Comparison of transdermal fentanyl and intramuscular oxymorphone on post-operative behaviour after ovariohysterectomy in dogs.

The effects of transdermal fentanyl and i.m. oxymorphone on behavioural and physiological responses, after ovariohysterectomy in dogs, were investigated. The study involved three groups of 10 dogs: fentanyl/surgery (FS), oxymorphone/surgery (OS), fentanyl/control (FC). A transdermal fentanyl delivery system (50 microg hour(-1)) (FS and FC) was applied 20 hours before surgery, or i.m. oxymorphone (OS) was administered. After ovariohysterectomy (FS and OS) or anaesthesia alone (FC), dogs were continuously videotaped for 24 hours and a standardised hourly interaction with a handler performed. The videotapes were analysed, and interactive and non-interactive behaviours evaluated. In addition, pain and sedation scores, pulse and respiratory rates, rectal temperature, arterial blood pressure, plasma cortisol and plasma fentanyl concentrations were measured. This study showed that transdermal fentanyl and i.m. oxymorphone (0.05 mg kg(-1)) produced comparable analgesic effects over a 24 hour recording period. I.m. oxymorphone produced significantly more sedation and lower rectal temperatures than transdermal fentanyl. There were no significant differences between groups in respiratory and heart rates, and arterial blood pressures.

Endotoxic shock. Part I: A review of causes.

Endotoxic shock is a complex phenomenon resulting from systemic release of inflammatory mediators. Endotoxin interacts with inflammatory cells, platelets, and vascular endothelium. Cytokines, such as tumor necrosis factor and interleukins, and lipid mediators (platelet activating factor, thromboxane, prostacyclin, leukotrienes) are released. These primary mediators act synergistically to cause many of the harmful effects associated with endotoxemia. Multiple secondary mediators are released in response to the primary mediators, compounding the damage. The end result is the species-specific clinical syndrome recognized as endotoxemia.

Endotoxic shock. Part II: A review of treatment.

Treatment of endotoxemia is difficult because of the numerous mediators involved in the body's response to endotoxin. There are three possible approaches in treating endotoxemia. The interaction of endotoxin with target cells can be blocked by inducing tolerance, decreasing plasma endotoxin concentrations, or interfering with endotoxin binding. Once endotoxin has interacted with target cells, endogenous mediators can be blocked with a huge variety of drugs. The effects of corticosteroids, cyclooxygenase blockers, leukotriene blockers, platelet activating factor blockers, tumor necrosis factor blockers, oxygen radical scavengers, opiate antagonists, antihistamines, calcium channel blockers are detailed. Supportive care of the endotoxemic patient continues to be a critical aspect of treatment. Controversies regarding solutions to use for volume support, vasoactive and cardiostimulant drugs, metabolic support, and treatment of disseminated intravascular coagulation are reviewed.

Percutaneous endoscopic gastrostomy. A retrospective study of 54 clinical cases in dogs and cats.

Results are presented of consecutive percutaneous endoscopic gastrostomies (PEGs) performed in 32 feline and 22 canine patients over a 30-month period. Indications for PEG placement were hepatic disease (33%), esophageal disease (32%), oronasal abnormalities (22%), and cranial nerve deficits (4%), with miscellaneous conditions accounting for 9%. The median duration that PEG tubes were in place was 18 days (range, 0-320 days). The suitability of this feeding technique for clinical use was assessed by evaluating mortality, procedure-related and delayed complications, and body weight changes by the end of the PEG feeding period. Fifty-two of 54 PEGs were placed and used successfully. One fatality occurred during tube insertion due to splenic laceration, and one dog died of aspiration pneumonia secondary to pharyngoesophageal dysfunction. Other than splenic laceration, procedure-related complications were benign pneumoperitoneum (1/54) and minor gastric hemorrhage resulting in melena (1/54). Delayed complications occurring 24 hours or longer after the procedure included aspiration (4/54), peristomal infection or excessive granulation tissue (3/54), and tube extraction or migration (3/54). Nineteen of 54 animals showed evidence of inadequate gastric emptying or volume intolerance when food was introduced after PEG placement. This effect was minor and easily resolved. Of the 44 animals for which follow-up body weight information was available, 19 gained weight, six remained static, and 19 lost weight during the PEG feeding period. Percutaneous gastrostomy is a relatively safe, effective procedure and should be given early consideration for medium- or long-term enteral nutritional support in appropriate canine and feline patients.

Splenic infarction in 16 dogs: a retrospective study.

Sixteen dogs with splenic infarction due to causes other than splenic torsion were identified. Dogs with splenic infarction often had multiple concurrent diseases, and surgical management of splenic infarction was associated with high mortality. Splenic infarction occurred in dogs with hypercoagulable conditions associated with liver disease, renal disease, and hyperadrenocorticism, or as a consequence of uniform splenomegaly, neoplasia, or thrombosis associated with cardiovascular disease. Clinical signs and common laboratory findings generally reflected the underlying disease process. A variety of splenic abnormalities were detected by abdominal ultrasound in 15 dogs, with the ventral extremity of the spleen being most often abnormal. Four dogs were euthanized or died because of the presence of severe systemic disease, whereas 12 dogs underwent laparotomy. Complete splenectomy was performed in 9 dogs and partial splenectomy was performed in 2 dogs. Seven dogs died in the immediate postoperative period, 3 required chronic veterinary care, and 2 had uncomplicated long-term recoveries. Splenic infaraction should be regarded as a sign of altered blood flow and coagulation, rather than as a primary disease, and surgical management should be reserved for patients with life-threatening complications such as hemoabdomen or sepsis.

Nonendoscopic antegrade percutaneous gastrostomy: the effect of preplacement gastric insufflation on tube position and intra-abdominal anatomy.

Nonendoscopic tube gastrostomy was performed on 47 anesthetized dogs using the technique of Fulton and Dennis with or without gastric insufflation prior to tube placement. Immediately after tube placement, dogs were euthanized and postmortem examinations performed. When gastric insufflation was not performed (group I), gastrostomy tubes penetrated the visceral surface of the stomach in 25% of dogs. The deep leaf of the omentum was interposed between stomach and body wall in the majority of these dogs, exposing other intra-abdominal organs to potential injury. Additionally, displacement and tethering of the spleen cranial to the gastrostomy site were observed in 33% of dogs in group I. Similar results were obtained when preplacement gastric insufflation was performed after the orogastric tube was inserted sufficiently far to displace the stomach laterally against the body wall (group II). In contrast, consistent positioning of gastrostomy tubes through the parietal surface of the stomach was achieved when the stomach was insufflated prior to lateralizing the left abdominal wall with the gastric end of the orogastric tube (group III). It was concluded that the blind percutaneous gastrostomy technique is made safer by insufflating the stomach immediately prior to pushing the gastric wall laterally into contact with the parietal peritoneum.

Intrahepatic postsinusoidal venous obstruction in a dog.

Intrahepatic postsinusoidal obstruction, similar to congenital Budd-Chiari syndrome in human patients, was diagnosed in a young Basenji dog. Sonographic, radiographic, and manometric studies were used in antemortem localization of this unusual functional lesion, that was believed to be congenital.

Abnormalities of the thoracic bellows: stress fractures of the ribs and hiatal hernia.

The thoracic bellows mechanism consists of the rib cage and the diaphragm. The purpose of this study was to determine if nontraumatically acquired lesions of the bellows were secondary to underlying disease. Abnormalities of the bellows, specifically stress fractures of the ribs and hiatal hernia, were found in 21 dogs and cats with underlying cardiopulmonary disease, neuromuscular disease, or metabolic disease. A case-control study of Bulldogs demonstrated that hiatal hernia was associated with the more severe manifestations of brachycephalic syndrome. Stress fractures occurred mostly in females and in cats, and involved multiple ribs. Fractures were usually related to severe respiratory effort, but also occurred in association with metabolic disease. Hiatal hernia was also associated with severe respiratory effort, but may be exacerbated if a neuromuscular disorder affecting the diaphragm is present. Abnormalities of the thoracic bellows, such as rib stress fractures and hiatal hernia, may be signs of underlying disease, rather than being primary causes of disease.

Disposition of transdermally administered fentanyl in dogs.

OBJECTIVE: To evaluate the disposition of fentanyl after i.v. and transdermal administrations. The hypothesis was that transdermal administration of fentanyl would result in a measurable plasma opioid concentration. DESIGN: Each dog received 2 treatments in a randomized, crossover design. ANIMALS: 6 clinically normal Beagles. PROCEDURE: 2 treatments consisting of i.v. fentanyl (50 micrograms/kg of body weight) and transdermal fentanyl (50 micrograms/h) administrations. Plasma fentanyl concentrations were measured at fixed times, and pharmacokinetic values were calculated. RESULTS: Intravenous pharmacokinetics of fentanyl was similar to those previously described in dogs and provided the distribution and clearance data necessary to calculate the rate of absorption of the transdermally administered opioid. The transdermal fentanyl patch produced average steady-state concentrations of 1.6 ng/ml. The actual rate of delivery of transdermal fentanyl was 35.7 (range, 13.7 to 49.8) micrograms/h, which represented 71.48% (range, 27.45 to 99.56%) of the theoretical rate of delivery. The mean elimination half-life of fentanyl after patch removal was 1.39 hours. CONCLUSIONS: Transdermally administered fentanyl resulted in fairly constant plasma concentrations, in the range generally considered to be analgesic, from 24 to 72 hours after application of the patch. The rate of drug delivery was less than expected, and there was substantial individual variation. CLINICAL RELEVANCE: Transdermally administered fentanyl has the potential to be a clinically useful analgesic regimen in dogs, and further evaluation of its analgesic actions and potential side effects warranted

Comparison of pharmacokinetics of fentanyl after intravenous and transdermal administration in cats.

OBJECTIVE: To compare pharmacokinetic and pharmacodynamic characteristics of fentanyl citrate after IV or transdermal administration in cats. ANIMALS: 6 healthy adult cats with a mean weight of 3.78 kg. PROCEDURE: Each cat was given fentanyl IV (25 mg/cat; mean +/- SD dosage, 7.19 +/- 1.17 mg/kg of body weight) and via a transdermal patch (25 microg of fentanyl/h). Plasma concentrations of fentanyl were measured by use of radioimmunoassay. Pharmacokinetic analyses of plasma drug concentrations were conducted, using an automated curve-stripping process followed by nonlinear, least-squares regression. Transdermal delivery of drug was calculated by use of IV pharmacokinetic data. RESULTS: Plasma concentrations of fentanyl given IV decreased rapidly (mean elimination half-life, 2.35 +/- 0.57 hours). Mean +/- SEM calculated rate of transdermal delivery of fentanyl was 8.48 +/- 1.7 mg/h (< 36% of the theoretical 25 mg/h). Median steady-state concentration of fentanyl 12 to 100 hours after application of the transdermal patch was 1.58 ng/ml. Plasma concentrations of fentanyl < 1.0 ng/ml were detected in 4 of 6 cats 12 hours after patch application, 5 of 6 cats 18 and 24 hours after application, and 6 of 6 cats 36 hours after application. CONCLUSIONS AND CLINICAL RELEVANCE: In cats, transdermal administration provides sustained plasma concentrations of fentanyl citrate throughout a 5-day period. Variation of plasma drug concentrations with transdermal absorption for each cat was pronounced. Transdermal administration of fentanyl has potential for use in cats for long-term control of pain after surgery or chronic pain associated with cancer.

Pharmacokinetics of flunixin meglumine in dogs.

The pharmacokinetics of flunixin meglumine, a potent nonsteroidal anti-inflammatory agent, were studied in 6 intact, awake dogs. Plasma samples were obtained up to 12 hours after IV administration of flunixin meglumine. Flunixin concentration was determined, using high performance liquid chromatography. Plasma data best fit a 2-compartment model. Distribution half-life was 0.55 hour; elimination half-life was 3.7 hours; volume of distribution (area) was 0.35 L/kg; volume of distribution at steady state was 0.18 L/kg; volume of the central compartment was 0.079 L/kg; and total body clearance was 0.064 L/hr/kg. Flunixin concentrations obtained over a 6-hour period in 3 dogs with septic peritonitis did not differ significantly from those obtained from healthy dogs.

Plasma-glucose concentrations in dogs and cats before and after surgery: comparison of healthy animals and animals with sepsis.

Various surgical procedures were performed in healthy dogs and cats and in dogs and cats with sepsis. Plasma-glucose concentrations after surgery were usually increased over presurgical values. After surgery, cats had significantly higher plasma-glucose concentrations (P less than 0.05) than did dogs. Postsurgical concentrations for healthy dogs were between 100 to 200 mg/dl, whereas the concentrations for dogs with sepsis ranged from 66 to 356 mg/dl. Of 8 dogs with sepsis that developed postsurgical plasma-glucose concentrations of greater than 150 mg/dl, 4 (50%) died, whereas of 7 dogs with sepsis that developed postsurgical concentrations of less than 150 mg/dl, only 1 (14%) died; however, the difference between these 2 mortality percentages was not significant (P = 0.08).

Escherichia coli-induced lung and liver dysfunction in dogs: effects of flunixin meglumine treatment.

Twelve dogs were infused with 10(10) Escherichia coli/kg of body weight through a portal vein catheter over a 1-hour period; 6 dogs were treated with flunixin meglumine (1 mg/kg) 15 minutes after the infusion had begun. Six dogs (controls) were infused with a comparable volume of sterile saline solution over the same period. Over a 4-hour monitoring period, nontreated septicemic dogs developed systemic hypotension, decreased cardiac output, increased portal pressure, increased serum alanine transaminase values, increased extravascular liver water, increased liver glycogen depletion, and decreased arterial oxygen tension compared with control dogs. Accumulations of polymorphonuclear leukocytes and E coli were found in the livers and lungs of septicemic dogs. Flunixin meglumine treatment prevented systemic hypotension and hypoxemia, reversed the early but not the late stages of portal hypertension, and decreased E coli concentrations in the lungs. Other effects of treatment were not noticed.

Lidocaine treatment of dogs with Escherichia coli septicemia.

Effects of lidocaine on organ localization of neutrophils and bacteria and on hemodynamic and metabolic variables were determined during septic shock in dogs. Twelve anesthetized dogs were infused with 10(10) Escherichia coli/kg of body weight through a portal vein catheter over a 1-hour period. Six of these 12 dogs were treated with 2 mg of lidocaine HCl/kg (6 mg/kg/h) 15 minutes after the bacterial infusion had begun. Six dogs not given E coli (surgical controls) were given saline solution at the same rate as the bacterial and lidocaine infusions. Over 4 hours, nontreated dogs with septicemia developed systemic hypotension, decreased cardiac output, increased portal pressure, increased serum alanine transaminase activity, increased liver extravascular water, increased liver glycogen depletion, and decreased PaO2, compared with control dogs. Accumulations of polymorphonuclear leukocytes and E coli were found in the liver and lungs of dogs with septicemia. Lidocaine treatment did not alter the hemodynamic measurements and resulted in metabolic acidosis and hypoalbuminemia. Decreased numbers of E coli were recovered from the liver of lidocaine-treated dogs, whereas increased numbers of organisms were recovered from the blood. Neutrophil sequestration was increased in the liver, but not the lungs of lidocaine-treated dogs.

Effect of time of cisplatin administration on its toxicity and pharmacokinetics in dogs.

Cisplatin (90 mg/m2) was administered in a 5-minute bolus IV infusion to dogs at 8 AM (n = 6) or 4 PM (n = 6). Blood and urine samples were collected over a 4-hour period for statistical moment pharmacokinetic analysis. Mean urinary excretion rate of total platinum was increased, whereas mean plasma residence time of ultrafilterable platinum was decreased, in the group treated at 4 PM (PM group), compared with those treated at 8 AM (AM group). Over a 2-week postinfusion-monitoring period, both groups of dogs developed decreases in creatinine clearance, urine/serum osmolality ratio (UOsm/SOsm), specific gravity, and increase in BUN, serum creatinine concentration, urine gamma-glutamyltranspeptidase/urine creatinine ratio (UGGT/UCr), fractional excretion of magnesium, and fractional excretion of phosphate. Urine specific gravity and UOsm/SOsm were significantly decreased, whereas UGGT/UCr and BUN were significantly increased in the AM group, compared with the PM group. The time of administration had a significant effect on the pharmacokinetics of cisplatin, which resulted in significant differences in cisplatin-induced renal toxicosis.

Neodymium:yttrium, aluminum, and garnet laser energy delivered transsclerally to the ciliary body of dogs.

Using a hand-held optical fiber, a surgical neodymium:yttrium, aluminum, and garnet laser was used transsclerally on the left ciliary body of 25 dogs. Dogs were assigned to groups and were given low (100 J) and high (238 J) energy levels. In 12 dogs given 100-J energy, the intraocular pressure decreased a mean value of 6 mm of Hg below that in the untreated right eye. However, intraocular pressure returned to the pretreatment value 1 week after treatment. Intraocular lesions were not found by histologic examination 28 days later. In the second group of 13 dogs treated with 238-J energy, 6 were euthanatized 7 days after treatment and 7 were euthanatized 28 days after treatment. A mean decrease in intraocular pressure of 10 mm of Hg in the treated left eye, relative to the untreated right eye, persisted throughout the evaluation period. In eyes examined histologically 7 days after treatment, ciliary hemorrhage and necrosis were prominent. Other histologic changes were minimal and consisted principally of iris stromal hemorrhage. Of 7 dogs examined for 28 days after treatment, 6 remained sighted; in 1 dog, extensive intraocular hemorrhage occurred, eventually resulting in phthisis bulbi. Ciliary atrophy and fibrosis were the important histologic lesions observed 28 days after treatment. Laser energy delivered transsclerally by this optical system effectively induced ciliary necrosis and may be an effective treatment for canine glaucoma.

Vascular permeability and coagulation during Rickettsia rickettsii infection in dogs.

The vascular permeability of the ocular fundus, alterations in the coagulation system, and plasma concentrations of thromboxane B2 (TXB2) and 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) were studied in dogs following intradermal inoculation with 5 x 10(5) TCID50 of Rickettsia rickettsii. Twenty-four to 48 hours after the onset of fever and rickettsemia, multifocal areas of retinal vasculitis were evident, which corresponded to areas of altered vascular permeability demonstrated by fluorescein angiography. The number and intensity of retinal vessels with sodium fluorescein leakage peaked during the second week after inoculation, and retinal vascular permeability remained altered during the third week of infection, well past the phase of clinical and clinicopathologic recovery. Development of retinal vasculitic foci was associated with thrombocytopenia, increased concentrations of circulating fibrinogen, and slight prolongation of activated partial thromboplastin time. Increased concentrations of fibrin/fibrinogen degradation products were detected in 4 of 9 dogs. Despite the degree of vascular endothelial damage evident on fluorescein angiographic and histologic studies in these dogs, plasma TXB2 and 6-keto-PGF1 alpha concentrations were not increased.

Treatment of canine actinomycosis.

Sixteen cases of actinomycosis seen at the University of Georgia were reviewed. Treatment in 15 cases consisted of long-term antibiotic therapy combined with lavage and drainage of the affected area. Surgical debridement was used in several cases. Treatment was successful in 12 cases.

Amyloidosis in a dog: treatment with dimethylsulfoxide.

A dog with hypoalbuminemia, proteinuria, and renal amyloidosis was treated with dimethylsulfoxide for 2 years. During a 1-year period, serum albumin concentrations increased to within normal range. The 24-hour urinary protein excretion was 5.7 g before treatment with dimethylsulfoxide. Two years after initiation of treatment, the 24-hour urinary protein excretion was 3.7 g. Removal of a testicle containing a Sertoli cell tumor and treatment of interdigital pyoderma may have been factors in the dog's clinical improvement. The only adverse effect from the dimethylsulfoxide treatment was the characteristic disagreeable odor.