CA2119973A1 - Electrosurgery monitor and apparatus - Google Patents
Electrosurgery monitor and apparatusInfo
- Publication number
- CA2119973A1 CA2119973A1 CA 2119973 CA2119973A CA2119973A1 CA 2119973 A1 CA2119973 A1 CA 2119973A1 CA 2119973 CA2119973 CA 2119973 CA 2119973 A CA2119973 A CA 2119973A CA 2119973 A1 CA2119973 A1 CA 2119973A1
- Authority
- CA
- Canada
- Prior art keywords
- cable
- electrode
- transformer
- connector
- oscillator
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
- F16L55/00—Devices or appurtenances for use in, or in connection with, pipes or pipe systems
- F16L55/26—Pigs or moles, i.e. devices movable in a pipe or conduit with or without self-contained propulsion means
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
- F16L55/00—Devices or appurtenances for use in, or in connection with, pipes or pipe systems
- F16L55/26—Pigs or moles, i.e. devices movable in a pipe or conduit with or without self-contained propulsion means
- F16L55/28—Constructional aspects
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- Coating Apparatus (AREA)
- Extrusion Moulding Of Plastics Or The Like (AREA)
- Surgical Instruments (AREA)
- Measurement And Recording Of Electrical Phenomena And Electrical Characteristics Of The Living Body (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
Electrosurgery apparatus has a large area return electrode, which can be of various different kinds and may have a monitor for detecting correct connection of the return electrode. In the present invention the monitor has three contacts in a socket that connect with two or three contacts on a plug connected to the return electrode. One pair of contacts in the socket is connected across an oscillator that provides an output to a first primary winding of the transformer when there is a low impedance between the contacts. Another pair of contacts is connected across a second primary winding and produces a loading on the transformer when short circuited by the return electrode. A detector is connected to the secondary winding of the transformer and produces an alarm and disable signal if the signal on the secondary winding falls below an upper limit or exceeds a lower limit.
Electrosurgery apparatus has a large area return electrode, which can be of various different kinds and may have a monitor for detecting correct connection of the return electrode. In the present invention the monitor has three contacts in a socket that connect with two or three contacts on a plug connected to the return electrode. One pair of contacts in the socket is connected across an oscillator that provides an output to a first primary winding of the transformer when there is a low impedance between the contacts. Another pair of contacts is connected across a second primary winding and produces a loading on the transformer when short circuited by the return electrode. A detector is connected to the secondary winding of the transformer and produces an alarm and disable signal if the signal on the secondary winding falls below an upper limit or exceeds a lower limit.
Description
ELECTROSURGERY MONITOR AND APPARATUS
Back~round of the Invention This invention relates to electrosurgery monitors and apparatus.
Electrosurgery apparatus, such as diatherrny apparatus, employs high frequency R~
energy to produce a surgical cutting or coagulation effect, or a combination of these effects.
The energy is applied to the patient via a hand-held, patient electrode, which concentrates the energy in a small region so that the current density in that region is sufficiently high to produce the desired effect. Energy is returned to the electrosurgery unit via a large area, return electrode ~.
in the form of a ~exible plate attached to the body. The large area of contact of the return electrode with the patient's skin ensures that the electrosurgery energy at the underlying skin : .
surface has a much lower current density; in this way, no electrosurgery effect is produced at the return electrode.
A problem occurs with electrosurgery apparatus if the return electrode is not connected ~-to the apparatus, since there will be no return path via the apparatus; this can lead to RF energy : `
returr~ing to earth via an altemative route. There is also a problem if the retum electrode becomes loose, or if contact with the skin is reduced for some other reason, such as drying of the conductive gel used between the electrode and the skin; this can result in a more localized contact of the return plate with the skin. In both cases, a higher return current density may . :
result, which in turn can produce burning of the skin.
:
In order to reduce the risk of burn injury to the patient, it is common practice for the electrosurgery apparatus to include some form of monitor to detect incorrect connection of the return electrode to the apparatus and separation ofthe return electrode from the skin. Because - . ..... .
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~119973 of the different forms that return electrodes can take, it can be difflcult to provide a monitor that can be used safely with different return electrodes.
Brief Summary of the Invention It is an object of the present invention to provide an improved electrosurgery monitor and apparatus According to one aspect of the present invention there is provided an electrosurgery monitor assembly including a monitor unit, a large area return electrode, and a cable connected at one end to the electrode and at its other end to a coMector, the monitor unit including at least a first and second input connection adapted to make electrical connection with the connector, an oscillator having an input coupled with the two input connections such that the output of the oscillator is dependent on a connection being established between the two input connections, and detector means responsive to the output ofthe oscillator to provide an alarm signal in the event ofthe absence of a correct connection at the input e onnections.
The monitor unit preferably includes a transformer, the oscillator being coMected to provide an alternating input to a primary winding of the transformer when there is a low impedance between the two input connections, and the detector means being connected to a secondary winding of the transformer and providing the alarm signal when the signal in the secondary winding falls below a predetennined value. The monitor unit preferably includes a third input connection, the second and third connections being connected to a second primary winding ofthe transformer, the detector means being arranged also to produce an alarm signal in the event of an output on the oscillator being above an upper threshold value, and the connector being arranged to produce a low impedance across the second and thirdconnections so that the second primary winding produces a loading on the transformer that reduces the output on the secondary ~inding below the upper threshold value. The assembly may include a further oscillator and a further transformer, the first osciDator being powered by the further . - .... - - -..
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, .. . .. .. -~119973 oscillator via the transformer. The alarm signal may be arranged to interrupt supply of electrosurgery power to the patient. The input connections may be spaced along the length of a socket, the connector being a plug and the connector having contacts spaced along the length of the plug.
The return electrode may be a single-plate electrode, the cable being a single-lead cable, and the connector having two contacts connected to the single lead. Alternatively, the return electrode may be a single-plate electrode, the cable being a double-lead cable and the connector ~ ~:
having two contacts connected to respective ones of the leads in the cable connected together at the electrode. Alternatively, the return electrode may be a single-plate electrode, the cable being a triple-lead cable, and the connector having three contacts connected to respective ones of the leads in the cable and connected together at the electrode. Alternatively, the return electrode may be a split-plate electrode, the cable being a double-lead cable, the two leads in the cable being connected to respective parts of the split-plate electrode and the connector having a first contact connected to one lead and a second contact connected to the other lead.
According to another aspect of the invention there is provided electrosurgery apparatus including an electrosurgery generator, an astive electrode and a monitor assembly according to the above one aspect of the invention.
, ~ ' Electrosurgery apparatus induding a monitor according to the present invention, will - ~ `
now be described, by way of example, with reference to the accompanying drawings.
.
BriefDescription of the Drawings Figure 1 is a schematic diagram of the electrosurgery apparatus;
Figure 2 shows the monitor unit of the apparatus in .
,: , . : . ' , greater detail; and Figures 3A show different forms of return electrode and 3E assembly.
Detailed Description of the Preferred Embodiments - With reference first to Figure 1, the apparatus includes an electrosurgery generator 1 of conventional construction supplying high frequency RF electrosurgery energy to a transformer 2. One end of the secondary winding 3 of the transformer is coMected via a capacitor 4 to an active hand-held electrode 5. The other end of the secondary winding 3 is connected via a monitor unit 6 to a return electrode assembly 10, 20, 30, 40 or 50.
,'-: ~' With reference now also to Figures 2 and 3, the monitor un~t 6 is connected to three contacts Pl, P2 and EN (enable) in a socket 60 on the casing ofthe apparatus. The contacts are spaced apart from one another along the length ofthe socket in the manner shown in Figure ~ ~ -3~ The monitor unit 6 provides an alarm signal on line 100 to an alarTn unit 101 when the monitor unit detects that the return electrode is not connected. A second alarm signal is given on line 102 to the alann unit 101 when the monitor 6 detects that the return electrode is not correctly attached to the patient.
The monitor unit 6 includes a first osciUator 103, which normaUy provides an alternating output to a primary winding 104 of a transformer 105. The first oscillator 103 derives its operating power from a second oscillator 106 via an isolating transformer 107. This arrangement ensures isolation ofthe patient from mains power. The first oscillator 103 has a control input connected across the contacts P2 and EN of the socket 60 and only provides an output when P2 and EN are connected together by a low impedance.
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The contacts Pl and P2 in the socket 60 are connected to opposite ends of a second primary winding 108 of the transformer 105. The electrosurgery return current is taken on line 109, which is connected to the junction of a series connection of two capacitors 110 and 111 between the two contacts P 1 and P2. Line 109 is connected to the secondary winding 3 of the ~ :~
transformer 2.
The transfonner 105 has a secondary winding 112 connected to a detector unit 113.
The detector unit 113 responds to a signal in the secondary winding 112 below a first threshold VL by producing an alarm signal on line 100 to indicate that the return electrode assembly has not been connected. If the signal in the secondary winding 112 rises above a second, highlevel threshold Vu, the detector 113 produces an alarm signal on line 102 to indicate that the return electrode is not correctly attached to the patient.
If either the first oscillator 103 or the second oscillator 106 should fail, this would result in the absence of a signal on the primary winding 104 and hence cause the detector unit 113 to -produce an alarm output on line 100.
'- - - ' .
The return electrode assembly 10, 20, 30, 40 or S0 may take any one of the five different forms illustrated in Figures 3A to 3E.
Figure 3A shows an assembly lO with a single plate electrode 11 coMected by a coMector to one end of a single-lead cable 12. The other end of the cable is coMected to a male coupling or plug 13 having two contacts 14 and lS, both of which are coMected to the sarne lead 12' in the cable. The plug 13 makes coMection with the socket 60, the spacing of the contacts being such that contacts Pl and P2 both make coMection to the same contact 14 on the plug. The other contact EN makes coMection with a second contact 15 at the tip ofthe plug.
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' .
. . . .
-6- ~'~19.973 In operation, it can be seen that contacts P2 and EN will be shorted at the plug 13 when this is inserted correctly in the socket 60, so that the oscillator 103 will operate and provide an output to the primary winding 104, which in turn produces an output on the secondary winding 112. The other primary winding 108 is effectively short circuited by the contact 14, which bridges the contacts Pl and P2 in the socket 60. The winding 108 thereby provides a loading on the transformer 105 reducing the output at the secondary winding 112 to a level below the upper threshold Vu but above the lower threshold VL. In this state, no alarm output is produced. If, however, the plug 13 were inadvertently pulled out of the socket 60, this would cause a high impedance across the contacts P2 and EN and cause the oscillator 103 to stop functioning. The output of the secondary winding 112 would then drop below the lower threshold VL and cause the detector 113 to produce an alarm on line 100. This in turn would cause the alarm unit 101 to provide a warning signal indicative of disconnection, which causes a buzer and/or lamp in the unit to be energised. The signal on line 100 is also supplied to the generator 1 to interrupt supply of power to the hand-held electrode S.
In this arrangement, the monitor unit 6 would not be able to detect if the return electrode 11 became detached from the patient or if the cable 12 became detached from the electrode.
Pigure 3B shows a return electrode assembly 20 with a single plate electrode 21 coMected by a double-lead cable assembly 22 to a two-contact plug 23 of the same kind as that shown in Figure 3A. One of the leads 22' of the cable is coMected to the contact 24, which makes connection with the contacts P1 and P2 in the socket 60. The other lead 22" is connected to the tip contact 25, which makes coMection with the contact EN in the socket 60.
At the other end of the cable assembly æ, because the two leads 22' and 22" are connected to the same plate electrode 21, they are effectively short circuited.
In this arrangement, the contacts P2 and EN will be bridged by the circuit between the two leads 22' and 22" and the short-circuiting ofthe two leads at their coMection to the .... . . .
. ... , , . . -:
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~ i. . . . .. . ~ . ~ . .
211~973 electrode 21. The monitor unit 6 responds in a similar way to the assembly 10 but it will also be able to detect disconnection of the electrode 21 from the cable 22 because this will break the circuit between the two leads and hence between the contacts. This will cause a discoMection alarm to be produced on line 100.
Figure 3C shows an assembly 30 with a single plate return electrode 31 coMected by a triple-lead cable assembly 32 to a three-contact plug 33. The three contacts 34, 35 and 36 of the plug 33 make coMection with respective ones of the three leads 32', 32" and 32"' in the cable 32. The contacts 34,35 and 36 make connection with respective ones of the contacts Pl, P2 and EN in the socket 60 when the plug 33 is inserted. At the opposite end of the cable assembly 32 each of the three leads is coMected to the same plate, thereby effectively short- - -circuiting the leads at the patient end.
. - , , .
The monitor unit 6 will be able to respond to discoMection ofthe assembly 30 either at the apparatus or at the return plate electrode 31, in the same way as with the electrode assembly 20 shown in Figure 3B.
' ' Figure 3D shows an assembly 40 with a split-plate electrode 41 having two electrode regions 42 and 43 electrically isolated from one another. The electrode 41 is coMected by a double-lead cable assembly 44 to a three-contact plug 45. One ofthe leads 44' ofthe cable is coMected at one end to the contact 46, which makes coMection with contact P1 in the socket, and at the other end to one of the electrode regions 42. The other of the leads 44" is coMected at one end to both contacts 47 and 48, which make connection with the contacts P2 and EN in the socket 60~ At its other end, the lead 44" is coMected to the other of the electrode regions 43.
With this cable assembly 40, the contacts P2 and EN is bridged at the plug 45 so that no discoMect alarm be produced as long as the plug remains inserted in the socket 60. While the , - . :
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. ~ . .
-8- ~ 73 electrode 41 remains in good electrical contact with the skin ofthe patient there is a relatively low impedance between the two regions 42 and 43. This ensures that the primary winding 108 of the transformer 105 gives an appreciable loading to the transformer so that the output of the secondary winding 112 is maintained below the upper threshold value Vu If, however, the electrode 41 should become detached from the skin this would increase the impedance between the two electrode regions 42 and 43 and hence increase the impedance between the contacts P
and P2. Consequently, the loading of the transformer 105 would be reduced and the output on the secondary winding 112 would increase above the upper threshold Vu. This would cause the detector unit 113 to produce a signal on line 102 to indicate that the return electrode plate is not attached to the patient. It will be appreciated that, if the electrode 41 should become discoMected from the patient end of the cable 44, this would also lead to an increase in the impedance across the contacts P1 and P2 and hence give an alarm indicative of detachment of the plate from the skin.
Figure 3E shows an assembly 50 with a split-plate electrode 51, ofthe same kind as shown in Figure 3D, having two electrode regions 52 and 53 electrically isolated from one another. The electrode 51 is coMected by a triple-lead sable assembly 54 to a three-contact plug 55. One ofthe leads 54' ofthe cable 54 is coMected, at one end, to a contact 56 in the plug 55, which makes coMection with contact Pl in the socket 60. At its other end, the lead 54' makes coMection to one of the electrode regions 52. A second lead 54" in the cable is coMected, at one end, to a contact 57 in the plug, which makes coMection with contact P2 in the socket 60. At its other end, the second lead 54" is coMected to the other electrode region 53. The third lead 54"' is coMected, at one end, to a contact 58 in the plug 55, which makes coMection with the contact EN in the socket 60. At its other end, the third lead 54"' is coMected to the same electrode region 53 as the second lead 54".
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2119973 ~
With this return electrode assembly 50, the monitor unit 6 will operate in a similar way to that when used with the assembly 40. However, with the assembly 50, there is a difference in that, if the plate 51 should become disconnected from the cable 54 at the patient end connector, this would break the circuit between the contacts P2 and EN and thereby prevent operation of the oscillator 103. This would cause the output of the secondary winding 112 to drop below VL and hence cause the detector unit 113 to produce an alarm signal on line 100 indicative of the absence of a connection.
It can be seen, therefore, that the electrosurgery apparatus can be used safely with all five different forms of return electrode assembly.
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Back~round of the Invention This invention relates to electrosurgery monitors and apparatus.
Electrosurgery apparatus, such as diatherrny apparatus, employs high frequency R~
energy to produce a surgical cutting or coagulation effect, or a combination of these effects.
The energy is applied to the patient via a hand-held, patient electrode, which concentrates the energy in a small region so that the current density in that region is sufficiently high to produce the desired effect. Energy is returned to the electrosurgery unit via a large area, return electrode ~.
in the form of a ~exible plate attached to the body. The large area of contact of the return electrode with the patient's skin ensures that the electrosurgery energy at the underlying skin : .
surface has a much lower current density; in this way, no electrosurgery effect is produced at the return electrode.
A problem occurs with electrosurgery apparatus if the return electrode is not connected ~-to the apparatus, since there will be no return path via the apparatus; this can lead to RF energy : `
returr~ing to earth via an altemative route. There is also a problem if the retum electrode becomes loose, or if contact with the skin is reduced for some other reason, such as drying of the conductive gel used between the electrode and the skin; this can result in a more localized contact of the return plate with the skin. In both cases, a higher return current density may . :
result, which in turn can produce burning of the skin.
:
In order to reduce the risk of burn injury to the patient, it is common practice for the electrosurgery apparatus to include some form of monitor to detect incorrect connection of the return electrode to the apparatus and separation ofthe return electrode from the skin. Because - . ..... .
.. .. ; . .. . .
: , . .
.
., ::
~119973 of the different forms that return electrodes can take, it can be difflcult to provide a monitor that can be used safely with different return electrodes.
Brief Summary of the Invention It is an object of the present invention to provide an improved electrosurgery monitor and apparatus According to one aspect of the present invention there is provided an electrosurgery monitor assembly including a monitor unit, a large area return electrode, and a cable connected at one end to the electrode and at its other end to a coMector, the monitor unit including at least a first and second input connection adapted to make electrical connection with the connector, an oscillator having an input coupled with the two input connections such that the output of the oscillator is dependent on a connection being established between the two input connections, and detector means responsive to the output ofthe oscillator to provide an alarm signal in the event ofthe absence of a correct connection at the input e onnections.
The monitor unit preferably includes a transformer, the oscillator being coMected to provide an alternating input to a primary winding of the transformer when there is a low impedance between the two input connections, and the detector means being connected to a secondary winding of the transformer and providing the alarm signal when the signal in the secondary winding falls below a predetennined value. The monitor unit preferably includes a third input connection, the second and third connections being connected to a second primary winding ofthe transformer, the detector means being arranged also to produce an alarm signal in the event of an output on the oscillator being above an upper threshold value, and the connector being arranged to produce a low impedance across the second and thirdconnections so that the second primary winding produces a loading on the transformer that reduces the output on the secondary ~inding below the upper threshold value. The assembly may include a further oscillator and a further transformer, the first osciDator being powered by the further . - .... - - -..
. ~ , ., ,. ,:.,. - . .. ;, .
: -~ - . , , . ~ ~ .... , . : ..
.,, ~, .. .. ..
, .. . .. .. -~119973 oscillator via the transformer. The alarm signal may be arranged to interrupt supply of electrosurgery power to the patient. The input connections may be spaced along the length of a socket, the connector being a plug and the connector having contacts spaced along the length of the plug.
The return electrode may be a single-plate electrode, the cable being a single-lead cable, and the connector having two contacts connected to the single lead. Alternatively, the return electrode may be a single-plate electrode, the cable being a double-lead cable and the connector ~ ~:
having two contacts connected to respective ones of the leads in the cable connected together at the electrode. Alternatively, the return electrode may be a single-plate electrode, the cable being a triple-lead cable, and the connector having three contacts connected to respective ones of the leads in the cable and connected together at the electrode. Alternatively, the return electrode may be a split-plate electrode, the cable being a double-lead cable, the two leads in the cable being connected to respective parts of the split-plate electrode and the connector having a first contact connected to one lead and a second contact connected to the other lead.
According to another aspect of the invention there is provided electrosurgery apparatus including an electrosurgery generator, an astive electrode and a monitor assembly according to the above one aspect of the invention.
, ~ ' Electrosurgery apparatus induding a monitor according to the present invention, will - ~ `
now be described, by way of example, with reference to the accompanying drawings.
.
BriefDescription of the Drawings Figure 1 is a schematic diagram of the electrosurgery apparatus;
Figure 2 shows the monitor unit of the apparatus in .
,: , . : . ' , greater detail; and Figures 3A show different forms of return electrode and 3E assembly.
Detailed Description of the Preferred Embodiments - With reference first to Figure 1, the apparatus includes an electrosurgery generator 1 of conventional construction supplying high frequency RF electrosurgery energy to a transformer 2. One end of the secondary winding 3 of the transformer is coMected via a capacitor 4 to an active hand-held electrode 5. The other end of the secondary winding 3 is connected via a monitor unit 6 to a return electrode assembly 10, 20, 30, 40 or 50.
,'-: ~' With reference now also to Figures 2 and 3, the monitor un~t 6 is connected to three contacts Pl, P2 and EN (enable) in a socket 60 on the casing ofthe apparatus. The contacts are spaced apart from one another along the length ofthe socket in the manner shown in Figure ~ ~ -3~ The monitor unit 6 provides an alarm signal on line 100 to an alarTn unit 101 when the monitor unit detects that the return electrode is not connected. A second alarm signal is given on line 102 to the alann unit 101 when the monitor 6 detects that the return electrode is not correctly attached to the patient.
The monitor unit 6 includes a first osciUator 103, which normaUy provides an alternating output to a primary winding 104 of a transformer 105. The first oscillator 103 derives its operating power from a second oscillator 106 via an isolating transformer 107. This arrangement ensures isolation ofthe patient from mains power. The first oscillator 103 has a control input connected across the contacts P2 and EN of the socket 60 and only provides an output when P2 and EN are connected together by a low impedance.
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The contacts Pl and P2 in the socket 60 are connected to opposite ends of a second primary winding 108 of the transformer 105. The electrosurgery return current is taken on line 109, which is connected to the junction of a series connection of two capacitors 110 and 111 between the two contacts P 1 and P2. Line 109 is connected to the secondary winding 3 of the ~ :~
transformer 2.
The transfonner 105 has a secondary winding 112 connected to a detector unit 113.
The detector unit 113 responds to a signal in the secondary winding 112 below a first threshold VL by producing an alarm signal on line 100 to indicate that the return electrode assembly has not been connected. If the signal in the secondary winding 112 rises above a second, highlevel threshold Vu, the detector 113 produces an alarm signal on line 102 to indicate that the return electrode is not correctly attached to the patient.
If either the first oscillator 103 or the second oscillator 106 should fail, this would result in the absence of a signal on the primary winding 104 and hence cause the detector unit 113 to -produce an alarm output on line 100.
'- - - ' .
The return electrode assembly 10, 20, 30, 40 or S0 may take any one of the five different forms illustrated in Figures 3A to 3E.
Figure 3A shows an assembly lO with a single plate electrode 11 coMected by a coMector to one end of a single-lead cable 12. The other end of the cable is coMected to a male coupling or plug 13 having two contacts 14 and lS, both of which are coMected to the sarne lead 12' in the cable. The plug 13 makes coMection with the socket 60, the spacing of the contacts being such that contacts Pl and P2 both make coMection to the same contact 14 on the plug. The other contact EN makes coMection with a second contact 15 at the tip ofthe plug.
. ~- , ' :.
: . : -: ~ . .. . .
' .
. . . .
-6- ~'~19.973 In operation, it can be seen that contacts P2 and EN will be shorted at the plug 13 when this is inserted correctly in the socket 60, so that the oscillator 103 will operate and provide an output to the primary winding 104, which in turn produces an output on the secondary winding 112. The other primary winding 108 is effectively short circuited by the contact 14, which bridges the contacts Pl and P2 in the socket 60. The winding 108 thereby provides a loading on the transformer 105 reducing the output at the secondary winding 112 to a level below the upper threshold Vu but above the lower threshold VL. In this state, no alarm output is produced. If, however, the plug 13 were inadvertently pulled out of the socket 60, this would cause a high impedance across the contacts P2 and EN and cause the oscillator 103 to stop functioning. The output of the secondary winding 112 would then drop below the lower threshold VL and cause the detector 113 to produce an alarm on line 100. This in turn would cause the alarm unit 101 to provide a warning signal indicative of disconnection, which causes a buzer and/or lamp in the unit to be energised. The signal on line 100 is also supplied to the generator 1 to interrupt supply of power to the hand-held electrode S.
In this arrangement, the monitor unit 6 would not be able to detect if the return electrode 11 became detached from the patient or if the cable 12 became detached from the electrode.
Pigure 3B shows a return electrode assembly 20 with a single plate electrode 21 coMected by a double-lead cable assembly 22 to a two-contact plug 23 of the same kind as that shown in Figure 3A. One of the leads 22' of the cable is coMected to the contact 24, which makes connection with the contacts P1 and P2 in the socket 60. The other lead 22" is connected to the tip contact 25, which makes coMection with the contact EN in the socket 60.
At the other end of the cable assembly æ, because the two leads 22' and 22" are connected to the same plate electrode 21, they are effectively short circuited.
In this arrangement, the contacts P2 and EN will be bridged by the circuit between the two leads 22' and 22" and the short-circuiting ofthe two leads at their coMection to the .... . . .
. ... , , . . -:
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~ i. . . . .. . ~ . ~ . .
211~973 electrode 21. The monitor unit 6 responds in a similar way to the assembly 10 but it will also be able to detect disconnection of the electrode 21 from the cable 22 because this will break the circuit between the two leads and hence between the contacts. This will cause a discoMection alarm to be produced on line 100.
Figure 3C shows an assembly 30 with a single plate return electrode 31 coMected by a triple-lead cable assembly 32 to a three-contact plug 33. The three contacts 34, 35 and 36 of the plug 33 make coMection with respective ones of the three leads 32', 32" and 32"' in the cable 32. The contacts 34,35 and 36 make connection with respective ones of the contacts Pl, P2 and EN in the socket 60 when the plug 33 is inserted. At the opposite end of the cable assembly 32 each of the three leads is coMected to the same plate, thereby effectively short- - -circuiting the leads at the patient end.
. - , , .
The monitor unit 6 will be able to respond to discoMection ofthe assembly 30 either at the apparatus or at the return plate electrode 31, in the same way as with the electrode assembly 20 shown in Figure 3B.
' ' Figure 3D shows an assembly 40 with a split-plate electrode 41 having two electrode regions 42 and 43 electrically isolated from one another. The electrode 41 is coMected by a double-lead cable assembly 44 to a three-contact plug 45. One ofthe leads 44' ofthe cable is coMected at one end to the contact 46, which makes coMection with contact P1 in the socket, and at the other end to one of the electrode regions 42. The other of the leads 44" is coMected at one end to both contacts 47 and 48, which make connection with the contacts P2 and EN in the socket 60~ At its other end, the lead 44" is coMected to the other of the electrode regions 43.
With this cable assembly 40, the contacts P2 and EN is bridged at the plug 45 so that no discoMect alarm be produced as long as the plug remains inserted in the socket 60. While the , - . :
' - ' '' ' , ,;
. ~ . .
-8- ~ 73 electrode 41 remains in good electrical contact with the skin ofthe patient there is a relatively low impedance between the two regions 42 and 43. This ensures that the primary winding 108 of the transformer 105 gives an appreciable loading to the transformer so that the output of the secondary winding 112 is maintained below the upper threshold value Vu If, however, the electrode 41 should become detached from the skin this would increase the impedance between the two electrode regions 42 and 43 and hence increase the impedance between the contacts P
and P2. Consequently, the loading of the transformer 105 would be reduced and the output on the secondary winding 112 would increase above the upper threshold Vu. This would cause the detector unit 113 to produce a signal on line 102 to indicate that the return electrode plate is not attached to the patient. It will be appreciated that, if the electrode 41 should become discoMected from the patient end of the cable 44, this would also lead to an increase in the impedance across the contacts P1 and P2 and hence give an alarm indicative of detachment of the plate from the skin.
Figure 3E shows an assembly 50 with a split-plate electrode 51, ofthe same kind as shown in Figure 3D, having two electrode regions 52 and 53 electrically isolated from one another. The electrode 51 is coMected by a triple-lead sable assembly 54 to a three-contact plug 55. One ofthe leads 54' ofthe cable 54 is coMected, at one end, to a contact 56 in the plug 55, which makes coMection with contact Pl in the socket 60. At its other end, the lead 54' makes coMection to one of the electrode regions 52. A second lead 54" in the cable is coMected, at one end, to a contact 57 in the plug, which makes coMection with contact P2 in the socket 60. At its other end, the second lead 54" is coMected to the other electrode region 53. The third lead 54"' is coMected, at one end, to a contact 58 in the plug 55, which makes coMection with the contact EN in the socket 60. At its other end, the third lead 54"' is coMected to the same electrode region 53 as the second lead 54".
. ..
2119973 ~
With this return electrode assembly 50, the monitor unit 6 will operate in a similar way to that when used with the assembly 40. However, with the assembly 50, there is a difference in that, if the plate 51 should become disconnected from the cable 54 at the patient end connector, this would break the circuit between the contacts P2 and EN and thereby prevent operation of the oscillator 103. This would cause the output of the secondary winding 112 to drop below VL and hence cause the detector unit 113 to produce an alarm signal on line 100 indicative of the absence of a connection.
It can be seen, therefore, that the electrosurgery apparatus can be used safely with all five different forms of return electrode assembly.
:. ' . . ~
.- , :
' . .
.- ,. . :-. . - ,, , :
Claims (13)
1. An electrosurgery monitor assembly comprising: a monitor unit; a large area return electrode; a cable; and a connector, the cable being connected at one endto the electrode and at its other end to the connector, wherein the monitor unitincludes at least a first and second input connection for making electrical connection with the connector, a first oscillator, said oscillator having an input coupled with said two input connections such that the output of said oscillator is dependent on a connection being established between said two input connections, and detector means responsive to the output of said oscillator to provide an alarm signal in the event of the absence of a correct connection at said input connections.
2. An assembly according to Claim 1, wherein said monitor unit includes a transformer, means connecting the output of said oscillator to a primary windingof said transformer so as to provide an alternating input to said primary winding when there is a low impedance between said two input connections, and wherein said detector means is connected to a secondary winding of the transformer and provides the alarm signal when the signal in the secondary winding falls below apredetermined value.
3. An assembly according to Claim 2, wherein said monitor unit includes a third input connection and means connecting said second and third connections to a second primary winding of the transformer, wherein said detector means also produces an alarm signal if the output of said oscillator is above an upper threshold value, and wherein said connector provides a low impedance across said second and third connections so that the second primary winding produces a loading on the transformer that reduces the output on said secondary winding below the upper threshold value.
4. An assembly according to Claim 1, including a further oscillator and a further transformer, and wherein said first oscillator is powered by said further oscillator via said further transformer.
5. An assembly according to Claim 1, including means for interrupting supply of electrosurgery power to the patient in response to said alarm signal.
6. An assembly according to any one of the preceding claims, wherein the input connections are spaced along the length of a socket, wherein the connector is a plug, and wherein the connector has contacts spaced along the length of the plug.
7. An assembly according to Claim 1, wherein said return electrode is a single plate electrode, wherein said cable is a single-lead cable, and wherein said connector has two contacts connected to the single lead.
8. An assembly according to Claim 1, wherein said return electrode is a single plate electrode, wherein said cable is a double-lead cable, and wherein said connectorhas two contacts connected to respective ones of leads in the cable and connected together at said electrode.
9. An assembly according to Claim 1, wherein said return electrode is a single plate electrode, wherein said cable is a triple-lead cable, and wherein said connectorhas three contacts connected to respective ones of leads in the cable and connected together at said electrode.
10. An assembly according to Claim 1, wherein said return electrode is a split-plate electrode, wherein said cable is a double-lead cable, wherein two leads in the cable are connected to respective parts of said split-plate electrode, and wherein said connector has a first contact connected to one lead and a second contact connected to the other lead.
11. An assembly according to Claim 1, wherein said return electrode is a split-plate electrode, wherein said cable is a triple-lead cable, wherein two leads of said cable are connected to respective parts of said split-plate electrode and a third lead is connected to the same part of the electrode as one of the other leads, and wherein said connector has a first contact connected to one lead, a second contact connected to another lead and a third contact connected to the third lead.
12. An electrosurgery monitor assembly comprising:
a monitor unit;
a large area return electrode;
a cable; and a connector, said cable being connected at one end to the electrode and at its other end to the connector, wherein the monitor unit includes three input connection for making electrical connection with the connector;
a transformer, said transformer having first and second primary windings;
an oscillator, said oscillator having two inputs coupled respectively with a first and second of said input connections, and an output connected to the first primary winding, the oscillator producing an output to the primary winding only when there is a low impedance across the first and second input connections;
means connecting the second and third input connection across the second primary winding so that the second primary winding produces a loading on the transformer when the connector produces a low impedance across the second and third input connections;
a detector; and means connecting said detector across said second winding of the transformer, said detector producing an alarm signal if the signal on said secondary winding is below a lower limit or above an upper limit.
a monitor unit;
a large area return electrode;
a cable; and a connector, said cable being connected at one end to the electrode and at its other end to the connector, wherein the monitor unit includes three input connection for making electrical connection with the connector;
a transformer, said transformer having first and second primary windings;
an oscillator, said oscillator having two inputs coupled respectively with a first and second of said input connections, and an output connected to the first primary winding, the oscillator producing an output to the primary winding only when there is a low impedance across the first and second input connections;
means connecting the second and third input connection across the second primary winding so that the second primary winding produces a loading on the transformer when the connector produces a low impedance across the second and third input connections;
a detector; and means connecting said detector across said second winding of the transformer, said detector producing an alarm signal if the signal on said secondary winding is below a lower limit or above an upper limit.
13. Electrosurgery apparatus comprising:
an electrosurgery generator;
an active electrode;
means connecting said active electrode to said generator; and a monitor assembly comprising:
a monitor unit;
a large area return electrode;
a cable; and a connector, said cable being connected at one end to the electrode and at its other end to the connector, wherein the monitor unit includes three input connection for making electrical connection with the connector;
a transformer, said transformer having first and second primary windings;
an oscillator, said oscillator having two inputs coupled respectively with a first and second of said input connections, and an output connected to the first primary winding, the oscillator producing an output to the primary winding only when there is a low impedance across the first and second input connections;
means connecting the second and third input connection across the second primary winding so that the second primary winding produces a loading on the transformer when the connector produces a low impedance across the second and third input connections;
a detector; and means connecting said detector across said second winding of the transformer, said detector producing an alarm signal to said generator if the signal on said secondary winding is below a lower limit or above an upper limit.
an electrosurgery generator;
an active electrode;
means connecting said active electrode to said generator; and a monitor assembly comprising:
a monitor unit;
a large area return electrode;
a cable; and a connector, said cable being connected at one end to the electrode and at its other end to the connector, wherein the monitor unit includes three input connection for making electrical connection with the connector;
a transformer, said transformer having first and second primary windings;
an oscillator, said oscillator having two inputs coupled respectively with a first and second of said input connections, and an output connected to the first primary winding, the oscillator producing an output to the primary winding only when there is a low impedance across the first and second input connections;
means connecting the second and third input connection across the second primary winding so that the second primary winding produces a loading on the transformer when the connector produces a low impedance across the second and third input connections;
a detector; and means connecting said detector across said second winding of the transformer, said detector producing an alarm signal to said generator if the signal on said secondary winding is below a lower limit or above an upper limit.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9306637 | 1993-03-30 | ||
| GB939307766A GB9307766D0 (en) | 1993-04-15 | 1993-04-15 | Coating machines and methods |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2119973A1 true CA2119973A1 (en) | 1994-10-01 |
Family
ID=10733858
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA 2119973 Abandoned CA2119973A1 (en) | 1993-03-30 | 1994-03-25 | Electrosurgery monitor and apparatus |
Country Status (3)
| Country | Link |
|---|---|
| CA (1) | CA2119973A1 (en) |
| FR (1) | FR2703929A1 (en) |
| GB (2) | GB9307766D0 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1039450C (en) * | 1994-03-18 | 1998-08-05 | 于善杰 | Anti-corrossion metal tube and making method thereof |
| DE19902977C2 (en) * | 1999-01-26 | 2002-05-29 | Dbs Gmbh | Coating system for the internal coating of pipes and similar elongated hollow bodies |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB547821A (en) * | 1941-02-10 | 1942-09-14 | Angus George Co Ltd | Improvements in fire hose |
| GB1180651A (en) * | 1967-05-30 | 1970-02-11 | Smith Corp A O | Internal surface applicator for tubular members |
| CH571365A5 (en) * | 1974-07-22 | 1976-01-15 | Fischer Ag Georg |
-
1993
- 1993-04-15 GB GB939307766A patent/GB9307766D0/en active Pending
-
1994
- 1994-02-28 GB GB9403795A patent/GB2277137A/en not_active Withdrawn
- 1994-03-09 FR FR9402904A patent/FR2703929A1/en active Pending
- 1994-03-25 CA CA 2119973 patent/CA2119973A1/en not_active Abandoned
Also Published As
| Publication number | Publication date |
|---|---|
| FR2703929A1 (en) | 1994-10-21 |
| GB9403795D0 (en) | 1994-04-20 |
| GB9307766D0 (en) | 1993-06-02 |
| GB2277137A (en) | 1994-10-19 |
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