Transcript Training

High voltage testing of
laparoscopic
accessories
Bruce Morrison
Hunter Area Health Service
John Hunter Hospital
Newcastle, NSW
Outline

Particular Issues arising with laparoscopic
instruments

Background to the NSW DOH guidelines
on testing laparoscopic instruments

Development of the guideline

Application of the guideline

Where to next ?
Minimally invasive surgery
- introduced in early 60’s
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Advantages
–
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less blood loss
low complication rate
minimal post op pain and discomfort
early discharge
reduced recovery time due to minimal tissue damage
Disadvantages
– can be more expensive
– electrosurgical burns can be a complication
– Surgeons take longer to master the technique
The ESU
Provides cut and coagulation power
 Should be functional and appropriately
adjusted

– Output power and waveform should be in
accord with manufacturers’ specifications
Return electrode should be appropriately
connected to the patient
 Lead integrity to the instruments in essential

The laparoscope
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Types of instruments
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–
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Forceps
Hooks
Scissors
Monopolar and bipolar
Leads
– single
– double
Parts of the instrument

Parts which make contact with the patient
– conductive parts
– non-conductive parts

Parts which do not make contact with the
patient
– handles
– terminations
Laparoscopic Instruments
A selection filmed
(somewhat poorly) in the CSSD
at John Hunter Hospital
- after cleaning and washing and
prior to testing before
packaging and sterilising
Risks to the patient

Burns
– operator induced
– insulation breakdown
direct
 capacitive coupled
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Limited field of view
– large sections of the leads and instruments are
not in the surgeon’s field of view (90%)
Background to the NSW
guideline
Patient incident - electrosurgical burns?
 Reference to the NSW Healthcare
Complaints Commission
 NSW HCCC asks BEAG (NSW) for advice
 BEAG gives preliminary advice

– preliminary advice published as 97/20
– considered advice published as 98/17
Development of the guideline
Preliminary discussions lead to publication of
Information Bulletin 97/20
 Bulletin widely distributed

– reference to further work by BEAG
– hospitals begin to expect testing will be done
NPCE working party develops a document
aimed at providing good guidance for testing
 Revision 2 sent to DOH and becomes
Information Bulletin 98/17

Application of the guideline

Guideline recommended testing by BME
– Original high voltage testers “dangerous”
– BME had done what testing was previously done
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Problems with tagging and tracking
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How often should instruments and leads be
tested
Older style high voltage tester
A newer “safe” HV tester
Testing in the CSSD

Newer “safe” testers allow testing in the CSSD
– OK for use by CSSD?
– Training
– Industrial issues

Why test in CSSD?
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no problems with tagging
no requirement to track instruments and leads
nothing is missed
safe instrument is presented to the patient every time
Where to now?
Development of Ver 3 of the guideline
 Publication by NSW DOH
 Version 3 contains …

– information on “safe” testers
– recommendations for testing in CSSD
– voltages and currents for testing

Version 3d is almost ready to go!
Need to assure the insulation integrity
of the non-conductive parts
which make contact with the patient
Visual inspection is not adequate
High voltage testing is required to
detect insulation breakdown
Testing laparoscopic
instruments
Practical experience from NSW
Testing statistics
Test jigs & all that jazz . . .
Testing protocols

From the NSW Guideline
– 3.0 kV rms 50Hz or 4.2 kV dc
– 0.5 mA current limit
– Compromise between
safety
 voltages found in laparoscopic surgery
 recommendations in AS-3894.1 1991
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Why 3 kV rms?
All reinsulated instruments can withstand
this test voltage.
 Newly manufactured or reinsulated
instruments typically withstand voltages
greater than 8kV rms.
 3kV is probably a higher voltage than
needed, but leaves some margin for
deterioration of insulating properties during
the use of the instrument.
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Who is testing?
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BME departments
– in almost all Area Health Services
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Outside contractors
– very few
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CSSD staff
– Hunter Area Health Service
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Politics of testing
– use of the guideline for industrial purposes
How often are they testing?
Every use - HAHS
 Monthly - many city hospitals
 Quarterly - some city and many country
hospitals
 Never - one city Area Health Service
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Mostly in theatre
– all in one sweep
Equipment?
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All respondents using the Hi-Pot 140 high
voltage tester
– 4 kV dc
– Very high output impedance
– Audible and visual breakdown indicators

Very few using test jigs
Test methods
Some more less than perfect
home snaps in the CSSD at
John Hunter Hospital
Testing results
Hunter Area Health Service
Western & South-Western Sydney
Area Health Services
INSTRUMENTS TESTED AND NUMBER FAILING AT JOHN HUNTER HOSPITAL
120
80
Number of Instruments Tested
60
Number of failures
40
20
Month of the Year 1998-99
Au
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o
No ber
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m
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0
Ju
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No ber
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Ja
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Fe ry
br
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M
ar
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Number of Instruments
100
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Month
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Fe
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Au
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Ju
ly
% Failed
CHART OF % OF INSTRUMENTS WHICH FAIL HIGH VOLTAGE TESTING AT JHH
12
10
8
6
% Failed
4
2
0
FAILURE RATES AT WSAHS AND SWSAHS HOSPITALS
45.0%
40.0%
35.0%
30.0%
Jan'99
25.0%
Apr'99
Jul'99
20.0%
Oct'99
Jan'00
15.0%
10.0%
5.0%
Hospital
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Failure Rate
Oct'98
Final thoughts on testing . . .

Manufacturers’ test methods
– 8 kV in saline bath
What parts of an instrument should we test?
 Should leads be tested?
 Packaging after testing - care required!
 What of Electroshield type devices?
 Who should test - BME or CSSD?
 The future of tracking?
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Questions and discussion