Forced expiratory flow in uninfected infants and children born to HIV-infected mothers

The Pediatric Pulmonary and Cardiovascular Complications of Vertically Transmitted HIV (P²C² HIV) Study is a multicenter study examining pulmonary and cardiac outcomes in offspring of HIV-infected mothers. This portion of the p²C² study tests the hypothesis that infants exposed to, but uninfected by, maternal HIV have normal maximal expiratory flow at functional residual capacity (V'maX, FRC). We obtained 500 measurements of V'max, FRC by rapid thoracic compression in 285 children ages 6-30 mo in five U.S. centers. The data were compared with those from a healthy cohort of children described elsewhere. V'max,_FRC rose with height in a linear relationship. The slope of the regression line in the exposed infants did not differ statistically from the slope in the comparison group, but the intercept was about 20% lower (p < 0.001). Height and weight were comparable in the two cohorts, and the differences between intercepts persisted after adjusting for birth weight and gestational age. However, maternal HIV infection cannot be assumed to be the cause as the cohorts may have differed in other variables, such as socioeconomic status and frequency of maternal smoking and drug use. Also, measurements varied substantially within and between our five centers, probably in part because of different racial and ethnic distributions. In summary, maternal HIV infection probably has only a modest effect, if any, on maximal expiratory flow at functional residual capacity in uninfected infants.