Mechanisms of Cardiovascular Changes of Phototherapy in Newborns with Hyperbilirubinemia.

During phototherapy of jaundiced newborns, vasodilation occurs in the skin circulation compensated by vasoconstriction in the renal and mesenteric circulation. Furthermore, there is a slight decrease in cardiac systolic volume, and blood pressure, as well as an increase in heart rate and discrete changes in the heart rate variability (HRV). The primary change during phototherapy is the skin vasodilation mediated by multiple mechanisms: 1) Passive vasodilation induced by direct skin heating effect of the body surface and subcutaneous blood vessels, modified by myogenic autoregulation. 2) Active vasodilation mediated via the mechanism provided by axon reflexes through nerve C-fibers and humoral mechanism via nitric oxide (NO) and endothelin 1 (ET-1). During and after phototherapy is a rise in the NO:ET-1 ratio. 3) Regulation of the skin circulation through the sympathetic nerves is unique, but their role in skin vasodilation during phototherapy was not studied. 4) Special mechanism is a photorelaxation independent of the skin heating. Melanopsin (opsin 4) - is thought to play a major role in systemic vascular photorelaxation. Signalling cascade of the photorelaxation is specific, independent of endothelium and NO. The increased skin blood flow during phototherapy is enabled by the restriction of blood flow in the renal and mesenteric circulation. An increase in heart rate indicates activation of the sympathetic system as is seen in the measures of the HRV. High-pressure, as well as low-pressure baroreflexes, may play important role in these adaptation responses. The integrated complex and specific mechanism responsible for the hemodynamic changes during phototherapy confirm adequate and functioning regulation of the neonatal cardiovascular system, including baroreflexes.

Cardiovascular changes during phototherapy in newborns.

Phototherapy is the most effective non-invasive method of neonatal hyperbilirubinemia treatment. Application of this method can be associated with side effects including changes in the cardiovascular system. During phototherapy, the primary effects in the cardiovascular system include cutaneous vasodilation leading to skin hyperperfusion and subsequent redistribution of blood. The increased blood flow through the skin is associated with increased transepidermal water loss. Further effects include an increase in cerebral blood flow. Redistribution of blood to the cutaneous bed is compensated by hypoperfusion in the splanchnic area (mostly postprandial) and a significant reduction of the renal blood flow. Regarding closure/reopening of the ductus arteriosus, the results suggest that that phototherapy does not affect ductal patency. During phototherapy the cardiac output can be slightly reduced due to a decreased stroke volume, especially in preterm newborns. Systemic blood pressure is decreased and heart rate is elevated in both preterm and term newborns during phototherapy. The heart rate variability is slightly reduced. Symbolic dynamics analysis of the short-term HRV showed that during phototherapy the activity of the ANS regulating the heart rate is shifted towards the dominancy of the sympathetic activity. The responses in the cardiovascular system of premature/mature newborns without other pathology confirm a well physiologically functioning control of this system, even under specific conditions of phototherapy.

Impact of early aggressive nutrition on retinal development in premature infants.

The normal retinal development is interrupted by preterm birth and a retinopathy of prematurity (ROP) may develop as its consequence. ROP is characterized by aberrant vessel formation in the retina as a response to multiple risk factors influencing the process of retinal angiogenesis. Insulin-like growth factor I (IGF-1) and vascular endothelial growth factor (VEGF) play an important role in the process of normal retinal vascularization. Insufficient nutrition during the first 4 postnatal weeks results in low serum levels of IGF-1, which is essential for correct retinal vessels formation, ensuring survival of the newly formed endothelial cells. Low IGF-1 level results in stop of angiogenesis in the retina, leaving it avascular and prompting the onset of ROP. Keeping the newborns in a positive energetic balance by providing enough nutrients and energy has a beneficial impact on their growth, neurodevelopment and decreased incidence of ROP. The best way to achieve this is the early parenteral nutrition with the high content of nutrients combined with early enteral feeding by the own mother´s breast milk. Multiple studies confirmed the safety and efficacy of early aggressive nutrition but information about its long-term effects on the metabolism, growth and development is still needed.

Accuracy of transcutaneous bilirubin measurement in newborns after phototherapy.

OBJECTIVE: We tested the accuracy of transcutaneous bilirubin (TcB) measure in newborns undergoing phototherapy. STUDY DESIGN: In a prospective study of 150 term Caucasian neonates, 255 measurements of total serum bilirubin (TSB) and TcB concentration were obtained 2 h after discontinuing phototherapy. TcB measurements obtained on the forehead, sternum, abdomen and covered lower abdomen were statistically compared with the corresponding TSB. RESULT: TcB consistently underestimated TSB levels significantly. The smallest but significant difference between TSB and TcB was found on the lower abdomen. The correlation between TSB and TcB was found to be moderately close (r=0.4 to 0.5). TcB measurements were inaccurate, regardless of phototherapy technique (Bilibed, conventional phototherapy). CONCLUSION: Phototherapy significantly interferes with the accuracy of transcutaneous bilirubinometry. TcB measurements performed 2 h after stopping phototherapy were not reliable, even if they were carried out on the unexposed body area. TSB assessment remains necessary, if treatment of hyperbilirubinemia is being considered.

Soluble receptor for advanced glycation end products in late-onset neonatal infection.

OBJECTIVES: To assess the plasma levels of sRAGE (soluble receptor for advanced glycation end products) in infected and non-infected preterm neonates and to compare their diagnostic values with standard infection biomarkers. BACKGROUND: RAGE activates pathways responsible for acute and chronic inflammation. The soluble type of this receptor, sRAGE, which acts as a decoy receptor, has been linked to the severity of sepsis and its outcome. METHODS: Prospective clinical study was carried out from January 2011 to August 2013. There were 33 neonates included according to their infection status and divided into subgroups as follows: infected (I), septic (S), non-infected controls (C). RESULTS: We found significantly lower values of sRAGE in the subgroup S (905.54±220.53 pg/mL; p < 0.028), while borderline values were higher in the subgroup I vs C (2158.33±197.33 pg/mL vs 1744.80±157.74 pg/mL; p < 0.064). By analysing the interobserver concordance we detected 70 % agreement as to sRAGE values detected in neonatal late-onset infections and sepsis, while procalcitonin was used as golden standard. CONCLUSION: Plasma sRAGE values reflect the severity of the inflammatory status in late-onset infection and sepsis in preterm neonates. Our results indicate that sRAGE could be a good potential biomarker of late-onset neonatal infection and sepsis (Tab. 2, Ref. 14).

Impact of updated European Consensus Guidelines on the management of neonatal respiratory distress syndrome on clinical outcome of preterm infants.

European Consensus Guidelines (ECG) on the management of respiratory distress syndrome (RDS) have been developed and updated twice since 2007 reflecting changes in practice as new evidence emerges. The aim of this study was to evaluate the progress in clinical outcome of babies after the implementation of the updated ECG in 2010. Forty-eight neonates born in 2002-2003 (Group 02/03; n = 15) and in 2012-2013 (Group 12/13; n = 33) at gestational age of 26.2 ± 1.7 weeks were included into this retrospective study. Resuscitation procedures, ventilation support, and postnatal administration of surfactant were assessed. In Group 12/13, compared with Group 02/03, there was a higher rate of maternal corticosteroid prophylactic treatment (33 % vs. 0 %, p < 0.001), more children received primary nasal continuous positive airway pressure (nCPAP) (54.5 % vs. 20 %, p < 0.01) and repeated doses of surfactant (33 % vs. 0 %, p < 0.001), and had a reduced rate of mortality, bronchopulmonary dysplasia, and necrotizing enterocolitis. We conclude that the management of extremely preterm newborns improved considerably over the decade resulting in a significant reduction of mortality and morbidity.

Impact of fetal pulse oximetry and ST analysis surveillance withdrawal on rates of obstetric surgery and frequency of low birth umbilical artery pH: a cause of rising caesarean rates?

A retrospective observational study on a sample of 13,413 deliveries analysed the effect of a withdrawal of the CTG additional diagnostic methods of fetal hypoxia (fetal pulse oximetry and ST analysis of the fetal ECG) on operative delivery rates and frequency of the umbilical arterial pH < 7.15. Following the withdrawal, obstetricians are more likely to perform caesarean sections for fetal hypoxia (OR 2.23, 95% CI 1.94-2.55, p < 0.0001) and labour dystocia (OR 1.45, 95% CI 1.18-1.77, p = 0.0003), which increases the overall caesarean rate (OR 1.49, 95% CI 1.38-1.61, p < 0.0001), although decreases the incidence of birth umbilical arterial pH < 7.15 (OR 0.43, 95% CI 0.22-0.85, p = 0.015). This also leads to the significant decline in overall frequency of instrumental vaginal deliveries (OR 0.58, 95% CI 0.48-0.71). In order to decrease the overall caesarean rate, obstetricians need to be supported by more accurate and possibly automated diagnostic tools for intrapartum fetal hypoxia.

Transcutaneous bilirubinometry in preterm neonates.

This prospective study was conducted to evaluate the accuracy of transcutaneous bilirubinometry in preterm newborns less than 32 weeks of gestation. Serum bilirubin values measured by direct spectrophotometry were considered as standard, the range was 2.2-12.5 mg/dL. 32 jaundiced infants of less than 32 weeks of gestation without phototherapy, including 10 ELBW neonates, were enrolled. Close correlation (R=0.933) existed between total serum bilirubin and transcutaneous bilirubin values measured over sternum.