Oscillometric Blood Pressure of Upper and Lower Extremities and Aortic Blood Flow Velocity in Neonates

ABSTRACT

PURPOSE: We studied the blood pressure difference between the upper and lower extremities in healthy newborn infants and the effect of isthmic narrowing of the aorta on making a possible difference. METHODS: The blood pressure was measured with an oscillometric blood pressure device from four extremities of 62 healthy infants aged 1-15 days. A Doppler echocardiography was performed for each infant to measure the aortic blood flow velocities in the ascending, just above and below the aortic arch isthmic narrowing. RESULTS: The blood pressure readings were as follow right arm 69.7 (+/-7.5)/42.7(+/-7.2)mmHg, right calf 69.5(+/-6.1)/42.6(+/-6.3)mmHg, left arm 69.0(+/-7.3)/43.1(+/-6.3)mmHg, and left calf 68.9(+/-7.4)/42.9(+/-5.6)mmHg. The estimated pressure gradient between the ascending aorta and aorta below the isthmus was 2.4+/-1.3mmHg and between opposite sides of the isthmus was 1.2+/-0.8 mmHg. CONCLUSION: Unlike in childhood and adolescence, the blood pressure in the lower extremities of healthy newborn infants is not higher than in the upper extremities. But the isthmic narrowing of the aortic arch does not explain this phenomenon.