The normal difference in bilateral indirect blood pressure recordings in normotensive individuals

If there is a significant dichotomy between bilateral blood pressure determ inations in both arms, it is often taken as a sign of some type of underlyi ng pathology, We wished to evaluate what the normal variation might be far significant differences between blood pressures in both arms, Significant d ifference was arbitrarily chosen as a systolic blood pressure value greater than 10 mm Hg. Bilateral indirect blood pressure determinations were obtai ned in 100 subjects with no known history of hypertension in the sitting po sition, The blood pressure was obtained by 2 observers, one who recorded th e systolic and diastolic blood pressure as announced by the person taking t he blood pressures who was blinded to the actual values taken. The coeffici ent of Variation in obtaining the blood pressures in each arm was determine d in 5 of the 100 subjects. The age, sex, and handedness of each individual were recorded as demographic variables. The average left and right systoli c blood pressures were 112.1 +/- 16,5 and 112.7 +/- 16.3 mm Hg, respectivel y, The average left and right diastolic pressures were 64.4 +/- 11.6 and 63 .5 +/- 9.9 mm Hg, respectively, There was no significant difference between left minus right systolic or diastolic differences (Student's paired t tes t). There were no significant differences in systolic or diastolic blood pr essure between gender or between right and left handed individuals (nonpair ed t-test), The average coefficients of variation for right and left arm sy stolic blood pressures were 5.41% and 5,81%, respectively. Fifteen subjects had differences in systolic blood pressure between both arms exceeding 10 mm Hg (7% to 22%, 95% confidence interval), Differences of more than 10 mm Hg in indirect bilateral blood pressure recordings are frequent in normoten sive individuals and probably do not per se indicate any abnormal pathology , In the right clinical situation, differences that are noted should probab ly be repeated and should be added to the total clinical picture when used to determine whether a pathologic condition is present. (Am J Emerg Med 200 1;19:43-45. Copyright (C) 2001 by W.B. Saunders Company).