A COMPARISON OF RESPIRATORY-FUNCTION IN AFRO-CARIBBEAN AND CAUCASIAN INFANTS

Race is recognized as an important determinant of lung function in chi ldren and adults, but limited data exist for infants. Accurate interpr etation of lung function tests during the neonatal period may depend o n appropriate values for predicting normality. The aim of this study w as to compare tidal breathing parameters, Hering-Breuer reflex (HBR) a ctivity, and total respiratory compliance (Crs) in healthy newborn cau casian (white) and Afro-Caribbean (black) infants, to determine whethe r separate reference values were required for these two ethnic groups. Respiratory function was measured in 33 healthy black infants, 18 of whom were premature, and 33 healthy white infants matched for sex, ges tational age, weight, postnatal age, and maternal smoking during pregn ancy. There were no significant paired differences between black and w hite infants with respect to minute ventilation, respiratory frequency , the ratio of time to reach peak expiratory flow to total expiratory time, or HBR activity. Values of Crs were similar in black and white f ull-term infants (37.5(SD 9.0) versus 35.0(6.3) ml.kPa(-1), respective ly) suggesting that, in the immediate newborn period, separate referen ce values are not necessary for these parameters. However, Crs was som ewhat lower in black than white preterm infants (26.0(5.2) versus 29.5 (7.2) ml.kPa(-1), this difference reaching statistical significance if results were expressed in relation to body weight (95% confidence int erval of within-pair differences -4.0 to -0.02 ml.kPa(-1).kg(-1); p<0. 05). We conclude that no separate reference values for tidal breathing , Hering-Breuer reflex activity or total respiratory compliance are re quired for white and black babies in the immediate newborn period. Fur ther studies are required to investigate sequential changes of Crs in preterm infants and to determine the potential influence of race on th e chest wall.