Coagulation device comprising an energy control
A device ( 10 ) for tissue coagulation, in particular for fusion, encompasses an electric source ( 18 ), which is connected or which can be connected to electrodes ( 12, 13 ) for influencing biological tissue ( 11 ) with current. A control unit ( 22 ) controls the source ( 18 ) during phases I and II of the tissue fusion. These phases I and II correspond to operating phases I, II and III of the device ( 10 ). During operating phase I, a monitoring unit ( 23 ) determines the energy E 1 , which is applied into the tissue ( 11 ). In the subsequent operating phases II and III, the control unit ( 22 ) controls the source ( 18 ) by means of the determined energy E 1 . Such a device turns out to be particularly reliable and to be robust in use.
1. A device ( 10 ) for tissue coagulation, the device comprising:
an electric source ( 18 ), configured to be connected to electrodes ( 12 , 13 ) for influencing biological tissue ( 11 ) with current,
a monitoring unit ( 23 ), which is connected to the electric source ( 18 ), configured to determine one or both of a current (I ACT ) output by the electric source ( 18 ) and a voltage (U ACT ) output by the electric source ( 18 ),
a control unit ( 22 ), which includes the monitoring unit ( 23 ) and which is connected to the electric source ( 18 ) in a controlling manner, the control unit ( 22 ) configured to:
determine an energy value (E 1 ) which corresponds to a total amount of energy the electric source ( 18 ) outputs to the electrodes ( 12 , 13 ) during a first operating phase (I), and
control the electric source ( 18 ) as a function of the energy value (E 1 ), which is determined in the first operating phase (I), in a subsequent second operating phase (II), wherein at least one of a minimum and a maximum duration of the second operating phase (II) is defined according to the energy value (E 1 ) from the first operating phase (I).
2. The device according to claim 1 , wherein the control unit ( 22 ) is interconnected with the electric source ( 18 ) in the first operating phase (I) as a current regulating circuit.
3. The device according to claim 1 wherein at an onset of the first operating phase (I), the control unit ( 22 ) is configured to define a chronologically increasing current (i 1 a ).
4. The device according to claim 1 wherein during at least a section (Ib) of the first operating phase (I), the control unit ( 22 ) is configured to define a constant current (i 1 b ).
5. The device according to claim 1 wherein the control unit ( 22 ) comprises a module ( 26 ) configured to determine a conclusion of the first operating phase (I) using at least one of:
a relationship between voltage and current at the electric source ( 18 ) increases beyond a threshold value (R Gmax ),
the relationship between voltage and current at the electric source ( 18 ) passes through a minimum (M),
an increased speed of change in the relationship between voltage and current at the electric source ( 18 ) exceeds a threshold value,
the voltage (U ACT ) at the electric source ( 18 ) exceeds a threshold value,
the current (I ACT ) falls below a threshold value.
6. The device according to claim 1 wherein at an onset of the second operating phase (II), the control unit ( 22 ) is equipped to adjust at least one variable of:
current (I ACT ) from the electric source ( 18 ),
voltage (U ACT ) at the electric source ( 18 ),
output power (P ACT ) of the electric source ( 18 ) to a same value the variable had at a conclusion of the first operating phase (I).
7. The device according to claim 1 wherein in the second operating phase (II), the control unit ( 22 ) is configured to define a course of time for changing of a relationship between the voltage (U ACT ) at the electric source ( 18 ) and the current (I ACT ) supplied by said source.
8. The device according to claim 7 , wherein the course of time encompasses a constant impedance increase (A).
9. The device according to claim 1 wherein the control unit ( 22 ) is configured to define a chronological length (t 2 ) of the second operating phase (II).
10. The device according to claim 1 wherein the control unit ( 22 ) is configured to define a chronological length (t 2 ) of the second operating phase (II) as a function of the energy value (E 1 ), which is determined in the first operating phase (I).
11. The device according to claim 1 wherein directly following the second operating phase (II), the control unit ( 22 ) is configured to merge into a third operating phase (III).
12. The device according to claim 11 , wherein in the third operating phase (III), the control unit ( 22 ) is configured to define and adjust a constant voltage (U 3 ).
13. The device according to claim 11 , wherein in the third operating phase (III), the control unit ( 22 ) is configured to define a voltage (U 3 ) of the electric source ( 18 ) to a value determined by the monitoring unit ( 23 ) at a conclusion of the second operating phase (II).
14. The device according to claim 11 , wherein the control unit ( 22 ) is configured to conclude the third operating phase (III), if:
a minimum treatment time (t min ) and a given total energy (E tot ) have been reached or
a maximum treatment time (t max ) has elapsed or
a maximum energy (E max ) has been applied.
15. The device according to claim 11 , wherein the control unit ( 22 ) is equipped to monitor a power output by the electric source ( 18 ) in the operating phase (II), so as to extend a time period (t 2 ) for the second or third operating phase (II, III), provided that the power has left a performance window, which is defined between a maximum power (P max ) and a minimum power (P min ).