Patent ID: 6736810
Filing Date: 2004-05-18
Classification: A61B

Abstract:
A system for ablating a target tissue of a body of a patient, comprising:a surgical instrument including an ablation electrode for delivery of RF current to the tissue and a fluid aperture for delivery of conductive fluid adjacent the ablation electrode; a return electrode; an RF current generator coupled to the ablation and return electrodes to deliver RE current between the ablation and return electrodes; a fluid source coupled to the fluid aperture to deliver the conductive fluid to the fluid aperture at a defined rate; an impedance measurer coupled to the ablation and return electrodes to measure rate of change of impedance between the ablation and return electrodes during delivery of the RF current; and a fluid flow controller coupled to the fluid source and adapted to progressively adjust the rate of delivery of the conductive fluid in response to the measured time rate of change of the impedance between the ablation and return electrodes based upon a pre-determined correlation between fluid flow rate and impedance rate of change.