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Objective—

To determine short-term results and complications of prepubertal gonadectomy in cats and dogs.

Design—

Prospective randomized study.

Animals—

775 cats and 1,213 dogs.

Procedure—

Animals undergoing gonadectomy were allotted into 3 groups on the basis of estimated age (group 1, < 12 weeks old; group 2, 12 to 23 weeks old; group 3, ≥ 24 weeks old). Complications during anesthesia, surgery, and the immediate postoperative period (7 days) were recorded. Complications were classified as major (required treatment and resulted in an increase in morbidity or mortality) or minor (required little or no treatment and caused a minimal increase in morbidity). An ANOVA was used to detect differences among groups in age, weight, body temperature, and duration of surgery. To detect differences in complication rates among groups, χ2 analysis was used.

Results—

Group 1 consisted of 723 animals, group 2 consisted of 532, and group 3 consisted of 733. Group-3 animals had a significantly higher overall complication rate (10.8%) than group-1 animals (6.5%), but did not differ from group-2 animals (8.8%). Differences were not detected among the 3 groups regarding major complications (2.9, 3.2, and 3.0% for groups 1, 2, and 3, respectively), but group-3 animals had significantly more minor complications (7.8%) than group-1 animals (3.6%), but not group-2 animals (5.6%).

Clinical Implications—

In this study, prepubertal gonadectomy did not increase morbidity or mortality on a short-term basis, compared with gonadectomy performed on animals at the traditional age. These procedures may be performed safely in prepubertal animals, provided that appropriate attention is given to anesthetic and surgical techniques. (J Am Vet Med Assoc 1997;211:57–62)

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objective

To determine existence of portal and systemic bacteremia in dogs with induced severe hepatic disease, compared with clinically normal dogs, before and after vena caval banding.

Animals

6 control dogs and 10 dogs with induced severe hepatic disease and multiple portosystemic shunts (PSS).

Procedure

Dogs of the diseased group were given dimethylnitrosamine (2 mg/kg of body weight, PO) twice weekly until multiple PSS developed. Surgery was performed on dogs of both groups, and blood for baseline aerobic and anaerobic bacterial culture was collected from catheters placed in the portal and hepatic veins and caudal vena cava. All dogs underwent vena caval banding, and blood for aerobic and anaerobic bacterial culture was collected from the portal and hepatic venous catheters at 120, 240, and 360 minutes after banding.

Results

Compared with control dogs (16% gram-positive and 84% gram-negative bacteria), diseased dogs had significantly higher percentage of gram-positive bacteria (42% of positive culture results, P ≤ 0.01) and significantly lower percentage of gram-negative bacteria (58% of positive culture results, P ≤ 0.01) isolated. Pseudomonas aeruginosa was isolated most frequently from dogs of both groups; more than 1 organism was isolated from 5 dogs of each group. Antimicrobial susceptibility included that to aminoglycosides (particularly amikacin), fluorinated quinolones, and imipenem.

Conclusions

Portal and systemic, predominantly gram-negative, bacteremia is present in catheterized, clinically normal dogs and dogs with dimethylnitrosamine-induced hepatic disease and multiple PSS. (Am J Vet Res 1999;60:181-185)

Free access
in American Journal of Veterinary Research

Abstract

Objective

To document presence of endotoxin in portal and systemic blood in a model of canine multiple portosystemic shunts (PSS), and compare values in clinically normal dogs, before and after vena caval banding.

Animals

6 control dogs and 10 dogs with dimethylnitrosamine-induced multiple PSS that were subjected to vena caval banding.

Procedure

Dimethylnitrosamine was administered orally (2 mg/kg of body weight, twice weekly) to the 10 dogs in the diseased group until multiple PSS developed. Surgery was then performed on all 16 dogs (both groups), and shunts were confirmed in the diseased dogs. Blood was collected from the portal vein, hepatic vein, and caudal vena cava for baseline endotoxin determination and aerobic and anaerobic blood culturing. Baseline pressure measurements were taken from the portal venous catheter; then vena caval banding was performed. Blood for endotoxin determinations was taken from all vessels 20, 40, 60, 120, 240, and 360 minutes after banding; portal pressure measurements were taken at the same time as sample acquisition. Blood for culturing was taken from the portal and hepatic venous catheters at 120, 240, and 360 minutes after banding.

Results

Dogs in the diseased group had significantly greater overall presence of endotoxin in the portal vein (P ≤ 0.0002), hepatic vein (P ≤ 0.0001), and caudal vena cava (P ≤ 0.0004) than did control dogs. With respect to time, endotoxin presence was greater in the diseased group before banding (P ≤ 0.0002), and at 20 (P ≤ 0.0008), 40 (P ≤ 0.002), 60 (P ≤ 0.006), and 120 (P ≤ 0.01) minutes after banding.

Conclusions

Endotoxemia is more frequently present in catheterized dogs with dimethylnitrosamine-induced hepatic disease and multiple PSS, compared with clinically normal dogs. Additionally, portal pressure changes induced by vena caval banding did not affect endotoxemia.

Clinical Relevance

Endotoxemia may exist in dogs with hepatic disease and multiple PSS, and should be kept in mind when formulating treatment (particularly antimicrobial selection) for dogs with suspected endotoxemia. (Am J Vet Res 1997;58:83–88)

Free access
in American Journal of Veterinary Research

Objective

To describe the long-term outcome in dogs with naturally developing multiple extrahepatic portosystemic shunts (PSS).

Design

Retrospective case series.

Animals

30 dogs with multiple PSS.

Procedure

Medical records of dogs with multiple PSS were reviewed. Follow-up data were obtained by 1 or more of the following methods: recheck at the veterinary teaching hospital (n = 6) or telephone contact with the referring veterinarian (n = 18) or owner (n = 10). The χ 2 or Mann-Whitney rank sum test was used to determine the association of clinical factors with long-term outcome. Survival curves were generated by the Kaplan-Meier product limit method.

Results

Median age at diagnosis was 1 year. Findings on exploratory surgery in 25 dogs included ascites; numerous tortuous vessels connecting the portal vein with systemic veins; a small, misshapen liver; and an enlarged portal vein. The most common lesions on histologic evaluation of hepatic tissue specimens were hepatocellular atrophy, portal vascular duplication, cirrhosis, inflammation, and bile duct proliferation. Twelve dogs were treated surgically with vena caval banding, whereas 13 dogs were treated conservatively with dietary restriction of protein and administration of antibiotics, diuretics, and other drugs. Long-term survival and quality of life were similar in dogs from both treatment groups. Median follow-up interval in dogs that survived hospitalization was 24 months (range, 1 to 54 months).

Clinical Implications

On the basis of these findings, vena caval banding in dogs with multiple PSS is not superior to medical and nutritional treatment. (J Am Vet Med Assoc 1996;208:1849-1854)

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To document blood nitric oxide concentrations in the portal vein and systemic circulation in a rat model of acute portal hypertension and compare values with a control group and a sham surgical group.

Animals—30 rats; 10 controls (group 1), 10 sham surgical (group 2), and 10 rats with surgically induced acute portal hypertension (group 3).

Procedure—Following induction of anesthesia, catheters were placed surgically in the carotid artery, jugular, and portal veins of group 2 and 3 rats and in the carotid artery and jugular vein of group 1 rats. Baseline heart and respiratory rates, rectal temperature, and vascular pressure measurements were obtained, and blood was drawn from all catheters for baseline nitric oxide (NO) concentrations. Acute portal hypertension was induced in the group 3 rats by tying a partially occluding suture around the portal vein and a 22-gauge catheter. The catheter was then removed, resulting in a repeatable degree of portal vein impingement. After catheter placement, all variables were remeasured at 15-minute intervals for 3 hours.

Results—Blood nitric oxide concentrations were greater in all vessels tested in group 3 than in group 2 rats.

Conclusions and Clinical Relevance—Acute portal hypertension in this experimental model results in increased concentrations of NO in the systemic and portal circulation. On the basis of information in the rat, it is possible that increased NO concentrations may develop in dogs following surgical treatment of congenital portosystemic shunts if acute life-threatening portal hypertension develops. Increased NO concentrations may contribute to the shock syndrome that develops in these dogs. (Am J Vet Res 2000;61:1173–1177)

Full access
in American Journal of Veterinary Research

Abstract

Objective—To determine the effect of treatment approach on outcome and the appropriateness of initial empirical antimicrobial treatment in dogs with pyothorax.

Design—Retrospective case series.

Animals—46 dogs with pyothorax confirmed by either (n = 15) or both (31) of the following: intracellular bacteria in pleural fluid or tissue (41) and bacteria recovered via culture of pleural fluid (36).

Procedures—Medical records of dogs treated for pyothorax from 1983 through 2001 were reviewed. Data on signalment, history, clinical signs, and treatment and results of diagnostic imaging and cytologic and microbiological evaluations were obtained. Follow-up was performed via reexamination (n = 15) and contact with referring veterinarians (26) and owners (24).

Results—46 dogs were treated with at least 1 antimicrobial and thoracocentesis (n = 7; noninvasive group), a thoracostomy tube (26; invasive group) with or without pleural lavage and heparin, or a thoracotomy (13; surgical group) and thoracostomy tube with or without pleural lavage and heparin. Pyothorax recurred in 7 dogs, and 5 of the 7 died or were euthanatized. In the respective groups, the short-term survival rate was 29%, 77%, and 92% and the long-term survival rate was 29%, 71%, and 70%. Pleural lavage and heparin treatment increased the likelihood of short- and long-term survival. Results of antimicrobial susceptibility testing suggested empirical antimicrobial selection was associated with a 35% risk of inefficacy.

Conclusions and Clinical Relevance—In the dogs with pyothorax in this study, favorable treatment effects were achieved with surgery (for short-term survival) and pleural lavage and heparin treatment (for short- and long-term survival). Findings failed to support the hypothesis that invasive (surgical) versus noninvasive treatment of pyothorax in dogs leads to a better long-term outcome.

Full access
in Journal of the American Veterinary Medical Association

Summary

Effects of vena caval banding on portal venous and vena caval hemodynamics were examined in 6 control dogs and in 10 dogs that had undergone attenuation (banding) of the abdominal part of the caudal vena cava and had dimethylnitrosamine-induced multiple portosystemic shunts (pss). Additionally, indocyanine green (icg) extraction and clearance after infusion to steady state were used to calculate hepatic plasma flow in these dogs. Sixteen dogs were randomly assigned to 2 groups: control (n = 6) or diseased(n= 10). Diseased dogs were administered dimethylnitrosamine (2 mg/kg, po, twice weekly) until multiple pss developed, as assessed by results of clinical laboratory tests, ultrasonography, and hepatic scintigraphy. Shunts were confirmed visually at celiotomy and by contrast portography. Venous pressures (caudal vena caval, portal, and hepatic) were recorded before and after vena caval banding for up to 7 days in dogs from both groups. Peritoneal cavity pressures were recorded in all dogs after closure of the body wall. To determine icg extraction and clearance, a bolus injection of icg (0.5 mg/kg, iv) was administered, followed by steady-state infusion of 0.097 mg/min. Extractions and clearances of icg were measured, and from these, hepatic plasma flow rates were determined immediately before and after banding and at 6 hours, 48 hours, and 7 days after banding.

The gradient (caudal vena caval pressure within 1 to 2 mm of Hg of portal pressure) between caudal vena cava and portal venous pressures established at banding was maintained after the first hour in both groups. Caudal vena cava pressures established at banding were maintained throughout the study, with the exception of the first hour in diseased dogs. Extraction ratios were higher in control dogs at all times, except at 48 hours. Clearance was higher in control dogs at all times. Hepatic plasma flow did not differ between groups, except immediately after banding, when flow was greater in diseased dogs, and differences were not found over time in either group. This study indicated that vena caval banding in this model of experimentally induced multiple pss increases and maintains caudal vena cava pressure, relative to portal venous pressure (after the first hour) for 7 days, and that calculated hepatic plasma flow is not persistently improved by vena caval banding.

Free access
in American Journal of Veterinary Research

Abstract

Objective—To determine long-term results and complications of gonadectomy performed at an early age (prepubertal) or at the traditional age in dogs.

Design—Cohort study.

Animals—269 dogs from animal shelters.

Procedure—Dogs that underwent gonadectomy were allotted to 2 groups on the basis of estimated age at surgery (traditional age, ≥ 24 weeks old; prepubertal, < 24 weeks old). Adoptive owner information was obtained from shelter records, and telephone interviews were conducted with owners to determine physical or behavioral problems observed in the dogs since adoption. Follow-up information was obtained from attending veterinarians for dogs with complex problems or when owners were uncertain regarding the exact nature of their dog's problem.

Results—Prepubertal gonadectomy did not result in an increased incidence of behavioral problems or problems associated with any body system, compared with traditional-age gonadectomy, during a median follow-up period of 48 months after gonadectomy. Rate of retention in the original adoptive household was the same for dogs that underwent prepubertal gonadectomy as those that underwent traditional- age gonadectomy. Infectious diseases, however, were more common in dogs that underwent prepubertal gonadectomy.

Conclusions and Clinical Implications—With the exception of infectious diseases, prepubertal gonadectomy may be safely performed in dogs without concern for increased incidence of physical or behavioral problems during at least a 4-year period after gonadectomy. (J Am Vet Med Assoc 2001;218: 217–221)

Full access
in Journal of the American Veterinary Medical Association

Objective

To evaluate adequacy of analgesia provided by postoperative administration of butorphanol to cats undergoing onychectomy.

Design

Randomized controlled trial.

Animals

63 cats undergoing elective onychectomy.

Procedure

Cats were randomly assigned to a treatment (n = 42) or control group (21). Cats in the treatment group were given butorphanol parenterally immediately and 4 hours after surgery and orally for 2 days after surgery. Rectal temperature, heart rate, and respiratory rate were recorded and scores were assigned for temperament, recovery, sedation, analgesia, and lameness for the first 24 hours after surgery. Owners provided scores for appetite, personality, and lameness the first and second days after discharge from the hospital.

Results

Heart rate, respiratory rate, rectal temperature, and temperament and sedation scores were not significantly different between groups at any evaluation time. Recovery scores were significantly better for butorphanol-treated than for control-group cats 10 minutes after extubation. Analgesia scores were significantly better for butorphanol-treated than for control-group cats between 5 and 24 hours after surgery. Fewer butorphanol-treated than control-group cats were lame at the time of discharge from the hospital. The first day after discharge, owners reported that percentages of butorphanol-treated cats that ate normally, acted normally, and had only mild or no lameness were significantly higher than percentages of control-group cats that did. Significant differences between groups were not detected the second day after discharge.

Clinical Implications

Results suggest that for cats undergoing onychectomy, administration of butorphanol the day of surgery and the first full day after surgery provides effective analgesia and improves recovery, appetite, and gait. (J Am Vet Med Assoc 1998;213:246-250)

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine long-term results and complications of gonadectomy performed at an early age (prepubertal) or at the traditional age in cats.

Design—Cohort study.

Animals—263 cats from animal shelters.

Procedure—Cats that underwent gonadectomy were allotted to 2 groups on the basis of estimated age at surgery (traditional age, ≥ 24 weeks old; prepubertal, < 24 weeks old). Adoptive owner information was obtained from shelter records, and telephone interviews were conducted with owners to determine physical or behavioral problems observed in the cats after adoption. Follow-up information was obtained from attending veterinarians for cats with complex problems or when owners were uncertain regarding the exact nature of their cat's problem.

Results—Compared with traditional-age gonadectomy, prepubertal gonadectomy did not result in an increased incidence of infectious disease, behavioral problems, or problems associated with any body system during a median follow-up period of 37 months. Additionally, the rate of retention in the original adoptive household was the same for cats that underwent prepubertal gonadectomy as those that underwent traditional-age gonadectomy.

Conclusions and Clinical Relevance—Prepubertal gonadectomy may be performed safely in cats without concern for increased incidence of physical or behavioral problems for at least a 3-year period after gonadectomy. (J Am Vet Med Assoc 2000;217: 1661–1665)

Full access
in Journal of the American Veterinary Medical Association