Echocardiographic prediction of patent ductus arteriosus in need of therapeutic intervention.

AIM: To evaluate the efficacy of various echocardiographic markers in predicting a patent ductus arteriosus (PDA) in need of treatment. METHODS: Forty-five preterm infants with a mean (SD) gestational age of 27.7 (1.9) weeks underwent echocardiography at a postnatal age of 24 ± 6 and 72 ± 6 h. Four echocardiographic markers were studied: ductus diameter, ductal flow Doppler curves, the left atrial to aortic root (LA/Ao) ratio and Doppler pixels representing ductal shunting. RESULTS: Twenty-eight infants had a PDA with a detectable left-to-right shunt. Of these, 12 (43%) were treated for a shunt through the PDA. Ductal diameter was the most accurate echocardiographic marker when it came to predicting a significant shunt, with a sensitivity of 89%, a specificity of 70%, a positive likelihood ratio of 2.97 and a negative likelihood ratio of 0.16 at the age of 72 h. The efficacy of the method at 72 h of age was 84%. The corresponding efficacy of the pulsatile Doppler curve was 72%, percentage of green colour pixels 63% and the LA/Ao ratio 53%. CONCLUSION: Ductus diameter appears to be the most important variable in determining the need for therapeutic intervention for PDA in preterm infants.

New insights into the development of retinopathy of prematurity--importance of early weight gain.

UNLABELLED: Evidence is accumulating that one of the strongest predictors of retinopathy of prematurity (ROP), in addition to low gestational age, is poor weight gain during the first weeks of life. In infants born preterm, the retina is not fully vascularised. The more premature the child, the larger is the avascular area. In response to hypoxia, vascular endothelial growth factor (VEGF) is secreted. For appropriate VEGF-induced vessel growth, sufficient levels of insulin-like growth factor I (IGF-I) in serum are necessary. IGF-I is a peptide, related to nutrition supply, which is essential for both pre- and post-natal general growth as well as for growth of the retinal vasculature. In prematurely born infants, serum levels are closely related to gestational age and are lower in more prematurely born infants. At preterm birth the placental supply of nutrients is lost, growth factors are suddenly reduced and general as well as vascular growth slows down or ceases. In addition, the relative hyperoxia of the extra-uterine milieu, together with supplemental oxygen, causes a regression of already developed retinal vessels. Postnatal growth retardation is a major problem in very preterm infants. Both poor early weight gain and low serum levels of IGF-I during the first weeks/months of life have been found to be correlated with severity of ROP. CONCLUSION: This review will focus on the mechanisms leading to ROP by exploring factors responsible for poor early weight gain and abnormal vascularisation of the eye of the preterm infant.

Inflammation at birth and the insulin-like growth factor system in very preterm infants.

BACKGROUND: Foetal inflammation is associated with an increased risk of brain damage in preterm infants whereas IGF-I is essential for cerebral development and exhibits anti-apoptotic properties. AIM: To assess levels of IGF-I and IGF binding proteins at very preterm birth and to evaluate their relationship with foetal pro-inflammation and cerebral damage. METHODS: Levels of IGF-I, IGF binding protein 3 (IGFBP-3), high- (hp) and low-phosphorylated (lp) IGFBP-1 in cord blood and neonatal blood at 72 h after delivery were analysed in relation to levels of cytokines and cerebral damage as detected by ultrasound in 74 inborn infants [mean gestational age (GA) 27.1 weeks]. Evaluation was performed separately according to birth weight for GA. RESULTS: In cord blood of infants appropriate for gestational age (AGA) higher levels of IL-6 and IL-8 were associated with lower IGF-I (r =-0.38, p = 0.008 and r =-0.36, p = 0.014). Higher levels of IL-6, IL-8 and TNF-alpha were associated with both higher levels of lpIGFBP-1 (r = 0.54, p < 0.001, r = 0.50, p < 0.001 and r = 0.13, p = 0.012, respectively) and hpIGFBP-1 (r = 0.55, p < 0.001, r = 0.45, p = 0.002 and r = 0.32, p = 0.026, respectively). Infants with intraventricular haemorrhage grade III (n = 5) had higher levels of lp/hpIGFBP-1 in cord blood (p = 0.001 and 0.002, respectively). CONCLUSION: Pro-inflammation at birth is associated with changes in the IGF-system. This may be of importance for development of brain damage in preterm infants.

Transdermal suctioning technique for serial sampling of interstitial fluid in newborn infants.

OVERVIEW: Use of a suction-induced epidermal mini-erosion for serial sampling of dermal interstitial fluid (IF) in 16 newborn infants with gestational age ranging from 24 to 42 weeks is reported. RESULTS: The mini-erosion formed reproducibly and electron microscopy showed that the split was located within the epidermis. IF was sampled serially by suctioning during 1-3 days without signs of stress or pain. IF sample volumes (10-50 microl) did not decrease with time. Glucose values in IF and blood were correlated (r(s) = 0.542; p = 0.000). IF glucose was lower than blood glucose on all 3 days. The epidermis regenerated within 4 +/- 0.9 days (mean, SD) after sampling was terminated. There were no complications. CONCLUSION: Serial transdermal sampling was performed without stress or pain in newborn infants. Systemic and temporal differences between glucose measured in IF and blood were observed.

Preterm male infants need more initial respiratory and circulatory support than female infants.

AIM: The aim of this study was to investigate possible gender-related differences in clinical parameters during the first week of life that could explain the higher morbidity and mortality of preterm male infants. METHODS: In total, 130 clinical variables were collected from 236 inborn infants (130 male and 106 female infants) with gestational age (GA) < 29 wk. A subgroup of 175 extremely low birthweight infants (ELBW) < 1000 g (n = 86 males; n = 89 females) was analysed separately. RESULTS: At 6 postnatal h, 60.8% of the male infants needed mechanical ventilation versus 46.2% of the females (p = 0.026). Chronic lung disease (CLD) developed in 36.2% of males versus 9.8% of female infants (p = 0.004). Inotrope support with dopamine was used in more than 50% of the infants; additional inotrope support to dopamine was needed by 19.4% of male and 9.7% of female infants (p = 0.041). The gender-related difference in need for inotrope support was more evident among the ELBW infants; 67.1% of male infants needed inotrope support versus 50.6% of females (p = 0.028). At 12-24 h, male ELBW infants had lower minimum mean arterial blood pressure (mean (SD) 25(4) mmHg vs 28(6) mmHg, p = 0.004)) and lower minimum PaCO2 than females infants (4.3 (1.1) kPa vs 4.7 (0.9) kPa, p = 0.043). CONCLUSIONS: There are early gender-related differences in need for ventilatory and circulatory support that may contribute to the worse long-term outcome in prematurely born male infants.