentially impair coagulation. The purpose of this case report is to demonstrate that a hemodiluted patient requires less heparin to sustain anticoagulation and less protamine to reverse heparin at cardiopulmonary bypass termination. Patient harm may ensue unless the effects of extreme hemodilution are recognized.
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Affiliation(s)
- Emilie Chang
- From the *Department of Anesthesiology, Loma Linda University School of Medicine, Loma Linda, California; and †Department of Pathology & Human Anatomy, Loma Linda University School of Medicine, Loma Linda, California
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Does Activated Clotting Time Help to Predict Innate Coagulopathy in End-Stage Liver Disease Patients? Transplant Proc 2017; 49:1076-1081. [DOI: 10.1016/j.transproceed.2017.03.042] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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Muster I, Haas T, Quandt D, Kretschmar O, Knirsch W. Factors Influencing ACT After Intravenous Bolus Administration of 100 IU/kg of Unfractionated Heparin During Cardiac Catheterization in Children. Clin Appl Thromb Hemost 2016; 23:740-747. [PMID: 27514640 DOI: 10.1177/1076029616660761] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Anticoagulation using intravenous bolus administration of unfractionated heparin (UFH) aims to prevent thromboembolic complications in children undergoing cardiac catheterization (CC). Optimal UFH dosage is needed to reduce bleeding complications. We analyzed the effect of bolus UFH on activated clotting time (ACT) in children undergoing CC focusing on age-dependent, anesthesia-related, or disease-related influencing factors. This retrospective single-center study of 183 pediatric patients receiving UFH during CC analyzed ACT measured at the end of CC. After bolus administration of 100 IU UFH/kg body weight, ACT values between 105 and 488 seconds were reached. Seventy-two percent were within target level of 160 to 240 seconds. Age-dependent differences were not obtained ( P = .407). The ACT values were lower due to hemodilution (total fluid and crystalloid administration during CC, both P < .001), with premedication of acetylsalicylic acid ( P = .014) and low-molecular-weight heparin ( P = .049). Arterial thrombosis (3.85%), venous thrombosis (0.55%), and bleeding (1.65%) following CC did not correlate with ACT values but occurred more frequently in children between 1 month and 1 year of age (91%). In conclusion, with a bolus of 100 IU UFH/kg, an ACT target level of 160 to 240 seconds can be achieved during CC in children in 72%, which is influenced by hemodilution and anticoagulant and antiplatelet premedication but not by age.
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Affiliation(s)
- Ileana Muster
- 1 Pediatric Cardiology, Pediatric Heart Center, University Children's Hospital Zurich, Zurich, Switzerland
- 2 Children's Research Center, University Children's Hospital Zurich, Zurich, Switzerland
| | - Thorsten Haas
- 2 Children's Research Center, University Children's Hospital Zurich, Zurich, Switzerland
- 3 Anesthesiology, University Children's Hospital Zurich, Zurich, Switzerland
| | - Daniel Quandt
- 1 Pediatric Cardiology, Pediatric Heart Center, University Children's Hospital Zurich, Zurich, Switzerland
- 2 Children's Research Center, University Children's Hospital Zurich, Zurich, Switzerland
| | - Oliver Kretschmar
- 1 Pediatric Cardiology, Pediatric Heart Center, University Children's Hospital Zurich, Zurich, Switzerland
- 2 Children's Research Center, University Children's Hospital Zurich, Zurich, Switzerland
- Oliver Kretschmar and Walter Knirsch contributed as senior authors
| | - Walter Knirsch
- 1 Pediatric Cardiology, Pediatric Heart Center, University Children's Hospital Zurich, Zurich, Switzerland
- 2 Children's Research Center, University Children's Hospital Zurich, Zurich, Switzerland
- Oliver Kretschmar and Walter Knirsch contributed as senior authors
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In vitro and in vivo effects of hemodilution on kaolin-based activated clotting time predicted heparin requirement using a heparin dose–response technique. J Anesth 2016; 30:923-928. [PMID: 27502398 DOI: 10.1007/s00540-016-2227-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2015] [Accepted: 07/25/2016] [Indexed: 10/21/2022]
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Dzemali O, Ganter MT, Zientara A, Graves K, Behr R, Genoni M, Hofer CK. Evaluation of a New Sonoclot Device for Heparin Management in Cardiac Surgery. Clin Appl Thromb Hemost 2016; 23:20-26. [DOI: 10.1177/1076029616651148] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Background: Sonoclot is used to measure kaolin-based activated clotting time (kACT) for heparin management. Apart from measuring kACT, the device assesses the patient’s coagulation status by glass bead–activated tests (gbACTs; measuring also clot rate [CR] and platelet function [PF]). Recently, a new version of the Sonoclot has been released, and the redesign may result in performance changes. The aim of this study was to evaluate and compare the performance of the new (S2) and the previous (S1) Sonoclot. Methods: The S1 was used in the routine management of 30 patients undergoing elective cardiac surgery. Blood samples were taken at baseline (T1), after heparin administration (200 U/kg, 100 U/kg; T2 and T3), during cardiopulmonary bypass (T4), after protamine infusion (T5), and before intensive care unit transfer (T6). Kaolin-based activated clotting time and gbACTs were measured in duplicate by both the old and the new device and performance compared by Bland-Altman analysis and percentage error calculation. Results: A total of 300 kACT and 180 gbACTs were available. Bland-Altman analysis for kACT revealed that S2 consistently reported results in shorter time compared to S1 (overall = −14.7%). Comparing S2 and S1, the glass bead–activated tests showed mean percentage differences of −18.9% (gbACTs), +37.4% (CR), and −3.7% (PF). Conclusion: Since clotting is faster in the new S2 compared to S1, shorter clotting times have to be considered in clinical practice. The use of S2 kACT in heparin management will result in higher heparin and protamine dosing unless heparin kACT target values are adjusted to correct for the differences in results between S1 and S2.
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Affiliation(s)
- Omer Dzemali
- Division of Cardiac Surgery, Triemli City Hospital, Zurich, Switzerland
| | - Michael T. Ganter
- Institute of Anaesthesiology and Pain Medicine, Kantonsspital Winterthur, Winterthur, Switzerland
| | - Alicja Zientara
- Division of Cardiac Surgery, Triemli City Hospital, Zurich, Switzerland
| | - Kirk Graves
- Division of Cardiac Surgery, Triemli City Hospital, Zurich, Switzerland
| | - Renate Behr
- Division of Cardiac Surgery, Triemli City Hospital, Zurich, Switzerland
| | - Michele Genoni
- Division of Cardiac Surgery, Triemli City Hospital, Zurich, Switzerland
| | - Christoph K. Hofer
- Institute of Anaesthesiology and Intensive Care Medicine, Triemli City Hospital, Zurich, Switzerland
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Levin AI, Heine AM, Coetzee JF, Coetzee A. Heparinase thromboelastography compared with activated coagulation time for protamine titration after cardiopulmonary bypass. J Cardiothorac Vasc Anesth 2014; 28:224-9. [PMID: 24461364 DOI: 10.1053/j.jvca.2013.10.026] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Indexed: 11/11/2022]
Abstract
OBJECTIVE The present study is a comparison of two point-of-care (POC) tests as endpoints of protamine titration after CPB. The authors hypothesized that using the heparinase-kaolin thromboelastography (TEG-HK) R-time difference would more readily identify residual heparin necessitating additional protamine than when using activated coagulation time (ACT). The primary endpoint was the between-group difference in protamine dose. Whether this approach would lessen postoperative bleeding and sequelae also was investigated. DESIGN Single center, blinded, prospective, randomized study. SETTING University teaching hospital. PARTICIPANTS Eighty-two adult patients for on-pump coronary artery bypass and/or valve surgery. INTERVENTIONS Patients were randomized. In the ACT group, protamine was titrated until ACT did not exceed baseline by more than 10%. In the TEG group, a TEG-HK R-time difference less than 20% was targeted. Protamine was repeated to achieve the endpoints. Clinicians in the ACT group were blinded to TEG data and vice versa. MEASUREMENTS AND MAIN RESULTS There was no between-group difference in total protamine dose (3.9 ± 0.6 and 4.2 ± 0.7; 95% CI of the difference between means: -0.544 to 0.008 mg/kg; p = 0.057) or protamine:heparin ratios (1.3:1 and 1.4:1; 95% CI of the difference between means: -0.05 to 0.03 mg/mg; p = 0.653). In the ACT group, 17% of patients required a second protamine dose, and in the TEG group, 24% of patients required a second protamine dose. No between-group differences in the postoperative transfusion requirements or intensive care unit length of stay were demonstrated. CONCLUSION No difference was identified in protamine dosing using either ACT or TEG-HK R-time difference as endpoints. Heparinase TEG may be useful for monitoring heparin reversal.
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Affiliation(s)
- Andrew Ian Levin
- Department of Anesthesiology and Critical Care, Faculty of Health Sciences, University of Stellenbosch and Tygerberg Hospital, Cape Town, South Africa.
| | | | - Johan Francois Coetzee
- Department of Anesthesiology and Critical Care, Faculty of Health Sciences, University of Stellenbosch and Tygerberg Hospital, Cape Town, South Africa
| | - André Coetzee
- Department of Anesthesiology and Critical Care, Faculty of Health Sciences, University of Stellenbosch and Tygerberg Hospital, Cape Town, South Africa
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Brauer SD, Applegate RL, Jameson JJ, Hay KL, Lauer RE, Herrmann PC, Bull BS. Association of Plasma Dilution With Cardiopulmonary Bypass-Associated Bleeding and Morbidity. J Cardiothorac Vasc Anesth 2013; 27:845-52. [DOI: 10.1053/j.jvca.2013.01.011] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/20/2012] [Indexed: 11/11/2022]
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Tennent-Brown BS, Epstein KL, Whelchel DD, Giguère S. Use of viscoelastic coagulation testing to monitor low molecular weight heparin administration to healthy horses. J Vet Emerg Crit Care (San Antonio) 2013; 23:291-9. [PMID: 23656212 DOI: 10.1111/vec.12049] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2012] [Accepted: 03/16/2013] [Indexed: 01/30/2023]
Abstract
OBJECTIVES To evaluate the utility of thromboelastography (TEG) and Sonoclot analyses to monitor the effects of low molecular weight heparin (LMWH) administration to healthy horses. DESIGN Randomized crossover study. SETTING Large animal veterinary teaching hospital. ANIMALS Six adult mixed breed healthy mares. INTERVENTIONS LMWH (dalteparin) was administered (50 U/kg subcutaneously) either every 12 or 24 h for 3 consecutive days. Blood samples were collected before LMWH administration and then at selected time points for analysis. Thromboelastography derived R-time (R), K-time (K), angle (ANG), and maximum amplitude (MA), and Sonoclot activated clot time (ACT), clot rate (CR), and platelet function (PF) were measured in whole blood 30 min after sample collection. Change (Δ) and percentage change (%Δ) from baseline of each TEG and Sonoclot variable were subsequently calculated. Anti-factor Xa activity and activated partial thromboplastin time (aPTT) were assayed in harvested plasma. The association between anti-factor Xa activity and TEG and Sonoclot (measured and calculated) variables was assessed by calculating correlation coefficients and multiple regression analysis. The ability of measured and calculated TEG and Sonoclot variables to predict when anti-factor Xa activity fell below suggested thromboprophylactic levels was assessed using receiver operating characteristic curve analysis. MEASUREMENTS AND MAIN RESULTS The correlation between aPTT and anti-factor Xa activity was weak (r = 0.343). Changes in TEG and Sonoclot variables following LMWH administration were consistent with hypocoagulation. All measured and calculated TEG variables were significantly correlated with anti-factor Xa activity. Sonoclot ACT, ΔACT, CR, ΔCR, and %ΔCR were also significantly correlated with anti-factor Xa activity. TEG ΔR and %ΔR best predicted anti-factor Xa activity below the suggested thromboprophylactic level. CONCLUSIONS Although correlations were modest, serial measurement of TEG variables may be used to monitor LMWH therapy in horses; however, further research is required in sick horses.
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Affiliation(s)
- Brett S Tennent-Brown
- Department of Large Animal Medicine, University of Georgia College of Veterinary Medicine, Athens, GA, USA.
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Finley A, Greenberg C. Review article: heparin sensitivity and resistance: management during cardiopulmonary bypass. Anesth Analg 2013; 116:1210-22. [PMID: 23408671 DOI: 10.1213/ane.0b013e31827e4e62] [Citation(s) in RCA: 133] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Heparin resistance during cardiac surgery is defined as the inability of an adequate heparin dose to increase the activated clotting time (ACT) to the desired level. Failure to attain the target ACT raises concerns that the patient is not fully anticoagulated and initiating cardiopulmonary bypass may result in excessive activation of the hemostatic system. Although antithrombin deficiency has generally been thought to be the primary mechanism of heparin resistance, the reasons for heparin resistance are both complex and multifactorial. Furthermore, the ACT is not specific to heparin's anticoagulant effect and is affected by multiple variables that are commonly present during cardiac surgery. Due to these many variables, it remains unclear whether decreased heparin responsiveness as measured by the ACT represents inadequate anticoagulation. Nevertheless, many clinicians choose a target ACT to assess anticoagulation, and interventions aimed at achieving the target ACT are routinely performed in the setting of heparin resistance. Treatments for heparin resistance/alterations in heparin responsiveness include additional heparin or antithrombin supplementation. In this review, we discuss the variability of heparin potency, heparin responsiveness as measured by the ACT, and the current management of heparin resistance.
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Affiliation(s)
- Alan Finley
- Department of Anesthesia and Perioperative Medicine, Medical University of South Carolina, 25 Courtenay Drive, Charleston, SC 29425, USA.
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Theusinger OM, Levy JH. Point of care devices for assessing bleeding and coagulation in the trauma patient. Anesthesiol Clin 2012; 31:55-65. [PMID: 23351534 DOI: 10.1016/j.anclin.2012.10.006] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Severe trauma is associated with bleeding, coagulopathy, and transfusion of blood and blood products, all contributing to higher rates of morbidity and mortality. The aim of this review is to focus on point-of-care devices to monitor coagulation in trauma. Close monitoring of bleeding and coagulation as well as platelet function in trauma patients allows goal-directed transfusion and an optimization of the patient's coagulation, reduces the exposure to blood products, reduces costs, and probably improves clinical outcome. Noninvasive hemoglobin measurements are not to be used in trauma patients due to a lack in specificity and sensitivity.
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Affiliation(s)
- Oliver M Theusinger
- Institute of Anesthesiology, University Zurich, University Hospital Zurich, Zurich, Switzerland.
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Ulmer FF, Baulig W, Béttex D, Spielmann N, Bürki C, Weiss M. Measurement of activated coagulation time in children: evaluation of the blood-saving kaolin i-STAT activated coagulation time technique in pediatric cardiac anesthesia. J Cardiothorac Vasc Anesth 2011; 25:395-401. [PMID: 21376632 DOI: 10.1053/j.jvca.2010.12.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/14/2010] [Indexed: 11/11/2022]
Abstract
OBJECTIVE To compare the activated coagulation times (ACTs) measured with the blood-saving kaolin i-STAT 1 ACT technique (Abbott Point of Care Inc, Princeton, NJ) with ACTs obtained from the widely used ACTR II device (Medtronic, Inc, Minneapolis, MN) in children undergoing cardiac surgery. DESIGN A prospective, observational single-center study. PARTICIPANTS Forty-four pediatric cardiac surgery patients. INTERVENTION Surgery was performed with cardiopulmonary bypass (CPB) necessitating heparinization. METHODS AND MAIN RESULTS ACTs measured on the i-STAT 1 device (2 × 95 μL) were compared with those obtained from the Medtronic ACTR II device (2 × 0.5 mL). Blood samples were drawn before, during, and after heparinization for CPB and paired for statistical analysis. The 2 techniques were compared using simple and multiregression analyses and the Bland-Altman method. In total, 179 intrarater and 142 interrater data pairs were analyzed. The intrarater reliability of the 2 devices was good, with a mean bias and limits of agreement of +2.0 and -55.5/+59.5 seconds for the Medtronic ACTR II and +0.5 and -59.9/+60.9 seconds for the i-STAT 1. An interrater reliability analysis of the mean of simultaneously measured ACT of the Medtronic ACTR II and both i-STAT 1 devices yielded a mean bias of -5.3 seconds and limits of agreement of -210.1/+199.5 seconds. A comparison of the higher of the paired ACT values from both devices showed similar results. After the removal of heparin, the i-STAT 1's ACT values became significantly lower than those measured on the Medtronic ACTR II (p < 0.001). Simple and multiregression analyses revealed that base excess independently influenced the mean bias of the ACT values from the Medtronic ACTR II (p = 0.037) and i-STAT 1 devices (p = 0.036). CONCLUSION The kaolin i-STAT 1 ACT technique agreed well with the Medtronic ACTR II technique during the nonheparinized phase that preceded CPB. The overall agreement between the ACT obtained from the 2 devices was poor. The routine use of i-STAT 1 measured ACT values cannot be recommended as a reliable alternative to the Medtronic ACTR II.
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Affiliation(s)
- Francis F Ulmer
- Section of Critical Care Medicine, Department of Pediatrics, Yale University, Yale New Haven Hospital, New Haven, CT 06520-8064, USA.
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Ganter MT, Hofer CK. Coagulation monitoring: current techniques and clinical use of viscoelastic point-of-care coagulation devices. Anesth Analg 2008; 106:1366-75. [PMID: 18420846 DOI: 10.1213/ane.0b013e318168b367] [Citation(s) in RCA: 463] [Impact Index Per Article: 28.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Perioperative monitoring of blood coagulation is critical to better understand causes of hemorrhage, to guide hemostatic therapies, and to predict the risk of bleeding during the consecutive anesthetic or surgical procedures. Point-of-care (POC) coagulation monitoring devices assessing the viscoelastic properties of whole blood, i.e., thrombelastography, rotation thrombelastometry, and Sonoclot analysis, may overcome several limitations of routine coagulation tests in the perioperative setting. The advantage of these techniques is that they have the potential to measure the clotting process, starting with fibrin formation and continue through to clot retraction and fibrinolysis at the bedside, with minimal delays. Furthermore, the coagulation status of patients is assessed in whole blood, allowing the plasmatic coagulation system to interact with platelets and red cells, and thereby providing useful additional information on platelet function. Viscoelastic POC coagulation devices are increasingly being used in clinical practice, especially in the management of patients undergoing cardiac and liver surgery. Furthermore, they provide useful information in a large variety of clinical scenarios, e.g., massive hemorrhage, assessment of hypo- and hypercoagulable states, guiding pro- and anticoagulant therapies, and in diagnosing of a surgical bleeding. A surgical etiology of bleeding has to be considered when viscoelastic test results are normal. In summary, viscoelastic POC coagulation devices may help identify the cause of bleeding and guide pro- and anticoagulant therapies. To ensure optimal accuracy and performance, standardized procedures for blood sampling and handling, strict quality controls and trained personnel are required.
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Affiliation(s)
- Michael T Ganter
- Department of Anesthesia and Perioperative Care, University of CA San Francisco, San Francisco, California, USA
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Aprotinin does not prolong the Sonoclot aprotinin-insensitive activated clotting time. J Clin Anesth 2007; 19:424-8. [PMID: 17967670 DOI: 10.1016/j.jclinane.2007.03.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2006] [Revised: 03/01/2007] [Accepted: 03/09/2007] [Indexed: 11/22/2022]
Abstract
STUDY OBJECTIVE To determine whether a new Sonoclot-based, aprotinin-insensitive activated clotting time (aiACT) assay yields stable results over a broad range of aprotinin concentrations. DESIGN Prospective trial conducted on in vitro blood samples. SETTING Tertiary-care teaching medical center. PARTICIPANTS 19 healthy adult volunteers. INTERVENTIONS Whole blood samples were collected from volunteers. Heparin (2 U/mL) and escalating concentrations of aprotinin of 160 to 500 kallikrein inhibitory units (KIU)/mL were added in vitro. MEASUREMENTS AND MAIN RESULTS Celite ACT, kaolin ACT, and aiACT assays were completed. The aiACT showed stable activated clotting time (ACT) results on heparinized, noncitrated blood with added aprotinin (P = nonsignificant). In contrast, celite ACT and kaolin ACT were greatly prolonged when aprotinin was added to heparinized, noncitrated, and citrated blood (P < 0.05). The aiACT had consistent results at all aprotinin concentrations (P = nonsignificant). CONCLUSIONS Aprotinin (160, 320, and 500 KIU/mL) significantly prolongs the ACT value with celite and kaolin activators but not with the aprotinin-insensitive activator.
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Tanaka KA, Szlam F, Sun HY, Taketomi T, Levy JH. Thrombin generation assay and viscoelastic coagulation monitors demonstrate differences in the mode of thrombin inhibition between unfractionated heparin and bivalirudin. Anesth Analg 2007; 105:933-9, table of contents. [PMID: 17898368 DOI: 10.1213/01.ane.0000278868.23814.3b] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
BACKGROUND Coagulation tests, such as activated partial thromboplastin time and activated clotting time, are used to monitor the effects of unfractionated heparin and the direct thrombin inhibitor, bivalirudin. These tests reflect only the initial phase of blood clotting, when <5% of thrombin has been formed. In this study, we sought to determine if similar increases in activated partial thromboplastin time or activated clotting time due to heparin or bivalirudin would reflect the same degree of inhibition of thrombin formation. METHODS Thrombin formation was evaluated in platelet-poor plasma activated in the presence of heparin (0-5 U/mL) or bivalirudin (0-30 microg/mL) using a thrombin generation assay (Thrombinoscope). Prothrombin activation was measured by prothrombin fragment 1.2 (F1.2) formation. Thrombus formation was further evaluated in kaolin-activated whole blood samples containing heparin (1.5 or 2.5 U/mL) or bivalirudin (12.5 or 25 microg/mL) using Sonoclot and thromboelastography. RESULTS Based on the Thrombinoscope results, increasing concentrations of bivalirudin and heparin progressively delayed the onset of thrombin formation, but only heparin dose-dependently decreased the amount of thrombin generated. Heparin and bivalirudin delayed the onset of F1.2 formation, but there was no difference in peak F1.2 levels between bivalirudin and non-anticoagulated samples (206 +/- 28.2 vs 182 +/- 23.9 nmol/L, P = 0.09). In heparinized samples, F1.2 levels were significantly lower (75.7 +/- 29.8 nmol/L, P < 0.05) than controls. Heparin and bivalirudin prolonged the onset of clotting on viscoelastic monitors, but only heparin decreased the rate of thrombus formation. CONCLUSION Thrombus formation kinetics differs between heparin and bivalirudin despite similar prolongation of clotting test values.
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Affiliation(s)
- Kenichi A Tanaka
- Department of Anesthesiology, Emory University School of Medicine, Atlanta, Georgia. USA.
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Point-of-care Coagulation Monitoring: Current Status of Viscoelastic Techniques. Intensive Care Med 2007. [DOI: 10.1007/978-0-387-49518-7_75] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Ganter MT, Monn A, Tavakoli R, Klaghofer R, Zollinger A, Hofer CK. Kaolin-Based Activated Coagulation Time Measured by Sonoclot in Patients Undergoing Cardiopulmonary Bypass. J Cardiothorac Vasc Anesth 2007; 21:524-8. [PMID: 17678778 DOI: 10.1053/j.jvca.2006.12.012] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2006] [Indexed: 11/11/2022]
Abstract
OBJECTIVES In vivo data for the kaolin-based ACT test from the Sonoclot Analyzer (SkACT, Sienco Inc, Arvada, CO) are lacking. The aim of this study was to compare SkACT with an established kaolin-based ACT from Hemochron (HkACT) and anti-Xa activity in patients undergoing cardiopulmonary bypass (CPB). DESIGN Prospective observational study. SETTING Community hospital. PARTICIPANTS Fifty patients scheduled for elective cardiac surgery. INTERVENTIONS Blood samples were taken before CPB at baseline (T0) and after heparinization (T1 and T2), on CPB after administration of aprotinin (5, 15, 30, 60 minutes; T3-T6), and at the end after protamine infusion (T7). MEASUREMENTS AND MAIN RESULTS A total of 375 blood samples were analyzed. ACT measurements were comparable for SkACT and HkACT at each measurement time point. Overall bias +/- standard deviation between SkACT and HkACT was -19 +/- 75 seconds (-2.4% +/- 11.7%). Mean bias between SkACT and HkACT at each time point ranged from -35 to 3 seconds (-4.5% to 2.6%) and showed no statistical significance over time. Heparin sensitivity of SkACT and HkACT, defined as (ACT(Tx)-ACT(T0))/(anti-Xa(Tx)-anti-Xa(T0)), significantly increased for measurements during CPB (p < 0.001) but without significant difference between the 2 methods. Test variability was comparable for both ACT measurement techniques. Overall test variability was 7.5% +/- 7.4% for SkACT and 7.8% +/- 11% for HkACT. CONCLUSIONS Accuracy and performance of SkACT and HkACT were comparable for heparin monitoring in patients undergoing CPB for elective cardiac surgery. However, both tests were affected significantly after initiating CPB and aprotinin infusion.
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Affiliation(s)
- Michael T Ganter
- Department of Anesthesia and Perioperative Care, University of California San Francisco, San Francisco, CA 94110, USA.
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