Professional Sphygmomanometers

It is likely that the air valve on your cuff is jammed. There are two issues that may contribute to this problem; either the valve has become clogged with dust or debris, or an internal component called the ‘slit stopper’ has become bound from an extended lack of use. In order to correct this problem, first examine the air valve closely and check for dust or debris that may be clogging it and preventing air from passing through. You will need to remove the air valve from the bulb and valve assembly to conduct this examination. Be sure to clear out any obvious obstructions to the air flow.

Although unlikely to occur with an ADC DIAGNOSTIX mercury sphyg, it can happen. ADC mercury sphygs hold just 2 oz of 99.9999% pure elemental mercury and can easily be contained with a mercury spill kit available through ADC or most laboratory and safety supply dealers. A mercury spill kit should be kept on the premises WHEREVER mercury instruments are used. Never use vacuums which may disperse mercury vapor. Always wear gloves and dispose of contained mercury in accordance with local regulations.

This condition will generally only occur on older latex style blood pressure devices. The phenomenon, known as frosting, is a chemical reaction caused by the exposure of latex to the ozone. Fluorescent lighting can exacerbate the problem. When properly cured during the manufacturing process latex should not frost. However, it can be difficult to determine optimal curing times which are dependent on ambient temperature, humidity, and the water content of the liquid latex.

Although properly designed mercurial instruments are required to provide a full pressure drop (300 mmHg to 20 mmHg with no back pressure) in 3 seconds, older instruments tend to slow down due to build up of dust or other obstructions within the system. This slow down will produce a lag - the air will release from the cuff FASTER than the mercury can drop in the column. In addition, some manufacturers whose cartridge tubes have a narrow inside bore (generally less than the mandated 3.9 mm dimension) will always suffer from some lag.

The only way to be 100% sure is to connect the manometer in series to an instrument of known accuracy and test during deflation at a variety of pressures (i.e. 300, 260, 180, 120, 60, etc.) When testing your sphygmomanometer, it is important that you check the accuracy in accordance with national or international standards that may be applicable to your device.

Yes and no. Some mercury compounds - mercury chemically bonded to other elements can be quite toxic. On the other hand, 99.9999% pure elemental liquid mercury will not be absorbed within the system. In fact, if accidentally ingested it will pass. However, prolonged exposure to elemental mercury vapor is very dangerous. ADC mercury blood pressure instruments contain less than 2 oz of elemental mercury and pose no measurable health risk.

If new, the unit must be within 3mmHg when tested against a reference instrument in order to meet ANSI/AAMI/ISO 81060 standards. ADC's PROSPHYG series instruments will always meet or exceed these standards. ADC's DIAGNOSTIX series manometers exceed these standards by as much as 66%. ADC DIAGNOSTIX brand mercury manometers are guaranteed to be within 1mmHg over their full range, while the DIAGNOSTIX brand aneroid manometers are guaranteed within 2mmHg when NEW.

It is critical. When the inside bore is too narrow two problems can result; mercury lag and mercury separation. Mercury lag is the phenomenon that occurs when the air deflates from the cuff faster than the mercury column can respond. When the forces of friction (of the mercury against the inner walls of the cartridge tube) that prevent the mercury from dropping exceed the gravitational forces, this causes the mercury to drop and results in mercury lag. That same friction can actually cause the column of liquid mercury to split - forcing an air pocket that will distort readings.

The AHA recommends a deflation rate of 2 - 3mmHg per second. During routine measurement, the system is typically inflated to about 180mmHg and deflated to about 60mmHg.  That’s a range of about 120mmHg (the actual range is determined by the patient's expected blood pressure). At a deflation rate of 2-3mmHg/sec, it should take 40 to 60 seconds to deflate the cuff correctly. Excessive deflation rates are one of the most common causes of measurement error - often distorting readings by 10mmHg to as much as 20mmHg.