Determination of Normal Values Using an Automated Coagulation Timer for Activated Coagulation Time and its Application in Dogs with Hemophilia

Reference interval, longitudinal variability and reliability of activated clotting time in healthy dogs using a point-of-care analyser

BACKGROUND

Activated clotting times (ACTs) are used to screen for coagulopathies and monitor heparin therapy.

OBJECTIVES

To determine a reference interval (RI) for ACT in dogs using a point-of-care analyser, to quantify intra-subject within- and between-day variability, to quantify analyser reliability and inter-analyser agreement and to study the influence of a delay in measurement.

METHODS

Forty-two healthy dogs were included. Measurements were performed on fresh venous blood using the i-STAT 1 analyser. The RI was determined using the Robust method. Intra-subject within-day variability and between-day variability were quantified between baseline and 2 h (n = 8) or 48 h (n = 10) later. Analyser reliability and inter-analyser agreement were studied by duplicate measurements (n = 8) on identical analysers. The influence of measurement delay was studied before and after a delay of one analytical run (n = 6).

RESULTS

Mean, lower and upper reference limits for ACT were 92.9 ± 9.1, 74.4 and 111.2 s, respectively. Coefficients of variation of intra-subject within- and between-day variability were 8.1% and 10.4%, respectively, resulting in a significant between-day measurement difference. Analyser reliability assessed by the intraclass correlation coefficient and coefficient of variation were 0.87% and 3.3%, respectively. Significantly lower ACT values were observed after a measurement delay compared to direct analysis.

CONCLUSIONS

Our study provides an RI for ACT in healthy dogs using the i-STAT 1 and suggests low intra-subject within- and between-day variability. Analyser reliability and inter-analyser agreement were good; however, analysis delay and between-day differences could significantly influence ACT results.

Hemostatic Patches Based on Crosslinked Chitosan Films Applied in Interventional Procedures

In this study, we manufactured biocompatible hemostatic crosslinked chitosan (CS) patches and analyzed their physicochemical and biological properties for femoral arterial puncture applications. CS is a representative hemostatic material but has some drawbacks, such as swelling, shrinkage, and brittleness. Thus, it was crosslinked via a 1-ethyl-3-(3-dimethyl aminopropyl) carbodiimide (EDC)/N-hydroxysuccinimide (NHS) coupling reaction and a nucleophilic addition reaction with citric acid (CA), glutaraldehyde (GTA), and genipin (GP) to remedy its shortcomings. The CSCA (crosslinked CS with CA/EDC), CSGTA (crosslinked CS with GTA), and CSG (crosslinked CS with GP) films showed low swelling degrees and good mechanical properties (excluding CSCA) compared with those of neat CS films. Additionally, every crosslinked CS film coated with thrombin (TB-CS) showed enhanced hemostatic ability in the whole blood clotting and activated partial thromboplastin time tests. Furthermore, the CSCA, CSGTA, and CSGP were nontoxic in an in vitro cell cytotoxicity test (3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide assay) using L-929 mouse fibroblasts cells.

Life-Threatening Mediastinal Hematoma Formation After Removal of the Hemodialysis Catheter in a Boxer: A Case Report

A 4-year-old female Boxer was referred for renal replacement therapy 2 days after observed grape ingestion. An 11-French dual-lumen dialysis catheter was placed into the right jugular vein and continuous renal replacement therapy was initiated for 66 h. Afterwards the patient received enoxaparin subcutaneously as a thromboprophylaxis. Four hours after removal of the dialysis catheter the patient developed severe dyspnea with hypercapnia and signs of hemorrhagic shock. Bedside ultrasound and X-rays of the thorax revealed a soft tissue opacity dorsally of the trachea, located in the mediastinum. The findings were consistent with mediastinal bleeding and hematoma formation. Blood gas examination indicated hypoventilation. The dog was managed conservatively with multiple blood transfusions and mechanical ventilation. The patient survived to discharge, and the hematoma was fully absorbed in the radiographs after 17 days. Patients with impaired kidney function should receive individualized enoxaparin dosage adjusted to anti-Xa levels and should be strictly monitored for complications. Mediastinal hemorrhage and hematoma formation should be considered as a potential complication in patients receiving a jugular vein catheter.

Treatment of a massive naproxen overdose with therapeutic plasma exchange in a dog

In comparison with other over-the-counter anti-inflammatory drugs, naproxen has a longer half-life in dogs and can lead to severe morbidity and mortality. This report describes the successful use of membrane-based therapeutic plasma exchange after a massive ingestion of naproxen by a dog resulting in 86% reduction in plasma concentration.

Point of Care Assessment of Coagulation

Disorders of hemostasis can be difficult to fully elucidate but can severely affect patient outcome. The optimal therapy for coagulopathies is also not always clear. Point of care (POC) testing in veterinary medicine can assist in the diagnosis of hemostatic disorders and also direct treatment. Advantages of POC testing include rapid turnaround times, ease of use, and proximity to the patient. Disadvantages include differences in analytic performance compared with reference laboratory devices, the potential for operator error, and limited test options per device. Conventional coagulation tests such as prothrombin time, activated partial thromboplastin time, and activated clotting time can be measured by POC devices and can accurately diagnose hypocoagulability, but they cannot detect hypercoagulability or disorders of fibrinolysis. Viscoelastic POC coagulation testing more accurately evaluates in vivo coagulation, and can detect hypocoagulability, hypercoagulability, and alterations in fibrinolysis. POC platelet function testing methodologies can detect platelet adhesion abnormalities including von Willebrand disease, and can be used to monitor the efficacy of antiplatelet drugs. It is unlikely that a single test would be ideal for assessing the complete coagulation status of all patients; therefore, the ideal combination of tests for a specific patient needs to be determined based on an understanding of the underlying disease, and protocols must be standardized to minimize interoperator and interinstitutional variability.