Chronic lymphocytic leukaemia in the cat: 18 cases (2000–2010)

There is little information regarding the presentation, biologic behaviour, treatment and prognosis in cats with chronic lymphocytic leukaemia (CLL), and further investigation is needed to characterize this disease in cats. The goal of this study was to describe the clinical presentation, response to treatment and prognosis of feline CLL. A multi‐institutional retrospective study of 18 cats diagnosed with CLL between 2000 and 2010 was performed. CLL was defined as the presence of a mature lymphocytosis (> 9000 lymphocytes µL^?1) and confirmation of an immunophenotypically monomorphic or clonal lymphoid population. Each patient was required to also have at least one of the two following criteria: (1) concurrent cytopenia of at least one cell line and/or (2) >15% mature lymphocytes in the bone marrow. Data on signalment, history, clinical signs, clinicopathologic features and response to treatment were reviewed. Median age of the cats at initial presentation was 12.5 years (range: 5–20 years). The most common presenting complaint was chronic weight loss, which was present in 8/18 (44%) cats. Sixteen of 18 (89%) cats were treated with chlorambucil and prednisolone; four of these cats also received vincristine. Two (11%) cats were treated with multi‐agent injectable chemotherapy (L‐CHOP, l ‐asparaginase, cyclophosphamide, doxorubicin, vincristine, prednisolone). Eighty‐eight percent of cats evaluable for response achieved a complete (nine cats) or partial (six cats) remission. Median overall remission was 15.7 months (range: 1.3–22.8 months). The median overall survival in the 17 cats with follow‐up data was 14.4 months (range: 0.9–25.3 months). Results of this study suggest that CLL affects older‐aged cats and responds favourably to treatment with oral chlorambucil and prednisolone.     

Effects of intravenous lidocaine on the minimum alveolar concentration of isoflurane in cats

Lidocaine has been reported to decrease the minimum alveolar concentration (MAC) of inhalation anesthetics in several species and has been used clinically to reduce the requirements for other anesthetic drugs. This study examined the effects of intravenous lidocaine on isoflurane MAC in cats. Six cats were studied. In experiment 1, the MAC of isoflurane was determined. An intravenous bolus of lidocaine 2 mg kg^–1 was then administrated and venous plasma lidocaine concentrations measured to determine pharmacokinetic values. In experiment 2, lidocaine was administered to achieve target plasma concentrations between 1 and 11 μg mL^–1 and the MAC of isoflurane was determined in triplicate at each lidocaine plasma concentration, using the tail‐clamp method. End‐tidal isoflurane concentration was determined using a calibrated infrared analyzer. Systolic blood pressure (Doppler), SpO2 and end‐tidal PCO2 (calibrated Raman spectrometer) were measured prior to each MAC determination. Body temperature was maintained between 38.5 and 39.5 °C by supplying external heat as needed. MAC values at the different lidocaine plasma concentrations were analyzed by a repeated measures ANOVA , using the Huynh–Feldt correction. The MAC of isoflurane in these cats was 2.21 ± 0.17. For the target concentrations of 1, 3, 5, 7, 9, and 11 μg mL^–1, the actual lidocaine plasma concentrations was 1.06 ± 0.12, 2.83 ±0.39, 4.93 ± 0.64, 6.86 ± 0.97, 8.86 ± 2.10, and 9.84 ± 1.34 μg mL^–1, respectively. At these target concentrations, the MAC of isoflurane was 2.14 ± 0.14, 1.88 ± 0.18, 1.66 ± 0.16, 1.47 ±0.13, 1.33 ± 0.23, and 1.06 ± 0.19%, respectively. Lidocaine, at target plasma concentrations of 1, 3, 5, 7, 9, and 11 μg mL^–1, linearly decreased isoflurane MAC by –6 to 6, 7 to 28, 19 to 35, 28 to 45, 29 to 53, and 44 to 59%, respectively. Lidocaine significantly dose‐dependently and linearly decreases the requirements for isoflurane in cats. No ceiling effect was observed within the range of plasma concentrations studied.     

Treatment of oral squamous cell carcinoma with accelerated radiation therapy and concomitant carboplatin in cats

Background: Feline oral squamous cell carcinoma (SCC) carries a very poor prognosis with traditional treatments. Hypothesis/Objectives: To examine the effectiveness of adding carboplatin to a previously published accelerated radiation protocol in the treatments of oral SCC in cats. Animals: Thirty‐one cases of oral SCC in cats. Tumor sites included lingual (n = 9), mandible (n = 10), maxilla (n = 7), tonsil (n = 4), and cheek (n = 1). Methods: Prospective trial using a planned radiation protocol consisting of 14 fractions of 3.5 Gy given within a 9‐day period with the addition of carboplatin given at 90–100 mg/m² on day 1 and day 4.5. Treatments were twice daily with a 6‐hour delay between treatments. All cats presenting with oral SCC without evidence of distant metastasis were eligible. Results: Median survival for all cats was 163 days (range 53–770 days) with a mean of 319 ± 53 days with significant predictors of survival being site (P= .004) and whether there was a complete response at 30 days (P= .001). Cats with tumors of tonsil origin or cheek responded best to therapy and were long‐term survivors with a mean survival of 724 days and the median had not been reached because of continued survival of 4 cats. Conclusions and Clinical Importance: This protocol offers an aggressive yet tolerable treatment of oral SCC in cats that might offer improved survival as compared with previously reported treatments. The long‐term survival of cats with tonsillar SCC has not been reported previously.     

A retrospective evaluation of lomustine (CeeNU) in 32 treatment naïve cats with intermediate to large cell gastrointestinal lymphoma (2006–2013)

Multi‐drug chemotherapy protocols for feline lymphoma have demonstrated variable efficacy and tolerability. In phase I trials, lomustine has demonstrated efficacy for cats with lymphoma though its use for treatment naïve feline intermediate/large cell gastrointestinal (GI) lymphoma remains unknown. This study evaluated the efficacy and tolerability of lomustine for the treatment of feline GI lymphoma. Thirty‐two cats with histologically or cytologically confirmed intermediate/large cell GI lymphoma were evaluated retrospectively. Factors assessed included clinical signs, hematologic/biochemical parameters and use of l ‐asparaginase at induction. A response rate of 50% (16/32), with median duration of response of 302 days (range 64–1450 days), was found. Median progression‐free interval was 132 days (range 31–1450 days), with overall median survival time of 108 days (range 4–1488 days). History of hyporexia, presence of anaemia and dose of lomustine were significantly associated with progression‐free survival. Overall, lomustine is a well‐tolerated and effective treatment for feline GI lymphoma.     

Historical and physical parameters as predictors of severe hyperkalemia in male cats with urethral obstruction

Objective: To evaluate selected historical and physical parameters as predictors of hyperkalemia in male cats with urethral obstruction. Design: Retrospective study. Setting: Veterinary teaching hospital. Animals: Two hundred and twenty‐three male cats. Interventions: None. Measurements and main results: The metabolic derangements of 223 male cats that presented with urethral obstruction from 1997 through 1999 were reported in a companion article. Approximately 12% of the cats had multiple, life‐threatening metabolic derangements. In the present study, historical and physical parameters were evaluated as predictors of hyperkalemia (K⁺≥8.0 mmol/L) in cats with urethral obstruction. The 4 historical parameters significantly associated with hyperkalemia were: first time obstruction, outdoor status, anorexia, or vomiting. The 5 physical parameters significantly associated with hyperkalemia were: rectal temperature, heart rate, respiratory rate, pulse quality, and the presence of arrhythmia. Of the physical parameters, a rectal temperature below 95–96.6°F (35–35.9°C) or a heart rate below 120 b.p.m. were the most accurate predictors. When used in combination (i.e., evidence of bradycardia and hypothermia), the specificity for hyperkalemia was 98–100%. Conclusions: Rectal temperature and heart rate were the best parameters for predicting hyperkalemia in this population.     

Comparison of the pharmacokinetics and thermal antinociceptive pharmacodynamics of 20 µg kg−1 buprenorphine administered sublingually or intravenously in cats

Little is known about the analgesic action of buprenorphine (BUP) in cats. Relative to man, the cat has a more alkaline oral pH, which may make this an effective route for administering BUP in this species. This study aimed to assess and compare the pharmacokinetics and pharmacodynamics of sublingual (S‐L) and IV administration of BUP. Thermal threshold (TT) was measured and blood samples were collected following IV or S‐L administration (20 µg kg^?1) of the injectable formulation. Six cats (five spayed females, one castrated male, 4.1–6.6 kg) were used. Each cat received both treatments in a randomized cross‐over study design with 1 month between experiments. Twenty‐four hours prior to each study, the lateral thorax of each of the cats was shaved, cephalic and jugular catheters placed, and oral pH measured. On the day of the study, TT was measured using a ‘thorax‐mounted’ thermal threshold‐testing device specifically developed for cats. The cats were free to move around. Skin temperature was recorded before each test, then the heater activated. When the cat responded by flinching, turning, or jumping, the stimulus was terminated and the threshold temperature was recorded. The thermal threshold cut‐off point was 55.5 °C. Three baseline thresholds were recorded before treatment with S‐L or IV (via cephalic catheter) BUP (20 µg kg^?1). Blood was withdrawn (jugular) at 1, 2, 4, 6, 10, 15, 30, 45, 60 minutes and at 2, 4, 6, 8, 12, and 24 hours post‐administration. TT was measured every 30 minutes?6 hours, 1–12 hours, and at 24 hours post‐administration. Plasma was immediately separated, stored at ?20.5 °C, and assayed within 4 months using a commercially available ¹²⁵I radioimmunoassay. Threshold data were analyzed using anova with a repeat factor of time. No adverse effects were noted. Pupils were dilated for up to 9 hours post‐BUP. Behavioral changes were calm euphoria. Measured oral pH was 9 in each cat. Pre‐treatment mean threshold (±SD) was 41.2 ± 0.9 °C in the S‐L group and 40.8 ± 0.85 °C in the IV group. There were no significant differences between the groups with respect to thresholds over time (p = 0.72). Thresholds were significantly increased from 30 to 360 minutes in both the groups (>44.615 °C). Peak plasma BUP (C_max) was lower (11 ± 6.7 ng mL^?1vs. 92.9 ± 107.9 ng mL^?1) and occurred later (T_max) (30 minutes vs. 1 minute) after S‐L compared to IV administration, respectively. BUP (20 µg kg^?1)‐administered S‐L or IV provided antinociception between 30 and 360 minutes after administration. Plasma levels did not correspond to TT.     

Feline discrete high‐grade gastrointestinal lymphoma treated with surgical resection and adjuvant CHOP‐based chemotherapy: retrospective study of 20 cases

The aim of this retrospective study was to evaluate the outcome of cats treated with surgical intervention for a discrete intermediate‐/high‐grade gastrointestinal lymphoma prior to CHOP‐based chemotherapy. Variables including sex, breed, haematocrit, white blood cell count, serum albumin concentration, clinical stage of disease, gastrointestinal obstruction and peritonitis were assessed for their effect on survival. Twenty cats met the inclusion criteria with three cats still alive at the time of data analysis. The overall median survival time (MST) was 417 days (range: 12–2962 days). The disease‐free interval (DFI) was 357 days (range: 0–1585 days) with six cats still deemed in remission prior to death. Only clinical stage had a significant effect on both MST and DFI. Cats with discrete intermediate/high‐grade gastrointestinal lymphoma that undergo surgical resection followed by adjuvant CHOP chemotherapy may achieve acceptable overall survival times.     

Use of itraconazole and either lime sulphur or Malaseb Concentrate Rinse® to treat shelter cats naturally infected with Microsporum canis: an open field trial

In an open non‐randomized study, 90 cats with severe dermatophytosis were treated with 21 days of oral itraconazole at 10 mg/kg and one of three topical antifungal rinses applied twice weekly: lime sulphur (LSO); reformulated lime sulphur with an odour‐masking agent (LSR); or a 0.2% miconazole nitrate and 0.2% chlorhexidine gluconate rinse (MC). Weekly examinations and fungal cultures were used to monitor the cats’ response to therapy. If at day 42 of treatment cats were still strongly fungal culture positive and/or developing new lesions, they were retreated with oral itraconazole and LSO. Cats were not prevented from licking the solutions and none developed oral ulcerations. Thirty‐one cats were treated with LSO, 27 with LSR and 32 with MC. The median number of days to cure was 30 (range 10–69 days) and 34 (range 23–80 days) for LSO and LSR, respectively. Thirty‐two cats were treated with MC, and 13 of 32 cats required repeat treatment because of persistent culture‐positive status and development of new lesions. Median number of days of treatment for the 19 cats that cured with MC was 48 (range 14–93 days). When the number of days to cure was compared between the groups, there was a significant difference between cats treated with LSO and LSR (P = 0.029) and cats treated with LSO and MC (P = 0.031), but no significant difference between the number of days to cure for cats treated with LSR and MC (P = 0.91).     

Assessment of blood pressure in cats presented with urethral obstruction

Objective: To determine the arterial blood pressure at presentation in male cats with acute urethral obstruction, and to determine whether there was any correlation between these measurements and concurrent metabolic abnormalities. Design: Prospective, single cohort, observational study. Setting: Private, small animal, after‐hours emergency clinic. Animals: Twenty‐eight client‐owned male cats with acute urethral obstruction and no other known coexisting disease. Interventions: Indirect oscillometric blood pressure measurements obtained before blood sampling and treatment. Measurements and main results: Mean arterial blood pressure (MAP) measurements, physical examination parameters, serum blood urea nitrogen (BUN), creatinine, potassium, phosphorus, total calcium and magnesium concentration, venous pH, lead II electrocardiogram, and urine volume in bladder were evaluated. No cats were hypotensive at presentation; 71% (20/28) were normotensive (median MAP=100 mmHg, range 93–140 mmHg); and 29% (8/28) were hypertensive (median MAP=153 mmHg, range 145–176 mmHg). Compared with hypertensive cats, normotensive cats had significantly lower heart rates (P=0.0201) and lower calcium (P=0.0152). For all 28 cats, MAP correlated with serum potassium and total calcium (P=0.0033). Conclusions: Though potassium and total calcium were inversely and directly correlated respectively with blood pressure in cats with urethral obstruction, none of the cats were hypotensive on presentation. Normotension on admission does not support the absence of biochemical and physical abnormalities in obstructed cats.     

Combination chemotherapy in feline lymphoma: treatment outcome, tolerability, and duration in 23 cats

BACKGROUND: Different chemotherapy regimes have been described for feline lymphoma with varying outcomes. HYPOTHESIS: In cats with lymphoma, a long-term, multiagent chemotherapy protocol will be effective and carry acceptable toxicity. ANIMALS: Twenty-three cats with histologically or cytologically confirmed diagnosis of lymphoma. METHODS: Prospective, single-arm clinical trial in which cats were treated with a chemotherapy protocol consisting of a cyclic combination of l-asparaginase, vincristine, cyclophosphamide, doxorubicin, methotrexate, and prednisolone with a planned total treatment time of 122 weeks. RESULTS: Complete remission (CR) rate was 74% (n = 17). Fourteen percent of cats attained partial remission (PR). Median duration of first CR was 264 days (range, 45-2,485 days). Six-month, 1-, and 2-5-year remission rates were 75, 50, and 34%, respectively. Duration of PR ranged between 23 and 63 days. Median survival in cats with CR was 296 days (range, 50-2,520 days). Six-month, 1-, 2-, and 3-5-year survival rates in cats with CR were 82, 47, 34, and 27%, respectively. Survival of cats achieving PR ranged between 38 and 120 days. Of the analyzed variables, only anatomical location had a significant influence on remission duration (P=.022). Actual median treatment time in cats with CR was 128 days (18 weeks). Hematologic and gastrointestinal toxicosis was infrequent and mostly low grade. CONCLUSIONS AND CLINICAL IMPORTANCE: In this population of cats with lymphoma, chemotherapy was effective. With infrequent and mostly low-grade toxicosis, tolerability of the protocol may be considered good.     

Urinary aldosterone to creatinine ratio in cats before and after suppression with salt or fludrocortisone acetate

Background: The endocrine diagnosis of primary hyperaldosteronism in cats currently is based on an increased plasma aldosterone to renin ratio, which has several disadvantages for use in veterinary practice. Objectives: To establish a reference range for the urinary aldosterone to creatinine ratio (UACR) and to determine whether oral administration of either sodium chloride or fludrocortisone acetate is effective for use in a suppression test. Animals: Forty‐two healthy cats from an animal shelter and 1 cat with primary hyperaldosteronism from a veterinary teaching hospital. Methods: Morning urine samples for determination of the basal UACR were collected from 42 healthy cats. For the suppression tests, urine samples for the UACR were collected after twice daily oral administration for 4 consecutive days of either sodium chloride, 0.25 g/kg body weight (n = 22) or fludrocortisone acetate, 0.05 mg/kg body weight (n = 15). Results: The median basal UACR was 7.2 × 10^?9 (range, 1.8–52.3 × 10^?9), with a calculated reference range of <46.5 × 10^?9. Administration of sodium chloride resulted in adequate salt loading in 10 of 22 cats, but without significant reduction in the UACR. Administration of fludrocortisone resulted in a significant decrease in the UACR (median, 78%; range, 44–97%; P < .001) in healthy cats. In the cat with an aldosterone‐producing adrenocortical carcinoma, the basal UACR and the UACR after fludrocortisone administration were 32 × 10^?9 and 36 × 10^?9, respectively. Conclusions and Clinical Importance: Using the UACR for an oral fludrocortisone suppression test may be useful for the diagnosis of primary hyperaldosteronism in cats.     

Evaluation of intraperitoneal and subcutaneous lidocaine and bupivacaine for analgesia following ovariohysterectomy in the dog

The role of ketamine (K) in pain management is controversial. It is reported to provide visceral analgesia in cats. This study aimed to assess its somatic actions using a thermal threshold (TT) model. Six cats (four spayed females, two castrated males, 4.3–7.2 kg) participated in the study. The day before each study, the thorax of each of the cats was shaved and a cephalic catheter was placed. TT was measured using a device specifically developed for cats. A heater element and temperature sensor housed in a small probe were held against the thorax of the cats with an elastic band and pressure bladder to assure consistent contact. The skin temperature was recorded before each test, then the heater was activated. When the cat responded by flinching, turning, or jumping, the stimulus was terminated and the threshold temperature was recorded. Treatments were 2 mg kg^?1 of K (10 mg mL^?1), or 0.2 mL kg^?1 of saline (S) IV, given in a randomized cross‐over design with at least 1 week between treatments. The investigator was blinded to the treatment. TT was measured thrice before treatment (baseline threshold) at 15 minutes, then every 30 minutes for 8 hours and once at 24 hours after injection. Data were analyzed using a four‐factor anova . Cats were sedated for 45 minutes following K treatment. There was no difference in baseline TT between treatments (K = 41.9 ± 1.7 °C, S = 41.0 ± 1.45 °C), and no change in TT at any time in the S group. TT increased significantly at 15 and 30 minutes after K, then decreased below baseline values between 210 and 390 minutes, with a nadir of 38.8 ± ± 1.05 °C at 390 minutes. During this time period, cats exhibited normal activity, but responses to thermal stimuli were exaggerated. This study suggested that K caused a delayed onset hyperalgesia in cats.     

Use of surgery and electron beam irradiation, with or without chemotherapy, for treatment of vaccine-associated sarcomas in cats: 78 cases (1996-2000).

OBJECTIVE: To evaluate responses of cats with vaccine-associated sarcomas to treatment with surgery and radiotherapy, with or without adjunctive chemotherapy. DESIGN: Retrospective study. ANIMALS: 76 cats (78 tumors). PROCEDURE: Medical records were reviewed. Factors potentially associated with survival time, time to recurrence, and time to development of metastases were evaluated. RESULTS: Following excision, electron beam radiation, and, in some cases, chemotherapy, 32 (41%) cats experienced recurrence, and 9 (12%) cats developed metastases. One- and 2-year survival rates were 86 and 44%, respectively. Median survival time from onset of disease was 730 days (range, 30 to 2,014 days). Median disease-free interval was 405 days (range, 30 to 925 days). Cats that underwent only 1 surgery prior to radiotherapy had a lower recurrence rate than did cats that underwent > 1 surgery and had a significantly longer disease-free interval. Survival time and disease-free interval decreased as time between surgery and the start of radiotherapy increased. Cats that developed metastases had significantly shorter survival times and disease-free intervals than did cats that did not develop metastases. Castrated male cats had a significantly shorter survival time than did spayed female cats. Cats with larger tumors prior to the first surgery had shorter survival times. Twenty-six cats received chemotherapy in addition to surgery and radiotherapy. Whether cats received chemotherapy was not associated with recurrence rate, metastasis rate, or survival time. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that excision followed by electron beam irradiation may be beneficial for treatment of cats with vaccine-associated sarcomas. Extent of excision prior to radiotherapy did not seem to be associated with recurrence rate.     

Platelet function in clinically healthy cats and cats with hypertrophic cardiomyopathy: analysis using the Platelet Function Analyzer‐100

Background: There is currently no simple analytical tool for the evaluation of hypercoagulability in cats. The Platelet Function Analyzer‐100^® (PFA‐100; Dade Behring Inc., Deerfield, IL, USA) is a bench‐top machine that evaluates platelet function by measuring closure time (CT) in citrated whole blood under high shear conditions. We hypothesized that cats with hypertrophic cardiomyopathy (HCM) have up‐regulated platelet function, which shortens their CT and increases their risk for thromboembolic events. Objectives: The goals of this study were to: (1) establish a feline reference interval for CT using the PFA‐100, (2) measure CT in blood from cats with HCM, and (3) determine if there is a measurable difference between the CT of healthy cats compared with cats with HCM. Methods: Citrated blood samples from 42 clinically healthy cats and 30 cats with HCM were analyzed according to manufacturer's specifications. CT was measured in triplicate and the mean value was used for analysis. Transformed data were compared between clinically healthy cats and cats with HCM using a Student's t‐test, and among cats with mild, moderate, or severe HCM using ANOVA. Results: The median CT of clinically healthy cats was 64 seconds (range 43–176 seconds). The median CT of cats with HCM was 74 seconds (range 48–197 seconds). There was no significant difference in CT between cats with HCM and clinically healthy cats. There also were no significant differences in cats with mild, moderate, or severe HCM. Conclusions: A feline reference interval for PFA‐100 CT will be useful in future studies of platelet function in cats. Cats with HCM do not have shorter CTs when compared with clinically healthy cats.     

Evaluation of factors associated with prolonged hospital stay and outcome of febrile neutropenic patients receiving chemotherapy: 70 cases (1997–2010)

Febrile neutropenia (FN) is an important sequela in veterinary patients receiving chemotherapy. The purpose of this study was to identify factors associated with prolonged hospital stay and outcome in canine patients developing FN secondary to chemotherapy administration. Medical records of 70 dogs treated for FN at the University of Pennsylvania from 1997 to 2010 were retrospectively evaluated. The mean interval between chemotherapy and hospitalization was 7 days. Two‐thirds of treated patients had lymphoma. The majority of patients (70%) received vincristine or doxorubicin prior to the development of FN. Tachycardia at admission, complicating medical issues, G‐CSF use and decreasing neutrophil count after admission were associated with prolonged hospital stay. Hypotension and G‐CSF use were significantly associated with death in‐hospital. Mortality was 8.5%. Identification of factors associated with prolonged hospital stay and mortality in patients with FN may enable the development of risk‐adapted treatment guidelines to minimize chemotherapy‐associated morbidity and mortality.     

The Relationship Between Body Weight,Body Condition,and Survival in Cats with Heart Failure

Background: Obese people with heart failure have improved survival compared with their normal or underweight counterparts. The purpose of this study was to determine if there is a relationship between body weight or body condition and survival in cats with heart failure. Hypothesis: Body weight and body condition score (BCS) are predictors of survival in cats with heart failure. Animals: One‐hundred and one cats with heart failure (International Small Animal Cardiac Health Council Classes II, IIIa, or IIIb) evaluated between March 2007 and June 2009. Methods: Data regarding initial body weight and BCS, subsequent changes in body weight, and treatment were collected from records and compared with survival times. Results: Median initial body weight was 5.1 kg (range, 2.2–9.5 kg). Median BCS was 5 (range, 3–9). Of the 68 cats that were discharged from the hospital, median body weight change was 0.0 kg (range, ?2.6 to +2.3 kg). Survival time for all 101 cats was 93 days (0–811 days). Survival could be predicted using a model combining initial body weight (P= .02), body weight squared (P= .02), and survival to discharge (P < .001) with a resulting global P value for this model of P < .0001. Conclusions and Clinical Importance: Cats with the lowest and highest body weights had reduced survival times compared with those with body weights in the intermediate ranges, suggesting a U‐shaped relationship between body weight and survival. Additional research into the effects of body composition could help to determine optimal management of cats with heart failure.     

Comparison of two injectable anesthetic regimes in feral cats at a large-volume spay clinic

Same‐day mass sterilization of feral cats requires rapid onset, short‐duration anesthesia. The purpose of this study was to compare our current anesthetic protocol, Telazol–ketamine–xylazine (TKX) with medetomidine–ketamine–buprenorphine (MKB). Feral female cats received either IM TKX (n = 68; 0.25 mL cat^?1; tiletamine 12.5 mg, zolazepam 12.5 mg, K 20 mg, and X 5 mg per 0.25 mL) or MKB (n = 17; M 40 µg kg^?1, K 15 mg kg^?1, and B 10 µg kg^?1). Intervals measured included time from injection to recumbency, time to surgery, duration of surgery, and time from reversal of anesthesia (TKX: yohimbine 0.50 mg cat^?1 IV; MKB: atipamezole 0.50 mg cat^?1 IM) to sternal recumbency. Following instrumentation (Vet/Ox 4403 and Vet/BP Plus 6500), physiological measurements were recorded at 5‐minute intervals, and included rectal temperature, heart rate (HR), respiratory rate (RR), SpO₂ (lingual or rectal probes), and indirect mean arterial blood pressure (MAP) (oscillometric method). Nonparametric means were compared using Mann–Whitney U‐tests. Parametric means were compared using a two‐factorial anova with Bonferroni's t‐tests. The alpha‐priori significance level was p < 0.05. Values were mean ± SD. Body weight (TKX: 2.9 ± 0.5 kg, MKB: 2.7 ± 0.7 kg), time to recumbency (TKX: 4 ± 1 minutes, MKB: 3 ± 1 minutes), time to surgery (TKX: 28 ± 7 minutes, MKB: 28 ± 5 minutes), and duration of surgery (TKX: 11 ± 7 minutes, MKB: 8 ± 5 minutes) did not differ between groups. In contrast, MKB cats required less time from reversal to sternal recumbency (TKX: 68 ± 41 minutes, MKB: 7 ± 2 minutes) and were recumbent for shorter duration (TKX: 114 ± 39 minutes, MKB: 53 ± 6 minutes). Temperature decreased during the study in both groups, but overall temperature was higher in MKB cats (38.0 ± 0.95 °C) than in TKX cats (37.5 ± 0.95 °C). RR, HR, and SpO₂ did not change during the study in either group. However, overall HR and RR were higher in TKX cats (RR: 18 ± 8 breaths minute^?1, HR: 153 ± 30 beats minute^?1) compared to MKB cats (RR: 15 ± 7 breaths minute^?1, HR: 128 ± 19 beats minute^?1). In contrast, overall SpO₂ was lower in the TKX group (90 ± 6%) compared to the MKB group (94 ± 4%). MAP was also lower in the TKX group (112 ± 29 mm Hg) compared to that in the MKB group (122 ± 20 mm Hg). However, MAP increased in the TKX group during surgery compared to pre‐surgical values, but did not change in the MKB group. The results of this study suggested that MKB might be more suitable as an anesthetic for the purpose of mass sterilization of feral female cats.     

Evaluation of the side-effects and thermal antinociceptive effects of intravenous hydromorphone in cats

Hydromorphone (H) may be an effective analgesic agent in cats, but fear of negative behavioral side‐effects associated with opioids is cited as a reason for avoiding this class of analgesics in cats. This study was designed to assess onset and duration of antinociception using an established feline thermal threshold model in cats, given an accepted clinical dose of 0.1 mg kg^?1 of H. In addition, cats were observed for changes in behavior and other side‐effects. Six adult cats from an established colony (four spayed females and two castrated males, 4.7–7.0 kg) received 0.1 mg kg^?1 H IV following establishment of baseline thermal threshold (TT) values. TT was tested at 15 minutes post‐injection, then at every 30–60 minutes for 12 hours. Side‐effects and behavior changes were recorded for 12 hours. Changes in TT over time were analyzed using a one‐way anova ; a p‐value <0.05 was considered significant. TT increased from a pre‐treatment value of (mean ± SD) 40.9 ± 1.65 °C to instrument cutout (55.5 °C) within 30 minutes for 5/6 cats. Mean TT was significantly elevated above baseline from 15 to 450 minutes after treatment. There was a significant increase in skin temperature from 15 to 300 minutes with peak increase of 1.55 °C at 135 minutes. Side‐effects included mydriasis (6/6) and nausea (4/6), characterized by licking, foaming, and gagging. Mydriasis occurred within 10–30 seconds of injection and persisted for 5–7 hours. Nausea was noted within 2 minutes of injection and persisted for 30–90 minutes; no vomiting occurred. Commonly observed behavioral changes included ventral tail curl (6/6 cats, onset 5–45 minutes, duration 4–5 hours) and euphoria (5/6 cats, onset <6 minutes for 4/6, duration 1–6 hours). 2/6 cats were profoundly sedate. Three cats showed signs of dysphoria with or without increased motor activity with variable onset and duration. Dysphoric behavior included staring, pacing, vocalizing, and sudden movements. 3/6 cats exhibited both euphoria and dysphoria at different times during the study. At no time were cats difficult to restrain or work with. Return to baseline behavior occurred 7–8.5 hours post‐injection. Mydriasis did not correlate closely with antinociception. Signs of sedation and euphoria corresponded with onset of antinociception, but not duration. Tail curl signs correlated with antinociception. In this model, H proved to be a rapid acting, potent, analgesic with a long (7.5 hours) duration of action. The most common behavioral changes noted were ventral tail curl, euphoria, and sedation. Mydriasis and nausea were noted as side‐effects.     

Efficacy and toxicity of BOPP and LOPP chemotherapy for the treatment of relapsed canine lymphoma*

Mechlorethamine (Mustargen^®, Oncovin^® (vincristine), procarbazine and prednisone (MOPP) chemotherapy is useful for relapsed canine lymphoma. This study evaluates the efficacy of MOPP after substitution of CCNU (lomustine, LOPP protocol) or BCNU (carmustine, BOPP protocol) for mechlorethamine in 60 dogs with relapsed lymphoma. Seven of 14 (50%) dogs treated with BOPP responded, for a median of 129.5 days for complete responders (range 9–354 days) and a median of 140 days for partial responders (range 4–276 days). Twenty‐three of 44 (52%) dogs treated with LOPP responded for a median of 112 days for complete responders (range 48–250 days) and a median of 84.5 days for partial responders (range 69–290 days). Two dogs receiving a combination of LOPP and BOPP partially responded for 28 and 163 days, respectively. With BOPP chemotherapy, nine dogs (20.5%) and seven dogs (50%) had one or more episodes of Grade II or higher neutropenia and thrombocytopenia, respectively. Seven dogs (50%) had one or more episodes of Grade II or higher gastrointestinal toxicity. While receiving LOPP chemotherapy, 28 dogs (63.6%) and 17 dogs (38.6%) had one or more episodes of Grade II or higher neutropenia and thrombocytopenia, respectively. Seventeen dogs (38.6%) had one or more episodes of Grade II or higher gastrointestinal toxicity. Overall, there were 17 non‐fatal treatment‐related episodes of sepsis requiring hospitalization. Eight dogs (13%) died or were euthanized because of treatment‐related sepsis and/or chemotherapy‐related complications. Severe haematologic toxicity, coupled with the improved response duration observed in dogs receiving reduced doses during B/L‐OPP rescue, underscores the need for protocol optimization.