Influence of dosage and chemical restraints on feline excretory urography

Three series of trials involving 10 domestic short-haired cats were carried out to determine the influence of dosage of contrast media or type of chemical restraint on feline excretory urography. The 1st series (group A) involved 5 cats sedated with 2.0 mg/kg intramuscular (i.m) injection of 2% xylazine and receiving 800 mg/kg of 76 % meglumine diatrizoate (urografin). The 2nd series (group B) involved another 5 cats sedated with 2.0 mg/kg (i.m) injection of 2% xylazine and receiving 1200 mg/kg of 76% urografin. The 3rd series (group C) involved the repeat urography of the group B cats but sedated with 15 mg/kg (i.m) injection of 5% ketamine hydrochloride. Ventrodorsal radiographs were obtained immediately, 5, 15 and 40 minutes after the injection of 76% urografin. Scores were assigned to nephrographic opacification as described in the literature. The heart rates, respiratory rates and rectal temperatures of the cats were also determined before sedation, after sedation, immediately after the injection of 76% urografin and at 15-minute intervals over a period of 60 minutes. In this study, there were significant differences (P < 0.05) in the nephrographic opacification scores between the group A and group B cats at times 0 and 40 minutes post-administration of urografin. Group A cats had good initial nephrographic opacification which faded later while the nephrographic opacification of group B cats progressively increased. Similarly, nephrographic opacification was significantly (P < 0.05) higher in the xylazine-sedated cats (groups A and B) than the ketamine-sedated cats (group C). However, there were no significant differences (P > 0.05) in heart rates, respiratory rates and rectal temperatures between the 3 groups of cats. It was therefore concluded that increasing the dosage of urografin above 800 mg/kg in cats does not provide additional beneficial effects on the nephrograms produced. Xylazine sedation was observed to produce better nephrographic opacification, however, with delayed nephrographic fading compared to ketamine sedation.