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

ObjectiveTo compare the ease of endoscopic duodenal intubation (EDI) in dogs during maintenance of general anaesthesia with isoflurane or propofol infusion.Study designProspective, randomized, partially blinded clinical trial.AnimalsA total of 22 dogs undergoing upper gastrointestinal tract endoscopy to include EDI were recruited.MethodsDogs 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^–1) and butorphanol (0.2 mg kg^–1), general anaesthesia was induced with propofol, to effect, maintained with 1.5% (vaporizer setting) isoflurane in 100% oxygen or 0.2 mg kg^–1 minute^–1 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.ResultsThere 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 relevanceMaintenance of general anaesthesia with either isoflurane or propofol did not affect EDI score or time to achieve EDI.