Systems and methods for detecting opening of the jaws of a vessel sealer mid-seal

A method of detecting whether jaws of an electrosurgical instrument are in a slow open condition, the method comprising:

• outputting through a radiofrequency (RF) output stage an electrosurgical waveform through the jaws of the electrosurgical instrument configured to grasp tissue;
• measuring an impedance of the tissue between the jaws;
• determining whether the impedance of the tissue disposed between the jaws exceeds an impedance threshold and whether a change in the impedance is greater than an upper change in impedance threshold;
• outputting an alarm indicative of the jaws being at least partially open based on the impedance exceeding the impedance threshold and on the change in impedance exceeding the upper change in impedance threshold;
• and
• controlling the RF output stage to output the electrosurgical waveform based on the impedance being lower than the impedance threshold and the change in impedance being lower than the upper change in impedance threshold.

A non-transitory computer-readable storage medium storing instructions which, when executed by a processor, cause an electrosurgical generator to:

• output through a radiofrequency (RF) stage an electrosurgical waveform through at least one pair of electrodes of an electrosurgical instrument;
• measure an impedance between the at least one pair of electrodes configured to grasp tissue;
• determine whether the impedance of the tissue disposed between the at least one pair of electrodes exceeds an impedance threshold and whether a change in the impedance is greater than an upper change in impedance threshold;
• and
• output an alarm indicative of the at least one pair of electrodes being at least partially open based on the impedance exceeding the impedance threshold and the change in impedance exceeding the upper change in impedance threshold;
• and
• control the RF output stage to output the electrosurgical waveform based on the impedance being lower than the impedance threshold and the change in impedance being lower than the upper change in impedance threshold.