Monitoring unit and high frequency surgery system having such a monitoring unit
A monitoring unit which is configured to monitor a patient during an operation of a high-frequency surgery device, wherein the high-frequency surgery device is configured to separate and/or coagulate biological tissue by means of high-frequency electrical energy, wherein the monitoring unit has: measuring electrodes which are disposed in a periphery of the patient, and an evaluation and control unit which is configured to impress a predetermined measuring alternating voltage or a predetermined measuring alternating current on the measuring electrodes, and to monitor an impedance decreasing between the measuring electrodes and to monitor a time curve of the impedance and/or to monitor a temporal change thereof.
1 . A monitoring unit configured to monitor a patient during an operation of a high-frequency surgery device, wherein the high-frequency surgery device is configured to separate and/or coagulate biological tissue by means of high-frequency electrical energy, the monitoring unit comprising:
measuring electrodes, separate from and not a part of the high frequency surgery device, adapted to be disposed in a periphery of the patient wherein the measuring electrodes are disposed on a surface of a patient table or integrated in the surface of the patient table; and
an evaluation and control unit configured to impress a predetermined measuring alternating voltage or a predetermined measuring alternating current on the measuring electrodes, and to monitor an impedance decreasing between the measuring electrodes, to monitor (a) a time curve of the impedance, (b) a temporal change thereof or (c) both the time curve of the impedance and the temporal change thereof.
2 . The monitoring unit according to claim 1 , wherein the evaluation and control unit is further configured to generate a warning signal if a relative change in impedance in the time curve of the impedance undercuts or exceeds a predetermined first limit value and/or the impedance undercuts a predetermined second limit value.
3 . The monitoring unit according to claim 2 , wherein the measuring electrodes are disposed on several components in the periphery of the patient, such that the evaluation and control unit is configured to determine a spatial impedance distribution in the periphery of the patient.
4 . The monitoring unit according to claim 3 , wherein the monitoring unit further has a display and wherein the evaluation and control unit is configured to display the warning signal in the form of a spatial position and location of a place in the periphery of the patient at which the first limit value is exceeded or undercut and/or the second limit value is undercut on the display.
5 . The monitoring unit according to claim 4 , wherein the measuring electrodes form a pattern of surface electrodes which are spatially distributed, adjacent and electrically insulated from each other and wherein the evaluation and control unit is configured to measure the impedance between each two adjacent surface electrodes.
6 . The monitoring unit according to claim 5 , wherein the measuring electrodes are realized in the form of an interdigital structure and wherein the predetermined measuring alternating voltage or the predetermined measuring alternating current has a frequency of 1 kHz to 10 kHz and/or does not correspond to a frequency by means of which the high-frequency surgery device is operated.
7 . The monitoring unit according to claim 4 , wherein the measuring electrodes are disposed such that they are in electroconductive contact with one or several body locations and/or clothing of the patient.
8 . The monitoring unit according to claim 7 , wherein a number of measuring electrodes is at least larger than a number of the one or several body location(s) of the patient to be monitored.
9 . The monitoring unit according to claim 1 , wherein the measuring electrodes are incorporated in a removable cover of a patient table.
10 . The monitoring unit according to claim 9 , wherein the measuring electrodes each have electroconductive threads which are woven into the cover.
11 . The monitoring unit according to claim 10 , wherein the measuring electrodes are metrologically differentially connected in series or in parallel or inductively or capacitively coupled to each other and, preferably in their entirety, serve as a dispersive electrode of the high-frequency surgery device which discharges the high-frequency electrical energy from the biological tissue.
12 . The monitoring unit according to claim 11 , wherein impressing the predetermined measuring alternating voltage or the predetermined measuring alternating current on the measuring electrodes takes place on the basis of a four-wire measurement.
13 . The monitoring unit according to claim 1 , wherein the measuring electrodes are electronically connected to each other as pairs of electrodes, such that impressing the predetermined measuring alternating voltage or the predetermined measuring alternating current and the measurement of the impedance is carried out in pairs, wherein each individual measuring electrode of the measuring electrodes is pairable with any other measuring electrode of the measuring electrodes, and wherein the measurement of the impedance per pair of measuring electrodes is preferably performed successively in time or simultaneously.
14 . The monitoring unit according to claim 13 , wherein the evaluation and control unit is configured to measure a real part and/or imaginary part of the impedance decreasing over the measuring electrodes and/or to measure an amplitude and phase of the measuring alternating voltage or the measuring alternating current.
15 . A monitoring unit configured to monitor a patient during an operation of a high-frequency surgery device, wherein the high-frequency surgery device is configured to separate and/or coagulate biological tissue by means of high-frequency electrical energy, the monitoring unit comprising:
measuring electrodes, separate from and not a part of the high frequency surgery device, adapted to be disposed in a periphery of the patient; and
an evaluation and control unit configured to impress a predetermined measuring alternating voltage or a predetermined measuring alternating current on the measuring electrodes, and to monitor an impedance decreasing between the measuring electrodes, to monitor (a) a time curve of the impedance, (b) a temporal change thereof or (c) both the time curve of the impedance and the temporal change thereof and wherein;
(1) the evaluation and control unit is further configured to generate a warning signal if a relative change in impedance in the time curve of the impedance undercuts or exceeds a predetermined first limit value and/or the impedance undercuts a predetermined second limit value;
(2) the measuring electrodes are disposed on several components in the periphery of the patient, such that the evaluation and control unit is configured to determine a spatial impedance distribution in the periphery of the patient; and
(3) the monitoring unit further has a display and wherein the evaluation and control unit is configured to display the warning signal in the form of a spatial position and location of a place in the periphery of the patient at which the first limit value is exceeded or undercut and/or the second limit value is undercut on the display.
16 . The monitoring unit according to claim 15 , wherein the measuring electrodes form a pattern of surface electrodes which are spatially distributed, adjacent and electrically insulated from each other and wherein the evaluation and control unit is configured to measure the impedance between each two adjacent surface electrodes.
17 . The monitoring unit according to claim 16 , wherein the measuring electrodes are realized in the form of an interdigital structure and wherein the predetermined measuring alternating voltage or the predetermined measuring alternating current has a frequency of 1 kHz to 10 kHz and/or does not correspond to a frequency by means of which the high-frequency surgery device is operated.
18 . The monitoring unit according to claim 15 , wherein the measuring electrodes are disposed such that they are in electroconductive contact with one or several body locations and/or clothing of the patient.
19 . The monitoring unit according to claim 18 , wherein a number of measuring electrodes is at least larger than a number of the one or several body location(s) of the patient to be monitored.
20 . The monitoring unit according to claim 15 , wherein the measuring electrodes are incorporated in a removable cover of a patient table.