Effects of measurement intervals on the values of repeated auscultatory blood pressure measurements.

Objective: For repeated measurements of blood pressure (BP) using the auscultatory method, current guidelines recommend intervals of 1-2 minutes; however, evidence to support this recommendation is insufficient. In the present study, the effects of intervals among repeated BP measurements using the auscultatory method were evaluated. Methods: Systolic and diastolic BPs were measured using the auscultatory method in 37 participants. The measurements were repeated 5 times each at intervals of 15, 30, 60, 90, and 120 seconds. The changes in the BP along with the increasing the number of repetitions were assessed at each measurement interval using a linear mixed model. Results: With an increasing number of measurements, the systolic and diastolic BPs showed significant progressive decrease and increase (p < 0.05), respectively, when the measurement interval was 15 seconds. However, the precision of BP measurements was not affected by performing the measurements at intervals of 30 seconds or longer. Conclusion: Repeated BP measurements using the auscultatory method need to have an interval of at least 30 seconds, which is shorter than the intervals recommended by the current guidelines.