Infusion

The first ambulatory infusion pump marketed was the Watkins Chrono-Fusor¹ in the late 1950s, used primarily for the continuous infusion in humans of chemothepeutic agent 5FU (Fluorouracil), still a major drug used in many cancer treatments. The Chrono-Fusor (Figure 1) was slightly smaller than today's programmable infusion. The power source was a mechanical keyed wind-up watch motor, much like a grandfather clock. The pump utilized a rotary peristaltic mechanism, identical to some of today's pumps.

Ambulatory infusion pumps developed slowly over the next two decades until the 1970s when the home infusion market prompted pump manufacturers to develop smaller, more cost-effective pumps. In the early 1980s, Deltec Systems (now SmithMedical MD) developed the CADD (Computerized Ambulatory Drug Delivery System) pump. The CADD pumps became the ambulatory pump of choice for many laboratory animal researchers. These pumps allowed for sophisticated drug delivery in ambulatory animals that was not previously possible. The early ambulatory infusion pumps were single therapy, and thus had limited capabilities. Sometimes, multiple pumps were required to deliver different rates or pumping profiles.

In the early 1990s, ambulatory infusion pumps evolved into multiple therapy pumps that could be programmed for various types of infusions. This added capability came with a price; it added significantly to the size and weight of the pumps, limiting their use in the laboratory animal market.

During the 1990s, pumps more suitable in size, weight, and capability for laboratory animal infusion appeared on the market. The CADD Legacy^® and CADD MICRO^® (Figure 2) became the standard for ambulatory animal infusions. The CADDMicro was small, lightweight, and allowed for precise delivery in smaller laboratory animals that was previously only available in tethered models. The Micro was limited to a 10 ml syringe, so its use was very specialized. The CADD Legacy pumps allowed for animals as small as 2-3 kg to carry a full-featured, complex, ambulatory infusion pump.