REDUCED GAS TRANSFER AT REST AND DURING EXERCISE IN SCHOOL-AGE SURVIVORS OF BRONCHOPULMONARY DYSPLASIA

School-age children who survive bronchopulmonary dysplasia (BPD) may h ave a permanent reduction in alveolar surface area that could limit ga s transfer both at rest and during exercise. To test this hypothesis, 10 survivors of BPD, 10 children born prematurely without BPD, and 10 healthy children born at term, 6 to 9 yr of age, underwent treadmill e xercise studies. During a three-phase protocol we measured intrabreath acetylene (C2H2) and carbon monoxide (CO) transfer, pulmonary functio n, and Sa(O2). Both at rest and during exercise, C2H2 transfer correct ed for body surface area was lower in survivors of BPD than it was in children born prematurely without BPD or children born at term. With e xercise the transfer of both gases increased sharply over resting valu es in children born prematurely and at term. In survivors of BPD C2H2 transfer with exercise did increase, but not as much as it did in cont rol subjects, and corrected CO transfer did not change at all. In surv ivors of BPD and children born prematurely, FEV1 fell during recovery from exercise, but this did not correlate with C2H2 transfer or DLCO/V A. Thus, soluble gas transfer at rest and during acute exercise is red uced in children who survive BPD. This is likely explained either by l ong-term derangements in lung structure or residual right ventricular dysfunction affecting cardiac output.