Evaluation of the effects of premedication on gastroduodenoscopy in cats

Endoscopic assessment of presumed acquired pyloric narrowing in cats: A retrospective study of 27 cases

Acquired pyloric narrowing is a rare and poorly-documented condition in cats, but the endoscopic appearance of pyloric narrowing has never previously been reported. The objectives of this study were to describe the clinical, endoscopic and histological features in cats with gastrointestinal signs where the pylorus could not be passed during endoscopy, and to compare these data with a control group. Medical files of cats that underwent upper GI endoscopy by the same operator between 2006 and 2015 were reviewed. Cats for which the pylorus could not be passed were assigned to the case group, whilst those with an easily-passable pylorus were assigned to the control group. The case group comprised 27 cats and control group comprised 35 cats. Median age and weight were not different between groups, but there were more Siamese cats in the case group (6/27) compared with the control group (1/35; P = 0.04). Chronic vomiting was the main clinical sign in both groups, but the vomitus was more likely to contain food in case group (23/25) than in cats in control group (17/30; P < 0.01). Endoscopic findings confirmed gastric inflammation in both groups, whilst histological findings revealed similar lymphoplasmacytic infiltration of the gastric mucosa and the duodenum in most cases, neoplastic features being infrequent. Acquired pyloric narrowing is probably an underdiagnosed condition in adult cats. A possible association between pyloric narrowing and gastrointestinal inflammatory disease requires further study but, for now, it is recommended that multiple gastric, pyloric, and duodenal biopsies be acquired during the endoscopy.

Comparison of the effects of methadone and butorphanol combined with acepromazine for canine gastroduodenoscopy

OBJECTIVE

To evaluate the feasibility of gastroduodenoscopy in dogs premedicated with acepromazine in combination with butorphanol or methadone.

STUDY DESIGN

Prospective, randomized, double-blinded clinical trial.

ANIMALS

A group of 40 client-owned dogs.

METHODS

Dogs were randomly allocated to one of two groups and give intramuscular acepromazine 0.02 mg kg^-1 combined with either butorphanol 0.3 mg kg^-1 (group ACEBUT) or methadone 0.2 mg kg^-1 (group ACEMET). General anaesthesia was induced with propofol and ketamine and maintained with sevoflurane (2.3%) in oxygen. Cardiopulmonary variables were recorded at 5 minute intervals during anaesthesia. Feasibility of the entire gastroduodenoscopy was evaluated with a visual analogue scale (VAS) from 0 (best) to 100 (worst) (primary outcome of the study). Lower oesophageal sphincter dilatation and duodenal intubation were scored. Pylorus diameter was measured with standard endoscopic inflatable balloons. Overall cardiovascular stability was assessed during anaesthesia, using a VAS (0-100), as was the presence of fluid in the oesophagus, regurgitation, need for mechanical ventilation, and intraoperative and postoperative rescue analgesia (secondary outcomes of the study). Differences between treatments were analysed with Mann-Whitney U, Student t test, Fisher exact test or mixed model analysis of variance as appropriate. Subsequently, feasibility VAS of the gastroduodenoscopy was assessed for noninferiority between groups. The noninferiority margin was set as -10.

RESULTS

All gastroduodenoscopies were successfully completed in both groups using an endoscope tip diameter of 12.8 mm in all but one dog. Feasibility of gastroduodenoscopy was evaluated as 2.9 ± 5.6 in group ACEBUT and 5.1 ± 5.8 in group ACEMET. No significant differences between groups were detected in any measured or assessed variables, and noninferiority was confirmed.

CONCLUSION AND CLINICAL RELEVANCE

In our study population, the effects of methadone and butorphanol when combined with acepromazine were comparable.

Effect of premedication with butorphanol or methadone on ease of endoscopic duodenal intubation in dogs

OBJECTIVE

The effect of premedication with butorphanol or methadone on ease of endoscopic duodenal intubation.

STUDY DESIGN

Prospective, randomized, blinded clinical trial.

ANIMALS

A group of 20 client-owned dogs.

METHODS

Dogs were assigned randomly to be administered intravenous (IV) premedication with either butorphanol (0.4 mg kg^-1) or methadone (0.3 mg kg^-1). General anaesthesia was induced with propofol to effect and maintained with isoflurane in 100% oxygen. Sedation score 20 minutes after premedication administration and induction dose of propofol were recorded. Heart rate, mean arterial pressure, haemoglobin oxygen saturation, respiratory rate and end-tidal isoflurane concentration were recorded every 5 minutes. Spontaneous lower oesophageal and pyloric sphincter opening, presence of gastro-oesophageal and duodeno-gastric reflux, antral peristaltic contractions and response to endoscopy were recorded as yes or no. Ease of duodenal intubation (EDI) was graded on a scale ranging from 1 (immediate entry with minimal manoeuvring required) to 4 (no entry after 2 minutes). Time (seconds) from the start of pyloric intubation to successfully entering the duodenum was recorded.

RESULTS

Median EDI score [3 ± 1 (butorphanol), 4 ± 1 (methadone), p = 0.035], time [65 ± 36 seconds (butorphanol), 120 ± 38 seconds (methadone), p = 0.028] and number of dogs with spontaneous pyloric sphincter opening [7/10 (butorphanol), 2/10 (methadone), p = 0.035] differed between groups. No other significant differences were found.

CONCLUSIONS AND CLINICAL RELEVANCE

In these clinical cases, duodenal intubation was performed with greater ease, shorter time and more frequent spontaneous opening of the pyloric sphincter after premedication with butorphanol in comparison to methadone. The use of butorphanol facilitated the passage of the endoscope and is therefore recommended for premedication prior to upper gastrointestinal tract endoscopy.

Flexible Gastrointestinal Endoscopy in Ferrets (Mustela putorius furo)

Gastrointestinal disease is a common complaint in ferrets (Mustela putorius furo). Their relatively simple and short gastrointestinal tract makes them good candidates for flexible endoscopy. However, apart from a few references in biomedical research articles, there is little information on the use of flexible endoscopy in ferrets. This review describes patient preparation, equipment, and select gastrointestinal endoscopy techniques in ferrets, including esophagoscopy, gastroscopy, duodenoscopy, percutaneous endoscopic gastrostomy, jejunoileoscopy, colonoscopy, and biopsy.

Sedative effects of intramuscular alfaxalone administered to cats

The sedative effects of intramuscular (IM) alfaxalone in 2-hydroxypropyl-beta-cyclodextrin (alfaxalone-HPCD) were evaluated in cats. The cats were treated with alfaxalone-HPCD in five occasions with a minimum 14-day interval between treatments: an IM injection of 1.0 mg/kg (IM1), 2.5 mg/kg (IM2.5), 5 mg/kg (IM5) or 10 mg/kg (IM10), or an intravenous injection of 5 mg/kg (IV5). The sedative effects were evaluated subjectively using a composite measurement scoring system (a maximum score of 16). Cardio-respiratory variables were measured non-invasively. The median sedation scores peaked at 10 min (score 9), 15 min (score 14), 10 min (score 16), 10 to 20 min (score 16) and 2 to 5 min (score 16) after the IM1, IM2.5, IM5, IM10 and IV5 treatments, respectively. The IM5 treatment produced longer lasting sedation, compared to the IV5 treatment. Durations of maintenance of lateral recumbency after the IM10 treatment (115 ± 22 min) were longer than those after the IM2.5 (40 ± 15 min), IM5 (76 ± 21 min) and IV5 treatments (50 ± 5 min). Cardio-respiratory variables remained within clinically acceptable ranges, except for each one cat that showed hypotension (<60 mmHg) after the IM10 and IV5 treatments. Tremors, ataxia and opisthotonus-like posture were observed during the early recovery period after the IM2.5, IM5, IM10 and IV5 treatments. In conclusion, IM alfaxalone-HPCD produced dose-dependent and clinically relevant sedative effect at 2.5 to 10 mg/kg in healthy cats. Hypotension may occur at higher IM doses of alfaxalone-HPCD.

Gastrointestinal endoscopy in the cat: equipment, techniques and normal findings

PRACTICAL RELEVANCE

Feline gastrointestinal (GI) endoscopy is in high demand, particularly by cat owners already aware of the clinical benefits and availability of this procedure within the human healthcare system. This article will provide a basic introduction to GI flexible endoscopy, covering important aspects of endoscope selection, clinical indications, and basic techniques required to perform a thorough and diagnostically meaningful examination in the cat.

CLINICAL CHALLENGES

Challenges associated with implementing endoscopy in GI tract investigations can include lack of appropriate/suitable-sized equipment to perform a thorough examination in the cat, insufficient operator training/understanding in how to 'drive the scope' through the GI tract, and/or lack of confidence in differentiating normal from abnormal.

AUDIENCE

This article is intended to familiarize and motivate the feline practitioner to develop basic endoscopic skills. Clinical proficiency can only be obtained through use of appropriate equipment, formal training and hours of practice indistinguishing normal from abnormal.

EVIDENCE BASE

The guidance contained in this article is based on a combination of the published literature, the authors' personal experience and the experience of colleagues.

Anesthesia for endoscopy in small animals

This article discusses considerations for general anesthesia for various endoscopic procedures in small animals. Specific drug and monitoring recommendations are made. Special physiologic concerns of individual procedures affecting the anesthetized patient are discussed.

Changes in minimal alveolar concentration of isoflurane following treatment with medetomidine and tiletamine/zolazepam, epidural morphine or systemic buprenorphine in pigs

The aim of this study was to determine the changes in minimal alveolar concentration (MAC) of isoflurane after treatment with medetomidine and tiletamine/zolazepam (MTZ), epidural morphine or systemic buprenorphine in 11 healthy crossbred pigs. The first part of this study was to measure the baseline values in pigs induced with isoflurane (5%) by face mask and maintained with isoflurane in air and oxygen for 2 h (ISO). Baseline isoflurane MAC was determined using mechanical stimulation. Thereafter, each pig was randomly chosen for a crossover test in which the same animal received three different treatments with at least one week in between treatments. The three treatments were as follows: induction of anaesthesia with medetomidine (0.05 mg kg(-1)) and tiletamine/zolazepam (2.5 mg kg(-1) each) given intramuscularly (MTZ); MTZ followed by epidural morphine (0.1 mg kg(-1); MTZ/M); and MTZ followed by intramuscular buprenorphine (0.1 mg kg(-1); MTZ/B). All pigs were maintained with isoflurane in oxygen and air for 2 h and their lungs were mechanically ventilated. The end-tidal isoflurane concentration, respiratory rate, inspiratory and expiratory O2 and CO2 concentrations, heart rate (HR) and arterial blood pressure were recorded every 10 min. Arterial blood gases were analysed every 20 min. Among the treatment groups, differences in isoflurane MAC were tested using GLM and Tukey's method for further comparison; P < 0.05 was adopted as significant. Isoflurane MAC was 1.9 +/- 0.3%. MTZ reduced isoflurane MAC to 0.6 +/- 0.1%. Additional morphine or buprenorphine reduced the MTZ isoflurane MAC further to 0.4 +/- 0.2 and 0.3 +/- 0.1%, respectively. During MTZ, MTZ/M and MTZ/B mean arterial blood pressure was higher and the alveolar-arterial oxygen tension difference was lower compared with ISO. In conclusion, induction of anaesthesia with MTZ reduced the isoflurane MAC in pigs by 68%. Additional epidural morphine or systemic buprenorphine decreased MTZ isoflurane MAC by 33 and 50%, respectively.