Shane W. Bateman’s research while affiliated with University of Guelph and other places

OBJECTIVE To assess the impact of mild hypothermia on the distribution and elimination of an IV crystalloid fluid bolus in healthy anesthetized cats using volume kinetic (VK) analysis. METHODS 10 adult cats were anesthetized and included in a prospective, randomized, cross-over study. The subjects were maintained either normothermic (38.3 ± −16.9 °C) or mildly hypothermic (35 ± −16.9 °C), with a 7-day washout period between anesthetic episodes. All cats received 20 mL/kg of a balanced isotonic solution (Normosol-R) IV over 20 minutes, following the achievement and stabilization of target temperature. Hemoglobin concentration, PCV, and urinary output were measured at established time points and served as input variables for VK analysis. RESULTS Hypothermia was associated with a larger central compartment volume (V c ); higher body weights were associated with an increased V c and a decreased elimination rate; higher end-tidal isoflurane concentration (ETISO) was associated with an increased V c and a higher distribution rate constant. Heart rate, blood pressure, and ETISO were significantly lower in the hypothermic group. No statistically significant difference was observed in urinary output between groups. CONCLUSIONS Body weight, temperature, and ETISO were significant covariates affecting VK parameters. Hypothermia did not induce cold diuresis but was associated with an increase in V c . The negative relationship between body weight and the elimination rate constant requires further verification. Hypothermia was associated with lower heart rate and blood pressure despite reduced ETISO. CLINICAL RELEVANCE Hypothermia was associated with smaller plasma volume expansion from fluid bolus. Fluid dosing based on ideal body weight should be considered to avoid overdosing.

The kinetics of intravenous (IV) fluid therapy and how it affects the movement of fluids within humans and animals is an ongoing research topic. Clinical researchers have in the past used a mathematical model adopted from pharmacokinetics that attempts to mimic these kinetics. This linear model is based on the ideas that the body tries to maintain fluid levels in various compartments at some baseline targets and that fluid movement between compartments is driven by differences between the actual volumes and the targets. Here a nonlinear pressure-based model is introduced, where the driving force of fluid movement out of the blood stream is the pressure differences, both hydrostatic and oncotic, between the capillaries and the interstitial space. This model is, like the linear model, a coarse representation of fluid movement on the whole body scale, but, unlike the linear model, it is based on some of the body’s biophysical processes. The abilities of both models to fit data from experiments on both awake and anesthetized cats was analyzed. The pressure-based model fit the data better than the linear model in all but one case, and was deemed statistically significantly better in a third of the cases.

OBJECTIVE To describe changes in circulating hyaluronic acid (HA) concentration, a biomarker of endothelial glycocalyx degradation, after administration of fresh-frozen plasma (FFP) in critically ill dogs. ANIMALS 12 client-owned dogs receiving an FFP transfusion due to underlying disease. METHODS Plasma samples were collected for HA concentration measurement pre-FFP transfusion (T0) and 10 minutes (T10) and 90 minutes (T90) following completion of FFP transfusion of a minimum volume of 7 mL/kg. Hyaluronic acid was also measured in the transfused FFP units following in-house validation of a commercial HA assay on citrate phosphate dextrose–anticoagulated plasma. Potential associations of the difference between pre-FFP and post-FFP HA plasma concentrations with the volume of FFP transfused, the cumulative volume of IV fluids administered during the study period, and the HA concentration in the transfused unit were explored. RESULTS Concentrations of HA were not significantly different between pre- and post-FFP transfusion measurements. The volume of FFP transfused, the cumulative volume of other IV fluids administered during the study time, and the concentration of HA in the FFP units had no significant effect on the change in HA concentration following FFP transfusion in this study. CLINICAL RELEVANCE This pilot study did not demonstrate an association between FFP administration and changes in plasma HA concentration. The results of this study may serve to help design future research. A commercial assay was validated to measure HA in citrate phosphate dextrose–anticoagulated plasma.

Methemoglobinemia secondary to administration of hydroxyurea is only reported in veterinary medicine as a result of accidental ingestion of high doses, and once at therapeutic dose in human medicine. A 2.5‐year‐old female spayed mixed breed dog was presented for acute signs of neurologic disease and diagnosed with severe erythrocytosis without an identified underlying cause, leading to suspicion of polycythemia vera. The dog was managed with phlebotomies, supportive care, and administration of hydroxyurea. Within 2 h of administration of hydroxyurea (37 mg/kg) administration, respiratory distress with cyanosis, and methemoglobinemia developed. Signs resolved within 24 h but recurred after a second administration of lower dosage of hydroxyurea (17 mg/kg) 20 days later. The dog remained asymptomatic except for mild cyanosis but was humanely euthanized for lack of relevant improvement of signs of neurologic disease. This case report documents the repeated occurrence of methemoglobinemia in a dog after administration of hydroxyurea at therapeutic doses.

Urine output measurement is critical for the management of hospitalized cats and their underlying conditions. Ultrasound-guided estimation of urinary bladder volume (UBV) is a non-invasive surrogate measurement that can provide important clinical information. The purpose of this study was to validate the accuracy of a novel 3D computation method in estimating UBV using 2D point-of-care ultrasonographic images. Bladder volume estimation was performed using coordinates from bladder circumference tracings on paired longitudinal and transverse ultrasonographic images (n = 359) aligned in 3D space for mathematical algorithmic computation. Ultrasonographic images were obtained by 2 different observers at 18 different time points on 10 healthy, purpose-bred male cats under general anesthesia in sternal recumbency. Actual urine volumes were measured via urinary catheterization and compared to UBV estimations using Lin's concordance correlation coefficient and Bland-Altman analysis. Estimation of UBV using the 3D computational bladder circumference tracing method showed moderate strength-of-agreement with actual bladder volume (ρc = 0.94 to 0.95) with clinically insignificant bias (3D computation-derived minus actual volume) of -1.96 mL (IQR = -3.89 to -0.57 mL, P < 0.001) and -2.42 mL (IQR = -4.64 to -0.66 mL, P < 0.001) for the 2 observers, respectively. Our study demonstrated acceptable accuracy of 3D computation method for UBV estimation in healthy cats. This method may provide a bridging alternative until 3D ultrasound becomes more readily accessible.

Objectives The objective of this study was to evaluate shedding of extended-spectrum beta-lactamase (ESBL)-producing bacteria in cats admitted to an animal shelter. Methods Fecal samples were collected from cats admitted to an animal shelter between 12 June and 23 August 2018. Selective enrichment culture for ESBL-producing bacteria was performed and isolates were speciated and tested for selected ESBL genes using PCR. Results ESBL-producing Enterobacterales were identified in fecal samples from 2/87 (2.3%; 95% confidence interval 0.6–8.0) cats. One isolate was an Escherichia coli that possessed bla CTX-M-1 , bla CMY-2 and bla TEM genes. The other was Enterobacter cloacae possessing bla CTX-M-1 and bla CMY-2 . Conclusions and relevance While the study sample size and prevalence rate for ESBL-producing bacteria were low, these data document that cats admitted to similar shelters could harbor these agents. The risk posed by ESBL-producing bacterium shedding in cats, both to cats and other species, is currently unclear. However, these findings support the need for more investigation of interspecies transmission of ESBL-producing bacteria and ESBL genes, as well as the importance of antimicrobial stewardship and routine infection control measures.

Our goal was to validate a human hyaluronic acid (HA) ELISA (Hyaluronic acid plus ELISA; TECOmedical Group) for use in feline plasma. Plasma from 5 healthy cats and 5 critically ill cats was used for validation of the assay. Validation methods performed included intra- and inter-assay variability, spike-and-recovery, and dilutional linearity. All measurements were performed in duplicate. The precision study revealed good intra-assay CV of 7.4–8.9%; inter-assay CV was 3.4–4.2%. Extraction efficiency via spiking tests yielded mean recovery of 89.6%. The assay met criteria for acceptable linearity using 3 serial dilutions. Our results demonstrate that this commercial HA ELISA had acceptable analytical performance using feline plasma and could be a useful tool in the veterinary clinical research setting.

Objective: To describe daily changes in serum concentrations of hyaluronic acid (HA), a biomarker of endothelial glycocalyx degradation, in dogs with septic peritonitis and to determine whether relationships exist among serum concentrations of HA and biomarkers of inflammation and patient fluid status. Animals: 8 client-owned dogs. Procedures: Serum samples that had been collected for a previous study and stored at -80°C were used. Blood samples were collected at admission and daily thereafter during hospitalization and were analyzed for concentrations of HA and interleukins 6, 8, and 10. Patient data including acute patient physiologic and laboratory evaluation score, type and amount of fluids administered daily, and daily CBC and lactate concentration results were recorded. To determine the significant predictors of HA concentration, a general linear mixed model for repeated measures was developed. Results: All dogs survived to discharge. Concentrations of HA ranged from 18 to 1,050 ng/mL (interquartile [25th to 75th percentile] range, 49 to 119 ng/mL) throughout hospitalization. Interleukin-6 concentration was a significant predictor of HA concentration as was total administered daily fluid volume when accounting for interleukin-6 concentration. When fluid volume was analyzed independent of inflammatory status, fluid volume was not a significant predictor. Concentrations of HA did not significantly change over time but tended to increase on day 2 or 3 of hospitalization. Conclusions and clinical relevance: Results supported the theory that inflammation is associated with endothelial glycocalyx degradation. Dogs recovering from septic peritonitis may become more susceptible to further endothelial glycocalyx damage as increasing fluid volumes are administered.