High voltage testing of laparoscopic accessories Bruce Morrison Hunter Area Health Service John...
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Transcript of High voltage testing of laparoscopic accessories Bruce Morrison Hunter Area Health Service John...
High voltage testing of High voltage testing of laparoscopic laparoscopic accessoriesaccessories
Bruce Morrison
Hunter Area Health Service
John Hunter Hospital
Newcastle, NSW
OutlineOutline
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 surgeryMinimally invasive surgery - - introduced in early 60’sintroduced in early 60’s
Advantages– 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 ESUThe 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 laparoscopeThe laparoscope Types of instruments
– Forceps– Hooks– Scissors– Monopolar and bipolar
Leads– single– double
Parts of the instrumentParts 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 InstrumentsLaparoscopic 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 patientRisks to the patient
Burns– operator induced– insulation breakdown
direct capacitive coupled
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 Background to the NSW guidelineguideline
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 guidelineDevelopment 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 guidelineApplication of the guideline
Guideline recommended testing by BME – Original high voltage testers “dangerous”
– BME had done what testing was previously done
Problems with tagging and tracking
How often should instruments and leads be
tested
Older style high voltage testerOlder style high voltage tester
A newer “safe” HV testerA newer “safe” HV tester
Testing in the CSSDTesting in the CSSD
Newer “safe” testers allow testing in the CSSD– OK for use by CSSD?– Training– Industrial issues
Why test in CSSD?– 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?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 Need to assure the insulation integrity of the non-conductive partsof the non-conductive partswhich make contact with the patient which make contact with the patient
Visual inspection is not adequateVisual inspection is not adequate
High voltage testing is required to High voltage testing is required to detect insulation breakdowndetect insulation breakdown
Need to assure the insulation integrity Need to assure the insulation integrity of the non-conductive partsof the non-conductive partswhich make contact with the patient which make contact with the patient
Visual inspection is not adequateVisual inspection is not adequate
High voltage testing is required to High voltage testing is required to detect insulation breakdowndetect insulation breakdown
Testing laparoscopic Testing laparoscopic instrumentsinstruments
Practical experience from NSW
Testing statistics
Test jigs & all that jazz . . .
Testing protocolsTesting 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
Why 3 kV rms?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.
Who is testing?Who is testing?
BME departments– in almost all Area Health Services
Outside contractors– very few
CSSD staff– Hunter Area Health Service
Politics of testing– use of the guideline for industrial purposes
How often are they testing?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
Mostly in theatre – all in one sweep
Equipment?Equipment?
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 methodsTest methods
Some more less than perfect
home snaps in the CSSD at
John Hunter Hospital
Testing resultsTesting results
Hunter Area Health Service
Western & South-Western Sydney
Area Health Services
INSTRUMENTS TESTED AND NUMBER FAILING AT JOHN HUNTER HOSPITAL
0
20
40
60
80
100
120
Month of the Year 1998-99
Nu
mb
er
of
Inst
rum
en
ts
Number of Instruments Tested
Number of failures
CHART OF % OF INSTRUMENTS WHICH FAIL HIGH VOLTAGE TESTING AT JHH
0
2
4
6
8
10
12
July
Augus
t
Septe
mbe
r
Oct
ober
Novem
ber
Decem
ber
Janu
ary
Febru
ary
March
April
MayJu
ne July
Augus
t
Septe
mbe
r
Oct
ober
Novem
ber
Month
% F
aile
d
% Failed
FAILURE RATES AT WSAHS AND SWSAHS HOSPITALS
0.0%
5.0%
10.0%
15.0%
20.0%
25.0%
30.0%
35.0%
40.0%
45.0%
Hospital
Fai
lure
Rat
e
Oct'98
Jan'99
Apr'99
Jul'99
Oct'99
Jan'00
Final thoughts on testing . . .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?
Questions and discussionQuestions and discussion