Patent ID: 6425878
Filing Date: 2002-07-30
Classification: A61B,A61M

Abstract:
A method for detecting extravasation of a fluid delivered from the tip of a catheter into tissue located under a first region of skin, the method comprising:(a) deploying on the skin a sensor system including: (i) a first sensor including a layer of piezoelectric film disposed in thermal and mechanical connection with the first region of skin, the first sensor providing a sensing signal, (ii) a second sensor including a layer of piezoelectric film disposed in mechanical connection with, but thermally isolated from, a second region of skin, the second sensor providing a reference signal, and (iii) a third sensor including a layer of piezoelectric film disposed in mechanical connection with, but thermally isolated from, a third region of skin, the third sensor providing a gate signal; (b) subtracting the reference signal from the sensing signal to generate a corrected sensing signal and from the gate signal to generate a corrected gate signal; (c) when an amplitude of the corrected gate signal is no greater than a predefined gate threshold value, monitoring the corrected sensing signal to detect at least one variation indicative of a malfunction; and (d) when an amplitude of the corrected gate signal is greater than the predefined gate threshold value, temporarily disregarding variations in the corrected sensing signal.