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