Effect of anaesthetic maintenance with isoflurane or propofol on ease of endoscopic duodenal intubation in dogs.

Objective: To compare the ease of endoscopic duodenal intubation (EDI) in dogs during maintenance of general anaesthesia with isoflurane or propofol infusion.

Study Design: Prospective, randomized, partially blinded clinical trial.

Animals: A total of 22 dogs undergoing upper gastrointestinal tract endoscopy to include EDI were recruited.

Methods: Dogs were randomly assigned isoflurane (ISO; n = 10) or propofol (PROP; n = 11) for maintenance of general anaesthesia. Following anaesthetic premedication with intramuscular medetomidine (0.005 mg kg) and butorphanol (0.2 mg kg), general anaesthesia was induced with propofol, to effect, maintained with 1.5% (vaporizer setting) isoflurane in 100% oxygen or 0.2 mg kg minute propofol. The dose of both agents was adjusted to maintain general anaesthesia adequate for the procedure. Degree of sedation 20 minutes post-anaesthetic premedication, propofol induction dose, anaesthetist and endoscopist training grade, animal's response to endoscopy, presence of gastro-oesophageal and duodenal-gastric reflux, spontaneous opening of the lower oesophageal and pyloric sphincters, antral movement and time to achieve EDI were recorded. EDI was scored 1 (immediate entry with minimal manoeuvring) to 4 (no entry after 120 seconds) by the endoscopist, blinded to the agent in use. Data were tested for normality (Shapiro-Wilk test) and differences between groups analysed using independent t test, Mann-Whitney U test and Fisher's exact test as appropriate.

Results: There were no significant differences between groups for EDI score [median (interquartile range): 2 (3) ISO, 2 (3) PROP] or time to achieve EDI [mean ± standard deviation: 52.50 ± 107.00 seconds (ISO), 70.00 ± 196.00 seconds (PROP)]. Significantly more dogs responded to passage of the endoscope into the oesophagus in group PROP compared with group ISO (p = 0.01).

Conclusions And Clinical Relevance: Maintenance of general anaesthesia with either isoflurane or propofol did not affect EDI score or time to achieve EDI.