Vaginourethroplasty for Treatment of Urethral Obstruction in the Bitch

Vaginourethroplasty was performed in six bitches with infiltrative, obstructive urethral disease. The initial clinical signs included dysuria, hematuria, pollakiuria, and stranguria. Diagnosis was based on the clinical signs, plain radiography and contrast vagino-urethrogram examination, and urethral biopsy. Five dogs were diagnosed as having urethral neoplasia; the sixth dog had granulomatous urethritis. In all six dogs, up to 50% of the urethra and the urethral tubercle were resected to ensure adequate surgical margins. One dog was euthanatized 4 months after surgery for recurrence of a transitional cell carcinoma at the surgical site. Long-term resolution of the problem (minimum of 12 months) was achieved in the other five dogs. The frequency of serious complications, including urinary incontinence and ascending lower urinary tract infections, was low.     

Evaluation of auditory evoked potentials to predict depth of anaesthesia during fentanyl/fluanisone−midazolam anaesthesia in rats

Objectives To assess a method for monitoring depth of anaesthesia using components of middle latency auditory evoked potential (AEP) waveforms during anaesthesia with fentanyl/fluanisone and midazolam. Study design Prospective observational study. Animals Five female Wistar rats weighing between 210 and 250 g. Methods Implanted electrodes were used to record AEPs in animals receiving five doses of anaesthetic. Recordings were made at 5 minutes post‐injection (deep anaesthesia; no pedal withdrawal response, PWR) and then at 25 minutes (light anaesthesia; strong PWR). Responses showed five characteristic peaks occurring at 11, 14, 23, 42 and 68 ms that were measured for latency of occurrence and peak amplitude. Results Auditory evoked potential peaks P14, N23 and P42 were increased significantly in latency with successive anaesthetic injections [avg. F(1,4) = 12.53, p < 0.001; avg. F(1,4) = 10.6, p < 0.001; avg. F(1,4) = 3.9, p = 0.02, respectively]. Peak N23 showed a significant reduction in latency during the 20 minute recovery period following both the first and second anaesthetic injections (t(3) = 7.52, p = 0.005; t(4) = 5.17, p = 0.007, respectively). Peak P42 occurred significantly earlier 20 minutes following the second anaesthetic injection (t(4) = 4.75, p = 0.009). The mean overall depth of anaesthesia assessed using PWR scores was significantly correlated with the mean latency of peak N23, such that as the strength of PWR increased, N23 occurred significantly earlier (r = ?0.99, p = 0.01). The amplitude difference between peaks N23 and P42 increased after the second and third drug administrations [avg. F(1,4) = 10.65, p = 0.031 and avg. F(1,4) = 11.24, p = 0.028, respectively]. Conclusion The characteristics of these peaks, and in particular latency of peak N23, may provide a useful tool for assessing depth of anaesthesia produced by this, and possibly other anaesthetic agents.     

Soil and agronomic factors associated with cadmium accumulations in kidneys of grazing sheep

SUMMARY Mean concentration of cadmium (Cd) in kidneys of hogget sheep from 67 flocks grazing in the Agricultural Region of Western Australia was tested for association with soil, pastoral, climatic and nutritional factors. Hoggets grazing pastures on acidic soils and soils with a sandy-textured surface had higher Cd concentrations in kidneys than hoggets grazing pastures on more alkaline soils or soils with a clay-textured surface. Application of more than 100 kg of phosphatic fertiliser during the past 3 years to loamy soils was also associated with greater Cd concentration in kidneys of the grazing animals.     

Assessment of ketamine/medetomidine anaesthesia in the New Zealand White rabbit

Objective To compare the characteristics of anaesthesia induced with four dose combinations of ketamine/medetomidine. Design Prospective randomized study. Animals Five female New Zealand White (NZW) rabbits of approximately 2.3 kg. Methods Rabbits were given one of four drug combinations (25/0.25; 15/0.5; 15/0.25 and 10/0.5 mg kg^?1 IM) on four successive occasions with a four day interval. Response to injection and then arterial blood gas and cardiovascular parameters were recorded at predetermined time points. Toe and ear pinch reflexes gave measures of total duration of surgical anaesthesia and total sleep time. Analyses used repeated measures analysis of variance. Results Induction was smooth with little reaction to injection and intubation achieved easily. Two combinations (15/0.25, 10/0.5) produced moderate hypoxaemia (mean pO₂ < 8.0 kPa) and two (25/0.25, 15/0.5) very marked hypoxaemia (mean pO₂ < 5.3 kPa). This was reversed within 15 minutes of oxygen administration and all rabbits recovered uneventfully. Heart rates fell in all cases, with only minimal effects on arterial blood pressure and no cardiac arrhythmias. Mean duration of surgical anaesthesia was significantly longer for dose groups 25/0.25 (57 ± 12 minutes) and 15/0.5 (59 ± 17 minutes, p = 0.01) compared to dose group 15/0.25 (27 ± 8 minutes). Only three animals in the 10/0.5 mg kg^?1 group achieved surgical anaesthesia. Mean duration of loss of the ear pinch reflex was similar between doses, being, respectively, 64 ± 13, 81 ± 7, 60 ± 22 and 62 ± 24 minutes. Sleep time was significantly longer for the 15/0.5 dose (112 ± 10 minutes) compared to 15/0.25 (86 ± 22 minutes, p = 0.04). Sleep times for the 25/0.25 and 10/0.5 mg kg^?1 doses were, respectively, 103 ± 23 and 108 ± 12 minutes. Conclusions Ketamine/medetomidine reliably produces smooth induction and recovery in the NZW rabbit, but due to the degree of hypoxaemia produced, should only be used with simultaneous provision of oxygen. Clinical relevance Currently recommended dose rates of ketamine/medetomidine for minor procedures such as ovariohysterectomy in rabbits (25 mg/0.5 mg kg^?1) are unnecessarily high; a dose of 15/0.25 mg kg^?1 should be adequate for 15–30 minutes of surgical anaesthesia.