Techniques, Materials, and Devices A New Apparatus for Chronic Intravenous Infusion in Unrestrained Rats

ABSTRACT. A new apparatus incorporating a unique type of swivel device was devised for chronic intravenous infusion in unrestrained rats. The swivel requires very little torque for rotation, ie, one-fourth that of the standard swivel, yet is 1/30 as expensive. A coil spring tube, located between the swivel and the catheter, allows the rat unhampered movement within the metabolic cage. Because the catheter follows the rats’ movements freely, only two silk sutures are required to secure it to the animal. No statistically significant differences between experimental and control rats were observed in terms of body weight gain, food intake, nitrogen balance, or caloric efficiency. This apparatus should prove useful in many areas of research. (Journal of Parenteral and Enteral Nutrition 12:93-99, 1988) Optimally, rats should be unrestrained during chronic intravenous infusion studies. Most reported technique