Cleveland Family Study

2.9 Checking Sphygmomanometer for Accuracy

Checking the sphygmomanometer used to record manual blood pressure readings is accomplished by checking them for accuracy against a mercurial sphygmomanometer. This checks the hand held sphygmomanometer against the mercurial unit for accuracy. If the unit is out of sync it should be returned for repair or a new one purchased. The new Parr units are marked with a Lifetime Certified stamp.

2.9.1 Procedure

1. Connect a two-way valve (found in the mercurial case) onto the Mercurial unit.
2. Apply the “Y” connector to that valve (This “Y” connector and straight hose is taken from the double-headed training stethoscope).
3. The straight piece of hosing is then connected to the “Y”.
4. The hose is connected to the hand held sphygmomanometer to be compared to the mercurial unit.
5. Take the calibration spirometer tube and wrap a standard adult blood pressure cuff around snuggly.
6. Attach the hose that once held a sphygmomanometer to the other end of the “Y” connector.
7. Turn on the mercurial sphygmomanometer switch to release the mercury.
8. By pumping up the blood pressure cuff, the hand held unit and mercury unit should both increase at the same rate. Take both units up to 230 mmHg then slowly release at a rate of 2mm per second while comparing the numbers. The reading should match on both units. It is possible to stop the airflow and again check both units for matching numbers.
9. Continue this all the way down to zero.
10. When done make sure you turn off the mercury switch at the bottom of the unit.
11. Record the serial number and date checked on the “Check Calibration of Sphygmomanometer Form" in the Procedures Manual.