Systems and methods for monitoring return patch impedances

An impedance measuring circuit for use in a tissue therapy system, the impedance measuring circuit electrically coupleable between i) at least one electrode of a catheter insertable in a patient, ii) a first return patch electrode configured to be applied to skin of the patient, and iii) a second return patch electrode configured to be applied to the skin of the patient, the impedance measuring circuit configured to:

• drive currents between the at least one catheter electrode, the first return patch electrode, and the second return patch electrode, wherein each of the driven currents comprises a unique frequency;
• detect, using a voltage at the at least one catheter electrode as a reference voltage, voltages generated in response to the driven currents;
• and
• simultaneously measure impedances based on the driven currents and the detected voltages.

A method of measuring impedances in a tissue therapy system, the method comprising:

• driving, using an impedance measuring circuit, currents between i) at least one electrode of a catheter insertered in a patient, ii) a first return patch electrode applied to skin of the patient, and iii) a second return patch electrode applied to the skin of the patient, wherein each of the driven currents comprises a unique frequency;
• detecting, by the impedance measuring circuit, using a voltage at the at least one catheter electrode as a reference voltage, voltages generated in response to the driven currents;
• and
• simultaneously measuring impedances based on the driven currents and the detected voltages.