Minimal renal pelvis dilation in cats diagnosed with benign ureteral obstruction by antegrade pyelography: a retrospective study of 82 cases (2012-2018).

OBJECTIVES: The aim of the study was to describe renal pelvis (RP) and ureteral ultrasonographic measurements in a population of cats with confirmed benign ureteral obstruction (UO) by antegrade pyelography. The secondary objective was to further describe clinical findings associated with minimally dilated obstructed kidneys in an attempt to better understand its occurrence. METHODS: Retrospective case series of cats diagnosed with benign UO were confirmed by antegrade pyelography. Medical records were reviewed and signalment, diagnostic imaging results, serum creatinine (SCr) concentration and urine culture results were recorded. Each obstructed kidney was categorized into two groups: group 1 included all RP measurements ⩽4 mm and group 2 included all RP measurements >4 mm. RESULTS: A total of 82 cats with 114 obstructed ureters met the inclusion criteria. Fifty (61%) cats had a unilateral UO and 32 (39%) had a bilateral UO. Thirty (26%) kidneys were included in group 1 while 84 (74%) were included in group 2. Nine (8%) kidneys had an RP dilation ⩽2 mm. Median RP and ureteral diameters were 6.6 mm (range 1.1-37.0 mm) and 3.2 mm (range 0.0-11.0 mm), respectively. RP size correlated positively with ureteral diameter in the study population (P <0.0001), but not in group 1 when analyzed separately (P = 0.47). UO was secondary to stones in 80 (70%) ureters. Seventeen (21%) cats had a positive urine culture. At admission, 79 (96%) cats were azotemic with a median preoperative SCr concentration of 444 µmol/l (range 108-1326 µmol/l). The mean (95% confidence interval [CI]) preoperative SCr concentration was significantly higher in group 1 (762 µmol/l [498-1165 µmol/l]) than in group 2 (409 µmol/l [333-502 µmol/l]). RP size in the two groups correlated negatively with preoperative SCr concentration (P = 0.0002). CONCLUSIONS AND RELEVANCE: Feline UO may be associated with minimal RP dilation and the severity of RP and ureteral dilation can be highly variable. Absence of significant RP dilation does not rule out UO in cats.

Evaluation of 1,2-o-dilauryl-rac-glycero-3-glutaric acid-(6'-methylresorufin) ester lipase concentrations in cats with kidney disease and with normal SNAP fPL.

Measuring 1,2-o-dilauryl-rac-glycero-3-glutaric acid-(6'-methylresorufin) ester (DGGR) lipase activity is a cost-effective test for diagnosing pancreatitis compared to the feline pancreas-specific lipase (Spec fPL) test. However, little is known about the influence of renal insufficiency on DGGR lipase in cats. This study evaluated the influence of renal function on serum DGGR lipase in the cat. Serum samples from 49 cats with normal pancreas-specific lipase immunoreactivity were analyzed for DGGR lipase activity and serum creatinine. Median serum DGGR lipase activity for cats with kidney disease (KD+) was 22 IU/L (range: 9 to 29 IU/L), whereas for cats without kidney disease (KD-) and healthy cats, the medians were 16 IU/L (range: 6 to 32 IUI/L), and 15 IU/L (range: 9 to 23 IU/L), respectively. The KD+ group had significantly higher DGGR lipase concentrations compared to the healthy group (P = 0.030), but most results were within the reference range. There was a weak positive correlation between creatinine and DGGR lipase values (R 2 = 19.6%; P = 0.0014) and no significant correlation between symmetric dimethylarginine (SDMA) and DGGR lipase. Key clinical message: Although cats with kidney disease had significantly higher serum DGGR lipase concentrations than the healthy controls, the difference was small and does not appear to be clinically relevant.

Évaluation de la concentration de la lipase de l'ester de l'1,2-o-dilauryl-rac-glycero-3-acide glutarique-(6'-methylresorufine) chez les chats présentant une maladie rénale et un SNAP fPL normal. La lipase d'ester 1,2-o-dilauryl-rac-glycero-3-glutarique ester (6'-méthylrésorufine) (DGGR) semble être utile pour le diagnostic ante-mortem de pancréatite et s'avère également une méthode économique par rapport au dosage de la lipase féline spécifique du pancréas (Spec fPL). Toutefois, l'influence de l'insuffisance rénale sur la lipase DGGR, est encore méconnue chez le chat. Le but de cette étude prospective est d'établir l'influence de la fonction rénale sur la lipase DGGR chez les chats. Du sérum a été prélevé chez 49 chats ayant un test semi-quantitatif normal pour l'estimation de l'immunoréactivité pancréatique féline (SNAP fPL) et a été analysé pour déterminer l'activité sérique de la DGGR lipase et de la créatinine. La médiane sérique de la lipase DGGR chez les chats atteints de maladie rénale (groupe KD+) était de 22 (intervalle: 9­29) UI/L, tandis que celle des chats sans maladie rénale (groupe KD−) et celle des chats sains était de 16 (6­32) UI/L et 15 (9­23) UI/L, respectivement. Le groupe KD+ présentait des concentrations sériques de lipase DGGR significativement plus élevées que le groupe de chats sains (P = 0,030), mais la plupart des résultats se situaient dans les valeurs de référence. Il y avait une corrélation positive statistiquement significative, mais faible, entre les valeurs de la créatinine et de la lipase de DGGR (R 2 = 19,6 %; P = 0,0014). Il n'y avait pas de corrélation significative entre la symétrique diméthylarginine (SDMA) et la lipase DGGR.Message clinique clé:Ainsi, les chats atteints d'une maladie rénale présentent des concentrations sériques de lipase DGGR significativement plus élevées que celles des chats sains. Cependant, la différence est légère et ne semble pas être cliniquement pertinente.(Traduit par les auteurs).

Fluoroscopic and radiographic assessment of variations in tracheal height during inspiration and expiration in healthy adult small-breed dogs.

The objective of this study was to document tidal variations in tracheal height during normal respiration in 19 healthy adult (> 1 y old) small-breed dogs (< 10 kg) using fluoroscopy and radiography. Each dog underwent tracheal fluoroscopic examination on inspiration and expiration while in a standing position (F-S) and in right lateral recumbency (F-RL), followed by radiographic projections obtained in right lateral recumbency. The percent variation in tracheal height during maximal inspiration and expiration was determined at 3 different locations [cervical region (CR), thoracic inlet (TI), and intrathoracic (IT) region]. When all imaging procedures and sites of measurement were considered, tracheal height varied during physiologic inspiration and expiration from 0% to 21.1%, with a mean of 4.5%. The mean percent variation in tracheal height was not significantly different among imaging modalities (F-S versus F-RL versus radiography) (P = 0.16) or measurement sites (CR versus TI versus IT) (P = 0.89). The body condition score (BCS) (P = 0.96), age (P = 0.95), and breed (P = 0.19) did not significantly influence the mean percent variation in tracheal height. The average variation in tracheal height during maximal physiological inspiration and expiration is small (< 6%) in most healthy adult small-breed dogs as assessed by fluoroscopy and radiography, although tracheal height may vary by as much as 21.1% in some healthy individuals. Inspiratory and expiratory radiographs acquired in right lateral recumbency provide an accurate assessment of tracheal height as an alternative to fluoroscopy.

L'objectif de la présente étude était de documenter les variations de la hauteur de la trachée durant la respiration normale chez 19 chiens adulte en santé (> 1 an) de petites races (< 10 kg) à l'aide de la fluoroscopie et de la radiographie. Chaque chien a été soumis à un examen fluoroscopique de la trachée lors de l'inspiration et de l'expiration alors qu'il était en position debout (F-S) et en décubitus latéral droit (F-RL), suivi d'images radiographiques obtenues en décubitus latéral droit. Le pourcentage de variation de la hauteur de la trachée durant l'inspiration et l'expiration maximales fut déterminé à trois endroits différents [région cervicale (CR), l'entrée thoracique (TI), et la région intrathoracique (IT)]. Lorsque toutes les procédures d'imagerie et les sites de mesure étaient considérés, la hauteur de la trachée variait durant l'inspiration et l'expiration physiologique de 0 % à 21,1 %, avec une moyenne de 4,5 %. Le pourcentage de variation moyen de la hauteur de la trachée n'était pas significativement différent parmi les différentes modalités d'imagerie (F-S versus F-RL versus radiographie) (P = 0,16) ou les sites de mesure (CR versus TI versus IT) (P = 0,89). Le score de condition corporelle (BCS) (P = 0,96), l'âge (P = 0,95), et la race (P = 0,19) n'influençaient pas significativement le pourcentage de variation moyen de la hauteur de la trachée. La variation moyenne de la hauteur de la trachée durant l'inspiration et l'expiration physiologique maximale est petite (< 6 %) chez la plupart des chiens adultes de petites races en santé telle qu'évalué par fluoroscopie et radiographie, bien que la hauteur de la trachée puisse varier jusqu'à 21,1 % chez certains individus en santé. Les radiographies à l'inspiration et à l'expiration obtenues en décubitus latéral droit fournissent une évaluation précise de la hauteur de la trachée comme alternative à la fluoroscopie.(Traduit par Docteur Serge Messier).

Retained laser fiber in the nidus of a recurrent cystine urolith in an intact male English bulldog.

A lithotripsy and percutaneous cystolithotomy (PCCL) were performed on a 5-year-old intact male English bulldog. The composition of the uroliths was 100% cystine. When a second PCCL was performed 2 months later, the nidus of the largest urolith was a segment of an optical fiber broken off during laser lithotripsy.

Fibre laser formant le nidus d'une urolithiase à cystine récurrente chez un Bulldog Anglais mâle entier. Une lithotripsie et une cystolithotomie percutanée (PCCL) ont été réalisées sur un Bulldog Anglais mâle entier de 5 ans. L'urolithe était constitué à 100 % de cystine. Lors d'une seconde PCCL réalisée 2 mois plus tard, le nidus du plus grand calcul de cystine se révéla être un fragment de fibre optique brisée durant la lithotripsie au laser.(Traduit par Dre Emmanuelle Butty).

In vitro effects of dalteparin on thrombin generation in canine plasma.

BACKGROUND: The calibrated automated thrombogram (CAT) is a functional thrombin generation (TG) assay that may provide a new approach for monitoring anticoagulant therapy in dogs. The effects of dalteparin on TG variables in dogs are unknown. OBJECTIVES: Objectives were to establish normal TG variable ranges in dogs and measure the in vitro TG variables in canine pooled platelet-poor plasma (PPP) spiked with different dalteparin concentrations. METHODS: In the first experiment, plasma samples from 25 adult healthy Beagle dogs and 11 client-owned healthy dogs of multiple breeds was measured individually for obtaining normal TG values. In the second experiment, separate pools of the remaining PPP from 24 of the 25 previous adult Beagles and from 45 different client-owned dogs were spiked with dalteparin at 9 concentrations with increasing anti-factor Xa (anti-FXa) activity. Activated partial thromboplastin time, tissue factor-induced TG, and anti-FXa activity were measured for each concentration. Concentration-response relationships were determined with ADAPT v.5, using various nonlinear regression models for stimulatory or inhibitory effects. RESULTS: Thrombin generation ranges of client-owned dogs and Beagles were equivalent only for time-to-peak (P < .05). In vitro dalteparin resulted in a concentration-dependent decrease in endogenous thrombin potential (ETP) in pooled PPP. The estimated dalteparin concentration that produced half the maximal inhibition of baseline ETP (IC50 ) was 0.289 U/mL. Thrombin generation and anti-FXa activity were more sensitive than APTT to detect the effects of dalteparin. CONCLUSIONS: The CAT assay can measure the effects of dalteparin in canine plasma, resulting in significant dose-dependent decreases in ETP, prompting further in vivo investigation.

Effect of dalteparin administration on thrombin generation kinetics in healthy dogs.

BACKGROUND: Dalteparin is used to prevent thrombotic complications in dogs. Measurement of anti-factor Xa (anti-FXa) activity is currently used for monitoring therapy, but remains a nonfunctional test. The calibrated automated thrombogram (CAT) could be a suitable approach for functional monitoring. OBJECTIVES: We hypothesized that the CAT will detect decreased endogenous thrombin potential (ETP) in healthy dogs receiving dalteparin. METHODS: Twenty-four healthy adult Beagles were randomly allocated to 4 equal groups. A single subcutaneous (SC) dose of 50 U/kg, 100 U/kg, or 150 U/kg of dalteparin was given. Platelet-poor plasma (PPP) was collected over a 24-hour period and evaluated by thrombin generation (TG) via CAT, anti-FXa activity, and APTT. Analysis was performed with a repeated-measures general linear mixed model, and the treated groups were compared to a placebo group. RESULTS: Time, dose, and time-dose interaction significantly affected ETP (P < .0001 for all effects), peak (P < .0001 for all effects), rate index (P < .0006 for all effects), and anti-FXa activity (P < .0001 for all effects). No significant time trend was detected in the control group. Dogs receiving the 100 U/kg dalteparin SC injection showed the most homogeneous response of ETP inhibition among treated groups. The % inhibition of ETP from baseline increased nonlinearly as a function of anti-FXa activity (r2 = .8186). CONCLUSIONS: The CAT assay can be employed to measure the effects of dalteparin at different doses in healthy dogs, showing sensitivity to time- and dose-dependent changes in ETP and other TG variables. Further investigation of the CAT as a tool for monitoring low molecular weight heparin therapy in dogs is warranted.

Heparinase-modified thromboelastography in cats.

BACKGROUND: Evaluation of underlying hemostatic function is challenging when feline patients are receiving an anticoagulant medication. Discontinuing the anticoagulant to obtain accurate results for hemostatic testing may lead to thrombotic complications. The addition of heparinase to blood samples may mitigate the effects of exogenous heparin and allow hemostatic testing. METHODS: Tissue factor (TF)-activated thromboelastography (TEG) was performed using citrated whole blood from 19 cats. Assays were performed using citrated whole blood, with and without addition of unfractionated heparin to a concentration of 0.2 U/mL. For each blood sample, TEG assays were performed using a standard cup and a heparinase-coated cup. KEY FINDINGS: For TEG variables R, k, α-angle, and MA, mean values were not statistically different when citrated blood was used with standard or heparinase-coated cups. Heparinized blood assayed in standard cups displayed a significantly increased R and k, and significantly decreased α-angle and MA when compared to heparinized blood assayed in heparinase-coated cups. TEG variables for heparinized blood assayed in heparinase cups was not statistically different from those of the citrated whole blood without added heparin. SIGNIFICANCE: Heparinase modified, TF-activated, TEG reverses heparin effects in feline-citrated blood.

Respective associations between ureteral obstruction and renomegaly, urine specific gravity, and serum creatinine concentration in cats: 29 cases (2006-2013).

OBJECTIVE: To determine the respective associations between ureteral obstruction and renomegaly, urine specific gravity (USG), and serum creatinine concentration and to assess the reliability of abdominal palpation for detection of renomegaly in cats. DESIGN: Retrospective case series. ANIMALS: 89 client-owned cats with (n = 29) or without ureteral obstruction and with (30) or without (30) kidney disease. PROCEDURES: Medical records of cats that underwent abdominal ultrasonography at a veterinary teaching hospital from January 2006 through April 2013 were reviewed. Cats were categorized as having ureteral obstruction (obstructed group) or no ureteral obstruction with (KD group) or without kidney disease (NKD group). Renomegaly and renal asymmetry were defined on the basis of mean renal length for NKD cats. Prevalence of renomegaly and renal asymmetry, mean USG and serum creatinine concentration, and abdominal palpation and ultrasonographic findings were compared among the groups. RESULTS: Renomegaly was identified in 2 obstructed cats and 1 KD cat and was not associated with ureteral obstruction. Renal asymmetry was detected in 18 obstructed cats and 11 KD cats. For obstructed and KD cats, the mean USG was significantly lower and the mean serum creatinine concentration was significantly greater than those for NKD cats. Twenty-eight of 29 cats with ureteral obstruction had hypercreatininemia. Abdominal palpation was not a reliable method for detection of renomegaly. CONCLUSIONS AND CLINICAL RELEVANCE: Results indicated renomegaly was not associated with ureteral obstruction in cats, and abdominal palpation was an unreliable method for detection of renomegaly. The most consistent abnormal finding for cats with ureteral obstruction was hypercreatininemia.

Effect of prednisone administration on coagulation variables in healthy Beagle dogs.

BACKGROUND: Long-term corticosteroid therapy has been associated with increased risk of thrombotic disease in dogs. OBJECTIVE: The purpose of this prospective study was to use thrombelastography (TEG) and thrombin generation (TG) to detect development of a hypercoagulable state in healthy Beagle dogs receiving oral prednisone. We hypothesized that administration of corticosteroids would result in a hypercoagulable profile on TEG tracings and an increase in TG. METHODS: Six healthy adult Beagles from the University of Montreal's research colony were used to conduct a prospective longitudinal study in which all dogs received 1 mg/kg of prednisone orally once daily for 2 weeks, followed by a 6-week washout period, and then 4 mg/kg of prednisone orally once daily for 2 weeks. TEG tracings on citrated whole blood and TG measurements on frozen-thawed platelet-poor plasma were obtained before prednisone administration (baseline), at the end of the washout period, and at the end of both corticosteroid trials. RESULTS: Significant differences compared with baseline values were obtained for K, α, and MA, with tracings compatible with a hypercoagulable profile following both corticosteroid trials. There was a significant increase in endogenous thrombin potential only after low-dose (1 mg/kg) prednisone. CONCLUSION: Administration of prednisone to healthy Beagles resulted in hypercoagulability as indicated by TEG tracings, whereas the effect on TG was more variable. Further studies are needed to determine the underlying mechanisms of hypercoagulability and its clinical impact.

Thrombectomy and thrombolysis: the interventional radiology approach.

OBJECTIVE: To present interventional therapeutic options for patients with thrombosis. ETIOLOGY: Thrombosis in small animals results from an unbalance in the normal hemostatic mechanisms leading to vessel occlusion. In veterinary medicine, thrombosis is recognized as a common complication of many acquired diseases, including cardiac, endocrine, immunological, inflammatory, and neoplastic disorders. DIAGNOSIS: Clinical signs are variable depending on the location of the thrombus and various laboratory and imaging modalities can aid in its identification and localization. THERAPY: Once identified, a decision must be made to whether or not intervene and which method is most appropriate. A number of minimally invasive approaches for dealing with thrombosis are available and offer veterinarians a choice of therapeutic options when dealing with a thrombotic patient. In the presence of thrombosis, a combined approach of vessel balloon dilatation, catheter-directed thrombolysis and stenting may be most appropriate. Percutaneous mechanical thrombectomy, if available, may also be appropriate. Embolic trapping devices can be used with vena cava thrombosis to help prevent pulmonary embolism. Anticoagulant therapy may be indicated in the postoperative period to prevent further thrombus formation while the patient's fibrinolytic system breaks the clot down. PROGNOSIS: Outcome is variable depending on the site of the thrombus formation. Arterial thrombosis can be life-threatening while venous thrombosis tends to be less life-threatening but may lead to pulmonary embolism.

Clinical significance of renal pelvic dilatation on ultrasound in dogs and cats.

Renal pelvic dilatation is often recognized sonographically in dogs and cats, but ranges of measurements expected with different urologic conditions remain unknown. Ultrasound images of 81 dogs and 66 cats with renal pelvic dilatation were reviewed, and six groups were formed based on medical records: (I) clinically normal renal function, and (II) clinically normal renal function with diuresis; (III) pyelonephritis; (IV) noninfectious renal insufficiency; (V) outflow obstruction; (VI) miscellaneous nonobstructive anomalies. Medians for maximal pelvic width (range) for group I was 2.0 mm (1.0-3.8) in 11 dogs, and 1.6 mm (0.8-3.2) in 10 cats; for group II, 2.5 mm (1.3-3.6) in 15 dogs, and 2.3mm (1.1-3.4) in 16 cats; for group III, 3.6 mm (1.9-12.0) in nine dogs, and 4.0 mm (1.7-12.4) in seven cats; for group IV, 3.1 mm (0.5-10.8) in 33 dogs, and 2.8 mm (1.2-7.3) in 13 cats; for group V, 15.1mm (5.1-76.2) in six dogs, and 6.8mm (1.2-39.1) in 17 cats; and for group VI, 3.8mm (1.2-7.6) in seven dogs, and 3.0 mm (1.3-7.5) in three cats. Pelvic width in group I was lower than in groups III-V (P = 0.0001), but did not significantly differ from group II. Pelvic width > or =13 mm always indicated obstruction. While the proportion of bilateral pelvic dilatation was not different among groups, the difference in pelvic width (maximal-minimal) was greater in group V vs. groups I, II, and IV (P = 0.0009). These results confirm that renal pelvic dilatation can be detected sonographically in dogs and cats with clinically normal renal function, and that it increases with renal insufficiency, pyelonephritis, or outflow obstruction. Nevertheless, renal pelvic width varies substantially within groups and should be interpreted with caution.

Nonsurgical resolution of gallbladder mucocele in two dogs.

CASE DESCRIPTION: A gallbladder mucocele was diagnosed in 2 dogs. In both dogs, the mucocele resolved with medical treatment but without the need for surgical intervention. CLINICAL FINDINGS: A 12-year-old spayed female Miniature Schnauzer had a history of signs of gastrointestinal tract disease and high serum liver enzyme activities. Gallbladder mucocele and hypothyroidism were diagnosed. A 6-year-old neutered mixed-breed dog had chronic intermittent diarrhea and recurrent otitis; gallbladder mucocele and hypothyroidism were diagnosed. TREATMENT AND OUTCOME: The first dog was treated with S-adenosyl-methionine, omega-3 fatty acids, famotidine, ursodiol, and levothyroxine. Substantial improvement in the gastrointestinal tract condition and complete resolution of the gallbladder mucocele within 3 months were evident, but the dog was not available for further follow-up monitoring. The second dog was treated with fenbendazole, ursodiol, and levothyroxine and fed a hypoallergenic diet. One month after evaluation, abdominal ultrasonography revealed that the gallbladder mucocele was resolving, and treatment was continued. Ultrasonographic evaluation 2 and 4 months later revealed complete resolution of the mucocele. CLINICAL RELEVANCE: Review of the clinical course of 2 dogs in which there was nonsurgical resolution of gallbladder mucocele revealed that surgery is not necessary in all dogs with gallbladder mucocele. Hypothyroidism may have resulted in delayed gallbladder emptying, and its role in the pathogenesis of gallbladder mucocele merits investigation. Despite this information, until further prospective trials with a control group and standardized treatments and follow-up monitoring can be performed, the authors recommend surgical intervention for treatment of dogs with gallbladder mucocele.

Noninvasive correction of a fractured endoluminal nitinol tracheal stent in a dog.

An 11-year-old, castrated male Pomeranian was presented for intractable cough and dyspnea secondary to severe tracheal collapse. An endoluminal nitinol tracheal stent was placed with good results. Five months following placement of the prosthesis, clinical signs acutely recurred and failure of the implant was noted. A second stent was superimposed over the fractured stent and resulted in resolution of all clinical signs. The dog died several months later from progression of the tracheal collapse to the carina and mainstem bronchi.

Clinical efficacy and safety of transdermal methimazole in the treatment of feline hyperthyroidism.

Thirteen cats, newly diagnosed with hyperthyroidism, were treated with a transdermal formulation of methimazole at a dose of 5 mg (0.1 mL) (concentration of 50 mg/mL) applied to the internal ear pinna every 12 h for 28 d. Baseline hematologic and biochemical values, along with serum thyroxine (T4) levels, were obtained on presentation (day 0). Cats were evaluated at 14 d (D14) and 28 d (D28) following transdermal therapy. At each visit, a physical examination, a complete blood cell count, a serum biochemical analysis, and a serum T4 evaluation were performed. Ten cats completed the study. Clinical improvement, as well as a significant decrease in T4, was noted in all cats. Serum T4 measured at D14 and D28 were significantly lower at 27.44 nmol/L, s = 37.51 and 14.63 nmol/L, s = 10.65, respectively (P < 0.0001), as compared with values at D0 (97.31 nmol/L, s = 37.55). Only 1 cat showed a cutaneous adverse reaction along with a marked thrombocytopenia. The results of this prospective clinical study suggest that transdermal methimazole is an effective and safe alternative to conventional oral formulations.

Effects of theophylline on tracheal mucociliary clearance rates in healthy cats.

OBJECTIVE: To determine tracheal mucociliary clearance rate (TMCCR) by use of a standard protocol in healthy anesthetized cats and to determine the effect of theophylline on TMCCR in healthy anesthetized cats. ANIMALS: 6 healthy cats. PROCEDURE: Cats were anesthetized with propofol, and a droplet of the radiopharmaceutical technetium Tc 99m macroaggregated albumin was placed endoscopically at the carina. Dynamic acquisition scintigraphic imaging was performed, using the larynx as the end point. The TMCCR was determined by measuring the distance the droplet traveled by frame rate. Each cat was imaged 6 times as follows: 3 times following placebo administration and 3 times following the administration of sustained release theophylline (25 mg/kg, PO). Serum theophylline concentrations were assessed during imaging to ensure therapeutic concentrations. RESULTS: The TMCCR in healthy adult cats anesthetized with propofol was 22.2 +/- 2.8 mm/min. Tracheal mucociliary clearance rate in cats receiving theophylline was 21.8 +/- 3.5 mm/min. Theophylline administration did not significantly alterTMCCR. CONCLUSIONS AND CLINICAL RELEVANCE: Theophylline has been shown to increase TMCCR in humans and dogs. In our study, we determined TMCCR in healthy anesthetized cats and found that it was not accelerated by the administration of theophylline.