24-hour intravenous infusion via the marginal ear vein in the New Zealand white rabbit.

A method was needed to conduct a 24-h intravenous infusion procedure in rabbits that minimized animal restraint and allowed unlimited access to the animal by research staff. We catheterized 16 male and 16 female New Zealand White rabbits (Oryctolagus cuniculus) by inserting an indwelling human infant catheter into the marginal ear vein. The catheter was connected, via an extension set, to a small, lightweight, ambulatory pump with predetermined pump rates; the pump was placed in a Lycra jacket that the rabbit was wearing. Toxicokinetic samples, electrocardiograms, and clinical pathology samples were collected at multiple time points. Pump accuracy was verified by collecting the pre- and post-dose weights of the pumps as well as infusion start and stop times. Depending on the infusion rate, pumps were changed every 5 or 10 h or at the end of 24 h. The accuracy of these pumps was between 5% and 10% of the calculated target volume from 0 to 20 h. The lack of need for surgery or long-term restraint and tethering is a refinement in infusion technology and animal use.