The use of therapeutic infusion systems to treat patients in hospitals is standard procedure but there are always occasional errors. Tubes can bend or connectors can detach. David Große Wentrup of the Münster University of Applied Sciences, Germany, has developed a technical system to monitor infusion systems, which now also completely monitors the lines.
Mr. Große Wentrup, how are infusion systems generally constructed?
David Große Wentrup: There is a broad spectrum of infusion systems. The simplest system consists of an infusion container with the IV solution, a mechanism to regulate the infusion flow rate, for instance a simple roller clamp, an infusion line and the patient access. However, the number of individual components as well as the complexity of infusion systems increases drastically in practice. Patients with more than ten infusion pumps in parallel are quite common in intensive care units. This number necessitates an abundance of lines, filters, manifolds and T-connectors. Keeping track of everything is understandably difficult at times.
How frequent are errors in infusion administration?
Große Wentrup: The number of deaths due to preventable adverse events in hospitals varies with the different studies. However, it is undisputed that the number of preventable incidents is far too high. Drug therapy makes up a significant percentage in this area while there can also be a number of incidents during infusion therapy. Infusion tubes can bend for example, connections can detach or T-connectors can be in the wrong position. Detecting these and other errors is made even more difficult for instance in situations with darkened operating room settings or partially covered patients. Added to this is the fact that the workload of clinical staff is already extremely high during the sometimes hectic day-to-day clinical practice.
Große Wentrup: Currently, clinical staff is responsible for monitoring patients and infusions. The infusion pumps have safety features such as pressure alarms for example. However, this doesn’t cover the entire infusion system. Infusion lines in particular remain largely overlooked. Our system uses pressure and acoustic impulses chiefly integrated into the infusion lines to monitor the infusion system. The impulses are integrated in and through the infusion pumps into the infusion systems and spread through the lines out to all linked components. The signal response of the originally transmitted signal is being detected with them.
All of the individual signal responses are sent to a computer system and analyzed with special algorithms. This makes it possible for us to determine the type of connections of the individual elements of the infusion system. Ultimately, we create a map with all infusion lines in real-time from this, similar to ski trail maps you might know from your winter vacation. If needed, we are able to indicate information about the infusion system and errors, so that the clinical staff is able to respond before the patient might be injured.
Can your system also be used for other applications?
Große Wentrup: Essentially yes. The physical foundations of our system are similar for all fluid-carrying systems regardless of whether we look at infusion lines, oil pipelines or other systems with fluids that are connected through lines. Medical technology, that being infusion therapy still represents a special case with very specific added problems and phenomena we had to face during the development of our system. Sterility, electrical safety, high validity of test results, impact of other systems as well as artifacts caused by patient movements or the smallest particles or air bubbles in the tubes were just some of these special challenges during the design and development.