Comparison of the systolic blood pressure of the upper and lower limbs in young adults.

Introduction: The anatomical structural origin of the left and right subclavian arteries is different. Could this difference translate into differences in blood pressure measurements? This was the question to be answered by this study. The experiments were done in the Department of Physiology at University of Zimbabwe-College of Health Sciences.

Methodology: A Dinamap (CRITIKON, TAMPA, FL 33634), automated, oscillation-based machine was used to take blood pressure measurements on the arms and ankles of 112 subjects, 23 females and 89 males, aged 19-25, recruited between 0800 to 1600 hours on Monday to Friday of the week for 2 months. A towel was used for blindfolding subjects.

Results: The mean systolic blood pressures (SBPs) were, right arm 121, left arm 117, right leg 152 and left leg 154 with the subjects sitting. The right arm systolic blood pressure (SBP) readings were higher in 62.1% of the subjects with a mean difference +/- S.E of (4.15 +/- 0.848). The right calf SBP readings were lower in 63.0% of the subjects with a mean difference +/- S.E of (3.44 +/- 2.29). Blinded subjects had lower SBP in 63.0% of the subjects with a mean difference +/- S.E of (2.06 +/- 0.779). The first was greater than the second sequential SBP readings in 81.5% of the subjects' right arm and was reduced to 59% by blindfolding the subjects, and the left was 67.2%. On the ankle pressure it was 67.2% left and 63.0% right.

Conclusion: Clinicians should be aware that the right arm systolic blood pressure is higher than the left in most people. Also that it is different in the legs whereby the left ankle pressure is higher than the right ankle pressure.