Medical fluid cassette leak detection methods and devices
Inventors
Garza, Hernando Garrido • Doctor, Akbar • Kodam, Preetam • Marchetti, Dante • Jacob, John
Assignees
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Publication Number
US-12427234-B2
Publication Date
2025-09-30
Expiration Date
Abstract
This disclosure relates to medical fluid cassette leak detection methods and devices. In some implementations, a method of detecting micro-leaks in a medical fluid cassette, the method includes decreasing a pressure between a vacuum reservoir of a medical treatment machine and a membrane of the medical fluid cassette when the medical fluid cassette is coupled to the medical treatment machine; measuring, using a flow meter, a rate of net fluid flow between the vacuum reservoir and the membrane of the medical fluid cassette; determining that the rate of net fluid flow between the vacuum reservoir and the membrane of the medical fluid cassette is above a threshold value; and in response to determining that the rate of net fluid flow is above the threshold value, causing the medical treatment machine to take a particular action.
Core Innovation
The invention detects micro-leaks in a medical fluid cassette by decreasing a pressure between a vacuum reservoir of a medical treatment machine and a membrane of the medical fluid cassette to a decreased predetermined pressure when the cassette is coupled to the machine. While maintaining the decreased predetermined pressure, the invention measures a rate of net fluid flow between the vacuum reservoir and the membrane using a flow meter. The measured rate of net fluid flow is compared to a threshold value, and micro-leak determination is made based on whether the rate is above the threshold value.
In response to determining that the rate of net fluid flow is above the threshold value, the invention causes the medical treatment machine to take a particular action. The particular action includes user warning and indication actions such as audible indication, visual indication, tactile indication, speaker warning, and screen message, together with machine control actions including disabling or terminating treatment until a leak-free cassette is installed. The disclosed approach is intended to identify micro-leaks that may not be reliably measurable using standard pressure-decay methods, including cases where a micro-leak corresponds to a membrane opening.
An alternate testing approach is described using positive pressure between a pressure reservoir and the cassette, combined with a protective porous cover stiffer than the membrane to prevent overexpansion. In this approach, a micro-flow sensor monitors net flow between the pressure reservoir and the cassette during a testing period, and repeat testing can be performed. The document further describes marking, discarding, destroying, and labeling cassettes determined to be defective, and using test results such as a net flow chart to classify cassettes based on net flow rates.
Claims Coverage
Independent claim 1 and independent claim 16 provide protection for both a method and a medical treatment system that detect micro-leaks by vacuum-based pressure control and flow-threshold determination, with both claims requiring a particular action when net fluid flow exceeds a threshold. The independent claims include a shared core of vacuum pressure decrease, net fluid flow measurement between a vacuum reservoir and a cassette membrane, threshold comparison, and triggering a particular action.
Vacuum pressure decrease between vacuum reservoir and cassette membrane with thresholded net flow determination
Decreasing a pressure between a vacuum reservoir of a medical treatment machine and a membrane of the medical fluid cassette to a decreased predetermined pressure, measuring a rate of net fluid flow between the vacuum reservoir and the membrane while maintaining the decreased predetermined pressure, determining that the rate is above a threshold value, and causing the medical treatment machine to take a particular action in response.
Medical treatment system with vacuum reservoir, flow meter, processor threshold determination, and action
Providing a medical treatment system including a vacuum reservoir, a flow meter positioned between the vacuum reservoir and the membrane when the cassette is coupled to the machine, and at least one processor configured to control the machine to decrease pressure to a decreased predetermined pressure, receive from the flow meter data indicating the rate of net fluid flow while maintaining that pressure, determine based on the data that the rate is above a threshold value, and cause the machine to take a particular action in response.
Across the two independent claims, the inventive coverage centers on vacuum-based pressure decrease to a decreased predetermined pressure, measuring net fluid flow between the vacuum reservoir and the cassette membrane, comparing the rate to a threshold value, and triggering a particular action when the measured rate is above the threshold.
Stated Advantages
Detects micro-leaks in a medical fluid cassette based on net fluid flow measurement compared to a threshold value.
Identifies micro-leaks that may not be reliably measurable by standard pressure-decay methods.
Provides user warnings and indications and machine control actions, such as disabling or terminating treatment, in response to detected micro-leaks.
Documented Applications
Micro-leak detection for a medical fluid cassette used with a medical treatment machine, including medical treatment systems such as peritoneal dialysis and a PD cycler.
Off-line or manufacturing testing of cassettes using positive pressure and a protective porous cover, including marking, discarding, destroying, and labeling of defective cassettes.
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