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Accuracy of Mercury Free Devices
in Health CareAsia Regional Conference
on
Mercury-Free Health Care
Manila, PhilippinesMarch 15, 2011
Prof. Peter Orris, MD, MPH, FACP, FACOEMChief, Ocupational & Environmental Medicine
University of Illinois at Chicago Medical Center
Great Lakes Centers For Environmental & Occupational Safety and HealthWorld Health Organization Collaborating Center
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MERCURY
Why Are We Concerned ?
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Chemical Forms of
MercuryElemental – Liquid metal
Inorganic salts – Mercuric chloride
Organic – Methyl, ethyl, dimethyl – Phenyl organic groups
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Acute Health Effects of Elemental Mercury
Acute exposure to high levels of elementalHg – tremors, slowed motor nerve functions, memory
loss
Acute inhalation of high amounts of elemental Hg – chest pains, acute renal failure, shortness of
breath
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Mercury in the Environment
Mercury cycle – Emitted from human activities& natural sources
– Circulates in the atmospherefrom 6 months to 1½ years
– Deposited back into land or bodies of water
– Converted into insoluble forms, settling into sediment
– Converted by bacteria into methyl mercury and entersthe food chain Source: New York State Department of Environmental Conservation
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Chronic Exposure to High Levelsof Methyl Mercury
Minamata disease : 2,265 cases confirmed inMinamata, Japan as of March 2001
Effects: – Constriction of visual fields – Irregular gait
– Loss of muscular coordination – Loss of speech, hearing, andtaste
– Emotional disturbance – “Livin wooden dolls”
Photo: William Eugene Smith
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Minimata 2011
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Mercury: Effects of Low Dose Prenatal Exposure
Grandjean, et. al., Neurotoxicology & Teratology, 19:6, 1997
P e r c e n t o f c h i l d r e n w i t
h l o w t e s t
s c o r e s a t a g e
7 y e a r s
40
30
20
10
0
MOTORATTENTION
VISUOSPATIAL
LANGUAGE
MEMORY
> 50 g/l
30-50 g/l15-300 g/l< 15 g/l
Children with low prenatal
mercuryexposure < 15 >50 30-50 15-30
Children with highprenatalmercury
exposure
% F a r o
e I s l a n d C h i l d r e n w
i t h
l o w e s t s c o r e s a t a g e
7 y e a r s
µg/l
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The Significance of Small Effects:EFFECTS OF A SMALL SHIFTIN IQ DISTRIBUTION IN A
POPULATION OF 300 MILLION
160 140 120 100 80 60 40
70 130 I.Q.
mean 100
7.0 million
"gifted"
7.0 million
"mentally disabled"
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5 Point Decrease in Mean IQ
160 140 120 100 80 60 40
Mean 95
70 130
4 million
" gifted " 11 million " mentally disabled”
57% INCREASE IN
"Mentally Disabled” Population
I.Q.
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$1.3 billioneach year is attributable
tomercury emissions from
U.S. power plants.
Leonardo Trasande, Philip J. Landrigan, and Clyde SchechterMount Sinai School of Medicine, New York, New York, USA
Environ Health Perspect 113:590 –596 (2005).
Public Health and EconomicConsequences of Methyl Mercury Toxicityto the Developing Brain
Photo: Illinois State Geological Survey
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Sources of mercury in health care
ThermometersSphygmomanometersDental amalgamGastrointestinal tubesLaboratory chemicals
Pharmaceutical productsElectrical applicationsMedical waste incineration, open burning,
burning in barrels, gasification, pyrolysis, etc.
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WHO/OMSFever Thermometers
Use: Fever thermometers measure human body temperature including oral,rectal, or auxiliary (armpit).
Mercury content: Content ranges from 0.5 to 3 grams.
Alternatives: Mercury-free alternatives include digital, alcohol, and glassgallium-indium-tin thermometers. Other alternatives include ear canalthermometers and flexible forehead thermometers. These alternatives can beas accurate as mercury thermometers, and are easier to read.
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Mercury Use Per Capita(grams mercury per person per year)
Russia (0.180) and China (0.152):highest level per capita in grams of mercury per person per year
– In 2005, 200.9 tons of mercury was consumed by medical thermometermanufacturers in China. 40.3% was exported.
– In 2002, 25.579 metric tons of mercury was consumed by the one medicalthermometer manufacturer in Russia .
Chile, Romania, and Belarus reported between 0.074 to 0.086 grams.
Lowell University Center Report for UNEP, 2009
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Mercury Thermometers
Breakage
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Thermometer Breakage An example glass thermometer containing 1 gram of mercury
A broken thermometer will release mercury which will evaporate
and to a concentration of 22.2 mg/m3 in the air measured ina in a 15 square meter, three meter high room.
China's provision of mercury maximum allowable concentration inindoor air is 0.01 mg/m3 and in US workplaces the PEL is 0.1
mg/M3 & STEL is 0.03 mg/M3 .Xueyu Li , Global village of Beijing: 12-20-2007
Young Children have been poisoned after less than 2weeks exposure to mercury vapor from a bedroom carpet after asingle thermometer broke.
Poisindex, 2010
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WHO/OMSFever Thermometers
Use: Fever thermometers measure human body temperature including oral,rectal, or auxiliary (armpit).
Mercury content: Content ranges from 0.5 to 3 grams.
Alternatives: Mercury-free alternatives include digital, alcohol, and glassgallium-indium-tin thermometers. Other alternatives include ear canalthermometers and flexible forehead thermometers. These alternatives can beas accurate as mercury thermometers, and are easier to read.
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Mercury Free Thermometers
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Accuracy IssuesLowell Center for Sustainable Production
University of Lowell Massachusetts
http://www.sustainablehospitals.org/cgi-bin/DB_Report.cgi?px=W&rpt=Cat&id=15
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STUDY OF NON MERCURY
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STUDY OF NON-MERCURY ALTERNATIVES AS AN ENVIRONMENTAL
ATTRIBUTE
Detailed Study of Non-Mercury Alternatives 8 U.S. Army Corps of Engineers, Baltimore District as an Environmental Attribute HQ Defense Logistics Agency January 2005
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Cost Issues
Hospital São Luiz in São Paulo, Brazil – A 116 bed hospital found that if they were to replace all
sphygmomanometers, wall thermometers and clinical
thermometers in the hospital with alternative devices, that thesavings on maintenance and calibration would pay back theinitial capital investment of more than U.S. $9,000 in five years,while saving another U.S. $2,000 a year after that.
In India, Toxics Link
– “a study in four hospitals has shown that the recurring cost withmercury instruments far exceeds this cost difference [with non-mercury instruments] in addition to the extra environmental andoccupational hazard cost.”
Toward The Tipping Point | WHO-HCWH Global Initiative to Substitute Mercury-Based Medical Devices in Health Care A Two-Year Progress Report Published by the World Health Organization and Health Care Without Harm (Discussion Draft ) - 2010
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Mercury Free Thermometers
Reducing Mercury in Health Care Setting: A case study of Four Hospitals in Delhi, India, Toxics Link 2009
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WHO/OMSSphygmomanometers
Use: Sphygmomanometers are manometers used to measure human bloodpressure.
Mercury content: Content can vary from 20 to 60 grams of mercury.
Alternatives: Alternatives to mercurial sphygmomanometers are aneroid anddigital products. Both are reliable, accepted as standard, and comparable tomercurial sphygmomanometers
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The largest amount of mercury is used inmercury sphygmomanometers (80 to100g/unit)
The largest mercury reservoir in the health-care setting.
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Accuracy of ReplacementsWhy I Am Concerned
Cook County Hospital:
Internal Medicine Residency: 1975 – 1978 Attending Physician Internal Medicine: 1979 – Emergency Room: 1979 – 1980Inpatient Internal Medicine: 1975 - 2009Outpatient Internal Medicine: 1975 -
President of the Medical Staff: 2001-2005
Professor of Internal MedicineFellow American College of PhysiciansOfficer County and State Medical Societies Hypertension
Cook County Hospital has alwaysbeen open to all patients,generally poor or destitute,and…immigrants arrived in the city .
Raffensperger, John G., and Louis G. Boshes, eds. The Old Lady on Harrison Street: Cook County Hospital, 1833 – 1995. International Healthcare Ethics, vol. 3. 1997.
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h
Recommendations for Blood Pressure
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Recommendations for Blood PressureMeasurement in Humans American Heart Association Council on
High Blood Pressure Research
It is surprising that nearly 100 years after it was firstdiscovered, and the subsequent recognition of its limitedaccuracy, the Korotkoff technique for measuring blood
pressure has continued to be used without anysubstantial improvement.
Circulation. 2005;111:697-716
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Gold Standard?
mm Hg = mm HgBP measurement with Hg = Accurate BP
??
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Recommendations for Blood Pressure Measurement inHumans
American Heart Association Council onHigh Blood Pressure Research
The gold standard for clinical blood pressure measurement has alwaysbeen readings taken by a trained health care provider using a mercurysphygmomanometer and the Korotkoff sound technique, but there isincreasing evidence that this procedure may lead to themisclassification of large numbers of individuals ashypertensive and also to a failure to diagnose blood pressurethat may be normal in the clinic setting but elevated at othertimes in some individuals.
Circulation. 2005;111:697-716Scipione Riva-Rocci. 1863 – 1937
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“THE GOLD STANDARD”
A survey of blood pressure devices used in a largeteaching hospital in London in 2000 (n=469 devices)
– 10% - the markings were difficult to read – 18% - either an obscured mercury column or faded markings, – 3 - were leaking mercury. – 8% - had “worn out”, damaged, or split cuffs – 35% - velcro cuffs did not stick well enough to resist bursting
apart on inflation above 180 mmHg – 7 - cuffs contained the wrong size bladder for the size of
the cuff.
Markandu et al, 2000
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“THE GOLD STANDARD” Electronic pressure gauges are more accurate andbetter for Y Tube calibration:
Mercury sphygmomanometers 3 mm Hg variationElectronic pressure devices
0·005 mmHg variation
– Coleman AJ, 2005
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Non Device Factors inBP Measurement Inaccuracy
The Health Care Provider
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End-digit preference in general practice:a comparison of the conventional auscultatory and electronic
oscillometric methods.
Very marked digit preferences were observed for both the
conventional and the automatic measurements, being mostprominent for the digit "0" (52% and 25%, respectively) followedby a preference for the digit "5" (19% and 15%).
Burnier M, Gasser UE.Service de Nephrologie et Consultation d'Hypertension, CHUV, Lausanne et Universitede Lausanne, and ClinResearch Ltd, Aesch, Switzerland.
Blood Press. 2008;17(2):104-9.
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Non Device Factors inBP Measurement Inaccuracy
The Patient
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Automated blood pressure measurement in routineclinical Practice
Martin G. MyersUniversity of Toronto, Toronto,
Ontario, Canada
Results:The mean initial automated reading (mmHg)taken with the observer present (162 ± 27/85± 12)was similar to the mean manual bloodpressure taken in duplicate (163± 23/86+ 12).
Both values were higher (P< 0.001) than themean of the next five readings taken with theautomated recorder when the patient was resting
quietly alone (142± 21/80± 12).
Women exhibited a greater fall in blood pressure
Blood Pressure Monitoring 2006, 11:59 – 62
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Clinical Experience
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The experiences of using mercury free blood pressureequipment
in the Swedish health care sector. by Kemi & Miljö AB for the Swedish Chemicals Inspectorate.
1992
Since 1992 thermometers and other measuring instrumentscontaining mercury may not be commerciallymanufactured or sold in Sweden.
All heads of department of clinical physiology in Swedishhospitals were contacted and asked to report theirexperiences from the phase out of mercury in bloodpressure equipment .
There are no problems in diagnosingany condition
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Studies
Accuracy of aneroid sphygmomanometer blood
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Accuracy of aneroid sphygmomanometer bloodpressure recording compared
with digital and mercury measurements inBrazil
Gill G, Ala L, Gurgel R, Cuevas L.Liverpool School of Tropical Medicine, UK.
Digital, mercury and aneroid blood pressuremeasurements were carried out in 400 South
American adults.There was slight under-reading of the aneroidinstrument (hypertension prevalence 30%, comparedwith 32% for digital and mercury)
Its robustness and simplicity makes it asuitable alternative to mercury machines intropical field conditions.
Trop Doct. 2004 Jan;34(1):26-7
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Accuracy of the pressure scale of
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Accuracy of the pressure scale of sphygmomanometers in clinical use within
primary care Andrew J. Coleman, Stephen D. Steel, Mark Ashworth,
Sarah L. Vowler and Andrew Shennan
45 general practices within Lambeth, Southwark and Lewisham.
A total of 279 sphygmomanometers.Calibrated using an accurate electronic referencepressure sensor.
Blood Pressure Monitoring 2005, 10:181 – 188
Accuracy of the pressure scale of
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y psphygmomanometers in clinical use within
primary care Andrew J. Coleman, Stephen D. Steel, Mark Ashworth,
Sarah L. Vowler and Andrew Shennan
RESULTS:17.9% of all surveyed devices gave errors exceedingthe +/-3 mmHg threshold.
53.2% of aneroid devices were found to be reading inerror by more than +/-3 mmHg compared with
7.8% of the combined population of mercury andautomated devices.
Significant differences in the performance of specificmodels of aneroid, mercury and automated deviceswere also identified.
Blood Pressure Monitoring 2005, 10:181 – 188
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Automated non-invasive blood pressuredevices: are they suitable for use?
Andrew J. Sims, Julian A. Menes, Derek R. Bousfield, Christopher A.
Reay and Alan Murray
Results: – 86 companies were found to be actively involved in the supply of
158 different models of automated non-invasive blood pressuredevice.
– 54 devices for use on the arm and 62 for use on the wrist – We received responses for 61% of the main category arm and wrist
devices and 80% of these provided claims for CE marking.
– Inconsistencies were found between claims for diagnostic suitabilityand claims for clinical validation.
Conclusions: – A majority of models available on the European
Union market were not validated by clinical trial toone of the recognized protocols
Blood Pressure Monitoring 2005, 10:275 – 281
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Criteria for Validating Devices
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BMJ 2001, 322:531-536
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In DevelopmentComing Soon
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Both mercury and aneroid sphygmomanometershave been in use for about 100 years, and when
working properly, either gives accurate results.
Aneroid sphygmomanometers provide accuratepressure measurements when a proper
maintenance protocol is followed.
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Both Aneroid And Mercury Sphygmomanometers
Must Be Checked RegularlyTo Avoid Errors.
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SUMMARY Clinical Use of Non – Hg Sphygmomanometers
Gold Standard ≠ Accurate BP Greatest Inaccuracies = Measurer
TechniquesHearingPosition of Cuff Size of Cuff Digit Preference
Greatest Variability = PatientPosition of Patient
Stress EffectTime of DayProduct Accuracy = Manufacturer
When Maintained and Calibrated Properly Nearly AllInter- Device Variability ≤ 4mm Hg
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SUMMARY Clinical Use of Non – Hg Sphygmomanometers
Conclusion:
• Aneroid sphygmomanometers are safe and
accurate substitutes for hg devices inclinical practice.• The oscillometric method is perhaps the best
device for office measurement
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Slides Developed FromMaterials of
WHO, HCWH, UNEPColleagues at University of IllinoisPostings on the Internet
Thanks to all these colleagues who permitted their slides and mat
edited by me for presentationAnd for support from the:The United Nations Development ProgrammeGlobal Environment Facility Global Project on Healthcare Waste
ACKNOWLEGEMENTS