Animal Infusion Pumps And Catheters For IV & CSF. How Low Can You Go?
Posted on Jan 22, 2012 by SolomonScientific
There are many applications for animal infusion pumps and catheter devices which administer low fluid volumes at low flow rates. Laboratory animal CSF infusion, for one, invariably requires low volumes of test article delivered at slow rates. Consider the following devices in the preclinical fluid circuit: programmable pump, drug reservoir, plastic tubing, and implanted animal port catheter. The goal is to utilize those devices which offer low flow rates and small dead volumes.
Pump: Only certain devices are suitable for these applications.
For low flow rates, the choice is a syringe pump, particularly one capable of infusing 1mL syringes and glass syringes. For dog or monkey ambulatory infusion (also called jacketed or portable), select either an insulin pump or, for longer infusions, choose a micro piston pump. The Orchesta™ Model 100 syringe pump, for instance, has a minimum flow rate of 0.01 mL/hour when using a 1mL syringe. For ambulatory use, the Orchesta Model 500-V (Pegasus® from Venner Medical) also delivers at 0.01mL/hour from reservoir bags that enable long periods of dose administration. The unique Model 500-V delivers in microsteps/micropulses of approx. 0.8 uL.
Drug Reservoir: Use syringes or small drug bags.
An advantage of syringe pumps is the variety of reservoirs from 1mL to 140mL. However, portable infusion pumps provide a more limited array of reservoir options. In the case of peristaltic pumps, the smallest reservoir often is 50mL. For a study pushing fluid at 0.1 mL/hr, three days of continuous flow consumes only 7.2mL—a fraction of the 50mL drug bag capacity. Alternatively, the largest insulin pump reservoir is only about 3mL, which may necessitate frequent reservoir changes in animal studies, even at low flow rates. Solomon Scientific supplies novel 5mL, 10mL, and 30mL drug bags for ambulatory infusion studies to fill the void.
Tubing: Small bore tubing is better than standard bore tubing.
Plastic tubing, often with luer connectors, connects the pump to the catheter. Standard bore tubing has an inner lumen of approximately 0.125” (3.2mm) while smaller bore tubing’s lumen is approximately 0.025” (0.6mm), 1/5 smaller than the standard bore. Twelve inches (30cm) of standard bore tubing has a dead volume of 2.4mL while a similar length of the above small bore tubing has 0.1mL. The relationship between diameter and volume is exponential, so efforts to reduce tubing diameter will yield substantial dead volume reductions.
Vascular Access Port Catheter: LOVOL™ ports minimize dead volume.
Regarding the catheter, the same lesson in tubing above applies to catheter sizes. However, the lesson is more critical with ports as flushing typically requires a volume of three to five ties the dead volume. Standard subcutaneous access devices (animal use) contain reservoir dead volumes from 150uL to 500uL. The innovative LOVOL line of devices made by Instech Solomon provides dead volumes of 15uL and 40uL respectively, 90% smaller than standard ports.
These LOVOL dog and monkey catheter devices combined with appropriate pumps, reservoirs, and tubing allow for CSF and IV drug studies requiring low volumes of fluids delivered at low flow rates.
