10 research outputs found
Impact of Ethnicity and Extreme Prematurity on Infant Pulmonary Function
Summary. The impact of birth before 27 completed weeks of gestation on infant pulmonary function (PF) was explored in a multi-ethnic population in comparison to more mature preterm controls (PTC) and healthy fullterm infants. Plethysmographic lung volume (FRC pleth ) and forced expired volume (FEV 0.5 .44] z-scores, P < 0.001), as was forced vital capacity (FVC) but there were no significant differences in FRC pleth or FEV 0.5 /FVC ratio. FEV 0.5 , FVC, and FEV 0.5 /FVC were significantly lower in both preterm groups when compared with fullterm controls. On multivariable analyses of the combined preterm dataset: FEV 0.5 at $1 year was 0.11 [0.05; 0.17] z-scores higher/week GA, and 1.28 (0.49; 2.08) z-scores lower in EP infants with prior BPD. Among nonwhite preterm infants, FEV 0.5 was 0.70 (0.17; 1.24) z-scores lower, with similar reductions in FVC, such that there were no ethnic differences in FEV 0.5 /FVC. Similar ethnic differences were observed among fullterm infants. These results confirm the negative impact of preterm birth on subsequent lung development, especially following a diagnosis of BPD, and emphasize the importance of taking ethnic background into account when interpreting results during infancy as in older subjects
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Pulmonary function deficits in newborn screened infants with cystic fibrosis managed with standard UK care are mild and transient
With the advent of novel designer molecules for cystic fibrosis (CF) treatment, there is huge need for early-life clinical trial outcomes, such as infant lung function (ILF). We investigated the degree and tracking of ILF abnormality during the first 2â
years of life in CF newborn screened infants.
Forced expiratory volume in 0.5â
s (FEVâ.â
), lung clearance index (LCI) and plethysmographic functional residual capacity were measured at âŒ3â
months, 1â
year and 2â
years in 62 infants with CF and 34 controls.
By 2â
years there was no significant difference in FEVâ.â
z-score between CF and controls, whereas mean LCI z-score was 0.81 (95% CI 0.45â1.17) higher in CF. However, there was no significant association between LCI z-score at 2â
years with either 3-month or 1-year results. Despite minimal average group changes in any ILF outcome during the second year of life, marked within-subject changes occurred. No child had abnormal LCI or FEVâ.â
on all test occasions, precluding the ability to identify âhigh-riskâ infants in early life.
In conclusion, changes in lung function are mild and transient during the first 2â
years of life in newborn screened infants with CF when managed according to a standardised UK treatment protocol. Their potential role in tracking disease to later childhood will be ascertained by ongoing follow-up
The influence of gestational and postnatal age on the maturation of the Hering-Breuer inflation reflex in infants
Introduction
Preterm infants are known to be at greater risk of sudden death in infancy. The peak
age for sudden infant death (SID) coincides with a time when young infants are
undergoing many changes in patterns of breathing, sleep organisation and
thermoregulation. As a result of these changes, or delays in normal maturational
processes, some infants may be more susceptible to sudden death during early infancy.
It has been shown that the activity of the vagally mediated Hering-Breuer inflation
reflex (HBIR), which is thought to play an important part in controlling the rate and
depth of breathing in newborns, remains unchanged in fullterm infants from birth to 6
weeks of life (Rabbette et al, 1991a) but diminishes at some time between 6 weeks
and 1 year of age (Rabbette et al, 1994). However, there remains uncertainty as to
exactly when reflex activity begins to decline in fullterm infants and whether the
maturational pattern differs in preterm infants.
Aims
The hypotheses examined in this research were that the HBIR activity begins to
decline by about 3 months of age, when the infant is undergoing other important
physiological changes, and that the pattern of maturational decline in HBIR activity is
delayed in preterm infants. The aim was, therefore, to determine the independent
effects of gestational and postnatal age on the strength and maturation of HBIR in
early infancy in healthy fullterm and preterm infants.
Methods
Using the end-inspiratory occlusion technique, serial measurements of HBIR activity
and respiratory system compliance were made in 25 preterm and 27 fullterm infants at
matched postnatal and postconceptional ages (where postconceptional age (PCA) =
gestational age (GA) + postnatal age (PNA)) during the first 6 months of life.
Results
The results from this study suggest that gestational age does not influence HBIR
activity at birth. However, the subsequent pattern of maturation is influenced by
preterm delivery. At 40 weeks PCA (i.e. term equivalent), HBIR activity and
respiratory rate were higher in preterm than fiillterm infants, which may reflect lower,
unstable lung volumes and/or increased metabolic rate in the former group. At 4
months PNA, HBIR activity remained significantly higher in preterm infants, but
decreased to values found in fullterm infants when measurements were repeated
approximately 4 months after the expected rather than actual date of delivery.
Discussion and conclusion
It has been reported that infants of short gestation who succumb to sudden infant death
tend to do so at a later postnatal age when compared with fullterm infants. Several
recent physiological studies have suggested that there may be a window of increased
vulnerability between 10-20 weeks PNA in fullterm infants. Findings from this study
clearly demonstrate that maturation of respiratory patterns and timing differ between
preterm and fullterm infants. In addition, these results suggest that the window of
increased vulnerability may extend over a more prolonged period in preterm infants,
such that interpretation of respiratory measurements from infants must take gestational
age into account during the first 6 months of life