University of Washington

Other

Elena M Bosque

William Michael Siler

Steven L Goldman

In some embodiments, a self-monitoring intravenous catheter system is provided. An alarm controller is provided that receives signals representing a pH value, an oxygen saturation value, and a pressure value in proximity to the distal end of the catheter. By performing a fuzzy logic analysis of the values, the alarm controller is able to detect that the catheter is about to fail or has failed, and can cause alerts to be presented. In some embodiments, an intravenous catheter is provided that has a pH sensor and an oximeter disposed at a distal end of the catheter to obtain the pH value and oxygen saturation values analyzed by the alarm controller. Embodiments of the catheter and self-monitoring intravenous catheter system may be particularly useful in treating neonates, who are sensitive to catheter failure and are not capable of detecting the signs of failure themselves.

Alarm system for intravenous pump or catheter based upon fuzzy logic

A new alarm system for pulse oximeters, based on fuzzy logic, will differentiate false alarms, caused by artifact, from true alarms. Numeric input variables and corresponding fuzzy sets (oxygen saturation HIGH (high O2), NO (normal O2) and YES (desaturation) and rate of change of oxygen saturation (HIGH, MEDIUM and LOW) and their membership functions are defined. An output fuzzy set ARTIFACT is defined. Input voltages from the pulse oximeter are sampled and converted to digital form. The sampled voltages are converted by the membership functions into confidences that each fuzzy set descriptor for oxygen desaturation and reate of change apply. Rules are specified which result in confidences that the fuzzy set descriptors for ARTIFACT apply. Further rules govern the issuance of alarms for oxygen desaturation or for artifacts, momentary or continuous, so that the nurse can take appropriate action. The fuzzy logic alarm system program is written in Quick Basic 4.5, by Microsoft (R). The advantage of using the fuzzy logic alarm system for a pulse oximeter used in infants is that there will be at least 34% fewer false alarms. Pulse oximeter alarms which better reflect the actual situation will improve the specificity of the alarm system and may decrease the potential 'Cry Wolf' response of the caretaker, which now exists.

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Pacifica, CA, United States of America

Elena M Bosque