Cleveland Family Study

9.3 Detailed Methods

9.3.1 Determination of the Maximal Inflation Level (MIL)

Determine the pressure to which to inflate the cuff for the measurement of the systolic blood pressure. Determine the MIL independently of the MIL found at seated BP measurement. (The Doppler is more sensitive, so these values may differ.) This assures that the cuff pressure at the start of the reading exceeds the systolic blood pressure and allows you to hear the first Korotkoff sound. Again, the examiner should be at eye level with the manometer. The maximal inflation level should be measured specifically for the ankle-arm index measurement, using the Doppler, independently from its measurement for the regular blood pressure measurement. The procedures for determining maximal inflation level are as follows:

1. Attach the cuff tubing on the arm to the conventional mercury sphygmomanometer.
2. Locate the brachial pulse with the Doppler.
3. Inflate the cuff until the brachial pulse is no longer heard—this is the Doppler systolic pressure.
4. Deflate the cuff quickly and completely.
5. Inflate the cuff to 30 mm Hg above the Doppler systolic pressure for all subsequent readings—this is the maximal inflation level (MIL).
6. Repeat procedure for both arms.

• Repeat the maximal inflation level if the first attempt was unsatisfactory or you have had to readjust the cuff after measuring the maximal inflation level. Wait 30 seconds before making a second attempt if the first is unsatisfactory.
• If the brachial pulse is still heard at a level of 270 mm Hg or higher (which means that the maximal inflation level is 300 mm Hg or higher), repeat the maximal inflation level. If the maximal inflation level is still 300 mm Hg, terminate the blood pressure measurements and write in “300” in the place for MIL on the Physical Measurements (PM) form. Indicate the Doppler systolic blood pressure at the level actually heard.