Prognostic factors associated with survival two years after surgery in dogs with malignant mammary tumors: 79 cases (1998-2002)

OBJECTIVE: To identify prognostic factors for female dogs that have undergone surgical removal of malignant mammary tumors. DESIGN: Retrospective case series. ANIMALS: 79 female dogs with malignant mammary tumors. PROCEDURE: Information obtained from the medical records included breed, age, sex, tumor size (maximum diameter), number and location of affected mammary glands, time between tumor identification and surgical removal, radiographic evidence of distant metastasis, surgical procedure, ovariohysterectomy (OHE) status, histologic classification of the tumor, and survival time. RESULTS: Results of univariate analyses indicated that clinical stage, tumor size, OHE status, metastasis to adjacent lymph nodes or distant sites, and histologic classification of the tumor were significantly associated with survival 2 years after surgery. Tumors > or = 5 cm in diameter and tumors that had been identified > 6 months before surgery were more likely to metastasize to adjacent lymph nodes. Ovariohysterectomy was more beneficial in dogs with complex carcinomas than in dogs with simple carcinomas. In multivariate analyses, clinical stage, tumor size, and OHE status were significantly associated with survival 2 years after surgery. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that tumor stage, tumor size, and OHE status were significant prognostic factors associated with survival 2 years after surgery in dogs with malignant mammary tumors. Further, either dogs with tumors > or = 5 cm in diameter or dogs with tumors present for > 6 months prior to surgery had a higher risk of having lymph node metastases.     

Minimally invasive patent ductus arteriosus occlusion in 5 dogs

OBJECTIVE: To report a technique for minimally invasive occlusion of patent ductus arteriosus (PDA) and outcome in 5 dogs. STUDY DESIGN: Clinical cases. Animals: Five, 4-6-month-old, dogs with PDA. MATERIALS AND METHODS: Titanium ligating clips were used for PDA closure in all dogs. Three dogs had video-enhanced mini-thoracotomy PDA occlusion. Two other dogs had thoracoscopic PDA occlusion using a custom-designed thoracoscopy clip applicator. RESULTS: Thoracoscopic PDA occlusion was successful in both dogs in which it was attempted. Complete PDA closure was achieved in 4 dogs. Three months after surgery, the largest dog had residual ductal flow that hemodynamically was insignificant. CONCLUSIONS: Although technically demanding, minimally invasive PDA occlusion is a safe and reliable technique in dogs. Preoperative measurement of the diameter of the PDA is crucial to determine if complete closure with metal clips can be achieved. CLINICAL RELEVANCE: Minimally invasive PDA occlusion should be considered as an alternative to occlusion via conventional thoracotomy.     

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

Objective To determine if intraperitoneal (IP) and incisional (SC) lidocaine or bupivacaine provide analgesia following ovariohysterectomy (OHE). Study Design Prospective, randomized, controlled, blinded clinical trial. Animals Thirty dogs presenting to the Veterinary Teaching Hospital for elective OHE. Methods Dogs were pre‐medicated with acepromazine and butorphanol, induced with thiopental and maintained with isoflurane. They were randomly assigned to three groups: 10 received 8.8 mg kg^?1 2% lidocaine with epinephrine IP (LID); 10 received 4.4 mg kg^?1 0.75% bupivacaine IP (BUP); and 10 received 0.9% saline IP (SAL) upon completion of OHE. All IP doses were standardized to 0.88 mL kg^?1 with saline. An additional 2 mL of undiluted solution was placed SC prior to incisional closure. Dogs were scored at 0.5, 1, 2, 3, 6, 8 and 18 hours post‐extubation by one observer. Dogs were evaluated using a visual analogue scale (VAS) for pain and sedation, and a composite pain scale (CPS) that included physiologic and behavioral variables. Dogs were treated with 0.22 mg kg^?1 butorphanol + acepromazine if their VAS (pain) score was >50. Parametric variables were analyzed using Student's t‐test or repeated measures anova as appropriate. Non‐parametric variables were analyzed by χ²‐test. Results There were no significant differences in age, weight, incision length, surgery time, anesthesia time, or total thiopental dose among groups. Peak post‐surgical pain scores for all groups occurred at 0.5 hours and returned to baseline by 18 hours. Dogs in the BUP group had significantly lower VAS‐pain scores overall than dogs in the SAL group. Seven out of 10 dogs in the SAL group, 4/10 in the LID group and 2/10 in the BUP group were treated with supplemental acepromazine and butorphanol. No differences between groups were detected with the CPS. No adverse side‐effects were observed. Conclusions and clinical relevance Our findings support the use of IP and SC bupivacaine for post‐operative analgesia following OHE in the dog.     

Ultrasound-guided retrieval of plant awns

In dogs, surgical removal of plant awns causing a foreign body granuloma or abscess may be challenging. The inability to localize the foreign body during surgical removal often leads to abscess recurrence. In this report, we describe ultrasound-guided retrieval as an alternative to standard surgical retrieval in animals where the plant awn can be identified sonographically. This procedure was used in six dogs with a superficial abscess due to a plant awn, and in all dogs the foreign body was successfully retrieved with Hartmann forceps. No complication was observed and no abscess recurred. Minimally invasive ultrasound-guided plant awn retrieval appears to be a safe effective method of retrieving superficially located plant awns in the dog.     

Clinical safety of percutaneous ultrasound‐guided fine‐needle aspiration of adrenal gland lesions in 19 dogs

Objective

To evaluate the safety of fine‐needle aspiration of adrenal gland lesions in dogs and to characterise the risks in a subset of patients with cytologically or histopathologically diagnosed phaeochromocytoma.

Materials and Methods

Retrospective review of medical records of dogs that underwent percutaneous ultrasound‐guided fine‐needle aspiration of adrenal gland lesions between August 2014 and December 2016. Nineteen dogs were identified, with three undergoing bilateral adrenal gland aspiration and one dog undergoing aspiration twice, yielding 23 cytology samples in total. Data collected included signalment, concurrent medical conditions, current medications, blood pressure and heart rate before adrenal fine‐needle aspiration, imaging characteristics of the adrenal gland lesions and any clinically apparent procedure‐related complications.

Results

Phaeochromocytoma was diagnosed in nine of 19 dogs, including one dog with bilateral phaeochromocytoma. One dog developed ventricular tachycardia following aspiration of an adrenal gland lesion cytologically consistent with a phaeochromocytoma.

Clinical Significance

Percutaneous ultrasound‐guided fine‐needle aspiration of adrenal gland lesions appears to be relatively safe, even in phaeochromocytoma, but further data are required to lend more weight to this finding. Minimally invasive aspirates could be considered as part of the diagnostic algorithm in the investigation of an incidentally detected adrenal gland lesion of uncertain clinical significance.     

CONTRAST‐ENHANCED PORTAL MAGNETIC RESONANCE ANGIOGRAPHY IN DOGS WITH SUSPECTED CONGENITAL PORTAL VASCULAR ANOMALIES

Contrast‐enhanced multiphase magnetic resonance angiography (CE‐MRA) was used in 17 dogs with a suspected congenital portal vascular anomaly. Portal vascular anomalies were identified in 16 of the 17 dogs. Eleven had a single intrahepatic portocaval shunt (two central divisional, three right divisional, and six left divisional), one dog had a double intrahepatic portocaval shunt, one dog had a hepatic arteriovenous malformation, one dog had a complex intrahepatic porto‐caval shunt. Two dogs had an extrahepatic portosystemic shunt and no shunt was identified in one dog. Total imaging time was <10 min and image quality was good to excellent in all dogs. Portal CE‐MRA is a feasible, fast and non invasive technique to diagnose portal vascular anomalies in dogs, with a large field‐of‐view and good anatomic depiction of the abnormal vessels. Based on these results, CE‐MRA is an efficient imaging technique for the diagnosis of portal vascular anomalies in dogs.     

Concentrations of 15F2t isoprostane in urine of dogs with intervertebral disk disease

OBJECTIVE: To measure 15F(2t) isoprostane concentrations in the urine of dogs undergoing ovariohysterectomy (OHE) and dogs undergoing surgery because of intervertebral disk disease (IVDD) and to assess relationships between urinary concentrations of 15F(2t) isoprostanes and neurologic score in dogs with IVDD. ANIMALS: 11 dogs undergoing OHE and 32 dogs with IVDD undergoing hemilaminectomy. PROCEDURES: Paired urine samples were obtained at induction of anesthesia and approximately 1 hour after OHE (controls) and were collected from dogs with IVDD at induction of anesthesia (28 samples) and approximately 1 hour after hemilaminectomy (31 samples); 26 paired urine samples were obtained from dogs with IVDD. Urinary isoprostane concentrations were measured by use of a commercial ELISA, and results were adjusted on the basis of urinary creatinine concentrations. Differences in the mean isoprostane-to-creatinine ratio were analyzed. Neurologic score was determined in dogs with IVDD by use of the modified Frankel scoring system. RESULTS: Urinary isoprostane-to-creatinine ratios were significantly higher in dogs with IVDD than in control dogs before and after surgery. There was no significant difference between values before and after surgery for either group. There was a significant correlation of neurologic score and urinary isoprostane-to-creatinine ratio because dogs that had higher neurologic scores (ie, less severely affected) generally had higher isoprostane-to-creatinine ratios. CONCLUSIONS AND CLINICAL RELEVANCE: Urinary isoprostane-to-creatinine ratios were higher in dogs with IVDD before and after surgery. Analysis of these data suggests that dogs with IVDD are in a state of oxidative stress and that preemptive treatment with antioxidants warrants further investigation.     

Clinical signs,diagnosis and treatment of three dogs with angiostrongylosis in Ireland

: Infection with Angiostrongylus vasorum was diagnosed at necropsy on a dog that died from acute pulmonary haemorrhage, and on recovery of L1 larvae by Baermann examination of faeces from two dogs, one of which had abdominal pain and retroperitoneal haemorrhage, while the other had right-sided heart failure due to cor pulmonale. The presenting signs included syncope (one dog), exercise intolerance (two dogs), cough (two dogs), abdominal pain (one dog) and depression (one dog). One-stage prothrombin time and activated partial thromboplastin time were prolonged in two dogs, buccal mucosal bleeding time was prolonged in one dog and globulin was elevated in all three dogs. Two dogs were treated with fenbendazole and recovered.     

Evaluation of induction characteristics and hypnotic potency of isoflurane and sevoflurane in healthy dogs

OBJECTIVE: To determine induction characteristics and the minimum alveolar concentration (MAC) at which consciousness returned (MACawake) in dogs anesthetized with isoflurane or sevoflurane. ANIMALS: 20 sexually intact male Beagles. PROCEDURES: In experiment 1, 20 dogs were randomly assigned to have anesthesia induced and maintained with isoflurane or sevoflurane. The MAC at which each dog awoke in response to auditory stimulation (MACawake-noise) was determined by decreasing the end-tidal concentration by 0.1 volume (vol %) every 15 minutes and delivering a standard audible stimulus at each concentration until the dog awoke. In experiment 2, 12 dogs received the same anesthetic agent they were administered in experiment 1. After duplicate MAC determination, the end-tidal concentration was continually decreased by 10% every 15 minutes until the dog awoke from anesthesia (MACawake). RESULTS: Mean induction time was significantly greater for isoflurane-anesthetized dogs (212 seconds), compared with the sevoflurane-anesthetized dogs (154 seconds). Mean+/-SD MACawake-noise was 1.1+/-0.1 vol % for isoflurane and 2.0+/-0.2 vol % for sevoflurane. Mean MAC was 1.3+/-0.2 vol % for isoflurane and 2.1+/-0.6 vol % for sevoflurane, and mean MACawake was 1.0+/-0.1 vol % for isoflurane and 1.3+/-0.3 vol % for sevoflurane. CONCLUSIONS AND CLINICAL RELEVANCE: Sevoflurane resulted in a more rapid induction than did isoflurane. The MACawake for dogs was higher than values reported for both agents in humans. Care should be taken to ensure that dogs are at an appropriate anesthetic depth to prevent consciousness, particularly when single-agent inhalant anesthesia is used.     

Evaluation of an endoscopically assisted gastropexy technique in dogs

OBJECTIVE: To evaluate the use of endoscopy in conjunction with a gastropexy technique in dogs as a potential means to aid prevention of gastric dilatation-volvulus. ANIMALS: 12 healthy adult medium- and large-breed dogs. PROCEDURES: 12 adult research dogs that had no abnormal physical examination findings each underwent an endoscopically assisted gastropexy procedure. On completion of the procedure, the dogs were euthanized and exploratory laparotomies were performed to evaluate the surgical site. Data recorded included anatomic location of the gastropexy, gastropexy length, and duration of procedure as well as any complications. RESULTS: Mean+/-SD gastropexy length was 3.3+/-0.25 cm, and mean duration of surgery was 18+/-7 minutes. In each dog, the stomach was located in its normal anatomic position and all gastropexies were sutured to the abdominal wall at the level of the pyloric antrum. The only complications during the procedure were needle bending and breakage at the time of stay suture placement. CONCLUSIONS AND CLINICAL RELEVANCE: On the basis of these findings, it appears that endoscopically assisted gastropexy is a simple, fast, safe, and reliable method of performing a prophylactic gastropexy in dogs when undertaken by a person who is skilled in endoscopy. Such a procedure maximizes the benefits of decreased morbidity and shorter duration of anesthesia associated with minimally invasive surgery. Further clinical studies are warranted to evaluate the long-term efficacy of this procedure in dogs at risk for development of gastric dilatation-volvulus.     

Multicenter, randomized controlled trial of pain-related behaviors following routine neutering in dogs

OBJECTIVE: To evaluate the degree of postoperative pain in dogs undergoing elective castration or ovariohysterectomy (OHE); determine whether an association exists between surgeon experience, incision length, or surgery duration and degree of postoperative pain; and determine whether analgesic treatment decreases expression of postoperative pain behaviors. DESIGN: Randomized controlled clinical trial. ANIMALS: 426 client-owned dogs undergoing OHE or castration. PROCEDURES: Dogs underwent OHE or castration performed by an experienced veterinarian or a fourth-year veterinary student. Dogs were randomly assigned to 1 of 4 treatment groups: no perioperative analgesic treatment (n = 44), preoperative administration of morphine (144), preoperative administration of nalbuphine (119), and postoperative administration of ketoprofen (119). Dogs were evaluated while in the hospital before anesthesia and for 4 hours after surgery and once a day at home for 3 days after surgery. RESULTS: Dogs in all 4 groups had significant increases in overall pain scores after surgery, compared with baseline scores. There were significant differences among groups, with control dogs having significantly higher increases in overall pain scores than dogs in the other groups. Factors that did not influence the frequency or severity of pain-related behaviors included breed, individual hospital, anesthetic induction protocol, surgeon experience, and duration of surgery. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that dogs expressed behaviors suggestive of pain following OHE and castration, that analgesic treatment mitigated the expression of pain-related behaviors, and that surgeon experience and surgery duration did not have any effect on expression of pain-related behaviors.     

Duration, complications, stress, and pain of open ovariohysterectomy versus a simple method of laparoscopic-assisted ovariohysterectomy in dogs

OBJECTIVE: To describe a simple method of laparoscopic-assisted ovariohysterectomy (LAOHE) and compare duration of surgery, complications, measures of surgical stress, and postoperative pain with open ovariohysterectomy (OHE) in dogs. DESIGN: Randomized, prospective clinical trial. ANIMALS: 20 healthy sexually intact female dogs weighing >10 kg (22 lb). PROCEDURES: Dogs were randomly allocated to receive conventional OHE or LAOHE. Intraoperative complications, anesthetic complications, total anesthesia time, and total surgery time were recorded. Serum cortisol and glucose concentrations, temperature, heart rate, and respiratory rate were measured preoperatively and 1, 2, 4, 6, 12, and 24 hours postoperatively. Pain scores were assigned by a nonblinded observer at 1, 2, 4, 6, 12, and 24 hours postoperatively. Duration of surgery, pain scores, objective measures of surgical stress, anesthetic complications, and surgical complications were compared between OHE and LAOHE. RESULTS: Age, weight, PCV, and duration of surgery did not differ between treatment groups. Nine of 10 dogs in the OHE group required additional pain medication on the basis of pain scores, whereas none of the dogs in the LAOHE group did. Blood glucose concentrations were significantly increased from preoperative concentrations in the OHE group at 1, 2, 4, and 6 hours postoperatively and at 1 hour postoperatively in the LAOHE group. Cortisol concentrations were significantly increased at 1 and 2 hours postoperatively in the OHE group. CONCLUSIONS AND CLINICAL RELEVANCE: LAOHE caused less pain and surgical stress than OHE and may be more appropriate for an outpatient setting.     

Cranial mediastinal carcinomas in nine dogs*

Nine dogs were diagnosed with cranial mediastinal carcinomas. Based on histological and immunohistochemical analysis, four dogs were diagnosed with ectopic follicular cell thyroid carcinomas, one dog with ectopic medullary cell thyroid carcinoma, two dogs with neuroendocrine carcinomas and two dogs with anaplastic carcinomas. Clinical signs and physical examination findings were associated with a space‐occupying mass, although one dog was diagnosed with functional hyperthyroidism. Surgical resection was attempted in eight dogs. The cranial mediastinal mass was invasive either into the heart or into the cranial vena cava in three dogs. Resection was complete in six dogs and unresectable in two dogs. All dogs survived surgery, but four dogs developed pulmonary thromboembolism and two dogs died of respiratory complications postoperatively. Adjunctive therapies included pre‐operative radiation therapy (n = 1) and postoperative chemotherapy (n = 3). Three dogs had metastasis at the time of diagnosis, but none developed metastasis following surgery. The overall median survival time was 243 days. Local invasion, pleural effusion and metastasis did not have a negative impact on survival time in this small case series.     

Evaluation of a low-dose synthetic adrenocorticotropic hormone stimulation test in clinically normal dogs and dogs with naturally developing hyperadrenocorticism.

OBJECTIVE: To determine whether low doses of synthetic ACTH could induce a maximal cortisol response in clinically normal dogs and to compare a low-dose ACTH stimulation protocol to a standard high-dose ACTH stimulation protocol in dogs with hyperadrenocorticism. DESIGN: Cohort study. ANIMALS: 6 clinically normal dogs and 7 dogs with hyperadrenocorticism. PROCEDURE: Each clinically normal dog was given 1 of 3 doses of cosyntropin (1, 5, or 10 micrograms/kg [0.45, 2.3, or 4.5 micrograms/lb] of body weight, i.v.) in random order at 2-week intervals. Samples for determination of plasma cortisol and ACTH concentrations were obtained before and 30, 60, 90, and 120 minutes after ACTH administration. Each dog with hyperadrenocorticism was given 2 doses of cosyntropin (5 micrograms/kg or 250 micrograms/dog) in random order at 2-week intervals. In these dogs, samples for determination of plasma cortisol concentrations were obtained before and 60 minutes after ACTH administration. RESULTS: In the clinically normal dogs, peak cortisol concentration and area under the plasma cortisol response curve did not differ significantly among the 3 doses. However, mean plasma cortisol concentration in dogs given 1 microgram/kg peaked at 60 minutes, whereas dogs given doses of 5 or 10 micrograms/kg had peak cortisol values at 90 minutes. In dogs with hyperadrenocorticism, significant differences were not detected between cortisol concentrations after administration of the low or high dose of cosyntropin. CLINICAL IMPLICATIONS: Administration of cosyntropin at a rate of 5 micrograms/kg resulted in maximal stimulation of the adrenal cortex in clinically normal dogs and dogs with hyperadrenocorticism.     

Assessment of the dark-adaptation time required for recovery of electroretinographic responses in dogs after fundus photography and indirect ophthalmoscopy

OBJECTIVE: To investigate the duration of dark-adaptation time required for recovery of electroretinographic responses after fundus photography or indirect ophthalmoscopy in dogs. ANIMALS: 6 dogs. PROCEDURE: Initially, scotopic-intensity series of electroretinograms (ERGs) were recorded after 20 minutes of dark adaptation. The fundus of the left eye of each dog was photographed (n = 10) or examined via indirect ophthalmoscopy for 5 minutes with moderate- (117 candela [cd]/m2) or bright-intensity (1,693 cd/m2) light; ERGs were repeated after a further 20 or 60 minutes of dark adaptation (6 procedures/dog). RESULTS: Following 20 minutes of dark adaptation after fundus photography, the b- and a-wave amplitudes were reduced in response to brighter stimuli, compared with pretest ERGs; after 60 minutes of dark adaptation, ERG amplitudes had recovered. Following 20 minutes of dark adaptation after indirect ophthalmoscopy (moderate-intensity light), significantly lower b-wave amplitudes were recorded in response to 2 of the brighter flash stimuli, compared with pretest ERGs; after 60 minutes of dark adaptation, ERG amplitudes had recovered. Following 20 minutes of dark adaptation after indirect ophthalmoscopy (bright-intensity light), all ERG amplitudes were significantly decreased and implicit times were significantly decreased at several flash intensities, compared with pretest ERGs; after 60 minutes of dark adaptation, ERG amplitudes and implicit times had returned to initial values, except for b-wave amplitudes recorded in response to dimmer stimuli. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that at least 60 minutes of dark adaptation should be allowed before ERGs are performed in dogs after fundus photography or indirect ophthalmoscopy.     

Evaluation of the six-minute walk test in dogs

OBJECTIVE: To determine the feasibility for use of a 6-minute walk test (6-MWT) in dogs with congestive heart failure (CHF) and document that the distance walked in 6 minutes decreases when a dog has CHF. ANIMALS: 16 young mature male hound-crossbred dogs weighing between 25 and 37 kg. PROCEDURE: An unobstructed path (22.73 m) was measured in a hallway. Each dog was walked on a leash for 6 minutes; each dog was allowed to set its own pace. At the end of 6 minutes (as measured by use of a stopwatch), the total distance walked was measured. Heart rate (HR) obtained by auscultation and mean systemic arterial pressure (MAP) obtained by oscillometry were recorded before and after the 6-MWT. Heart failure was induced by use of rapid ventricular pacing. Mean of the distance walked, HR, and MAP before and after the 6-MWT were compared between the control period and after dogs developed induced CHF. RESULTS: Dogs with CHF had a significant increase in resting HR, significant decrease in MAP, and a significant decrease in the distance walked in 6 minutes. The MAP increased slightly after exercise during the control period but decreased slightly after exercise during the CHF period. Fractional shortening decreased significantly when dogs had CHF. CONCLUSIONS AND CLINICAL RELEVANCE: Analysis of these results indicated that the distance walked in 6 minutes decreased significantly when a dog had CHF. The 6-MWT requires little time, space, or equipment and may replace the treadmill exercise test.     

Comparison of laparoscopic ovariohysterectomy and ovariohysterectomy in dogs

OBJECTIVES: To evaluate technique, complication rates, postoperative pain scores, and clinical outcomes in dogs after laparoscopic ovariohysterectomy (LOVH) or traditional ovariohysterectomy (OVH). STUDY DESIGN: Prospective clinical trial. ANIMALS OR SAMPLE POPULATION: Thirty-four intact female dogs, weighing 2.4-31 kg. METHODS: LOVH (16 dogs) was performed by ligation of the uterus and ovaries with surgical wire, and then removal by an assisted laparoscopic technique. OVH was performed in 18 dogs. Subjective and objective pain scores were assigned at 0, 2, 8, and 24 hours. Surgical time, complications, and pain and incision scores were evaluated. Dogs were followed for up to 6 months. RESULTS: The mean surgical time for LOVH (120 minutes; range, 47-175 minutes) was significantly longer than for OVH (69 minutes; range, 25-140 minutes). Significantly lower pain scores (subjective, in 2 of 10 categories; objective, in 8 of 10 categories) were identified with LOVH at 1 or more time periods. Surgical complications with LOVH were postoperative fever and anorexia (1 dog), minor splenic (3) or pedicle hemorrhage (4), intermittent vaginal hemorrhagic discharge (1), and suture reaction (3). Surgical complications with OVH were hemorrhage from an ovarian pedicle requiring reoperation (1 dog), dehiscence of the abdominal wall (1), and seroma (1). Anesthetic complications included hypotension in 8 OVH dogs and 1 LOVH dog, and hypothermia in 4 OVH and 9 LOVH dogs. The mean incision scores were lower for LOVH at all time periods. CONCLUSION: LOVH was performed successfully in young nonparous dogs >10 kg. Surgical time and complication rates were greater; however, LOVH postoperative pain scores were < or =OVH scores. CLINICAL RELEVANCE: LOVH is a potentially safe surgical alternative to traditional OVH in dogs. Equipment cost and necessity for more than 1 surgeon may limit its usefulness in small animal practice.     

Influence of a preload of hydroxyethylstarch 6% on the cardiovascular effects of epidural administration of ropivacaine 0.75% in anaesthetized dogs

ObjectiveTo evaluate the cardiovascular effects of a preload of hydroxyethylstarch 6% (HES), preceding an epidural administration of ropivacaine 0.75% in isoflurane anaesthetized dogs.AnimalsSix female, neutered Beagle dogs (mean 13.3 ± SD 1.0 kg; 3.6 ± 0.1 years).Study designRandomized experimental cross-over study (washout of 1 month).MethodsAnaesthesia was induced with propofol and maintained with isoflurane in oxygen/air. All dogs were anaesthetized twice to receive either treatment HESR (continuous rate infusion [CRI] of 7 mL kg^?1 HES started 30 minutes [T-30] prior to epidural administration of ropivacaine 0.75% 1.65 mg kg^?1 at T0) or treatment R (no HES preload and similar dose and timing of epidural ropivacaine administration). Baseline measurements were obtained at T-5. Heart rate (HR), mean (MAP), diastolic (DAP) and systolic (SAP) invasive arterial pressures, cardiac output (Lithium dilution and pulse contour analysis) and derived parameters were recorded every 5 minutes for 60 minutes. Statistical analysis was performed on five dogs, due to the death of one dog.ResultsClinically relevant decreases in MAP (<60 mmHg) were observed for 20 and 40 minutes following epidural administration in treatments HESR and R respectively. Significant decreases in MAP and DAP were present after treatment HESR for up to 20 minutes following epidural administration. No significant within-treatment and overall differences were observed for other cardiovascular parameters. A transient unilateral Horner's syndrome occurred in two dogs (one in each treatment). One dog died after severe hypotension, associated with epidural anaesthesia.Conclusions and clinical relevanceA CRI of 7 mL kg^?1 HES administered over 30 minutes before epidural treatment did not prevent hypotension induced by epidural ropivacaine 0.75%. Epidural administration of ropivacaine 0.75% in isoflurane anaesthetized dogs was associated with a high incidence of adverse effects in this study.     

Kinetic analysis of demethylation of 13C-aminopyrine in healthy dogs

OBJECTIVE: To describe the kinetics of demethylation of 13C-aminopyrine in healthy dogs for use in determining the most appropriate time for collection of blood samples for a 13C-aminopyrine demethylation blood test for evaluation of hepatic function. ANIMALS: 9 healthy dogs. PROCEDURES: A 2-mL baseline blood sample was collected into an evacuated heparinized tube, and 13C-aminopyrine was administered to each dog (2 mg/kg, IV). Additional 2-mL blood samples were collected 15, 30, 45, 60, 75, 90, 105, 120, 135, 150, 180, 240, 300, and 360 minutes after 13C-aminopyrine administration. The CO2 was extracted from blood samples by addition of a strong acid, and the percentage dose of 13CO2 (PCD) in the extracted gas was determined by fractional mass spectrometry. RESULTS: No dogs had gross evidence of adverse effects, and all had an increase in PCD after IV administration of 13C-aminopyrine. The PCD had the least variability among 5 variables used to evaluate hepatic demethylating capacity. Peak PCD was detected at 30 minutes in 1 dog, 45 minutes in 5 dogs, 60 minutes in 2 dogs, and 75 minutes in 1 dog. The mean PCD for the 9 dogs peaked at 45 minutes after 13C-aminopyrine administration. CONCLUSIONS AND CLINICAL RELEVANCE: PCD appears to be the preferable variable for evaluation of hepatic demethylating capacity. Intravenous administration of 13C-aminopyrine leads to a consistent increase in PCD. Mean PCD peaked 45 minutes after administration, suggesting that blood sample collection 45 minutes after 13C-aminopyrine administration may be appropriate for use in estimating hepatic demethylating capacity.     

Effect of dry, soft moist, and canned dog foods on postprandial blood glucose and insulin concentrations in healthy dogs

The effect of dry, soft moist, and canned dog foods on immediate postprandial plasma glucose and insulin concentrations was evaluated in clinically normal dogs. Dogs were fed either dry (10 dogs; group I), soft moist (10 dogs; group II), or canned (8 dogs; group III) dog food for 5 consecutive days. On the fifth day, plasma glucose and insulin concentrations were determined in each dog prior to, during, and at 5, 10, 15, 30, 45, 60, 90, 120, 180, and 240 minutes after ingestion of the food. The alterations in plasma glucose concentrations were not significantly different from prefeeding values until 240 and 180 minutes after feeding for groups I and III, respectively. In contrast, the increments in plasma glucose were significantly (P less than 0.01) increased from basal concentrations at 30 and 45 minutes after feeding in group-II dogs. The maximal mean postprandial plasma glucose concentration was significantly (P less than 0.0001) less for group III, compared with concentrations for groups I and II, but there was no significant difference between concentrations for groups I and II. Although a biphasic insulin secretory response was found in all 3 groups of dogs, the patterns of phase-2 insulin secretion and the total amount of insulin secreted during the study were significantly different. There was a rapid increase in the plasma insulin concentration immediately after phase 1 in group II, with maximal plasma insulin concentrations occurring 30 minutes after feeding, followed by a gradual decrease in concentrations throughout the remainder of the study.(ABSTRACT TRUNCATED AT 250 WORDS)