Sex differences in pulmonary vascular control: focus on the nitric oxide pathway

Although the incidence of pulmonary hypertension is higher in females, the severity and prognosis of pulmonary vascular disease in both neonates and adults have been shown to be worse in male subjects. Studies of sex differences in pulmonary hypertension have mainly focused on the role of sex hormones. However, the contribution of sex differences in terms of vascular signaling pathways regulating pulmonary vascular function remains incompletely understood. Consequently, we investigated pulmonary vascular function of male and female swine in vivo, both at rest and during exercise, and in isolated small pulmonary arteries in vitro, with a particular focus on the NO-cGMP-PDE5 pathway. Pulmonary hemodynamics at rest and during exercise were virtually identical in male and female swine. Moreover, NO synthase inhibition resulted in a similar degree of pulmonary vasoconstriction in male and female swine. However, NO synthase inhibition blunted bradykinin-induced vasodilation in pulmonary small arteries to a greater extent in male than in female swine. PDE5 inhibition resulted in a similar degree of vasodilation in male and female swine at rest, while during exercise there was a trend towards a larger effect in male swine. In small pulmonary arteries, PDE5 inhibition failed to augment bradykinin-induced vasodilation in either sex. Finally, in the presence of NO synthase inhibition, the pulmonary vasodilator effect of PDE5 inhibition was significantly larger in female swine both in vivo and in vitro. In conclusion, the present study demonstrated significant sex differences in the regulation of pulmonary vascular tone, which may contribute to understanding sex differences in incidence, treatment response, and prognosis of pulmonary vascular disease

Cutaneous microcirculation in preterm neonates: comparison between sidestream dark field (SDF) and incident dark field (IDF) imaging

Incident dark field imaging (IDF) is a new generation handheld microscope for bedside visualization and quantification of microcirculatory alterations. IDF is the technical successor of sidestream dark field imaging (SDF), currently the most used device for microcirculatory measurements. In (pre)term neonates the reduced thickness of the skin allows non-invasive transcutaneous measurements. The goal of this study was to compare the existing device (SDF) and its technical successor (IDF) in preterm neonates. We hypothesized that IDF imaging produces higher quality images resulting in a higher vessel density. After written informed consent was given by the parents, skin microcirculation was consecutively measured on the inner upper arm with de SDF and IDF device. Images were exported and analyzed offline using existing software (AVA 3.0). Vessel density and perfusion were calculated using the total vessel density (TVD) proportion of perfused vessels (PPV) and perfused vessel density. The microcirculation images quality score was used to evaluate the quality of the video images. In a heterogeneous group of twenty preterm neonates (median GA 27.6 weeks, range 24–33.4) IDF imaging visualized 19.9 % more vessels resulting in a significantly higher vessel density (TVD 16.9 vs. 14.1/mm, p value < 0.001). The perfusion of vessels could be determined more accurately in the IDF images, resulting in a significant lower PPV (88.7 vs. 93.9 %, p value 0.002). The IDF video images scored optimal in a higher percentage compared to the SDF video images. IDF imaging of the cutaneous microcirculation in preterm neonates resulted in a higher vessel density and lower perfusion compared to the existing SDF device

Waiting 2 minutes after sucrose administration-unnecessary?

Background Worldwide, oral sucrose is standard of care in many neonatal intensive care units to relieve procedural pain in neonates. This study aims to determine if time interval between sucrose administration and heelstick correlates with pain scores. Methods Neonates were prospectively studied with variable time intervals and assessed with the Premature Infant Pain Profile-Revised (PIPP-R). Results 150 neonates were included with a median gestational age of 30+6 (IQR 27+6-33+2) weeks and a median time interval of 72 (IQR 39-115) seconds between sucrose administration and heelstick. In multiple regression analysis, this time interval was not significantly related to the PIPP-R (B=0.004, 95% CI -0.005 to 0.013, p=0.37). Providing non-nutritive sucking combined with sucrose was significantly related to lower PIPP-R scores (B=-3.50, 95% CI -4.7 to -2.3, p<0.001). Conclusions Our study suggests that there is no need to wait 2 min after sucrose administration before a painful procedure. Sucrose-induced non-nutritive sucking shows a fast pain-relieving effect in neonates

Oxidative injury of the pulmonary circulation in the perinatal period: Short- and long-term consequences for the human cardiopulmonary system

Development of the pulmonary circulation is a complex process with a spatial pattern that is tightly controlled. This process is vulnerable for disruption by various events in the prenatal and early postnatal periods. Disruption of normal pulmonary vascular development leads to abnormal structure and function of the lung vasculature, causing neonatal pulmonary vascular diseases. Premature babies are especially at risk of the development of these diseases, including persistent pulmonary hypertension and bronchopulmonary dysplasia. Reactive oxygen species play a key role in the pathogenesis of neonatal pulmonary vascular diseases and can be caused by hyperoxia, mechanical ventilation, hypoxia, and inflammation. Besides the well-established short-term consequences, exposure of the developing lung to injurious stimuli in the perinatal period, including oxidative stress, may also contribute to the development of pulmonary vascular diseases later in life, through so-called ‘‘fetal or perinatal programming.’’ Because of these long-term consequences, it is important to develop a follow-up program tailored to adolescent survivors of neonatal pulmonary vascular diseases, aimed at early detection of adult pulmonary vascular diseases, and thereby opening the possibility of early intervention and interfering with disease progression. This review focuses on pathophysiologic events in the perinatal period that have been shown to disrupt human normal pulmonary vascular development, leading to neonatal pulmonary vascular diseases that can extend even into adulthood. This knowledge may be particularly important for expremature adults who are at risk of the long-term consequences of pulmonary vascular diseases, thereby contributing disproportionately to the burden of adult cardiovascular disease in the future

Reproducibility of the Pleth Variability Index in premature infants

The aim was to assess the reproducibility of the Pleth Variability Index (PVI), developed for non-invasive monitoring of peripheral perfusion, in preterm neonates below 32 weeks of gestational age. Three PVI measurements were consecutively performed in stable, comfortable preterm neonates in the first 48 h of life. On each occasion, pulse oximeter sensors were attached to two different limbs for 5 min. Reproducibility was assessed with the intra-class correlation coefficient (ICC) and Bland–Altman analysis. A total of 25 preterm neonates were included. Inter-limb comparison showed fair to moderate ICC’s with 95%-confidence intervals (95%-CI). Left hand–right hand ICC = 0.498, 95%-CI (0.119–0.753); right foot–right hand ICC = 0.314 (−0.088–0.644); right foot–left foot ICC = 0.315 (−0.089–0.628). Intra-limb comparison showed fair to moderate ICC for right foot–right foot ICC = 0.380 (−0.014–0.677); and good ICC for right hand–right hand ICC = 0.646 (0.194–0.852). Bland–Altman plots showed moderate reproducibility of measurements between different limbs and of the same limb in consecutive time periods, with large biases and wide limits of agreement. The findings from this study indicate that PVI measurement is poorly reproducible when measured on different limbs and on the same limb in stable and comfortable preterm neonates

Do hospitalized premature infants benefit from music interventions? A systematic review of randomized controlled trials

Objective: Neonatal intensive care units (NICU) around the world increasingly use music interventions. The most recent systematic review of randomized controlled trials (RCT) dates from 2009. Since then, 15 new RCTs have been published. We provide an updated systematic review on the possible benefits of music interventions on premature infants' well-being. Methods: We searched 13 electronic databases and 12 journals from their first available date until August 2016. Included were all RCTs published in English with at least 10 participants per group, including infants born prematurely and admitted to the NICU. Interventions were either recorded music interventions or live music therapy interventions. All control conditions were accepted as long as the effects of the music intervention could be analysed separately. A meta-analysis was not possible due to incompleteness and heterogeneity of the data. Results: After removal of duplicates the searches retrieved 4893 citations, 20 of which fulfilled the inclusion/exclusion criteria. The 20 included studies encompassed 1128 participants receiving recorded or live music interventions in the NICU between 24 and 40 weeks gestational age. Twenty-six different outcomes were reported which we classified into three categories: physiological parameters; growth and feeding; behavioural state, relaxation outcomes and pain. Live music interventions were shown to improve sleep in three out of the four studies and heart rate in two out of the four studies. Recorded music improved heart rate in two out of six studies. Better feeding and sucking outcomes were reported in one study using live music and in two studies using recorded music. Conclusions: Although music interventions show promising results in some studies, the variation in quality of the studies, age groups, outcome measures and timing of the interventions across the studies makes it difficult to draw strong conclusions on the effects of music in premature infants

Periconception maternal folate status and human embryonic cerebellum growth trajectories: The Rotterdam predict study

We aimed to investigate whether periconceptional maternal folate status affects human embryonic cerebellar size and growth trajectories. In a prospective periconceptional cohort participants filled out questionnaires and received weekly transvaginal 3D-ultrasounds between 7+0 and 12+6 weeks gestational age (GA). Viable non-malformed singleton pregnancies were selected for cerebellar measurements; transcerebellar diameter, (TCD), left and right cerebellar diameters (LCD, RCD). Linear mixed models were performed to estimate associations between questionnaire data on the timing of maternal folic acid supplement initiation and longitudinal cerebellar measurements as a function of crown-rump length (CRL) and GA. Maternal red blood cell folate concentrations were analysed before 8 weeks GA to validate the associations. A total of 263 serial high quality three-dimensional ultrasound scans of 135 pregnancies were studied. Preconceptional compared to postconceptional initiation of folic acid use was associated with slightly larger cerebellar diameters per millimetre increase of CRL (TCD: β = 0.260mm, 95%CI = 0.023-0.491, p<0.05; LCD: β = 0.171mm, 95%CI = 0.038-0.305, p<0.05; RCD: β = 0.156mm, 95%CI = 0.032-0.280, p<0.05) and with proportional cerebellar growth (TCD/CRL:β = 0.015mm/mm, 95%CI = 0.005-0.024, p<0.01; LCD/CRL:β = 0.012mm/mm, 95%CI = 0.005-0.018, p<0.01; RCD/ CRL:β = 0.011mm/mm, 95%CI = 0.005-0.017, p

Randomized controlled trial comparing different single doses of intravenous paracetamol for placement of peripherally inserted central catheters in preterm infants

__Background:__ The availability of a safe and effective pharmacological therapy to reduce procedural pain in preterm infants is limited. The effective analgesic single dose of intravenous paracetamol in preterm infants is unknown. Comparative studies on efficacy of different paracetamol doses in preterm infants are lacking. __Objectives:__ To determine the analgesic effects of different single intravenous paracetamol doses on pain from peripherally inserted central catheter (PICC) placement in preterm infants. __Methods:__ In a blinded randomized controlled trial, the an

Impacts on prenatal development of the human cerebellum: a systematic review

Purpose: The cerebellum is essential for normal neurodevelopment and is particularlysusceptible for intra-uterine disruptions. Although some causal prenatal exposures havebeen identified, the origin of neurodevelopmental disorders remains mostly unclear. Therefore,a systematic literature search was conducted to provide an overview of parental environmentalexposures and intrinsic factors influencing prenatal cerebellar growth and development inhumans. Materials and methods: The literature search was limited to human studies in the Englishlanguage and was conducted in Embase, Medline, Cochrane, Web of Science, Pubmed andGoogleScholar. Eligible studies were selected by three independent reviewers and study qualitywas scored by two independent reviewers. Results: The search yielded 3872 articles. We found 15 eligible studies reporting associationsbetween cerebellar development and maternal smoking (4), use of alcohol (3),in vitrofertilization mediums (1), mercury (1), mifepristone (2), aminopropionitriles (1), ethnicity (2) andcortisol levels (1). No studies reported on paternal factors. Conclusions: Current literature on associations between parental environmental exposures,intrinsic factors and human cerebellar development is scarce. Yet, this systematic reviewprovided an essential overview of human studies demonstrating the vulnerability of thecerebellum to the intra-uterine environment