Effects of acepromazine, hydromorphone, or an acepromazine-hydromorphone combination on the degree of sedation in clinically normal dogs.

OBJECTIVE: To determine the effects of IM administration of acepromazine, hydromorphone, or the acepromazine-hydromorphone combination on degree of sedation in clinically normal dogs and to compare 2 sedation scoring techniques. DESIGN: Prospective, randomized, blinded, controlled trial. Animals-46 random-source dogs. PROCEDURES: Dogs were assigned to receive IM administrations of acepromazine (0.05 mg/kg [0.023 mg/lb]; [DOSAGE ERROR CORRECTED] n = 12), hydromorphone (0.1 mg/kg [0.045 mg/lb]; 11), acepromazine-hydromorphone (0.5 mg/kg and 0.1 mg/kg, respectively; 12), or saline (0.9% NaCI) solution (0.05 mL/kg [0.023 mL/lb]; 11). Sedation scores were determined at 0 (time of administration), 15, 30, 45, and 60 minutes by use of a subjective scoring system (SSS) and a simple numeric rating scale (NRS). RESULTS: Acepromazine caused significantly greater sedation than did saline solution at 15, 30, 45, and 60 minutes. Acepromazine-hydromorphone caused significantly greater sedation than did saline solution at 15, 30, 45, and 60 minutes and than did hydromorphone alone at 30 minutes. Hydromorphone alone did not cause significantly greater sedation than did saline solution. All treatments, including saline solution, caused significantly greater sedation at 45 and 60 minutes, compared with sedation at time 0. There was a significant correlation (r(2) = 0.72) between scores obtained with the SSS and NRS, but the NRS was less sensitive for detecting clinically important sedation. CONCLUSIONS AND CLINICAL RELEVANCE: Administration of acepromazine or acepromazine-hydromorphone caused sedation in clinically normal dogs, whereas administration of hydromorphone alone did not. The NRS was a less-reliable measure of sedation.

Effects of topical 2% dorzolamide hydrochloride alone and in combination with 0.5% timolol maleate on intraocular pressure in normal feline eyes.

OBJECTIVE: To evaluate the effect of topical 2% dorzolamide alone, and in combination with topical 0.5% timolol, on intraocular pressure (IOP) in normal cats. ANIMALS: Twenty-four healthy Domestic Short-haired cats. PROCEDURE: Baseline values of IOP were established at 7 am, 10 am, 1 pm, 5 pm and 9 pm during pretreatment phase (days 1-2). During treatment phase (days 3-10) cats received 2% dorzolamide HCl q 12 h in group A (n = 6), q 8 h in group B (n = 6), and combined with 0.5% timolol maleate q 12 h in group C (n = 6). Cats in control group D (n = 6) received artificial tears q 8 h. During treatment phase IOP measurements were continued at the same time-points as in the pretreatment phase. RESULTS: Mean pretreatment IOP in all cats was 18.46 +/- 2.99 mmHg. Mean IOP decreased significantly (P < 0.0086) in all treatment groups compared to pretreatment values (group A: 16.40 +/- 0.49 mmHg, group B: 16.04 +/- 0.49 mmHg, group C: 17.76 +/- 0.49 mmHg). IOP did not decrease in control group D (18.55 +/- 0.49 mmHg). The difference in IOP between treatment groups (A, B, C) was not statistically significant, but comparison of IOP between each treatment group and the control group was statistically significant (A-D; P = 0.0057; B-D, P = 0.0012; C-D, P = 0.0212). CONCLUSION: Topical 2% dorzolamide significantly lowers IOP in normal cats but the effect is mild. Concomitant application of 2% dorzolamide and 0.5% timolol does significantly decrease IOP, but the effect is not significantly greater than q 8 h administration of dorzolamide alone.

Effects of treatment with and without adjuvant radiation therapy on recurrence of ocular and adnexal squamous cell carcinoma in horses: 157 cases (1985-2002).

OBJECTIVE: To determine the effects of treatment with and without adjuvant radiation therapy on recurrence of ocular and adnexal squamous cell carcinoma (SCC) at specific anatomic locations in horses. DESIGN: Retrospective study. ANIMALS: 91 horses. PROCEDURES: Medical records of horses with histologically confirmed ocular and adnexal SCC evaluated from 1985 to 2002 were reviewed. Sex, breed, age, type of treatment, location, and recurrence of SCC were recorded. Two treatment groups determined by recurrence of SCCs treated with and without adjuvant radiation therapy were established. RESULTS: The anatomic site with the highest recurrence rate was the limbus (junction of the cornea and sclera) or bulbar conjunctiva (477%), independent of treatment group. There was a significant difference in recurrence rates of ocular and adnexal SCCs between the 2 treatment groups, independent of anatomic location. Recurrence rates of SCCs treated with and without adjuvant radiation therapy were 11.9% and 44.1%, respectively. Recurrence rates for SCCs of the eyelid, limbus or bulbar conjunctiva, and cornea treated with adjuvant radiation therapy were significantly different from those for SCCs treated without adjuvant radiation therapy. The most frequently represented anatomic site for ocular and adnexal SCCs was the eyelid (28.7%). Coat color, breed, and the interaction of age and breed had a significant effect on tumor recurrence regardless of treatment type and anatomic location. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated that ocular and adnexal SCCs treated with adjuvant radiation therapy had a significantly lower recurrence rate, compared with SCCs treated without adjuvant radiation therapy, independent of anatomic location.

Effects of transcorneal iridal photocoagulation on the canine corneal endothelium using a diode laser.

OBJECTIVE: To investigate the potential damage to the canine corneal endothelium following transcorneal iridal laser photocoagulation using a semiconductor diode laser. ANIMALS STUDIED: Sixteen young mongrel dogs. PROCEDURES: Baseline corneal endothelial cell counts and corneal thickness were measured in the central and temporal quadrants using a noncontact specular microscope under general anesthesia. Transcorneal iridal photocoagulation was applied using a semiconductor diode laser in a continuous mode with the use of an operating microscope. Fifteen dogs were treated, and the sixteenth dog served as a control. Fifteen different treatment combinations were randomly assigned to the 30 eyes; the fellow eye was treated differently. Three treatment factors were investigated: (1) laser energy intensity, (2) target tissue to endothelial distance, and (3) laser application duration. After 3 weeks the dogs were euthanized, specular microscopy was repeated, and the cornea was examined by scanning electron microscopy. RESULTS: Dyscoria and focal iris darkening were noted in all eyes immediately following laser treatment. Focal corneal edema (n = 2) and an incipient anterior capsular cataract (n = 1) were also noted. Baseline mean corneal endothelial cell densities were 2530 cells/mm2 centrally and 2607 cells/mm2 temporally. Postlaser corneal endothelial cell densities were 2499 cells/mm2 centrally and 2523 cells/mm2 temporally. Mean prelaser corneal thickness measurements were 0.555 mm centrally and 0.549 mm temporally. Postlaser corneal thickness measurements were 0.580 mm centrally and 0.554 mm temporally. Statistical analyzes revealed no significant changes in endothelial cell densities (P > 0.05) or corneal thickness (P > 0.05) induced by any treatment combination. Aside from tissue handling and processing artifacts, scanning electron microscopy revealed no endothelial cell damage. CONCLUSIONS: Our study demonstrated by specular and scanning electron microscopy that diode laser iridal photocoagulation had no significant effect on the canine corneal endothelium within the parameters described. However, one must take into consideration the young age of the dogs and the potential for corneal endothelial cell regeneration in young dogs, and the relatively short period of postoperative study.