The Importance Of Blood Pressure Measurement
How is blood pressure measured?
What is blood pressure?
How can I tell if I have high blood pressure?
What is hypertension?
What is low blood pressure?
What kinds of manometers are available?
What is elemental mercury?
What about the issue of elemental mercury causing toxicity?
Is there a simple way to recycle elemental mercury?
Material Safety Data Sheet (MSDS)
MSDS - Clarification of Mercury Vaporization Rates
Why should I use a mercury-gravity sphygmomanometer?
How do you prove the accuracy of a mercury-gravity sphygmomanometer?
The Mercury in Baumanometer® Instruments.
How can you be sure Baumanometer® Clinical Sphygmomanometers are safe?
Testing Instrument Accuracy
Question: What is elemental mercury?
Mercury is a natural element found in the earth's crust. Historians as far back as Pliny the Elder have noted its existence. It is introduced into the environment naturally through geological occurrences such as volcanic activity or erosion. W. A. Baum Company uses triple-distilled, American Dental Association Grade, elemental mercury in the manufacture of its blood pressure instruments. Some of its unusual characteristics are:
• It is non-wetting liquid.
• It has tremendous surface tension, which allows a drop or bead to remain almost round, like a ball bearing.
• It is thirteen times heavier than water.
• Triple-distilled mercury is 99.999% pure and can easily be cleaned, distilled and recycled.
• It has a very low vapor pressure - it does not vaporize rapidly or readily at room temperature.
• It is listed as a corrosive; however, it is not corrosive to hard metals, linoleum, wood, fabric, ceramic tile, etc. It is corrosive to soft metals such as copper, tin, gold, silver and aluminum.
• It has a rather low freezing point (-38.0° F) and a rather high boiling point (674° F).
Effective substitutes for this unique element are currently unavailable.
Question: What about the issue of elemental mercury causing toxicity?
According to Clarence E. Grim, Garcia J. Fong RJ, C.R. Drew University of Medicine and Science, Los Angeles, CA, ASH Abstracts, AJH, April 1994, "We have reviewed the world's literature on Hg toxicity and could not find a single instance in which anyone has been harmed by the Hg from a manometer used in a health care setting...the actual risks of toxicity from the Hg and the Hg manometer seemed to be dwarfed by the consequences of the widespread use of inaccurate aneroid devices."
According to Consumer Reports, May 1991, "The Mercury in Your Mouth." There's no evidence that even potentially vulnerable populations, such as pregnant women and young children, are at any risk from amalgams...Given low doses, the human body can rid itself of toxic agents such as mercury or render them harmless."
Question: Why should I use a mercury-gravity sphygmomanometer?
According to the sixth report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure - known as "JNC6", "Measurements should be taken preferably with a mercury sphygmomanometer. Hypertension detection begins with proper blood pressure measurements which should be obtained at each health care encounter...Blood pressures should be measured in a standardized fashion using equipment that meets certification criteria...The mercury sphygmomanometer is still the most accurate device for clinical use."
Question: How do you prove the accuracy of a mercury-gravity sphygmomanometer?
The mercury-gravity sphygmomanometer is accurate and should be used as the pressure standard if: The mercury meniscus is at zero with no pressure applied to the instrument. The instrument is in a vertical position. The instrument responds promptly to pressure changes.
Any two Baumanometer® instruments, regardless of age, will provide accurate, linear pressure readings at every pressure level if they meet the stated criteria for a correctly functioning manometer.
Aneroid and electronic devices must be compared to a mercury-gravity standard and need to be checked for accuracy over the entire range of pressure. Adjustments and repair of the devices can be complex and costly.
Question: How can you be sure Baumanometer® Clinical Sphygmomanometers are safe?
All Baumanometer® instruments have reservoirs with specially designed, stainless steel "snorkel" nozzles that extend to the reservoir's center. The crimped nozzle forms a narrow, slit-shaped access to apply and release the air pressure in the cuff. It is covered with a stainless steel clip, which prevents the escape of mercury from the reservoir nipple. According to John Baum, President of W.A. Baum Co., "Baumanometer® clinical sphygmomanometers have been accepted as the gold standard of accuracy in blood pressure measurement. But it is sometimes overlooked that accuracy also means safety when it comes to patients' health. You can't get a more reliable or safer blood pressure reading than with a Baumanometer® mercury-gravity instrument."