Urodynamic and morphometric characteristics of the lower urogenital tract of male Beagle littermates from four months to two years of age.

OBJECTIVE: To describe functional and anatomic changes of the lower urogenital tract of healthy male dogs during the sexually immature period and up to 2 years of age by urodynamic and morphometric assessment. ANIMALS: 6 sexually intact male Beagle littermates. PROCEDURES: Dogs underwent electromyography-coupled urodynamic tests, CT-assisted retrograde urethrography, prostatic washes, and blood sampling monthly from 4 through 12 months of age and then at 3-month intervals. Urodynamic and morphometric variables and serum canine prostate-specific esterase concentrations were analyzed by statistical methods. RESULTS: Integrated pressure of the urethra was significantly increased beginning at 8 months of age, compared with earlier time points. Urethral pressure peak amplitudes varied among anatomic regions. During bladder filling, few electromyographic signals were concurrent with urethral pressure peaks; these were most commonly detected in the penile portion of the urethra. Urethral length and prostate gland volume were significantly greater from 7 to 24 months of age than at younger ages. Urethral length was approximately 26 to 27 cm after 9 months, and prostate gland volume was approximately 11 to 12 cm3 after 11 months of age. Serum canine prostate-specific esterase concentrations correlated with prostate gland volume. Urinary bladder threshold volume was significantly increased at 6 months of age, compared with that at 4 months, with a maximum of 197.7 mL at 24 months. CONCLUSIONS AND CLINICAL RELEVANCE: Urethral resistance was acquired at approximately 8 months of age, when growth of the lower urinary tract was incomplete. Electromyographic and integrated pressure measurement results and the distribution and amplitude of urethral pressure peaks highlighted the potential role of the prostate gland and possibly the bulbocavernosus muscles in control of continence.

Onset and duration of cis-atracurium neuromuscular block during fentanyl and lidocaine infusions in isoflurane-anaesthetised dogs.

BACKGROUND: This retrospective study assessed the onset and duration of the neuromuscular block (NMB) induced by cis-atracurium 0.15 mg/kg intravenously with and without fentanyl or lidocaine infusions in 45 isoflurane-anaesthetised dogs. METHODS: Dogs with neuromuscular function assessed by a calibrated train-of-four (TOF) monitor with stimulation (every 13 s) of the peroneal nerve were included. The onset and duration of the NMB were defined as the time from cis-atracurium administration until TOF=0 and the time during TOF=0 display, respectively. RESULTS: The NMB onset was shorter during fentanyl (mean±sd) (1.9±0.7 minutes; P=0.0042) and lidocaine (2.0±0.7 minutes; P=0.0154) compared with control (2.9±0.8 minutes). The NMB duration was shorter in the fentanyl (27.5±7.3 minutes; P=0.0491), but not in the lidocaine group (32.3±6.9 minutes; P=0.0790), compared with control (33.7±9.1 minutes). The NMB onset was poorly but significantly correlated with the dose of fentanyl and lidocaine administered before cis-atracurium (r=-0.3396; P=0.0225). The fentanyl and lidocaine groups received more crystalloid and colloid boluses than the control. CONCLUSIONS: Fentanyl and lidocaine shortened the NMB onset and the former decreased the NMB duration. Further prospective studies are required to clarify whether this was associated with an indirect decrease in blood pressure or a direct interaction between cis-atracurium and fentanyl and lidocaine.