Abstract. The selective inhibition of platelet function in whole blood coagulation testing may allow insights into the nature of hypercoagulability in dogs with critical illness. To determine the effects of cytochalasin D and abciximab on hemostatic parameters in canine citrated whole blood, an in-vitro study was designed using thromboelastography (TEG) and a platelet function analyzer (PFA-100®). 8 clinically healthy mixed breed dogs donated blood that was anticoagulated with 3.2% sodium citrate in a 9:1 blood-to-citrate ratio. Addition of cytochalasin D to citrated whole blood from 6 dogs at concentrations ranging from 0 µg/ml to 10 µg/ml caused a maximal reduction of TEG maximum amplitude (MA) at a concentration of 7.5 µg/ml (52.7 ± 4.3 to 14.3 ± 7.8 mm). Addition of abciximab to canine citrated whole blood at concentrations of either 20 µg/ml or 40 µg/ ml did not affect the TEG tracing; however, addition of abciximab to citrated canine whole blood at concentrations of 10 µg/ ml and 20 µg/ml significantly prolonged PFA-100 closure times (72.5 ± 15 to 149.2 ± 91 sec and 275.6 ± 54 sec, respectively, P < 0.04). Inhibition of canine platelet function by cytochalasin D is demonstrated by TEG, but abciximab did not change TEG tracings. Abciximab does, however, inhibit platelet aggregation under shear stress as measured by the PFA-100. Inhibition of canine platelet function with cytochalasin D may allow further TEG studies in dogs with clinical disease.

Sevoflurane and isoflurane are commonly used in veterinary anesthesia. The objective of this prospective, randomized, open-label clinical study was to compare the cardiovascular effects of sevoflurane and isoflurane via direct arterial blood pressure measurements and the lithium dilution cardiac output (LDCO) on premedicated healthy dogs undergoing elective tibial plateau leveling osteotomy (TPLO). Nineteen client-owned dogs were included. All dogs were premedicated with hydromorphone (0.05 mg/kg IV and glycopyrrolate 0.01 mg/kg subcutaneously). Ten dogs were anesthetized with sevoflurane and nine dogs were anesthetized with isoflurane. Eighteen dogs were instrumented with a dorsal pedal arterial catheter, and one dog had a femoral arterial catheter. All dogs had continuous, direct systolic (SAP), diastolic (DAP), and mean arterial (MAP) blood pressure readings as well as heart rate (HR), cardiac output (CO), cardiac index (CI), systemic vascular resistance (SVR), systemic vascular resistance index (SVRI), stroke volume variation (SVV), and pulse pressure variation (PPV) recorded q 5 min during the surgical procedure. There was no significant statistical difference in all parameters between the sevoflurane and isoflurane treatment groups. Both sevoflurane and isoflurane inhalant anesthetics appear to have similar hemodynamic effects when used as part of a multimodal anesthetic protocol in premedicated healthy dogs undergoing an elective surgical procedure.

Substance P- and CGRP-containing nerve fibers are not disrupted by EWST or RPWT. Further studies are needed to identify the mechanism of analgesia observed in association with these treatment modalities.