A simple oral endotracheal intubation technique in rats using a modified 5-Fr vascular sheath and a commercially available ear-pick endoscope.

Oral endotracheal intubation in rats is useful for cranial, thoracic, and survival experiments but remains technically demanding. We evaluated a simple method using a modified 5-Fr vascular sheath and a smartphone-connected ear-pick endoscope in 30 male Sprague-Dawley rats (8-12 weeks, 300-400 g). Under 3% isoflurane anesthesia and vecuronium bromide-induced neuromuscular blockade, the sheath was shortened to approximately 8 cm, and its modified inner dilator was advanced into the trachea under endoscopic visualization; the sheath was then advanced over the dilator and connected to mechanical ventilation. Intubation was successful in all rats, with first-attempt success in 28/30 (93.3%). No major complications occurred, although minor oral bleeding was observed in several rats. This method may provide a practical option for rat airway management.