Pilot study to determine the feasibility of radiation therapy for dogs with right atrial masses and hemorrhagic pericardial effusion.

OBJECTIVES: To determine the short-term safety and biologic activity of radiation therapy (RT) for presumptive cardiac hemangiosarcoma in pet dogs. ANIMALS: Six dogs with echocardiographic evidence of a right atrial/auricular mass, and hemorrhagic pericardial effusion, were enrolled in a prospective, single-arm clinical trial. METHODS: A single fraction of 12 Gy was delivered using conformal external beam irradiation. Serum cardiac troponin I and plasma concentrations of vascular endothelial growth factor were quantified before, 4 and 24 h after RT. The frequency of required pericardiocenteses (quantified as the number of pericardiocenteses per week) before RT was compared to that after treatment. Overall survival time was determined. RESULTS: No treatment-related complications were observed. Pericardiocentesis was performed an average of 0.91 times per week before RT, and an average of 0.21 times per week after RT; this difference was statistically significant (p=0.03, as compared using a Wilcoxon signed-rank test of paired data). Pre- and post-treatment plasma vascular endothelial growth factor concentrations were not significantly different at any time point; there was a statistically significant (p=0.04; Friedman's test for non-parametric repeated measures) increase in cardiac troponin concentrations 4 h after irradiation. Median overall survival time was 79 days. CONCLUSIONS: In this population of dogs, RT was delivered without complication, and appears to have reduced the frequency of periacardial tamponade that necessitated pericardiocentesis. Serum cardiac troponin levels are altered after RT. RT alone, or in combination with chemotherapy, may provide clinical benefit to dogs with presumptive diagnoses of cardiac hemangiosarcoma.

Propofol with ketamine following sedation with xylazine for routine induction of general anaesthesia in horses.

To document the suitability of intravenous propofol and ketamine following sedation with xylazine for routine anaesthetic induction in horses. Retrospective. 100 client-owned horses. Anaesthetic records were evaluated to determine: signalment, anaesthetic drug and dosages, need for additional induction agents, notation of any adverse events, duration of anaesthesia and recovery characteristics (rough or smooth, and rapid or prolonged). Horses were sedated with xylazine 0.99±(0.2) mg/kg intravenous and 23 horses were also administered butorphanol 0.02±(0.001) mg/kg intravenous. Horses were anaesthetised with a combination of propofol 0.40±(0.1) mg/kg intravenous and ketamine 2.8±(0.3) mg/kg intravenous. Six horses required additional ketamine. None became apnoeic and no adverse events were noted. Anaesthesia was maintained with isoflurane in 66 horses and a combination of guaifenesin, ketamine and xylazine (GKX) in 34 horses. Total anaesthesia time was 125.4±(46) minutes. Fifty-one horses were administered romifidine 0.016 (±0.008) mg/kg intravenous at recovery. Time from orotracheal extubation to standing was 27.6±(25) minutes. Of the 58 records with recovery characteristics, the number per category was: rapid n=6, prolonged n=3, smooth n=46, rough n=6. Intravenous propofol and ketamine following xylazine provided satisfactory anaesthetic inductions and recoveries in a varied population of horses without any clinically relevant adverse events.

Comparison of the effect of intratesticular lidocaine/bupivacaine vs. saline placebo on pain scores and incision site reactions in dogs undergoing routine castration.

Post-operative pain scores and incision site reactions were compared in healthy dogs undergoing routine castration at a county animal shelter and assigned to two treatment groups, namely: (1) lidocaine/bupivacaine (1mg/kg lidocaine+1mg/kg bupivacaine mixture; n=17), or (2) placebo (0.9% saline; n=16), administered via intratesticular injection. Dogs were injected with an equivalent volume of solution based on bodyweight. Premedication, induction and anesthetic maintenance protocols were identical in all animals. Pain scores were assessed at 15min, 60min, 120min and 24h post-recovery from anesthesia. Surgical site evaluation based on swelling and bruising was evaluated at 24h. The addition of lidocaine/bupivacaine did not impact pain scores compared to the saline placebo (P>0.05). Incision site reactions were statistically similar between the two groups.

Pharmacokinetics of intravenous and intramuscular buprenorphine in the horse.

The purpose of this study was to determine the pharmacokinetics of buprenorphine following intravenous (i.v.) and intramuscular (i.m.) administration in horses. Six horses received i.v. or i.m. buprenorphine (0.005 mg/kg) in a randomized, crossover design. Plasma samples were collected at predetermined times and horses were monitored for adverse reactions. Buprenorphine concentrations were measured using ultra-performance liquid chromatography with electrospray ionization mass spectrometry. Following i.v. administration, clearance was 7.97±5.16 mL/kg/min, and half-life (T(1/2)) was 3.58 h (harmonic mean). Volume of distribution was 3.01±1.69 L/kg. Following i.m. administration, maximum concentration (C(max)) was 1.74±0.09 ng/mL, which was significantly lower than the highest measured concentration (4.34±1.22 ng/mL) after i.v. administration (P<0.001). Time to C(max) was 0.9±0.69 h and T(1/2) was 4.24 h. Bioavailability was variable (51-88%). Several horses showed signs of excitement. Gut sounds were decreased 10±2.19 and 8.67±1.63 h in the i.v. and i.m. group, respectively. Buprenorphine has a moderate T(1/2) in the horse and was detected at concentrations expected to be therapeutic in other species after i.v. and i.m. administration of 0.005 mg/kg. Signs of excitement and gastrointestinal stasis may be noted.

Fetal oxygen content is restored after maternal hemorrhage and fluid replacement with polymerized bovine hemoglobin, but not with hetastarch, in pregnant sheep.

UNLABELLED: We investigated the ability of hemoglobin-based oxygen carrying solutions (HBOCs) to alleviate fetal hypoxemia from maternal hemorrhage. Fifteen pregnant ewes (132-day gestational age) were hemorrhaged 20 mL/kg over 1 h; they were randomized to receive 20 mL/kg IV of HBOC, hetastarch (HTS), or autologous blood (BLD) (n = 5 each) over 30 min and were monitored for 2 h. Hemorrhage significantly (P < or = 0.05) decreased maternal mean blood pressure (from 98 to 48 mm Hg, median), arterial oxygen content (from 12.2 to 11.1 mL/dL), and fetal arterial oxygen content (from 8.1 to 3.9 mL/dL). Fluid replacement restored maternal blood pressure in all groups, although maternal oxygen content immediately returned to baseline only after BLD or HBOC. Maternal oxygen saturation decreased after HBOC (from 98% to 88%). Fetal oxygen content rapidly returned to baseline with either BLD (7.1 mL/dL) or HBOC (8.0 mL/dL) but was never restored with HTS (4.7 mL/dL), and, 60 min after fluid replacement, it was higher with HBOC (8.3 mL/dL) than with HTS (4.7 mL/dL). Fetal plasma-free hemoglobin did not change after HBOC. In conclusion, maternal fluid replacement with HBOC or BLD effectively restored fetal oxygenation, primarily by restoring maternal oxygen content, whereas HTS did not. IMPLICATIONS: Hemoglobin solutions eliminate many limitations of blood transfusions. Our results show that fluid replacement with either blood or a hemoglobin solution, compared with hetastarch, restored fetal oxygenation in pregnant ewes after hemorrhage. If applicable to women, these results suggest a potential for the use of hemoglobin solutions in obstetrics.