ABSTRACT
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.
Subject(s)
Animals, Laboratory , Intubation, Intratracheal/instrumentation , Intubation, Intratracheal/methods , Intubation, Intratracheal/veterinary , Animals , Fiber Optic Technology , Larynx/anatomy & histology , Mice , Optical Fibers , RatsABSTRACT
The presence of motion artifacts is a typical problem in thoracic imaging. However, synchronizing the respiratory cycle with computed tomography (CT) image acquisition can reduce these artifacts. We currently employ a method of in vivo respiratory-gated micro-CT imaging for small laboratory animals (mice). This procedure involves the use of a ventilator that controls the respiratory cycle of the animal and provides a digital output signal that is used to trigger data acquisition. After inspection of the default respiratory trigger timing, we hypothesized that image quality could be improved by moving the data-acquisition window to a portion of the cycle with less respiratory motion. For this reason, we developed a simple delay circuit to adjust the timing of the ventilator signal that initiates micro-CT data acquisition. This delay circuit decreases motion artifacts and substantially improves image quality.
