Evaluation of tumescent local anesthesia in cats undergoing unilateral mastectomy.

OBJECTIVE: To evaluate the analgesic efficacy and safety of tumescent local anesthesia (TLA) in cats undergoing unilateral mastectomy. STUDY DESIGN: Prospective clinical trial. ANIMALS: A total of 12 ovariohysterectomized female cats. METHODS: All animals were premedicated with pethidine (4 mg kg-1) intramuscularly (IM), followed by induction of anesthesia with propofol (5 mg kg-1) intravenously and maintenance with isoflurane in oxygen. A refrigerated TLA solution (15 mL kg-1, 8 °C) was injected using a Klein cannula. The solution was composed of 0.5 mL of epinephrine (1 mg mL-1) and 40 mL of 2% lidocaine added to 210 mL lactated Ringer's solution (final lidocaine concentration 0.32%). Heart and respiratory rates, systolic arterial blood pressure, temperature and oxygen saturation were measured during anesthesia. Blood samples were collected from the jugular vein for measurement of plasma lidocaine concentration using high performance liquid chromatography. Postoperative pain scores were evaluated hourly for 6 hours. Analgesic rescue was performed with tramadol (2 mg kg-1) IM and meloxicam (0.15 mg kg-1) subcutaneously. RESULTS: Plasma lidocaine concentration peaked at 90 minutes after injection of TLA, but no concentration considered toxic for the species was measured. The median postoperative analgesia time was 6 hours after injection of TLA. CONCLUSIONS: This study found that TLA prevented sympathetic response to noxious stimuli during anesthesia and provided satisfactory postoperative analgesia in cats submitted to total unilateral mastectomy, with no apparent signs of toxicity. CLINICAL RELEVANCE: TLA can prevent sympathetic stimulation resulting from noxious stimuli during anesthesia, promoting good intraoperative conditions, proving to be a viable addition to analgesia in cats submitted to a total unilateral mastectomy.

The effects of lidocaine-prilocaine cream on responses to intravenous catheter placement in cats sedated with dexmedetomidine and either methadone or nalbuphine.

OBJECTIVE: To compare the reaction to cephalic intravenous (IV) catheter placement with or without lidocaine-prilocaine cream in cats sedated with dexmedetomidine and methadone or nalbuphine. STUDY DESIGN: Prospective, randomized, blind study. ANIMALS: A group of 24 female mixed breed cats. METHODS: Cats were randomly allocated to one of the two sedation protocols: dexmedetomidine (0.01 mg kg-1) and methadone (0.3 mg kg-1; DEXMET) or dexmedetomidine (0.01 mg kg-1) and nalbuphine (0.3 mg kg-1; DEXNALB). Sedation was scored 30 minutes later using a visual analog scale. Subsequently, a 2 × 3.5 cm area of the antebrachium over the cephalic vein was clipped, and half the cats within each protocol were randomly assigned for topical lidocaine-prilocaine cream (treatment), whereas no cream was applied to other cats (control). After 20 minutes, an attempt was made to place a 24 gauge catheter into the cephalic vein and the reaction of the cats to this procedure was scored using a numeric scale 0-3. Sedation and catheterization reaction scores were compared between sedation protocols and whether cats were administered lidocaine-prilocaine cream or not using the Friedman test followed by the Bonferroni procedure. A p value < 0.05 was considered significant. RESULTS: Sedation scores were not different between sedation protocols or between treatment and control cats within each protocol. All cats administered lidocaine-prilocaine cream showed no reaction to IV catheter placement. Among the control cats, no response was observed in one cat in DEXNALB. Catheterization reaction score was lower in the treatment cats in both the sedation protocols when compared with their respective controls. CONCLUSIONS AND CLINICAL RELEVANCE: Lidocaine-prilocaine cream applied for 20 minutes abolished the reaction to catheterization in cats sedated with dexmedetomidine and nalbuphine or methadone. Facilitation of IV catheter placement occurred within 20 minutes of lidocaine-prilocaine application.

Effect of administration rate on propofol requirement in cats.

Objectives The objective of this study was to determine the effect of administration rate on propofol dose for induction of anesthesia and the effect of methadone on this dose. Methods This was a prospective, randomized, blinded clinical study. Forty male cats (mean ± SD age 1.5 ± 0.8 years) were admitted for orchiectomy. Cats were randomly allocated to receive acepromazine (0.05 mg/kg) with either methadone (MET; 0.3 mg/kg) or saline (SAL; 0.03 ml/kg). Each premedication group then received anesthetic induction with propofol at 5 (F) or 1.5 mg/kg/min (S), resulting in the following four groups: MET-F, SAL-F, MET-S and SAL-S. Sedation scores were assigned at 15 and 30 mins after premedication using a simple descriptive scale (SDS) and a visual analog scale (VAS). After assignment of sedation scores, respiratory frequency ( fR) was recorded, and anesthetic induction began and was continued until cats lost their palpebral reflexes and jaw tone, and the eye globe rotated ventromedially. The time for induction and the total amount of propofol needed was recorded, and intubation was then performed. After intubation, fR was also recorded. Results SDS and VAS sedation scores were low at 15 and 30 mins after premedication. There was no significant difference in sedation scores by time or between the groups at any time on any scale. The amount of propofol needed to achieve anesthetic induction was 5.3 ± 1.1 mg/kg in group MET-F, which was statistically lower when compared with the other three groups, which demonstrated no difference among them. Conclusions and relevance Premedication with acepromazine and methadone was not able to produce adequate sedation in healthy cats. The slow induction rate is not adequate for use in cats considering that all of the animals demonstrated excitement during anesthetic induction. The fast administration rate was able to produce adequate induction of anesthesia and reduce the amount of propofol needed to achieve intubation only when using methadone.

Histologic evaluation of Ki-67 and cleaved caspase-3 expression in feline mammary carcinoma.

Objectives The purpose of this study was to evaluate histopathologic aspects of, and the expression of Ki-67 and cleaved caspase-3 in, feline mammary carcinoma (FMC). Methods Feline mammary tumors were surgically obtained by mastectomy from 30 female cats and were fixed with formalin and embedded in paraffin wax. Four-micron sections were stained with hematoxylin and eosin for histopathologic diagnosis. Ki-67 and cleaved caspase-3 were analyzed by immunohistochemistry. Results Samples were histologically confirmed as FMC. Positive immunostaining was observed in all cancer samples for both nuclear Ki-67 and cleaved caspase-3, with a mean positive staining percentage of 27.5% and 21.2%, respectively. No statistically significant correlations between Ki-67 and cleaved caspase-3 were observed within FMC. Conclusions and relevance A high proliferation index was found in feline mammary tumors. This is the first study evaluating cleaved caspase-3 expression in FMC.

Successful subtotal orbitectomy in a cat with osteoma.

CASE SUMMARY: A 14-year-old Siamese neutered male cat was evaluated for anorexia and a left periorbital mass. Skull radiographic findings showed a well-defined lesion resembling new compact bone formation without destruction. A subtotal orbitectomy was indicated. The tumor was removed intact with a normal tissue margin of at least 1 cm. There were no postsurgical complications. Histopathologic examination revealed an osteoma. The cat returned to normal appetite and activity 15 days after surgery. Six months after surgery, there were no gross signs of recurrence. RELEVANCE AND NOVEL INFORMATION: Periorbital tumors are infrequently diagnosed in companion animals and most are malignant. In this case, the diagnosis was orbital osteoma. The most commonly affected bone for osteoma in cats is the mandibular bone; few cases have been identified in orbital bones. Orbital surgery has the potential to be challenging owing to complex anatomy, difficult exposure and the tendency to bleed. Surgical complications are common. In this case, although the disease was advanced, subtotal orbitectomy was successfully performed.