A secure and rapid method for orotracheal intubation of laboratory rats utilising handy instruments

Tracheal intubation of anaesthetised rats for laboratory experiments remains an essential yet challenging procedure.

We aimed to investigate whether tracheal intubation can be safely and securely accomplished in laboratory rats employing only handy instruments and with minimal experience.

The feasibility and safety of a modified orotracheal intubation method was evaluated in rats undergoing open-chest surgery as part of another research protocol, and compared with an existing technique.

The study was carried out in a tertiary medical centre-affiliated animal laboratory.

Eighty-five rats weighing 250 to 350 g anaesthetised with intraperitoneal pentobarbital (60 mg kg(-1)).

Orotracheal intubation was performed on 35 animals (group Jou) using a previously reported technique and then on another 50 rats (group New) using the modified method employing a 3-ml syringe-derived intubation wedge, a 0.025-inch guidewire and a 16-gauge 45-mm-long intravenous catheter.

The time for completion, the number of attempts and the incidence of difficulties and complications were recorded. The intubated tracheas were subsequently examined macroscopically and microscopically to determine position of the intubation catheter and the integrity of epithelial lining.

Compared with the previous technique, the new method was completed more rapidly (1 ± 0.2 vs. 5 ± 2.4 min; P < 0.001), more smoothly (difficulties encountered in 8 vs. 74%; P < 0.001), with greater overall success (100 vs. 86%; P=0.022) and with fewer attempts [1 (1 to 1) vs. 2 (2 to 4); P < 0.001) for the new and Jou techniques, respectively, and with a lower incidence of procedure-related complications. Postmortem analysis confirmed there was no microscopic injury to the tracheal epithelial lining with the new technique in contrast to 57% in those using the Jou technique (P < 0.001).

Tracheal intubation for laboratory rats can be securely and safely completed with the modified method employing a short learning curve and easily available devices.