Randomised clinical trial evaluating the effect of a single preappointment dose of gabapentin on signs of stress in hyperthyroid cats.

OBJECTIVES: The aim of this study was to evaluate the efficacy of gabapentin as an anxiolytic in hyperthyroid cats. METHODS: Cats (n = 47) with confirmed hyperthyroidism were successfully enrolled. The cat owner allocated a temperament score and a transport stress score at their first visit. For the second visit the cat owner (blinded to treatment) administered either liquid gabapentin 20 mg/kg (n = 22) or an indistinguishable placebo solution (n = 25) 1 h prior to leaving home. A second transport score was allocated by the cat owner at this visit. Upon admission a compliance score was independently assigned by two veterinary nurses blinded to treatment. Excess blood from routine blood draw was analysed for gabapentin plasma concentration from cats in the gabapentin group. RESULTS: There were no significant differences in baseline transport score between groups (P = 0.13), but significant differences were noted in the second visit transport score between cats medicated with gabapentin compared with placebo (P = 0.018). Mean compliance scores were significantly different between cats in the treatment group compared with placebo (P = 0.019). Further sedation was required to complete the procedures in 24% of cats in the placebo group compared to 9% in the gabapentin group (P = 0.25). Mean plasma gabapentin concentrations were 10.1 mg/l (range 1.7-22.7) in the gabapentin group within a 1-3 h time frame post-administration. CONCLUSIONS AND RELEVANCE: Hyperthyroid cats medicated with 20 mg/kg gabapentin 1 h prior to leaving home were more relaxed during transport and more compliant with veterinary procedures than cats administered a placebo solution.

Suspected vagal reflex and hyperkalaemia inducing asystole in an anaesthetised horse.

A 10-year-old 466 kg mustang gelding presented to an equine referral hospital for surgical repair of nasal, frontal and lacrimal bone fractures from an unknown trauma. Surgical repair was performed under general anaesthesia, including a right-sided maxillary regional anaesthetic block with mepivacaine hydrochloride. Progressive hyperkalaemia was documented perianaesthetically (T-3 mins; 134 mins after induction; potassium 6.4 mmol/L (ref 3.5-5.1 mmol/L). Perianaesthetic bradycardia was attributed to alpha -2 agonist infusion administration, and other characteristic ECG changes (flattened P waves, narrow T waves of increased amplitude, prolonged QRS complex) were not documented. Asystole occurred 137 min after induction of anaesthesia; however, a review of the available literature suggests the degree of hyperkalaemia documented was unlikely to be the primary cause of asystole but may have been a contributing factor. It is hypothesised that a trigeminocardiac reflex was the primary contributory factor to asystole in the described case, and may represent a maxillomandibulocardiac reflex that has not been previously described in the horse.

Analgesia for pelvic limb surgery. A review of peripheral nerve blocks and the extradural technique.

OBJECTIVES: To describe the anatomy and approaches reported for peripheral nerve blockade (PNB) of the pelvic limb in dogs and cats and to consider the role of PNB in relation to the extradural technique. DATABASES USED: This review was conducted using the terms 'nerve block', 'extradural' 'dog' and 'cat' entered into Pubmed and Google. Results were filtered manually to narrow the field to pelvic limb nerve blocks. The reference lists of retrieved papers were scrutinized to identify further studies for inclusion. CONCLUSIONS: Successful PNB techniques require thorough anatomical knowledge for the establishment of reliable landmarks, puncture sites, the direction and depth of needle insertion, and relevant structures to be avoided. To date, clinical evaluations have been made in subjects undergoing stifle surgery where the sciatic nerve has been blocked in combination with various approaches to the femoral nerve. Currently the bulk of literature examines new approaches to these nerves and each of these is described. To date there are no veterinary studies directly comparing one approach versus another, and therefore one is unable to draw conclusions of superiority. The role of PNB's versus the extradural technique is discussed.