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Abstract

OBJECTIVE To define learning curves for fourth-year veterinary students performing ovariohysterectomy procedures in dogs and cats and castration in dogs.

DESIGN Retrospective study.

SAMPLE 3,196 ovariohysterectomies or castrations performed in dogs and cats by 88 veterinary students during a spay-neuter surgery and animal shelter rotation (n = 3,056) or by 1 experienced general practitioner (n = 140).

PROCEDURES Data collected from medical records included patient signalment, type and duration of procedure, and sequence (by date and time) of the procedure within a list of procedures of the same type generated for each student. For each procedure type, geometric mean surgery time and 95% confidence intervals were determined for each number of surgeries completed by ≥ 10 students. Median surgery times for the same procedure types were determined for the experienced practitioner. The learning curve for each procedure was modeled with nonlinear (3-factor exponential equation with a nonzero asymptote) and linear regression. For each procedure, the asymptote (optimal surgery time) for students was compared with the experienced practitioner's median surgery time.

RESULTS 2,945 surgeries (mean, 33/student) performed by ≥ 10 students were analyzed. Surgery time decreased in a nonlinear manner as student experience increased for castration of adult or pediatric dogs and ovariohysterectomy of pediatric dogs and adult or pediatric cats. Surgery time decreased in a linear manner as experience increased for ovariohysterectomy of adult dogs.

CONCLUSIONS AND CLINICAL RELEVANCE To the authors' knowledge, this was the first study to map surgery times for common surgical procedures consecutively performed by veterinary students. Results clearly indicated the value of repetition to improve surgical skills (as measured by surgery time) during a 3-week period.

Restricted access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To compare toxicokinetic variables and associated tissue drug concentrations with severity of articular lesions in weight-bearing joints of juvenile rabbits after oral administration of a fluoroquinolone.

Animals—Ten 6- to 7-week-old, 800- to 1,200-g, New Zealand White rabbits.

Procedures—Rabbits were gavaged daily with the fluoroquinolone PD 117596 at 500 mg/kg of body weight for 5 days. Blood samples were collected on day 4 at preestablished times, up to 24 hours after drug administration. On day 5 gross lesion severity and prevalence were evaluated in the major weight-bearing joints, and tissue specimens were collected (60 minutes after drug administration). Serum and tissue drug concentrations were determined by microbiologic plate assay.

Results—Macroscopically, treatment rabbits had a high prevalence of arthropathy with the distal portion of the femur having the highest prevalence and severity of lesions. Grossly, alterations to articular cartilage included 1 to 4 mm in diameter vesicles or erosions. Histologically, vesicles were identified in the midzone or close to the zone of calcified cartilage of treatment rabbits. Chondrocyte cellularity was reduced in affected areas, and perivesicular regions had reduced staining with Safranin O. Correlation analysis of area under the curve values with total scores for lesion severity had a significant positive relationship.

Conclusions—Our findings support the use of juvenile rabbits as a model for arthropathic changes induced by fluoroquinolone administration. (Am J Vet Res 2000;61:1396–1402)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To evaluate the cardiopulmonary effects of IV fentanyl administration in dogs during isoflurane anesthesia and during anesthetic recovery with or without dexmedetomidine or acepromazine.

Animals—7 sexually intact male purpose-bred hound-type dogs aged 11 to 12 months.

Procedures—Dogs received a loading dose of fentanyl (5 μg/kg, IV) followed by an IV infusion (5 μg/kg/h) for 120 minutes while anesthetized with isoflurane and for an additional 60 minutes after anesthesia was discontinued. Dogs were randomly assigned in a crossover design to receive dexmedetomidine (2.5 μg/kg), acepromazine (0.05 mg/kg), or saline (0.9% NaCl) solution (1 mL) IV after anesthesia ceased. Cardiopulmonary data were obtained during anesthesia and for 90 minutes after treatment administration during anesthetic recovery.

Results—Concurrent administration of fentanyl and isoflurane resulted in significant decreases in mean arterial blood pressure, heart rate, and cardiac index and a significant increase in Paco2. All but Paco2 returned to pretreatment values before isoflurane anesthesia was discontinued. During recovery, dexmedetomidine administration resulted in significant decreases in heart rate, cardiac index, and mixed venous oxygen tension and a significant increase in arterial blood pressure, compared with values for saline solution and acepromazine treatments. Acepromazine administration resulted in significantly lower blood pressure and higher cardiac index and Po2 in mixed venous blood than did the other treatments. Dexmedetomidine treatment resulted in significantly lower values for Pao2 and arterial pH and higher Paco2 values than both other treatments.

Conclusions and Clinical Relevance—Fentanyl resulted in transient pronounced cardiorespiratory effects when administered during isoflurane anesthesia. During anesthetic recovery, when administered concurrently with an IV fentanyl infusion, dexmedetomidine resulted in evidence of cardiopulmonary compromise and acepromazine transiently improved cardiopulmonary performance.

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE To quantify plasma concentrations and determine adverse ocular, renal, or hepatic effects associated with repeated topical ophthalmic application of 0.1% diclofenac to healthy cats.

ANIMALS 8 healthy sexually intact male cats.

PROCEDURES A randomized, placebo-controlled crossover study was conducted. A topical formulation of 0.1% diclofenac was administered 4 times/d for 7 days to 4 cats, and artificial tear (control) solution was administered to the other 4 cats. After a 12-day washout period, cats received the other treatment. Ophthalmic examinations were performed daily. Plasma samples were obtained on days 1 and 7 for pharmacokinetic analysis. A CBC, serum biochemical analysis, urinalysis, determination of urine protein-to-creatinine ratio, and determination of glomerular filtration rate were performed before the start of the study and after each 7-day treatment period.

RESULTS Mild conjunctival hyperemia was the only adverse ocular effect detected. Maximal drug concentration and area under the curve were significantly higher on day 7 than on day 1. Diclofenac-treated cats had a significantly lower glomerular filtration rate than did control-treated cats after the second but not after the first treatment period, presumably associated with iatrogenic hypovolemia.

CONCLUSIONS AND CLINICAL RELEVANCE Topical ophthalmic administration of 0.1% diclofenac was well tolerated in healthy cats, with only mild signs of ocular irritation. Detectable systemic concentrations of diclofenac were achieved with accumulation over 7 days. Systemic absorption of diclofenac may be associated with reduced glomerular filtration rate, particularly in volume-contracted animals. Topical ophthalmic 0.1% diclofenac should be used with caution in volume-contracted or systemically ill cats.

Full access
in American Journal of Veterinary Research

Abstract

OBJECTIVE To evaluate the effects of IV diphenhydramine hydrochloride administration on cardiorespiratory variables in anesthetized dogs undergoing mast cell tumor (MCT) excision.

DESIGN Randomized, blinded clinical trial.

ANIMALS 16 client-owned dogs with MCTs.

PROCEDURES In a standardized isoflurane anesthesia session that included mechanical ventilation, dogs received diphenhydramine hydrochloride (1 mg/kg [0.45 mg/lb], IV; n = 8) or an equivalent volume of saline (0.9% NaCl) solution (IV; control treatment; 8) 10 minutes after induction. Cardiorespiratory variables were recorded throughout anesthesia and MCT excision, and blood samples for determination of plasma diphenhydramine and histamine concentrations were collected prior to premedication (baseline), throughout anesthesia, and 2 hours after extubation.

RESULTS Cardiorespiratory values in both treatment groups were acceptable for anesthetized dogs. Mean ± SD diastolic arterial blood pressure was significantly lower in the diphenhydramine versus control group during tumor dissection (52 ± 10 mm Hg vs 62 ± 9 mm Hg) and surgical closure (51 ± 10 mm Hg vs 65 ± 9 mm Hg). Mean arterial blood pressure was significantly lower in the diphenhydramine versus control group during surgical closure (65 ± 12 mm Hg vs 78 ± 11 mm Hg), despite a higher cardiac index value. Plasma histamine concentrations were nonsignificantly higher than baseline during maximal manipulation of the tumor and surgical preparation in the diphenhydramine group and during surgical dissection in the control group.

CONCLUSIONS AND CLINICAL RELEVANCE IV administration of diphenhydramine prior to MCT excision had no clear clinical cardiorespiratory benefits over placebo in isoflurane-anesthetized dogs.

Restricted access
in Journal of the American Veterinary Medical Association