A novel method for endotracheal intubation of mice and rats used in imaging studies

A safe and efficient method for endotracheal intubation was needed to mechanically ventilate mice and rats for various research projects. We developed an easy, reliable, and expeditious method for intubating these rodents. Inexpensive disposable Teflon intravenous catheters are used as endotracheal tubes. Both mice and rats are anesthetized using a combination of injectable and inhalational anesthetics before intubation. A relatively inexpensive custom-designed fiber-optic light guide and battery-powered light source allows visualization of the oropharynx for quick and easy intubation. The fiber-optic light guide has two functions: 1) the light guide transports light from the illuminator to the tip of the fiber for direct visualization of the larynx, and 2) the fiber is used as a stylet to stiffen the Teflon catheter. Direct illumination of the larynx allows its clear visualization and makes the procedure easier and more efficient and, as a result, less traumatic to the animals. This method has been easy to learn, and it allows repeated intubations, even in debilitated or dyspneic animals, for respiratory-gated, noninvasive imaging procedures. With it, we can acquire higher-quality images with fewer motion artifacts than we could before.