Peristaltic Pumping Technology
Most large volume pumps (LVPs) on the market today work using peristaltic pumping technology. A peristaltic infusion pump uses mechanics, like fingers or paddles, to pinch down on the tubing, pushing fluid forward1,2—it creates positive displacement from compression and relaxation of the tubing,2 much like our esophagus does when we swallow food.3 While this technology was an advancement over gravity pumps, it can have drawbacks.
When mechanics are used to push fluid, bursts of fluid through the tubing can occur. At each of these moments, the patient may receive an exponentially higher or lower amount of medication. Normally this is not clinically significant. But it may become a concern when you consider drugs that have an immediate effect on the patient’s condition, such as vasopressors or sedation. These drugs have a short half-life and duration of action; therefore, they are administered via continuous infusion so they can be titrated for desired effects.4,5
Pneumatic Pumping Technology
Unlike the peristaltic pump, the Ivenix LVP uses a pneumatically driven silicone diaphragm to pull fluid from an IV bag, fill an internal chamber, and then push the fluid through the tubing toward the patient. The fluid flow is measured via closed-loop control of the pneumatic drive, and flow is regulated in real time. This can have several effects on infusion delivery accuracy.
Bag height independence:
With closed-loop flow measurement, fluid bags don’t have to be hung on IV poles above the pump because the pneumatic drive pulls fluid into the diaphragm chamber without gravity assistance. Pump users can hang the bag(s) directly on the pump, up high or down low, and the pump will infuse consistently and accurately under typical clinical conditions.*6
Piggyback setup autonomy:
Because this same system is controlling flow of the secondary inlet port, piggybacking a secondary no longer requires that the primary bag be placed below the secondary bag.6
Free from heart-level requirements:
Pneumatic pumping with Ivenix is adaptive, so accuracy is maintained at any pump mounting position on the IV pole.6
Measuring Accuracy
In technical literature, both accuracy and continuity are depicted through trumpet curves, which adhere to the international standard for infusion devices (IEC 60601-2-24). These curves serve as graphical representations, offering insights into the adherence of the pump’s performance to the desired flow rate and uniformity. They provide a standardized method for evaluating and comparing various infusion devices across the industry. The following trumpet curves are graphical views of the maximum deviation in flow rate from the programmed delivery rate for the Ivenix LVP 6
The Ivenix LVP utilizes adaptive control of the fluid output to ensure that the accuracy specification of +/- 5% for flow rate output is maintained across the full range of operating conditions seen by the pump, which is depicted in the graphics above.6 These include ambient temperature and pressure, head height, backpressure, fluid viscosity, and tubing configuration.*6
Recapping the Mechanics
Peristaltic IV pumps work by squeezing a tube to push fluid through it.1,2 These devices use set measurements to control how fast the pump squeezes the tube, assuming it will deliver the right amount of fluid.2 But sometimes, other factors, like changes in pressure from the IV bag or diameter of the tubing, can affect how much fluid actually gets through.2 Consequently, peristaltic technology lacks the capability to actively adjust for these variations, potentially impacting the precision of IV fluid administration.2
Unlike traditional peristaltic pumps, pneumatically driven pumping technology like Ivenix is adaptive, measuring and controlling the actual volume of fluid leaving the pump and entering the patient.7 This direct measurement lets the pump’s control software adjust the flow rate to match the desired target, even if external conditions change.6 For example, if there’s more pressure pushing against the flow, causing it to slow down, the system detects this and automatically adjusts to maintain the desired flow rate.6
Why Mechanics Matter
The mechanism underlying smart infusion pumps plays a pivotal role in determining their accuracy in clinical settings. While peristaltic pumps have been a longstanding choice, their reliance on mechanical paddles or fingers may lead to fluctuations in fluid delivery. On the other hand, pneumatically driven pumping technology, as used by the Ivenix LVP, offers an innovative approach. By directly measuring fluid volume and adjusting flow rates accordingly, these pumps detect and adjust to factors affecting infusion accuracy, helping to ensure consistent and precise medication delivery under typical clinical conditions.
Please see full list of warnings and cautions associated with this device
*Overall accuracy +/- 5% under the following conditions: 0.5-1000 mL/hr; 5°C to 35°C ambient temperature; 10 PSIA-15.5 PSIA ambient pressure; -100 mmHg to 525 mmHg backpressure; +/- 24″ inlet head height; viscosities up to 70% dextrose solution; up to 96-hour duration; microbore and macrobore sets.
- U.S. Food & Drug Administration. What is an infusion pump? Accessed February 22, 2024. https://www.fda.gov/medical-devices/infusion-pumps/what-infusion-pump#:~:text=In%20an%20elastomeric%20pump%2C%20fluid,flexible%20tubing%2C%20pushing%20fluid%20forward
Klespitz J, Kovács L. Peristaltic pumps – a review on working and
control possibilities. 2014 IEEE 12th International Symposium on Applied Machine Intelligence and Informatics (SAMI), Herl’any, Slovakia, 2014, pp. 191-194. Accessed February 26, 2024. https://real.mtak.hu/27727/1/37_sami2014.pdf
- National Institute of Diabetes and Digestive and Kidney Diseases. Your digestive system & how it works. Accessed February 22, 2024. https://www.niddk.nih.gov/health-information/digestive-diseases/digestive-system-how-it-works
- Grigsby SM. Caring for patients receiving vasopressors and inotropes in the ICU. American Nurse Journal. February 3, 2021. Accessed February 26, 2024. https://www.myamericannurse.com/vasopressors-inotropes-icu/
- VanValkinburgh D, Kerndt CC, Hashmi MF. Inotropes and Vasopressors. In: StatPearls. Treasure Island (FL): StatPearls Publishing; February 19, 2023.
- Ivenix Infusion System Large Volume Pump (LVP) Instructions for Use. Bad Homburg, Germany: Fresenius Kabi; 2024.
- Penoyer D, Giuliano K, Middleton A. Comparison of safety and usability between peristaltic and pneumatic large-volume intravenous smart pumps during actual clinical use. BMJ Innovations. 2022;8:78-86.
