Pulmonary hypertension in infants with chronic lung disease: non-invasive evaluation and short term effect of oxygen treatment.

A total of 45 examinations on 30 premature infants with chronic lung disease (CLD) of prematurity were made using Doppler echocardiography. Pulmonary systolic time intervals and tricuspid regurgitant velocity were measured to assess the prevalence of pulmonary hypertension and short term responsiveness of the pulmonary circulation to oxygen. Twelve preterm infants matched for gestational age, served as controls. Tricuspid regurgitation (TR) was detected in 14 of the patients. Eleven of those with TR had pulmonary hypertension, of whom eight responded to oxygen treatment. Of the remaining three patients with 'fixed' pulmonary hypertension, one subsequently died. The detection of TR was the basis of the preferred method for measuring pulmonary artery pressure (Ppa) non-invasively, but the degree of correlation between the Ppa estimated from TR and pulmonary systolic time intervals was high (r = -0.84, p = 0.001). In the absence of TR, systolic time intervals are an effective way to monitor pulmonary artery pressure in infants with CLD. Without these measurements, it would have been impossible to predict which subjects had pulmonary hypertension, and which might respond to oxygen treatment.