Inter-arm Blood Pressure Differences

 

interarm difference in systolic blood pressure =

= ABS((SBP in left arm) - (SBP in right arm))

 

interarm difference in diastolic blood pressure =

= ABS((DBP in left arm) - (DBP in right arm))

 

Various authors use different cutoffs for a significant difference. Some use > 10 mm Hg, some > 20 mm Hg and some both.

 

Blood Pressure	Difference	Percent of Population
systolic	> 10 mm Hg	20%
systolic	> 20 mm Hg	3.5%
diastolic	> 10 mm Hg	11%
diastolic	> 20 mm Hg	3.5%

data of Lane et al

 

Significance of interarm blood pressure difference:

(1) The presence of an inter-arm blood pressure difference may identify a patient at increased risk for coronary artery disease and/or peripheral vascular disease.

(2) A significant difference in blood pressure can occur following surgery or major trauma.

(3) When monitoring blood pressure in these patients the same arm should be used for all readings.