Flow rate monitor for fluid cooled microwave ablation probe
A microwave ablation system includes an antenna assembly configured to deliver microwave energy from a power source to tissue and a coolant source operably coupled to the power source and configured to selectively provide fluid to the antenna assembly via a fluid path. The system also includes a controller operably coupled to the power source and a sensor operably coupled to the fluid path and the controller. The sensor is configured to detect fluid flow through the fluid path and the controller is configured to control the energy source based on the detected fluid flow.
1. An electrosurgical system, comprising:
an electrosurgical instrument configured to deliver electrosurgical energy to tissue;
a coolant source operably coupled to the electrosurgical instrument via a fluid conduit, the coolant source configured to supply a fluid to the electrosurgical instrument through the fluid conduit;
a sensor operatively coupled to the fluid conduit, the sensor configured to sense a flow of the fluid through the fluid conduit and to sense presence of an air bubble in the fluid and to generate a signal indicative of the flow of the fluid; and
a controller operably coupled to the sensor, the controller configured to:
receive the signal indicative of the flow of the fluid from the sensor; and
detect an interruption in the flow of the fluid based on a variation of the signal resulting from the presence or absence of an air bubble in the fluid.
2. The electrosurgical system according to claim 1 , further comprising a power source coupled to the electrosurgical instrument, the controller configured to control the power source based on the flow of the fluid.
3. The electrosurgical system according to claim 1 , further comprising an amplifier operably coupled to the controller, the amplifier configured to amplify the signal.
4. The electrosurgical system according to claim 3 , wherein the sensor is disposed in a resonant feedback loop with the amplifier.
5. The electrosurgical system according to claim 1 , wherein the sensor is a capacitive device disposed about the fluid conduit, the capacitive device configured to sense a capacitance of the fluid.
6. The electrosurgical system according to claim 5 , wherein the capacitive device includes a pair of parallel capacitive plates and a dielectric disposed therebetween.
7. The electrosurgical system according to claim 1 , wherein the fluid conduit includes an inflow lumen and an outflow lumen.
8. An electrosurgical system, comprising:
a power source;
an electrosurgical instrument configured to couple to the power source and configured to deliver electrosurgical energy from the power source to tissue;
a coolant source operably coupled to the electrosurgical instrument via a fluid conduit, the coolant source configured to supply a fluid to the electrosurgical instrument through the fluid conduit;
a sensor operatively coupled to the fluid conduit, the sensor configured to sense a flow of the fluid through the fluid conduit and to sense presence of an air bubble in the fluid and to generate a signal indicative of the flow of the fluid;
an amplifier coupled to the sensor and configured to generate an amplified signal;
a bandpass filter coupled to the amplifier and configured to filter the amplified signal, the bandpass filter being centered on a resonant frequency consistent with fluid flow through the fluid conduit; and
a controller operably coupled to the amplifier and the power source, the controller configured to detect an interruption in the flow of the fluid based on a variation of the amplified signal resulting from the presence of an air bubble in the fluid and modify output of energy from the power source based on the amplified signal.
9. The electrosurgical system according to claim 8 , wherein the sensor is a capacitive device disposed about the fluid conduit, the capacitive device configured to sense a capacitance of the fluid.
10. The electrosurgical system according to claim 9 , wherein the capacitive device includes a pair of parallel capacitive plates and a dielectric disposed therebetween.
11. The electrosurgical system according to claim 9 , wherein the controller is configured to compare the capacitance to a predetermined range.
12. The electrosurgical system according to claim 11 , wherein the controller is configured to modify output of energy from the power source based on the comparison of the capacitance to the predetermined range.
13. The electrosurgical system according to claim 8 , wherein the controller is configured to detect at least one peak in the amplified signal.
14. The electrosurgical system according to claim 8 , wherein the fluid conduit includes an inflow lumen and an outflow lumen.