Childhood Adenotonsillectomy Trial

3.2.6 Blood Pressure Readings

Next, the observer should proceed to carry out the first BP reading. The systolic value (1st phase Korotkoff) can be identified as the pressure level where the first of 2 or more sounds are heard in the appropriate rhythm. The diastolic value (5th phase Korotkoff) can be identified as the pressure level where the last of these rhythmic sounds is heard.

NOTE: A single sound heard in isolation (i.e., not in rhythmic sequence) before the first of the rhythmic sounds (systolic) or following the last of the rhythmic sounds (diastolic) does not meet criteria for the systolic or diastolic endpoints. If the sounds are heard all the way to 0 mm Hg, record the 4th phase DBP as follows:

The measurement should be recorded as Korotkoff 1 - Korotkoff 4 - Korotoff 5 (e.g., 122/60/0) on the source document for future reference. When this occurs you must record the resting blood pressure on the BP CRF as: SBP is defined as Kortokoff 1 (K1) and DBP as Korotoff 5 (K5).

The American Heart Association (1980) defines the K-sounds as follows: (American Heart Association. Recommendation for Human Blood Pressure Determination by Sphygmomanometer. Dallas, American Heart Association, 1980).

• Phase I: The point marked by the first appearance of faint, clear tapping sounds that gradually increase in intensity.
• Phase IV: The point marked by the distinct, abrupt muffling of sound so that a soft, blowing quality is heard.
• Phase V: The point at which the sound disappears.