Capnography-guided Endotracheal Intubation as an Alternative to Existing Intubation Methods in Rabbits.

Rabbits provide a unique challenge for routine endotracheal intubation in clinical practice because of various distinctiveanatomic and physiologic features. Many previously proposed methods for endotracheal intubation in rabbits are limited byseveral factors, including the needs for expensive equipment and high levels of technical expertise. We evaluated capnographyfor its effectiveness in assisting endotracheal intubation in rabbits. New Zealand white rabbits were divided into 3 groupsof 5 animals. In the first 2 groups, mainstream (nondiverting) or sidestream (diverting) capnography (MC and SC groups, respectively)was used; in the third group (LS group), a laryngoscope with a size 00 Miller blade was used to guide endotracheal tube placement. Anesthesia was induced through intramuscular administration of ketamine (10 mg/kg), medetomidine (0.1 mg/kg), and midazolam (1 mg/kg) mixed in the same syringe prior to administration. Intubation time was defined from thepoint of opening the jaws to the completion of the first capnogram after intubation. Intubation was accomplished successfully in all animals in both capnography groups, but 2 rabbits in the laryngoscopy group could not be intubated. Intubation time was compared among groups was compared by using one-way ANOVA, and posthoc Bonferroni testing was applied to isolate significant differences between groups. The intubation time (mean ± 1 SD) was 46.4 ± 12.6 s in the MC group, 147.2 ± 44.2 s in the SC group, and 385.0 ± 114.1 in the LS group, with intubation time significantly differing among all groups. In conclusion, both mainstream and sidestream capnography-guided endotracheal intubation techniques were more effective and efficient than conventional laryngoscope-guided endotracheal intubation in rabbits. Furthermore, mainstream capnography waspreferred over sidestream capnography because mainstream capnography resulted in significantly shorter intubation times.