Comparison of rabbit oropharyngeal and tracheal anatomical angle during endotracheal intubation using rigid and flexible endoscopes

Abstract

Endotracheal intubation in rabbits is always challenged due to the complexity of anatomical structures. To improve intubation success, this study determined the relation of head placement angles guided by endoscope-assisted visualized techniques on intubation success rate. Thirty-two rabbit cadavers were used in the study. Six veterinary practitioners who had no experience with rabbit intubation were randomly assigned to intubate rabbit cadavers using the guidance of either a rigid endoscope (RE) or flexible endoscope (FE) with the head placement angles with an uprising neck at 90, 100, 110, 120 and 130 degrees. The intubation completed in 90 seconds was determined to be a success. The success rates using RE and FE were 97.2% and 95.9% respectively. Means and standard error of means (SEM) of intubation times for the RE and FE guided were 53.7 ± 4.68, and 55.2 ± 4.24 seconds, respectively. Results from survival time analysis show that the 5 veterinarians had successfully intubated the rabbit within 90 seconds regardless of different types of endoscopes. Angle was the only significant factor that effect the intubation success. The head placement angle at 110 and 120 had the most success rate of intubation compared to 90 degrees angle (p≤0.05). In conclusion, for inexperienced veterinarians, the success of endotracheal intubation in rabbits, guided by endoscope-assisted visualized techniques regardless of rigid endoscope or flexible endoscope guidance, is improved when the head extension is 110 and 120 degrees.