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Rotational Thromboelastometry (ROTEM) allows for the global assessment of hemostasis in whole blood samples. Preanalytical and analytical factors may influence test results, and data about the reliability and reproducibility of lyophilized ROTEM tests are scarce. Therefore, the objective of this study was to evaluate the influence of blood collection site on ROTEM S parameters and to assess intrarater and in-between device variability. A total of thirty, healthy, staff-owned dogs were included. Blood collection and ROTEM analysis were performed by trained staff according to a standardized protocol. Extrinsically activated (tissue factor; Ex-TEM S), with the addition of cytochalasin for platelet inhibition (Fib-TEM S), and intrinsically activated (In-TEM) analyses were performed. Analysis of our data showed significant variability for various Ex-TEM S and Fib-TEM S parameters from different collection sites and intrarater and in-between device measurements. We conclude that serial monitoring with ROTEM should be performed on the same device, with blood always taken from the same collection site using a standardized blood sampling technique. While In-TEM S, apart from maximum lysis, showed very stable and reliable results, we suggest interpreting especially clotting and clot formation parameters from Ex-TEM S and Fib-TEM S tests with caution and using duplicate measurements to detect outliers and to prevent initiation of incorrect therapies.

Viscoelastic testing as a bedside test to assess global haemostasis has gained popularity in the past decade, with rotational thromboelastometry (ROTEM) and thromboelastography (TEG) being the two commonly used devices. TEG studies suggest analysis 30 min after blood sampling. However, the reproducibility of results over time for ROTEM analysis using lyophilized samples in dogs has not been established. In this study, we investigated the influence of time on viscoelastic testing, using 33 healthy staff-/client-owned dogs for blood sampling and repeated measurements of ROTEM tracings at three different time points after blood collection. Additionally, a group of 21 hospitalized patients with suspected coagulation disorders were included to investigate whether stability over time was comparable between healthy and ill dogs. We demonstrated a significant difference of ROTEM tracings over time, with a tendency towards hypocoagulability over time. These changes do have a clinical relevance as they exceed reference intervals and could therefore lead to erroneous conclusions about a patient’s coagulation status. Therefore, time-specific reference intervals are proposed and presented in this publication.

English Effect of early administration of tranexamic acid on ongoing haemorrhage in dogs with non-surgically treated haemoabdomen Tranexamic acid (TXA) is an antifibrinolytic drug used for the prophylaxis and treatment of haemorrhage of various origin. This retrospective study investigated the effect of TXA on ongoing bleeding in dogs with nonsurgically treated haemoabdomen. The study population consisted of 48 dogs treated in the period 2009–2020 at the Small Animal Clinic of the Vetsuisse Faculty of Zurich. Twenty-eight of 48 dogs were treated with 20 mg/kg TXA IV within 3h of diagnosis of haemoabdomen. Dogs treated with and without TXA were monitored over 48 hours for signs of ongoing haemorrhage. Ongoing haemorrhage was defined as an increase in abdominal fluid accumulation, a decrease in haematocrit of >5% over time or need for surgical exploration after at least 12 hours of medical treatment. Transfusion requirements, cumulative amount of fluid therapy, heart rate, respiratory rate, temperature, systolic and mean arterial pressure, estimate of abdominal fluid identified by FAST analysis, venous haematocrit, abdominal haematocrit, serum albumin, serum lactate and thrombocyte count were extracted from patient records at 6, 12, 24 and 48 hours after diagnosis of haemoabdomen. Groups were comparable at presentation, however dogs of the TXA group showed a significantly lower abdominal haematocrit at presentation (37 vs 45%, P=0,034) and a higher fluid accumulation (P=0,019), both persisting over time. None of the outcome parameters for ongoing haemorrhage was significantly different between groups. Transfusion requirement was low and similar in both groups. Of interest, none of the 16 dogs undergoing thromboelastometry showed hyperfibrinolysis at presentation. We conclude that other mechanisms than antifibrinolytic therapy was responsible for cessation of bleeding in the majority of patients. Keywords: Antifibrinolytic, canine, fibrinolysis, hemoperitoneum, trauma

Rotational thromboelastometry (ROTEM) is a viscoelastic coagulation test that allows the evaluation of haemostasis from clot formation to clot dissolution. The aim of this retrospective study was to describe the changes in haemostasis using ROTEM parameters in dogs presenting with spontaneous or traumatic haemoperitoneum and to evaluate any associations between clinical and laboratory parameters at presentation with the ROTEM. We hypothesized that the dogs would show signs of hypocoagulability and hyperfibrinolysis and that these changes would correlate with the degree of hypoperfusion. Clinical records were searched for a period of 5 years for dogs presenting with a haemoperitoneum und for whom a -ROTEM analysis at presentation was carried out. Forty dogs were identified, and various clinical and laboratory parameter (heart rate, blood pressure, blood glucose, lactate, serum albumin concentration, PCV (venous and abdominal), ionized calcium, pH and base excess) were retrieved. The following ROTEM parameters were analysed: extrinsic clotting time (ExTEM CT), clot formation time (ExTEM CFT), clot firmness (ExTEM MCF) and maximum lysis (ExTEM ML), as well as fibrinogen (FibTEM) CT and MCF. Compared to institutional reference intervals, dogs with haemoabdomen showed prolongation of ExTEM and FibTEM CT, ExTEM CFT and 50% were hypocoagulable and 62% thrombocytopenic. No hyperfibrinolysis could be detected. Multiple linear regression models showed an association between decreased base excess, trauma and ROTEM signs for hypocoagulability. Furthermore, age was associated with a stronger fibrin clot. In conclusion, 50% of the dogs presented hypocoagulable and changes in ROTEM parameters are similar to those seen with consumption coagulopathy. Base excess and trauma were associated with hypocoagulability, while increasing age was associated with a stronger fibrin clot.

In people, the antifibrinolytic drug tranexamic acid reduces bleeding and the need for blood products with both normal and exaggerated fibrinolysis without increasing the number of thromboembolic events. In dogs, in addition to prevention and treatment of bleeding, higher doses of tranexamic acid can be used to induce vomiting. The objective of this study was to evaluate the effect of a high dose of tranexamic acid on the coagulation of healthy Beagle dogs. A prospective trial was conducted in eight healthy Beagles receiving tranexamic acid for a concurrent trial evaluating different antiemetics. Rotational thromboelastometry (ROTEM) analysis (EXTEM, APTEM, FIBTEM, INTEM) was performed before and 30 minutes after intravenous administration of 50 mg/kg tranexamic acid. ROTEM parameters before and after tranexamic acid administration and between EXTEM and APTEM were compared with Wilcoxon matched-pairs signed rank test and data is presented as median (range). After tranexamic acid administration, FIBTEM clotting time became significantly shorter (p=0.03) from 37 s (28-124 s) to 33 s (27-40 s) and INTEM clot formation time significantly decreased (p=0.02) from 82 s (47-132 s) to 60 s (43-107 s). After tranexamic acid APTEM MCF was significantly weaker (p=0.01) with 45 mm (30-63 mm) than EXTEM MCF with 55 mm (43-69 mm) and than APTEM MCF before tranexamic acid with 55 mm (43-69 mm) (p=0.02). All other analysed parameters including maximum lysis did not change after administration of tranexamic acid. The administration of 50 mg/kg intravenous tranexamic acid resulted in small changes in ROTEM profiles without inducing a hypercoagulable clot. In conclusion, tranexamic acid can safely be administered to healthy dogs with normal coagulation profiles. As an additional finding, APTEM parameters measured in the current study do not support the use of this test in dogs

Tranexamic acid (TXA) is an antifibrinolytic drug that is used for uncontrolled bleeding of various origin. This retrospective study investigated the effect of tranexamic acid administration on bleeding tendency in dogs with surgically managed hemoperitoneum. Thirty dogs were treated with (TXA group) and 25 dogs without (CTR group) tranexamic acid prior to surgery. Various parameters (decrease in haematocrit, number of transfusions, shock index and changes in abdominal fluid accumulation) were used for characterization of bleeding tendency and compared between groups. Groups were similar at presentation and prior to surgery. None of the dogs undergoing rotational thromboelastography analysis showed hyperfibrinolysis prior to surgery. Overall transfusion and erythrocyte transfusion requirements as well as bleeding tendency, hospitalisation time and hospital discharge rate were similar between groups. Dogs of the TXA group received significantly more intraoperative plasma transfusions (P=0.013) and showed a higher systolic and mean arterial blood pressure (P=0.002 and 0.050) and lower shock index (P=0.028) with less dogs being in shock (P=0.012) at 24h. In summary, in this study population of dogs with surgically managed spontaneous hemoperitoneum dogs treated with tranexamic acid received more plasma transfusions intraoperatively and showed a lower shock index 24h after presentation. In dogs with surgically treated hemoabdomen tranexamic acid administration prior to surgery does not reduce red blood cell transfusion requirements or postoperative bleeding tendency.

The use of synthetic colloids (SCs), particularly hydroxyethyl starch (HES), in people has changed in recent years following new evidence raising concerns about their efficacy and safety. Although fluid therapy guidelines for small animals are often extrapolated from human medicine, little information exists on current practice in veterinary medicine. The objective of the present study was to investigate current fluid selection, use of plasma volume expanders including SCs, and recent changes in their use in small animal practice. An Internet-based survey was conducted, inviting veterinarians to report their practices in fluid resuscitation and colloid osmotic pressure support, their choice of SC, and perceived adverse effects and contraindications associated with SC use. There were 1,134 respondents from 42 countries, including 46% general practitioners and 38% diplomates. Isotonic crystalloids, HES, and hypertonic saline were chosen by most respondents for fluid resuscitation, and HES by 75% of respondents for colloid osmotic support. Dextran and gelatin were used by some European respondents. Human serum albumin was used more than canine albumin but 45% of respondents, particularly those from Australia and New Zealand, used no albumin product. The majority (70%) of respondents changed their practice regarding SCs in recent years (mostly by limiting their use), largely due to safety concerns. However, only 27% of respondents worked in an institution that had a general policy on SC use. Impaired renal function, coagulopathy, and hypertension were most often considered contraindications; impaired coagulation tests and increased respiratory rate were the most frequently perceived adverse effects. The use of HES remains widespread practice in small animals, regardless of geographic location. Nevertheless, awareness of safety issues and restrictions on the use of SCs imposed in human medicine seems to have prompted a decrease in use of SCs by veterinarians. Given the p

Background: Hydroxyethyl starch (HES) solutions may cause acute kidney injury (AKI) in humans. Objective: To compare AKI grades in 94 dogs exposed and 90 dogs that were unexposed to 6% HES-130/0.4. Animals: Dogs receiving 6% HES-130/0.4 (HES cohort) or crystalloids (unexposed cohort) between 2013 and 2015. Methods: Historical cohort study. Diagnosis, total cumulative dose and total mL/kg of HES administered, time frame of HES administration and serum creatinine concentrations up to 90 days after initiation of HES treatment were retrospectively reviewed. The AKI grades were retrospectively determined by IRIS guidelines. Results: Exposed dogs received a median cumulative dose of 69.4 mL/kg (range, 2–429 mL/kg) HES over a median of 4 (range, 1–16) days, resulting in a median dose of 20.7 (range, 2–87) mL/kg/d. Although the cohorts differed in terms of age and diagnosis, AKI grades were not significantly different at the evaluated short- and long-term time points. Results of ordinal logistic regression identified the number of days of HES administration as significantly associated with an increase in AKI grade within 10 days (P = .038), whereas there was no significant association among HES exposure, HES mL/kg/d, and an increase in AKI grade. Conclusions and Clinical Importance: HES-130/0.4-treated dogs were not more prone to develop AKI than HES-untreated, but the number of HES days was significantly associated with an increase in AKI grade within 10 days post-HES administration. The time frame of HES treatment should be kept short. Prospective, randomized clinical trials are required to assess the effect of HES on renal function in dogs.