Cleveland Family Study

2.3 Arm Measurement

The proper cuff size must be used to avoid under- or over-estimating the correct BP. To determine the proper cuff size, the observer must measure the arm circumference at the midpoint of the arm. This measurement is taken on the left arm that has been bared from the shoulder. (If blood pressure is known to be different in the right vs. the left arm, use the arm with the higher pressure. In this circumstance, it must be assured that all BP readings are recorded on the same arm.)

After the initial determination of proper cuff size, this arm measurement does not need to be carried out at each measurement.

2.3.1 Procedure

1. With the participant in the supine position, holding the forearm horizontal, measure the arm length from the acromion (or bony extremity of the shoulder girdle) to the olecranon (or tip of the elbow), with a metric tape, allowing the tape to hang freely.
2. Mark the midpoint on the dorsal surface.
3. Have the participant relax the arm along the side of the body.
4. Measure the arm circumference by drawing the tape snugly around the arm at the level of the midpoint marking.

• Care must be taken to keep the tape horizontal.
• The tape should not indent the skin.

2.3.2 Table 1: Cuff Size Indicated by Measured Arm Circumference

The chart of arm circumference measurements and corresponding cuff sizes (below) is consulted, and the indicated cuff size is checked on the study form and used. (A copy of this chart should be attached to the sphygmomanometer for easy reference.) If the proper cuff size is wider than the length of the arm, use the next smaller cuff in order to get the most reliable readings. This chart should be consulted for each arm measurement. The markings found on most BP cuffs should not be used for reference, as they may be incorrect.

Bladder widths shown are at least 40% of the largest corresponding arm circumferences.