Mark Senior

Prospective evaluation of postoperative pain in cats undergoing ovariohysterectomy by a midline or flank approach.

Twenty entire female cats were randomly assigned to two groups of 10; the cats in one group underwent ovariohysterectomy by a midline approach and the cats in the other group by a flank approach. Cats were assessed for signs of pain and scores were assigned pre- and postoperatively. There was a tendency for the cats neutered by a flank approach to be in more pain postoperatively (P=0·05). The final pain score for cats in either group was equal to or lower than their baseline score.

Use of acetaminophen (paracetamol) as a short-term adjunctive analgesic in a laminitic pony.

We would like to describe the use of acetaminophen (paracetamol) as an adjunctive analgesic agent in a pony with severe laminitis. An 8-year-old obese Welsh section C gelding weighing 450 kg was presented to the Philip Leverhulme Equine Hospital. The pony was sweating and had an unsteady gait. The heart rate was 84 beats minute and the Obel laminitis grade was 4 (Menzies-Gow et al. 2010). Following further examination and diagnostic tests, equine metabolic syndrome with laminitis in all four hooves was diagnosed. Marked rotation (10 , 10.4 and 10.6 ) and sinking of three of the distal phalanges was evident. Based on an estimated weight, morphine (morphine sulphate; Martindale Pharmaceuticals, UK) 0.13 mg kg and flunixin (Meflosyl; Pfizer Animal Health, UK) 0.89 mg kg were administered intravenously (IV). Subsequently the heart rate reduced to 64 beats minute, sweating and weight-shifting decreased and demeanor improved. Four hourly monitoring of clinical and laboratory parameters was instituted. The pony was fed soaked hay and all four hooves were packed with silicone putty (Newmarket Sole Support, Newmarket Premixes Ltd, UK). Despite this management, the pony still was weight-shifting, lying down frequently and remained tachycardic. Further analgesia was provided, with varying degrees of efficacy, over the subsequent 4 days, including phenylbutazone (Equipalazone; Dechra Veterinary Products Ltd, UK) at 4.4 mg kg twice daily per os (PO), lidocaine (lidocaine 0.2% in 5% glucose; Fresenius Kabi, UK) 1.3 mg kg IV bolus followed by 3 mg kg hour IV infusion and morphine 0.08 mg kg epidurally. Unfortunately by day 5, technical and financial limitations led to the removal of both IV and epidural catheters. The pony was receiving phenylbutazone 4.4 mg kg twice daily IV but was still graded as Obel 3, had a poor appetite and demonstrated frequent weight-shifting. Heart rate was now 44 beats minute. Euthanasia was discussed with the owners at this stage. An adjunctive analgesic was sought which would have a rapid onset with few side-effects, be inexpensive, suitable for enteral administration and be appropriate to use under the licensing cascade. Acetaminophen (Paracetamol; M&A Pharmachem Ltd, UK) 25 mg kg was administered via a nasogastric tube on day 6. Within 2 hours the pony showed improved demeanor, appetite, mobility and stance and reduced Obel grade to 2. The decision was made with the owner’s consent to continue treatment and phenylbutazone treatment 4.4 mg kg IV twice daily was continued. Fortytwo hours from first administration of acetaminophen, the Obel grade increased to 3 and the pony was recumbent more frequently, and had a reduced appetite. A second dose of acetaminophen 20 mg kg was crushed into water and administered PO by dosing syringe. Within 1 hour, the Obel grade was 2. The dosing was maintained thereafter with acetaminophen 20 mg kg and phenylbutazone 4.4 mg kg, both twice daily PO. On day 9, the pony was shod with plastic heart bar shoes, after which the Obel grade was 0 and the pony did not display a laminitic gait. The pony was discharged on day 11 and received a further week of acetaminophen at 20 mg kg and 1 week of phenylbutazone 3.3 mg kg, then phenylbutazone 2.2 mg kg for a further week, all twice daily PO. The pony remained comfortable until a recurrence of laminitic pain after 10 weeks, at which stage the owners elected to have the pony euthanased. Acetaminophen (N-acetyl-p-aminophenol) is a phenolic compound which has a marketing authorization combined with codeine (Pardale-V; Dechra Veterinary Products, UK) for oral use in dogs for the short-term treatment of pain. Analgesia is thought

A study of the correlation between objective and subjective indices of recovery quality after inhalation anaesthesia in equids

OBJECTIVE To examine the association between objective and subjective descriptors used for assessing recovery quality in horses after anaesthesia. STUDY DESIGN Prospective clinical study. ANIMALS Two hundred and seventy-six equids (110 mares, 85 entire males and 81 geldings), ASA 1-5, weighing 50-850 kg and aged 1 month - 25 years. METHODS Recoveries after general anaesthesia were assisted with head and tail ropes by two anaesthetists. One scored dichotomous objective descriptors (DOD) of recovery. Two dichotomous objective scales (DOS) were then generated from those descriptors. The same individual also scored overall recovery quality using a visual analogue scale (VAS). The second anaesthetist scored recovery (good or bad) using a dichotomous subjective scale (DSS). Each DOD, the DSS and VAS were compared with each other using Pearsons chi-square test. DOSs were compared to the DSS using Wilcoxons test and to the VAS using a Spearmans correlation test. RESULTS Most DODs were associated (p < 0.05) with DSS and VAS. The DSS was not associated with resting/not resting in sternal recumbency (p = 0.535) nor with the time spent in sternal recumbency (p = 0.09). VAS and DSS scores were strongly associated (p < 0.0001). The two DOSs were in agreement with DSS (p < 0.0001) and negatively correlated to VAS (r(1)(2) = 0.38, r(2)(2) = 0.34, respectively, p-value <0.0001). CONCLUSION Objective descriptors were linked closely with the subjective evaluations of recovery quality except for the presence or absence of a sternal recumbency phase and its duration. CLINICAL RELEVANCE These components may not be essential in recovery scoring systems. The DOS were in agreement with DSS and VAS and could be a useful tool for further studies on recoveries.

Expression of purinergic P2X receptor subtypes 1, 2, 3 and 7 in equine laminitis.

Tissue sensitisation and chronic pain have been described in chronic-active laminitis in the horse, making treatment of such cases difficult. Purinergic P2X receptors are linked to chronic pain and inflammation. The aim of this study was to examine the expression of purinergic P2X receptor subtypes 1, 2, 3 and 7 in the hoof, palmar digital vessels and nerve, dorsal root ganglia and spinal cord in horses with chronic-active laminitis (n=5) compared to non-laminitic horses (n=5). Immunohistochemical analysis was performed on tissue sections using antibodies against P2X receptor subtypes 1-3 and 7. In horses with laminitis, there was a reduction in the thickness of the tunica media layer of the palmar digital vein as a proportion of the whole vessel diameter (0.48±0.05) compared to the non-laminitic group (0.57±0.04; P=0.02). P2X receptor subtype 3 was expressed in the smooth muscle layer (tunica media) of the palmar digital artery of horses with laminitis, but was absent in horses without laminitis. There was strong expression of P2X receptor subtype 7 in the proliferating, partially keratinised, epidermal cells of the secondary epidermal lamellae in the hooves of horses with laminitis, but no immunopositivity in horses without laminitis.

Suspected vagal reflex bradycardia in a calf undergoing surgical resection of an infected urachus

A four-week-old Charolais heifer was referred for surgical treatment of an infected umbilicus. The heifer was sedated with intravenous xylazine, and an indwelling intravenous jugular cannula was placed. General anaesthesia was induced with intravenous ketamine and maintained with isoflurane in 100 per cent oxygen. Surgical exploration of the abdomen revealed an infected urachus originating from the apex of the bladder and bilaterally infected umbilical arteries. Anaesthesia was stable for 35 minutes until surgical traction of the urachus and umbilical arteries resulted in bradycardia and hypoventilation/apnoea, which resolved when the traction was released, but recurred as and when traction was reinitiated. Collaboration between the anaesthetist and the surgeon was necessary to progress the procedure while minimising perturbations in physiology. Towards the end of the procedure, during peritoneal lavage with sterile saline, severe bradycardia developed (heart rate <20 bpm) and was successfully treated with atropine 0.04 mg/kg intravenously. The heifer recovered uneventfully from anaesthesia.