Patent ID: 7648465

Claim:
A method for determining an irrigation path resistance ratio in an irrigation system having an irrigation pressure sensor, comprising the steps of: a) connecting a source of irrigation fluid to a surgical handpiece through an irrigation line, the source of irrigation fluid under control of a surgical system; b) connecting a source of aspiration vacuum to the surgical handpiece through an aspiration line, the source of aspiration under the control of the surgical system; c) installing a test chamber on the surgical handpiece so as to provide a closed fluid path from the source of irrigation fluid to the source of aspiration vacuum; d) exposing the test chamber to a vacuum generated by the source of aspiration vacuum by aspirating a known fluid volume, while closing the irrigation line; e) refilling the test chamber by opening the irrigation line; f) monitoring a pressure recovery profile in one of the irrigation or aspiration lines; g) detecting a characteristic test chamber refill segment in the monitored pressure recovery profile; h) determining an irrigation line pressure during the detected test chamber refill segment, as an irrigation pressure sensor (IPS) reading during the refilling of the test chamber; i) determining a pressure drop from the source of irrigation fluid to the irrigation pressure sensor during the detected test chamber refill segment; j) determining a pressure drop from the irrigation pressure sensor to the test chamber during the detected test chamber refill segment; and k) using the pressure drop from the source of irrigation fluid to the irrigation pressure sensor during the detected test chamber refill segment and the pressure drop from the irrigation pressure sensor to the test chamber during the detected test chamber refill segment to determine the irrigation path resistance ratio (K R ) of a resistance to irrigation flow from the source of irrigation fluid to the irrigation pressure sensor to a resistance to irrigation flow from the irrigation pressure sensor to the test chamber.