Aj Dart

Objective: Evaluate the effect of topical 1% cannabidiol on second intention wound healing in distal limb wounds of horses.Design: Experimental.Animals: Six Standardbred horses.Methods: A total of five 2.5 cm × 2.5 cm full thickness skin wounds were created on the dorsomedial aspect of the metacarpi of 6 horses. Wounds were contaminated with faeces on the day of wound creation. Each wound was then assigned to a treatment group; compounded 1% cannabidiol in unique manuka factor (UMF) 5 manuka honey, UMF 5 manuka honey, UMF 20 manuka honey or saline. Each treatment was applied topically daily for a total of 42 days. Legs were bandaged and bandages were changed, daily, for 13 days postoperatively. Digital photographs of each wound were taken on day 1 then weekly for 6 weeks. Wound size, daily healing rate and total time to healing were recorded and compared statistically.Results: Irrespective of the treatment, wounds did not retract as expected in the first 7 days after wound creation. There was no difference in wound area, daily healing rate, days to complete healing between treatment groups.Conclusions: This preliminary study failed to demonstrate any difference in wound healing variables between treatment groups in this model of second intention wound healing. This was unexpected due to the established effects of UMF 20 manuka honey on wound healing using the same model. This may be due to systemic effects of cannabidiol and study design. Further research into the use of cannabidiol in equine wounds is warranted.

Summary: Regional limb perfusion (RLP) is a technique widely used for the treatment of limb infections in horses. The objective is to deliver high concentrations of an antimicrobial to a focal region to optimise the bacterial kill with minimal systemic effects. However, experimentally, realising these objectives has been unreliable because conflicting methodologies have produced highly variable results. The aim of this study is to review all of the experimental and clinical literature on RLP between 1990 and 2019 to determine whether there is evidence that RLP has a consistent and practical application for the treatment of distal limb infections in equine practice. A large number of reports have been published on RLP in the horse; however, there are many variations in the technique including the drug used, dose, volume and concentration of perfusate, dosing interval, the type, method and duration of application of the tourniquet and whether the procedure is performed standing or anaesthetised. Prospective clinical studies are lacking, retrospective studies are limited by their nature, while wide differences in treatment regimen and methodology in retrospective and experimental studies have complicated the interpretation of the findings and make it difficult to rationalise an approach that provides a reliable and repeatable outcome. The optimal method of performing RLP has not been established, so the apparent clinical benefits of the technique are often difficult to confirm and quantify. Future studies need to standardise methodologies to enable meaningful comparisons.

Objective: To quantify the time to clear dexamethasone from plasma and urine of horses following a single nebulisation.Design: Experimental using six Standardbred mares.Methods: Dexamethasone sodium phosphate (0.04 mg/kg) diluted in 0.9% sodium chloride was administered as an aerosol using a Flexineb E2® nebuliser. Blood samples (0, 2, 4, 6, 8, 10, 12, 24, 32, 48, 72 and 96 h) and urine samples (0, 1, 4, 8, 24, 32, 48, 72 and 96 h) were collected for analysis using liquid chromatography mass spectrometry.Results: Maximum plasma concentrations (t_max) were reached by the earliest detection point (2 h) after nebulisation (0.6–1.8 ng/mL), but was no longer detectable at 48 h. However, in one horse 0.1 ng/mL was found at 96 h after three consecutive readings of 0 ng/mL. The t_maxin urine was reached by the earliest collection point (1 h) after nebulisation (3.2–23.8 ng/mL), but was no longer present in urine at 72 h in five horses, while detectable levels (0.1 ng/mL) were still present at 96 h in one horse.Conclusions: A single dose of 0.04 mg/kg of DSP administered as an aerosol through a FlexinebE2® mask was no longer detectable in blood at 48 h in six horses tested, but one horse returned a reading of 0.1 ng/mL at 96 h after having no detectable levels. Dexamethasone was not detectable in urine at 72 h in five horses but was detectable at a low concentration (0.1 ng/mL) at 96 h in one horse.

AIMS: To compare the effect of oxygen supplementation using flow-by or a face mask on the partial pressure of arterial oxygen (PaO₂) in sedated dogs. METHODS: Twenty healthy dogs weighing >15 kg, of mixed sex and breed, were enrolled in a randomised cross-over study. Each dog was sedated with I/M 0.015 mg/kg medetomidine and 0.5 mg/kg methadone. Twenty minutes later dogs were exposed to two 5-minute treatment periods of oxygen supplementation separated by a 15-minute washout period during which dogs were allowed to breathe room air. During the treatment periods, oxygen was delivered at a flow rate of 3 L/minute either through a face mask (face mask oxygenation), or via a tube held 2 cm from the dog’s nares (flow-by oxygenation). The order in which the treatments were administered was randomised. Arterial blood was collected for blood gas analysis and rectal temperature measured at four times: prior to commencing treatments, after each treatment, and at the end of the 15 minutes washout period between treatments. RESULTS: The mean PaO₂ in arterial samples taken from the dogs after face mask oxygen supplementation was 371.3 (SE 13.74) mmHg which was higher than in samples taken after they received flow-by oxygen supplementation (182.2 (SE 6.741) mmHg; p < 0.001). The mean PaO₂ in samples taken after receiving either form of oxygen supplementation was higher than in samples taken after the dogs had been breathing room air (82.43 (SE 2.143) mmHg; p < 0.001). There was no association between sex, age, weight or breed of dogs and blood gas parameters or rectal temperature (p > 0.05). CONCLUSIONS: Oxygen supplementation delivered using a face mask was more effective at increasing PaO₂ than flow-by oxygen supplementation. Flow-by oxygen supplementation at a distance of 2 cm from the nose may be a suitable alternative when the use of a face mask is not tolerated by the patient.

Objective: To compare the effects of two concentrations of oxygen delivered to the anaesthetic breathing circuit on oxygenation in mechanically ventilated horses anaesthetised with isoflurane and positioned in dorsal or lateral recumbency.Methods: Selected respiratory parameters and blood lactate were measured and oxygenation indices calculated, before and during general anaesthesia, in 24 laterally or dorsally recumbent horses. Horses were randomly assigned to receive 100% or 60% oxygen during anaesthesia. All horses were anaesthetised using the same protocol and intermittent positive pressure ventilation (IPPV) was commenced immediately following anaesthetic induction and endotracheal intubation. Arterial blood gas analysis was performed and oxygenation indices calculated before premedication, immediately after induction, at 10 and 45 min after the commencement of mechanical ventilation, and in recovery.Results: During anaesthesia, the arterial partial pressure of oxygen was adequate in all horses, regardless of position of recumbency or the concentration of oxygen provided. At 10 and 45 min after commencing IPPV, the arterial partial pressure of oxygen was lower in horses in dorsal recumbency compared with those in lateral recumbency, irrespective of the concentration of oxygen supplied. Based on oxygenation indices, pulmonary function during general anaesthesia in horses placed in dorsal recumbency was more compromised than in horses in lateral recumbency, irrespective of the concentration of oxygen provided.Conclusion: During general anaesthesia, using oxygen at a concentration of 60% instead of 100% maintains adequate arterial oxygenation in horses in dorsal or lateral recumbency. However, it will not reduce pulmonary function abnormalities induced by anaesthesia and recumbency.

(2018). Imbrication of the medial retinaculum to repair a bilateral traumatic lateral patellar luxation in an alpaca (Vicugna pacos) New Zealand Veterinary Journal: Vol. 66, No. 1, pp. 48-49.

To compare the efficacy of an enteric coated esomeprazole paste with an enteric coated omeprazole paste to increase gastric pH after oral administration in horses.Nine adult Standardbred horses wer...

Objective: To compare the effect of application of manuka honey with unique manuka factor (UMF) 5 or 20 with a generic multifloral honey on equine wound healing variables.Methods: Two full‐thickness skin wounds (2.5 × 2.5 cm) were created on the metatarsus of both hindlimbs of eight Standardbred horses. The wounds on each horse were assigned to 1 of 4 treatments: UMF20 (UMF20) and UMF5 (UMF5) manuka honey; generic multifloral honey (GH); and a saline control. Bandages were changed daily for 12 days, after which treatment was stopped and the bandages were removed. Wound area was measured on day 1, then weekly until day 42. Overall wound healing rate (cm²/day) and time to complete healing were recorded.Results: There was no difference in wound area for any of the treatments on any measurement day except for day 21, where the mean wound area for wounds treated with UMF20 was smaller than the mean wound area for the UMF5‐treated wounds (P = 0.031). There was no difference in mean (± SE) overall healing rate (cm²/day) among the treatment groups. There were differences in mean (± SE) days to complete healing. Wounds treated with UMF20 healed faster than wounds treated with GH (P = 0.02) and control wounds (P = 0.01).Conclusions: Treatment of wounds with UMF20 reduced overall wound healing time compared with wounds treated with GH and control wounds. However, using this model the difference in the overall time to complete healing was small.