Choosing Mercury-Free Blood Pressure Monitors
Dr. Kazuomi Kario
Professor and Chairman, Division of Cardiovascular Medicine, Jichi Medical University, Japan
The Minamata Convention on Mercury requires mercury blood pressure monitors to be phased out in 2020. Because of this, recently we often hear phrases such as ‘Switching to Mercury-Free’ and ‘Collection and abolition of mercury blood pressure monitors’.
However, it seems many users in the medical field are unsure about which kind of mercury-free devices they are going to switch to. Today, I would like to help clarify the details about choosing mercury-free blood pressure monitors properly.
What are 'Mercury-free blood pressure monitors'?
After hearing ‘Mercury blood pressure monitors will be phased out’, some people think auscultatory (=Korotkoff sounds) blood pressure method will also be phased out, but this understanding is not right. After the Minamata Convention on Mercury becomes effective, the auscultatory method will remain the gold standard for blood pressure measurement.
Therefore, we can say the most needed device in the medical field is a reliable alternative mercury-free auscultatory blood pressure monitor to replace traditional mercury blood pressure monitors.
Recommended mercury-free blood pressure monitors
- Hybrid Sphygmomanometer (=blood pressure monitor) -
UM-102 (A&D Medical)
Recently, in hypertension societies and medical settings around the world, Hybrid Sphygmomanometers are being accepted as alternative devices to mercury blood pressure monitors.
A Hybrid Sphygmomanometer is a mercury blood pressure monitor with auscultatory measurement and a digital display that is similar in appearance to traditional mercury blood pressure monitors. The LCD column moves smoothly like a mercury column and measurements can be done in a similar way to mercury blood pressure monitors. Therefore, they are easy to use for those who already use mercury blood pressure monitors regularly.
You can mark specific values like systolic and diastolic blood pressure (you don’t have to memorize or write down the records) and see a pulse rate on the LCD display after measurement. These are original functions for Hybrid Sphygmomanometers and are not available on traditional mercury blood pressure monitors.
These devices are also suitable for use in educational institutions, such as medical schools and nursing schools.
- Dual Measurement Mode Blood Pressure Monitor -
Blood Pressure Monitor
UM-211 (A&D Medical)
Some of the latest devices provide dual measurement mode (auscultatory mode and oscillometric mode). This kind of device is especially suitable for users who use oscillometric blood pressure monitors regularly and sometimes measure by auscultatory method when it is necessary to reconfirm the data.
- Aneroid blood pressure monitors are not recommended -
'Are aneroid blood pressure monitors suitable as alternatives to mercury blood pressure monitors?' This is the most frequently asked question.
An aneroid blood pressure monitor is an auscultatory measurement device to use with a stethoscope which is relatively popular in the U.S. and European countries.
I don’t recommend the use of aneroid blood pressure monitors (as hypertension societies of various regions already expressed), because their mechanical construction easily produces errors of measurement due to external shocks and they can deteriorate over time. Moreover, there is a serious risk for users to continue using without finding errors, because it is not possible to find errors from its appearance.
Please look for 'Clinically Validated' devices
After you have found a mercury-free blood pressure monitor that suits your needs, one more key point you ought to check is if this device is clinically validated.
Clinical validation ensures the measurement accuracy of a blood pressure monitor has been tested in a clinical setting. The algorithm (calculation method of blood pressure) for oscillometric blood pressure monitors is different for each manufacturer and users have no way to evaluate the accuracy before purchase.
The procedure of clinical test is to compare the results between oscillometric blood pressure monitors and mercury blood pressure monitors. Therefore if the clinical test result is 'Pass', it can be said that measurement accuracy of the device is assured.
It is essential to know that a blood pressure monitor has been clinically validated beforehand so that you will not regret your purchase afterward.
George S. Stergiou, Periklis P. Giovas, Charilaos P. Gkinos and Dimitris G. Tzamouranis. Validation of the A&D UM-101 professional hybrid device for office blood pressure measurement according to the International Protocol. Blood Pressure Monitoring 2008; 13:37-42
Gregory K. Davis, Lynne M. Roberts, George J. Mangos and Mark A. Brown. Comparisons of auscultatory hybrid and automated sphygmomanometers with mercury sphygmomanometry in hypertensive and normotensive pregnant women: parallel validation studies. Journal of Hypertension 2015; 33:499-506