A Simple and Reliable Method of Endotracheal Intubation in Mice: Advantages of Exposing the Trachea
Mice are popular models in experimental studies because they can be genetically modified and have a short gestation period. In long-term studies requiring recovery from anesthesia or repeated measurements of pulmonary function, endotracheal intubation is advantageous. However, this is difficult because of the small anatomic structures involved. Various methods have been previously reported, the majority of them calling for expensive devices or techniques which require special training. Therefore, we have created a simple method of endotracheal intubation in mice using a light-emitting diode (LED) light, a metal laryngoscope, a 22-gauge plastic cannula and a stylet made of a 0.3mm piano wire, which can all be easily prepared. Transillumination after exposure of the trachea makes it possible to illuminate the oropharynx with a lowpriced LED light and a metal laryngoscope provides good visualization of the tracheal opening. With direct vision, a 22-gauge plastic cannula can easily be inserted into the trachea. The custom-made stylet is suitably flexible for performing tracheal intubation without tissue injury. In a series of 42 mice, the success rate with the procedure was 97.6% (n=41). Only in one case was it necessary for the procedure to be repeated. There were no airway complications. Though exposure of the trachea is invasive, it does have advantages. We conclude that this method is simple, safe and inexpensive, and could be used by any researchers interested in it, no matter how small their budget.