Is normal saline an acceptable alternative to silicone for lubricating fibrescopes?

This article describes a model designed to measure the forces acting on a fibrescope when it is pushed through an endotracheal tube. Lubrication with either silicone or normal saline leads to a reduction in friction forces. Fibrescopes lubricated with normal saline require a larger force to be advanced through endotracheal tubes when compared to silicone; however, the difference is clinically unimportant and is outweighed by the advantageous properties of normal saline. A theoretical model is presented which is in close agreement with experimentally derived data.