Finalist: An Air Removal System For a Wearable Renal Therapy Device

This is a project to develop an automatic air removal system that can be used safely in a wearable renal therapy device with minimal user intervention.

All existing dialysis systems require a method of preventing air bubbles introduced in the dialysis process from being returned into the patient's blood circulation. Most existing systems use a drip chamber with a level detector where the blood exits from the bottom and the air rises to the top. The equipment operator observes the drip chamber level and makes level adjustments when required. These systems must always be maintained in a vertical orientation in order to function safely.

Wearable systems as per their portable nature may not always be in the vertical orientation. Because of the difficulty involved in removing air from a system that may be in different orientations, the air removal devices on some wearable systems that have been proposed are minimal or nonexistent.

This system uses an air removal filter of the design used in cardiopulmonary bypass (CPB) and extracorporeal membrane oxygenation (ECMO) systems. These filters also must be in the vertical orientation in order to remove air that accumulates in the chamber, however, they will continue to remove air from the blood path even when they are not in that vertical orientation.

This system ensures that the air accumulated in the chamber is removed only at times when the filter is in the vertical orientation and will prompt the user if that orientation has not been maintained in a recent period of time. This system can also determine and signal the patient with an alarm if the hydrophobic isolation filter element has been wetted and thus has reduced the accuracy of the integrated return blood pressure monitor.

Submitted by Morteza Ahmadi and Clarence Graansma on behalf of QidniLabs.