Corrin Boyd

Balanced isotonic crystalloids are appropriately the mainstay of fluid therapy in veterinary medicine. They are an appropriate option in many circumstances, including treatment of shock, dehydration, ongoing fluid losses, and provision of maintenance fluid requirements. However, a variety of other fluid types may be indicated in specific circumstances. These include 0.9% sodium chloride, hypertonic crystalloids, hypotonic crystalloids, synthetic colloids, albumin solutions, and plasma products. Knowledge of the indications and risks of these varied fluid therapy products allows for tailored selection of the most appropriate fluid for individual animals.

Introduction
The use of rivaroxaban, an oral direct factor Xa inhibitor, has only been described in a small number of publications in cats. The study objective was to describe the use of rivaroxaban in a large population of hospitalised cats.

Methods
Cases were retrospectively identified from June 2017 to July 2024 at seven veterinary specialty hospitals. Any cat prescribed rivaroxaban was eligible for inclusion. Data extracted from the medical records included signalment (age, sex, breed), body weight, reason for commencing rivaroxaban, dose and duration of rivaroxaban, concurrent anticoagulant and antiplatelet therapies, potential rivaroxaban adverse effects, and outcome. Non-parametric descriptive statistics are reported.

Results
In total, 66 cats were included. Median rivaroxaban dose was 2.5 mg (Min-Max 1.25–10, Q1-Q3 2.5–5.0), equal to 0.73 mg/kg/day (Min-Max 0.28–1.87, Q1-Q3 0.53–1.0). A total of 36 cats (54.5%) were within the suggested dose range of 0.5–1 mg/kg/day of the Consensus on the Rational Use of Antithrombotics in Veterinary Critical Care (CURATIVE) guidelines, 14 (21.2%) were below, while 16 (24.2%) were above. Median duration of rivaroxaban was 26.5 days (Min-Max 0–442, Q1-Q3 2–60), although followup was variable. The indication for rivaroxaban administration was confirmed thrombosis (48, 72.7%), strong clinical suspicion of thrombosis (6, 9.1%), and prophylaxis (12, 18.2%). Most thrombi were arterial, including aortic thromboembolism affecting both pelvic limbs (25/54 cats with thrombosis, 46.3%), arterial thrombosis affecting a single limb (16, 29.6%), and cardiac chamber thrombus (7, 13%). Cardiac disease was the most common thrombosis risk factor (53/66, 80.3%). Other CURATIVE defined risk factors included immune-mediated haemolytic anaemia in four cats (6.1%) and sepsis in one cat. Other thromboprophylaxis administered included clopidogrel in 58 cats (87.9%), dalteparin in 8 cats (12.1%), and aspirin in 4 cats (6.1%). Potential adverse effects prompting rivaroxaban discontinuation included one case each of vomiting, a cerebrovascular accident, gastrointestinal bleeding, and haemorrhagic pleural effusion. Forty-five cats (68.2%) survived to hospital discharge, 14 (21.2%) were euthanised, two (3%) died, and five (7.6%) were taken home against medical advice.

Conclusion
Rivaroxaban was well tolerated in a large population of cats, predominantly prescribed for arterial thrombosis associated with cardiac disease.

Introduction
Prokinetics are used to treat gastrointestinal (GI) dysmotility in critically ill dogs but there have been no published studies characterizing their use. The objective of this multi-institutional retrospective cohort study was to describe the use of the prokinetics erythromycin and metoclopramide in dogs hospitalized in two institutions. We hypothesized that there would be change over time and differences between institutions in the use of erythromycin and metoclopramide.

Methods
Dogs for inclusion were identified by fee code searches for injectable erythromycin and metoclopramide in the electronic medical record systems of The Animal Hospital at Murdoch University and Western Australian Veterinary Emergency and Specialty Hospital for the years 2018 and 2023. 75 cases from each hospital in each year were selected for inclusion from the search results using a formal randomization procedure to yield a total case number of 300. Data collected for each dog included signalment, diagnosis, reason(s) for starting prokinetics, the injectable prokinetic(s) used, frequency, and doses. Chi square or Fisher’s exact tests were used as appropriate to compare the proportions of dogs receiving metoclopramide alone, erythromycin alone, or both prokinetics in 2018 and 2023, the proportions of dogs receiving metoclopramide or erythromycin as sole prokinetics between the two institutions, and the proportions of dogs receiving a single prokinetic versus dual prokinetics between the two institutions.

Results
Primary GI diseases accounted for the majority of the diagnoses. The most common reasons for starting a prokinetic were vomiting, an imaging diagnosis of ileus, prophylaxis following abdominal surgery, and regurgitation. Metoclopramide was administered as a sole prokinetic in the majority of dogs, fewer cases received erythromycin alone, or both prokinetics. Use of metoclopramide alone decreased from 2018 to 2023, with more dogs receiving erythromycin alone or both prokinetics in 2023. There were also significant differences in prokinetic use between institutions.

Discussion
Prospective studies to investigate the effectiveness and safety of metoclopramide and erythromycin as prokinetics in dogs are warranted.

Objective
To document clinical complications and intervention options associated with norepinephrine (NE) extravasation in dogs and cats.

Design
Cases were identified between 2015 and 2021. Because this is an uncommon complication, the findings are compiled as a descriptive retrospective study.

Setting
Cases were provided from 4 universities and 2 private practice groups in the United States, Canada, and Australia.

Animals
Fourteen patients (13 dogs, 1 cat) that experienced extravasation events (16 total).

Interventions
Small animal patients were included where extravasation of a NE constant rate infusion (CRI) was documented. Records were reviewed for information, including suspected underlying condition, description of the interventions pursued after identification of extravasation, clinical signs after extravasation, and survival to discharge or reason for patient death or euthanasia. When available, information was collected pertaining to the NE dose, dilution, total duration of CRI, and duration of CRI before extravasation was recognized.

Measurements and Main Results
The most commonly reported clinical signs after extravasation of NE were skin necrosis (n = 9 [64.3%]) and swelling (n = 6 [42.9%]). In 10 of 16 events (62.5%), discontinuation of the NE CRI and/or application of a warm compress to the extravasation site were performed; these were the most common nonpharmacological rescue measures. Two patients received subcutaneous phentolamine, and 1 patient underwent hyperbaric oxygen therapy. While surgical intervention was recommended for 4 dogs, 2 improved without surgical debridement. The overall survival rate from underlying disease processes was 57% (n = 8), with only 1 patient (7%) euthanized due to an injury from the extravasation.

Conclusions
Severe lesions can result from NE extravasation in dogs and cats, leading to euthanasia. Although phentolamine remains the treatment of choice, lesions may heal with alternative supportive measures.

Exercise-induced muscle damage (EIMD) results in the generation of reactive oxygen species (ROS), but little is known about the temporal profile of change in ROS post-EIMD and how ROS levels relate to the onset of and recovery from EIMD. Our primary aim was to examine the effect of EIMD on the pattern of change in the blood level of thiol-oxidised albumin, a marker of oxidative stress.
Seven male participants were subjected on separate days to eccentric muscle contraction to cause EIMD or a no-exercise condition. After each session, the participants collected daily dried blood spots to measure thiol-oxidised albumin and returned to the laboratory every 2 days for the assessment of indirect markers of EIMD, namely maximal voluntary contraction (MVC), delayed onset muscle soreness (DOMS), creatine kinase (CK), and myoglobin.
Eccentric exercise resulted in a significant decrease in MVC and increase in DOMS, CK, myoglobin, and thiol-oxidised albumin with the latter reaching above baseline level within 24-48 h post-exercise. All the markers of EIMD returned to baseline level within 6 days post-exercise, but not the level of thiol-oxidised albumin which remained elevated for 10 days after exercise. There was a moderate correlation between changes in thiol-oxidised albumin and DOMS, but no significant relationship between any other markers of muscle damage.
The levels of thiol-oxidised albumin increase in response to EIMD and remain elevated for several days post-exercise. The temporal pattern of change in the level of thiol-oxidised albumin suggests that this may be a useful biomarker of muscle repair post-EIMD.

Objectives: To compare the hemostatic characteristics of cold-stored whole blood (CSWB) from non-greyhound dogs (NGD) and greyhound dogs (GD) over 42 days of storage, notably, platelet closure time (PCT) (NGD only), manual platelet count (PLT) (GD only), ellagic acid (INTEM) and tissue factor activated (EXTEM) rotational thromboelastometry, prothrombin (PT) and activated partial thromboplastin time (aPTT), fibrinogen concentration (FIB), and the activities of factors (F) FII, FV, FVII, FVIII, FIX, FX, FXIII antigen (FXIII:Ag), and von Willebrand factor antigen (vWF:Ag).

Design: Whole blood from 10 NGD and 10 GD, was refrigerated in CPD blood bags at 4 degrees C for 42 days. Blood was analyzed before refrigeration (day 0) and at day 1 (d1), 3, 5, 7, 10, 14, 17, 21, 24, 28, 31, 35, 38, and 42. Multivariate linear mixed effects models were created to evaluate coagulation parameters over time and compare NGD and GD. Data are summarized as estimated marginal means with 95% confidence intervals. Significance was set at P < 0.05.

Results: The PCT for all NGD CSWB was above the device limit by d7. The PLT for GD CSWB did not change during storage. The mean alpha-angle for INTEM and EXTEM decreased to < 50% of baseline at d38 and d31 for NGD, and d31 and d17 for GD CSWB. The mean maximum clot firmness (MCF) for INTEM and EXTEM reduced to < 50% of baseline at d42 and d28 for both GD and NGD. PT and aPTT for NGD and GD increased over time. For NGD CSWB, the mean FVIII and vWF:Ag activities decreased to < 50% of baseline at d7 and d28, respectively, and FIB reached 0.982 g/dL by d24. For GD CSWB, FVIII, FXIII:Ag and FV activities decreased to < 50% of baseline by d3, d38, and d38, respectively, and FIB was 0.982 g/dL at baseline. Alpha-angle and MCF for both INTEM and EXTEM, and activities for FII, FV, FIX, FXIII:Ag were significantly lower, and vWF:Ag was significantly higher overall in GD CSWB compared with NGD. A significant difference in the pattern of change over time was detected between NGD and GD in EXTEM alpha-angle, INTEM and EXTEM MCF, FII, and FVIII activities.

Conclusions: The in vitro viscoelastic parameters of GD and NGD CSWB declines over 42 days, but numerous hemostatic parameters (INTEM and EXTEM alpha-angle and MCF, activity of FII, FV, FV, FVII, FIX, FX, FXIII:Ag, vWF:Ag, and FIB) remain within 50% of baseline for more than 14 days. CSWB from GD compared to NGD has reduced hemostatic activity overall, but a similar pattern of decline for most parameters over time.

Thawed plasma (TP) refers to defrosted fresh frozen plasma stored refrigerated. TP is used in human medicine for the rapid provision of coagulation factors and resuscitation of haemorrhagic shock, but its use in dogs is poorly described. The objectives of this historical case series were to describe the reasons for TP transfusion, treatment outcomes, and adverse events associated with canine TP transfusions in a veterinary teaching hospital. We hypothesised that TP would be used most commonly for the treatment of haemorrhage secondary to anticoagulant rodenticide intoxication and trauma. Blood bank plasma transfusion logs were searched to identify dogs that received at least one unit of TP between December 2015 and June 2021. Briefly, 166 dogs received a total of 262 units of TP. Anticoagulant rodenticide intoxication (37/166, 22.3%) was the most common reason for transfusion, followed by traumatic haemorrhage (23, 13.9%) and spontaneous haemoperitoneum (22, 13.2%). The majority of dogs received one unit of TP (111/166, 67.1%) and pRBCs were commonly simultaneously transfused with TP (65, 39.2%). Severe prolongations of prothrombin time and activated partial thromboplastin time were reduced following TP transfusions. Allergic reactions were the most common transfusion reaction (19/166, 11.4%). Most dogs survived to discharge (101/166, 60.8%).

Objectives: To compare concentrations of biomarkers of; allergy [mast cell tryptase (MCT) and histamine], inflammation [interleukin (IL)-6,-10, and−18, CXCL8, CCL2, keratinocyte chemoattractant (KC), C-reactive protein (CRP)], endothelial glycocalyx shedding (hyaluronan), coagulation [prothrombin time, activated partial thromboplastin time, fibrinogen concentration, and von Willebrand Factor antigen, protein C (PC) and antithrombin (AT) activity], and hepatopathy [alanine transaminase (ALT), aspartate transaminase (AST), alkaline phosphatase (ALP), and total bilirubin] between dogs with anaphylaxis after suspected insect exposure, dogs with critical illness, and healthy dogs. Design: This was a single center prospective clinical observational comparative biomarker study that included 25 dogs with anaphylaxis (evidence of insect exposure, acute dermatological signs, and other organ involvement), 30 dogs with other critical illness, and 20 healthy dogs. Differences across groups in biomarker concentrations were tested using one-way ANOVA or Kruskal-Wallis test, with significant P values (<0.05) reported for pairwise differences detected by post-hoc tests. Logistic regression models were used to calculate the area under the receiver operator characteristic curve (AUROC) for discrimination between anaphylaxis and non-anaphylactic illness. Results: Histamine concentration was significantly higher in the anaphylaxis group than the healthy (P < 0.001) and critically ill groups (P < 0.001), whereas no differences in MCT were detected amongst groups. Biomarker concentrations that were increased relative to healthy dogs in both the anaphylaxis and critically ill groups included IL-10 (P < 0.001 and P = 0.007, respectively), CCL2 (P = 0.007 and P < 0.001, respectively) and AST (both P < 0.001), whereas only the critically ill group had significantly increased CRP (P < 0.001), IL-6 (P < 0.001), KC (P < 0.001), ALP (P < 0.001), and fibrinogen (P = 0.016) concentrations, compared to the healthy group. Only dogs with anaphylaxis had significantly higher hyaluronan (P = 0.021) and ALT (P = 0.021) concentrations, and lower PC (P = 0.030) and AT (P = 0.032) activities, compared to healthy dogs. Both CRP and histamine concentration showed good discrimination between anaphylaxis and other critical illness, with an AUROC of 0.96 (95% CI 0.91–1) and 0.81 (95% CI 0.69–0.93), respectively. Conclusions: This preliminary study in dogs with anaphylaxis after suspected insect exposure, found evidence of an early innate immune response, glycocalyx shedding and anticoagulant consumption. Both CRP and histamine showed potential clinical utility for differentiation between anaphylaxis and other critical illness.

Background Prestorage leukoreduction of red blood cell (RBC) bags prevents accumulation of pro-inflammatory mediators and experimentally attenuates post-transfusion inflammation in healthy dogs. However, the effect of leukoreduction on post-transfusion inflammation in critically ill dogs is unclear. Hypothesis Dogs transfused with leukoreduced (LR) RBC will have lower concentrations of leukocytes, interleukin (IL)-6, IL-8, monocyte chemoattractant protein-1 (MCP-1), and C-reactive protein (CRP) within 24 hours of post-transfusion compared to dogs transfused with nonleukoreduced (NLR) RBC. Animals Sixty-one RBC-transfused dogs (LR = 34, NLR = 27). Methods Randomized, blinded, controlled preliminary clinical trial. Blood bag processing was randomized to create identically appearing LR and NLR bags. Group allocation occurred with transfusion of the oldest compatible RBC bag. Blood samples were collected pretransfusion and at 8 and 24 hours post-transfusion for leukocyte count, IL-6, IL-8, MCP-1, and CRP. Data were analyzed on an intention-to-treat basis using linear mixed effects models. Significance was set at P < .05. Results No significant differences were found between groups in concentrations of leukocytes (P = .93), IL-6 (P = .99), IL-8 (P = .75), MCP-1 (P = .69), or CRP (P = .18) over time. Eleven LR dogs (32%) and 4 NLR dogs (15%) were euthanized in the hospital (P = .14). No natural deaths occurred. Conclusions and Clinical Importance No differences in inflammation biomarker concentrations were detected over time between dogs transfused with LR or NLR RBC, but heterogeneity likely hampered the ability to detect a difference with this sample size. The novel randomization and enrollment protocol was successfully implemented across 2 participating institutions and will be easily scaled up for a future multicenter clinical trial.