Clinical Research Papers

Brinton TJ, Walls ED, Chio S-S, Pulse Metric, Inc., San Diego, CA.

Although both Auscultatory (AUSC) and oscillometric (OSC) measurement techniques have been examined extensively, the variability between these two methods with respect to age still needs further investigation. We evaluated 154 (50M/104F) subjects, ranging in age from 11 to 85 years (mean± SEM = 45± 1.6 years), for systolic (SBP, mmHg) and diastolic (DBP, mmHg) blood pressures using both techniques. Two qualified nurses used Korotkoff sounds to determine SBP (phase 1) and DBP (phase IV) during simultaneous monitoring by a Pulse Dynamic OSC technology. This previously reported OSC technology utilizes phasic changes in the cuff pulsation signal to determine SBP and DBP. Values for each subject reflect the average of three recordings. Subjects were placed into one of three age groups: Group 1 (ages 11→ 32, n = 51), Group 2 (ages 33→ 54, n=51), Group 3 (ages 55→ 85, n=52) (TABLE). SBP was significantly lower in Group 1 using the AUSC method (p = 0.03).

A similar trend was observed in group 2 (p = 0.06). However, there was no significant difference in BP between the two methods in group 3 (p>0.1). Interestingly, DBP showed no significant variation for any group (p>0.1). The difference in SBP may be attributed to the difficulty in identifying phase I Korotkoff sounds for younger subjects. These subjects generally have more elastic arteries that may dampen phase I sounds, and thus make AUSC determination of SBP quite difficult. This phenomenon may not be a factor at DBP due to differing hemodynamic conditions.

*Presented at the American Socicty of Hypertension 11th Annual Scientific Meetings, 1996 (see American Journal of Hypertension 1996 Vol 9, No.4, Part 2, pg. 105A).