Effect of blood pressure cuffs on neonatal circulation: their potential application to newborns with persistent pulmonary hypertension.

The contribution of vasoactive pharmacologic agents to the care of the infant with primary pulmonary hypertension of the newborn (PPHN) is hampered by their limited ability to act selectively on different vascular beds. In contrast, blood pressure (BP) cuffs decrease flow and increase resistance only in the extremities around which they are applied. They therefore offer a means of increasing systemic vascular resistance without affecting pulmonary vascular resistance, a hemodynamic effect that may be particularly desirable among PPHN patients receiving vasodilators. We studied the effect of BP cuffs on the circulation of nine healthy neonates and three infants with severe PPHN. Among the healthy neonates, inflation of the cuffs to 20 mmHg had no discernible hemodynamic effect. Inflation to systolic pressures, however, caused the left ventricular preejection period to increase from 36 +/- 9 ms to 45 +/- 10 ms, the end-diastolic dimension to increase from 1.80 +/- 0.16 cm to 1.92 +/- 0.16 cm, and the cardiac output to fall to 87 +/- 12% of baseline (all p < 0.05)--changes indicative of an increase in systemic vascular resistance. Application of BP cuffs to the patients with PPHN was associated with 10-25 mmHg increases in transcutaneous arterial oxygen tensions. Administration of tolazoline to these patients while the cuffs were inflated resulted in additional 10-20 mmHg increases and did not precipitate hypotension. These observations suggest that BP cuffs can play a useful role in the management of patients with PPHN.