Systolic pressure amplification in pedal arteries in children

Sphygmomanometric indirect blood pressure readings on the arm were compared to direct blood pressure readings from the radial and pedal arteries in pediatric patients. The direct systolic pressure in the pedal arteries was significantly (p less than 0.001) greater (25.1 +/- 12.3 mm Hg) than the indirect arm systolic pressure. The direct systolic pressure from the radial artery was identical to the indirect systolic arm pressure. Although there were no statistical differences between direct and indirect diastolic pressures, correlations for diastolic pressures were relatively poor. These data indicate that (1) there is a significant and unpredictable amplification of systolic pressure in the pedal arteries which may result in erroneous diagnosis of hypertension or jeopardize early detection of circulatory shock, (2) indirect blood pressure measurement with the recommended cuff width (125% of arm diameter or 40% of arm circumference) accurately reflects direct systolic pressure in the radial artery, and (3) indirect blood pressure measurement gives a relatively poor prediction of direct diastolic pressures.