Early molecular markers of ventilator-associated pneumonia in bronchoalveolar lavage in preterm infants.

INTRODUCTION: Ventilator-associated pneumonia (VAP) constitutes a serious nosocomial infection. Our aim was to evaluate the reliability of cytokines and oxidative stress/inflammation biomarkers in bronchoalveolar lavage fluid (BALF) and tracheal aspirates (TA) as early biomarkers of VAP in preterm infants. METHODS: Two cohorts were enrolled, one to select candidates and the other for validation. In both, we included preterms with suspected VAP, according to BALF culture, they were classified into confirmed VAP and no VAP. Concentration of 16 cytokines and 8 oxidative stress/inflammation biomarkers in BALF and TA was determined in all patients. RESULTS: In the first batch, IL-17A and TNF-α in BALF, and in the second one IL-10, IL-6, and TNF-α in BALF were significantly higher in VAP patients. BALF TNF-α AUC in both cohorts was 0.86 (sensitivity 0.83, specificity 0.88). No cytokine was shown to be predictive of VAP in TA. A statistically significant increase in the VAP group was found for glutathione sulfonamide (GSA) in BALF and TA. CONCLUSIONS: TNF-α in BALF and GSA in BALF and TA were associated with VAP in preterm newborns; thus, they could be used as early biomarkers of VAP. Further studies with an increased number of patients are needed to confirm these results. IMPACT: We found that TNF-α BALF and GSA in both BALF and TA are capable of discriminating preterm infants with VAP from those with pulmonary pathology without infection. This is the first study in preterm infants aiming to evaluate the reliability of cytokines and oxidative stress/inflammation biomarkers in BALF and TA as early diagnostic markers of VAP. We have validated these results in two independent cohorts of patients. Previously studies have focused on full-term neonates and toddlers and determined biomarkers mostly in TA, but none was exclusively conducted in preterm infants.

Transcriptome profiles discriminate between Gram-positive and Gram-negative sepsis in preterm neonates.

BACKGROUND: Genome-wide expression profiles have been previously employed as clinical research diagnostic tools for newborn sepsis. We aimed to determine if transcriptomic profiles could discriminate between Gram-positive and Gram-negative bacterial sepsis in preterm infants. METHODS: Prospective, observational, double-cohort study was conducted in very low birth weight infants with clinical signs and culture-positive sepsis. Blood samples were collected when clinical signs became apparent. Total RNA was processed for transcriptomic analysis. Results were validated by both reverse-transcription polymerase chain reaction and a mathematical model. RESULTS: We included 25 septic preterm infants, 17 with Gram-positive and 8 with Gram-negative bacteria. The principal component analysis identified these two clusters of patients. We performed a predictive model based on 21 genes that showed an area under the receiver-operating characteristic curve of 1. Eight genes were overexpressed in Gram-positive septic infants: CD37, CSK, MAN2B2, MGAT1, MOB3A, MYO9B, SH2D3C, and TEP1. The most significantly overexpressed pathways were related to metabolic and immunomodulating responses that translated into an equilibrium between pro- and anti-inflammatory responses. CONCLUSIONS: The transcriptomic profile allowed identification of whether the causative agent was Gram-positive or Gram-negative bacteria. The overexpression of genes such as CD37 and CSK, which control cytokine production and cell survival, could explain the better clinical outcome in sepsis caused by Gram-positive bacteria. IMPACT: Transcriptomic profiles not only enable an early diagnosis of sepsis in very low birth weight infants but also discriminate between Gram-positive and Gram-negative bacteria as causative agents. The overexpression of some genes related to cytokine production and cell survival could explain the better clinical outcome in sepsis caused by Gram-positive bacteria, and could lead us to a future, targeted therapy.

The Oxygen Load Supplied during Delivery Room Stabilization of Preterm Infants Modifies the DNA Methylation Profile.

OBJECTIVES: To determine whether the amount of oxygen provided during postnatal stabilization changes the DNA methylome in preterm infants. STUDY DESIGN: This prospective, observational study included 32 preterm infants ≤32 weeks of gestation who received oxygen in the delivery room. Patients were monitored using a respiratory function monitor to determine the amount of oxygen received upon stabilization. Blood samples were processed for comparison of DNA methylation before and after resuscitation using a DNA methylation high-resolution microarray Infinium Human DNA methylation EPIC 850K BeadChip. RESULTS: The median amount oxygen provided to preterm infants during stabilization was 644 mLO2/kg. Male sex and vaginal delivery were associated with increased oxygen needs. There were 2626 differentially methylated CpGs representing 1567 genes that showed an association with oxygen load selected and, of these, 85% were hypomethylated. We found that oxygen loads of >500 mLO2/kg changed the methylation pattern of the selected CpGs. Genes associated with these CpGs were "enriched" in KEGG pathways involved in cell cycle progression, DNA repair, and oxidative stress. CONCLUSIONS: The oxygen load provided upon resuscitation modified the DNA methylome. Differential methylation may lead to altered expression of genes related to cell cycle progression, oxidative stress, and DNA repair. The reversibility of these early epigenetic changes is unknown but merits further study.

Oxygen needs during resuscitation and surfactant to achieve stabilisation were independent risks factors for pulmonary interstitial emphysema in preterm infants.

AIM: Pulmonary interstitial emphysema is a severe complication of mechanical ventilation in preterm infants that leads to air leakage and, or, chronic lung disease. We determined the associated risk factors. METHODS: This was a retrospective case-control study from 2005 to 2014 at a regional referral centre in Valencia, Spain. The cases were 54 preterm infants up to 30 weeks' gestation and, or, born weighing less than 1500 g, who were diagnosed with pulmonary interstitial emphysema (PIE). The 54 controls were preterm infants without PIE matched by gestational age. Univariate analysis and multivariate analysis were performed to assess the independent predicting factors. RESULTS: Infants with PIE had been resuscitated with higher mean fractional inspired oxygen concentration (FiO2 ) (p = 0.008), had received higher peak mean positive end expiratory pressure (p = 0.00) and higher mean airway pressure (p = 0.026) 24 hours before diagnosis. PIE patients also received more surfactant (p = 0.00) and had higher mortality (p = 0.034). A Cox regression model identified that independent risk factors were the total amount of surfactant administered and the mean FiO2 during the 24 hours before diagnosis. CONCLUSION: Independent risk factors for pulmonary interstitial emphysema in preterm infants were higher oxygen during resuscitation and a higher need for surfactant and ventilatory pressures before diagnosis.

Factors influencing gastrointestinal tract and microbiota immune interaction in preterm infants.

The role of microbial colonization is indispensable for keeping a balanced immune response in life. However, the events that regulate the establishment of the microbiota, their timing, and the way in which they interact with the host are not yet fully understood. Factors such as gestational age, mode of delivery, environment, hygienic measures, and diet influence the establishment of microbiota in the perinatal period. Environmental microbes constitute the most important group of exogenous stimuli in this critical time frame. However, the settlement of a stable gut microbiota in preterm infants is delayed compared to term infants. Preterm infants have an immature gastrointestinal tract and immune system which predisposes to infectious morbidity. Neonatal microbial dynamics and alterations in early gut microbiota may precede and/or predispose to diseases such as necrotizing enterocolitis (NEC), late-onset sepsis or others. During this critical period, nutrition is the principal contributor for immunological and metabolic development, and microbiological programming. Breast milk is a known source of molecules that act synergistically to protect the gut barrier and enhance the maturation of the gut-related immune response. Host-microbe interactions in preterm infants and the protective role of diet focused on breast milk impact are beginning to be unveiled.

Minimally invasive surfactant therapy with a gastric tube is as effective as the intubation, surfactant, and extubation technique in preterm babies.

AIM: Preterm infants requiring surfactant replacement have been treated using the INSURE technique, which requires sedation and comprises tracheal intubation, surfactant instillation and extubation. However, minimally invasive surfactant therapy (MIST) does not require sedation, minimises airway injury and avoids placing positive pressure ventilation on an immature lung. This study compared the feasibility of the two techniques and the outcomes in preterm babies with respiratory distress syndrome (RDS). METHODS: Preterm infants with RDS prospectively received surfactant via a gastric tube placed in the trachea by direct laryngoscopy with no sedation. Technique-related complications and respiratory outcomes were analysed. RESULTS: We compared 44 patients who received MIST with a historic cohort of 31 patients who received INSURE. This showed no differences in the rate of intubation and mechanical ventilation in the first 72 h, or secondary respiratory outcomes and relevant morbidities, between the babies who received INSURE and those who received MIST. More babies in the MIST group (35%) needed a second dose of surfactant than the INSURE group (6.5%) (p < 0.0001). CONCLUSION: Surfactant administration using MIST, with no sedation, is feasible in preterm infants with RDS. No significant differences in secondary respiratory outcomes were found between the MIST and INSURE techniques.

Health care-associated infections in neonatology.

Health care-associated infections are common in neonatology, but there is no consensus on their definitions. This makes it difficult to compare their incidence or assess the effectiveness of prevention bundles. This is why we think it is very important to achieve a consensus on the definitions and diagnostic criteria for one of the most frequent causes of morbidity in hospitalised neonates. This document aims to standardise the definitions for the most frequent health care-associated infections, such as catheter-associated bloodstream infection, ventilator-associated pneumonia and surgical wound infection, as well as the approach to their diagnosis and treatment.

Do Lower Levels of Fetal Hemoglobin in Preterm Infants Relate to Oxidative Stress?

Fetal hemoglobin (HbF) has a higher affinity to oxygen than adult hemoglobin, allowing for a slower oxygen transfer to peripheral tissue, creating a microenvironment conducive to adequate fetal development in utero. However, most preterm infants receive packed red blood cell transfusions from adult donors leading to a drastic nonphysiological descent of circulating HbF. We hypothesized that this drop could enhance oxygen delivery to peripheral tissues generating a hyperoxic pro-oxidant environment. To investigate this, we assessed differences in oxidative stress biomarkers determined in urine samples in a cohort of 56 preterm infants born <32 weeks' gestation. Median oxidative stress biomarkers were compared between patients with circulating HbF above or below median HbF levels using Wilcoxon rank sum test. Oxidative stress biomarkers were significantly higher in the group of patients with lower levels of HbF. This study provides the initial evidence indicating elevated levels of oxidative stress biomarkers in preterm neonates with lower HbF levels. Based on the results, we hypothesize that HbF may contribute to preventing free radical-associated conditions during the newborn period. Antioxid. Redox Signal. 40, 453-459.

Ventilator-associated pneumonia in newborn infants diagnosed with an invasive bronchoalveolar lavage technique: a prospective observational study.

OBJECTIVES: To establish the incidence, etiology, risk factors, and outcomes associated with ventilator-associated pneumonia using an invasive sampling technique to avoid contamination. PATIENTS: Eligible patients were intubated neonates treated with mechanical ventilation who followed the criteria of the Centers for Disease Control and Prevention/National Nosocomial Infection Surveillance. Bronchoalveolar lavage samples were collected using a blind-protected catheter to avoid contamination of upper respiratory microorganisms. Isolation of >10(3) colony-forming unit/mL was required for diagnosis. MEASUREMENTS AND MAIN RESULTS: In 198 neonates intubated for >48 hrs, a total of 18 episodes of ventilator-associated pneumonia in 16 infants representing a prevalence of 8.1 were diagnosed. The pooled mean ventilator-associated pneumonia rate was 10.9/1,000 ventilator days. The mean age at diagnosis of ventilator-associated pneumonia was 29 ± 15 days after a mean of 21 ± 16 days of mechanical ventilation. Gram-negative bacteria were the most commonly isolated pathogens and Pseudomonas aeruginosa was the most frequent causative agent. Hospital length of stay was significantly longer for ventilator-associated pneumonia patients; however, no significant differences in mortality were found. Univariate analysis comparing patients with and without ventilator-associated pneumonia showed that days of mechanical ventilation, days of oxygen, number of reintubations, number of transfusions, bloodstream infection, and enteral feeding were all significantly associated with ventilator-associated pneumonia. However, in multivariate analysis the unique independent risk factor was days of mechanical ventilation (odds ratio 1.12, confidence interval 95% 1.07-1.17). CONCLUSIONS: Ventilator-associated pneumonia is a frequent nosocomial infection in newborns. Only duration of mechanical ventilation has been identified as an independent risk factor for ventilator-associated pneumonia. The use of a blind invasive sampling technique seems to diminish sample contamination.

Care levels in neonatal units in Spain: an updated vision for a new reality.

The Spanish Society of Neonatology established the care levels of the Neonatal Units in Spain in 2013. Since then, the birth rate in our country, as well as the universalization of knowledge, techniques and patient treatment devices, has evolved significantly. This situation forces a redefinition of the current levels of care based on quality criteria that allow better comparability between the Units and represents a challenge to improve the care of our newborns.

Effects of Sepsis on Immune Response, Microbiome and Oxidative Metabolism in Preterm Infants.

This is a narrative review about the mechanisms involved in bacterial sepsis in preterm infants, which is an illness with a high incidence, morbidity, and mortality. The role of the innate immune response and its relationship with oxidative stress in the pathogenesis are described as well as their potential implementation as early biomarkers. Moreover, we address the impact that all the mechanisms triggered by sepsis have on the dysbiosis and the changes on neonatal microbiota.

Effect of autologous umbilical cord blood transfusion in the development of retinopathy of prematurity: randomized clinical trial - study protocol.

Background: Currently, the treatment of anemia in preterm infants is based on packed red blood cell (RBC) transfusions from adult donors. Oxygen (O2) is mainly transported to the tissues bound to hemoglobin (Hb). In extremely low gestational age neonates (ELGANs), fetal hemoglobin (HbF), which has a higher affinity for O2, represents up to 95% of circulating hemoglobin. During the first month of life, the majority of ELGANs will require an adult-donor RBC transfusion causing HbF levels to rapidly drop. HbA releases 50% more oxygen in peripheral tissues than HbF. Increased release of O2 in the retina is one of the main factors related to the development of retinopathy of prematurity (ROP). Collecting umbilical cord blood and using autologous umbilical cord whole blood (UCB) transfusions would contribute to maintaining physiological HbF concentrations in newborns and avoid oxygen-in-excess derived damage. Methods: This is a randomized, double-blinded, multicenter clinical trial. ELGANs ≤28 weeks of gestational age will be randomized 1:1 to receive an autologous umbilical cord blood transfusion (intervention arm) or standard transfusion of packed RBC from an adult donor (control arm) to assess ROP development. Assuming a 50% reduction in ROP incidence, 134 patients (67 per group) will be recruited. When blood transfusion is indicated, the Blook Bank will supply UCB or RCB according to the patient's group. The primary endpoint is the incidence of any ROP. Secondary endpoints are assessessment of treatment safety, results of biomarkers related to ROP and its chronology, and urine oxidative stress markers. In addition, the cellular composition of umbilical cord blood and its relationship with prematurity-related pathologies will be analyzed. All patients will be followed-up to 24 months of corrected age to evaluate their neurodevelopment. Discussion: ROP is a major cause of irreversible blindness in preterm newborns. Transfusions with adult donor blood can lead to complications, including ROP. UCB transfusions offer advantages by maintaining physiological HbF levels and potentially optimizing postnatal development. Moreover, autologous UCB transfusion could reduce risks associated with heterologous blood products, although volume collection remains challenging. UCB contains growth factors and progenitor cells that may impact ROP.

Cord blood interleukin-6 as a predictor of early-onset neonatal sepsis.

AIM: To compare diagnostic accuracy in cord blood of interleukin-6 (IL-6) with C-reactive protein (CRP) as predictors of early-onset neonatal sepsis (EOS) in newborns with prenatal risk factors for infection. METHODS: During 12 months, cord blood IL-6 and CRP were measured immediately after birth in neonates with prenatal risk factors of infection. The odds of developing sepsis based on IL-6 and CRP values were calculated using likelihood ratios (LR), and their accuracy as predictors was compared by binary logistic regression. Multivariable logistic regression analyses were performed to identify independent risk factors for sepsis. RESULTS: Ten of 128 neonates (7.8%) were diagnosed with EOS confirmed with positive blood culture in five cases (3.9%). Cord blood IL-6 was a greater predictor of sepsis than CRP [ROC for IL-6 (0.88) vs. CRP (0.70)]. IL-6-positive and IL-6-negative LR [7.14 vs. -0.11] were superior to those calculated for CRP [2.86 vs. -0.51]. Chorioamnionitis and Apgar at 1 min were identified as independent risk factors for EOS. CONCLUSIONS: Cord blood IL-6 showed superior LR than CRP; therefore, it is a better predictor to initiate treatment in neonates with prenatal infectious risk factors immediately after birth.

Recommendations for transfusion of blood products in neonatology.

The scant evidence on the use of transfusions in neonatal care explains the limitations of current clinical guidelines. Despite this, in this document we explore the most recent evidence to make recommendations for the clinical practice. The prevention of anaemia of prematurity, the use of protocols and restrictive transfusion strategies constitute the best approach for clinicians in this field. In the case of platelet transfusions, the risk of bleeding must be assessed, combining clinical and laboratory features. Lastly, fresh frozen plasma is recommended in neonates with coagulopathy and active bleeding, with congenital factor deficiencies for which there is no specific treatment or with disseminated intravascular coagulation. All blood products have adverse effects that warrant a personalised and thorough assessment of the need for transfusion.

Clinical and immunological aspects of microRNAs in neonatal sepsis.

Neonatal sepsis constitutes a highly relevant public health challenge and is the most common cause of infant morbidity and mortality worldwide. Recent studies have demonstrated that during infection epigenetic changes may occur leading to reprogramming of gene expression. Post-transcriptional regulation by short non-coding RNAs (e.g., microRNAs) have recently acquired special relevance because of their role in the regulation of the pathophysiology of sepsis and their potential clinical use as biomarkers. ~22-nucleotide of microRNAs are not only involved in regulating multiple relevant cellular and molecular functions, such as immune cell function and inflammatory response, but have also been proposed as good candidates as biomarkers in sepsis. Nevertheless, establishing clinical practice guidelines based on microRNA patterns as biomarkers for diagnosis and prognosis in neonatal sepsis has yet to be achieved. Given their differential expression across tissues in neonates, the release of specific microRNAs to blood and their expression pattern can differ compared to sepsis in adult patients. Further in-depth research is necessary to fully understand the biological relevance of microRNAs and assess their potential use in clinical settings. This review provides a general overview of microRNAs, their structure, function and biogenesis before exploring their potential clinical interest as diagnostic and prognostic biomarkers of neonatal sepsis. An important part of the review is focused on immune and inflammatory aspects of selected microRNAs that may become biomarkers for clinical use and therapeutic intervention.

Perinatal palliative care.

Perinatal Palliative Care is a model of care designed to prevent and treat the physical, spiritual, emotional, and social needs of fetuses and newborn infants with life-threatening or life-limiting conditions. The care extends to the infant's family. It is delivered by an interdisciplinary team to improve the quality of life from the time of diagnosis (possibly in utero) into death and bereavement (days, months or years later). To guarantee the access of this vulnerable population to high quality palliative care, structured programs and protocols need to be further developed in tertiary hospitals that treat highly complex obstetric and neonatal pathologies. Basic training is required for all the professionals involved.

miRNomic Signature in Very Low Birth-Weight Neonates Discriminates Late-Onset Gram-Positive Sepsis from Controls.

BACKGROUND AND OBJECTIVES: Neonatal sepsis is a serious condition with a high rate of mortality and morbidity. Currently, the gold standard for sepsis diagnosis is a positive blood culture, which takes 48-72 h to yield results. We hypothesized that identifying differentially expressed miRNA pattern in neonates with late-onset Gram-positive sepsis would help with an earlier diagnosis and therapy. METHODS: This is a prospective observational study in newborn infants with late-onset Gram positive bacterial sepsis and non-septic controls. Complementary to blood culture, an aliquot of 0.5 mL of blood was used to determine small non-coding RNA expression profiling using the GeneChip miRNA 4.0 Array. RESULTS: A total of 11 very low birth-weight neonates with late-onset Gram-positive sepsis and 16 controls were analyzed. Further, 217 differentially expressed miRNAs were obtained between both groups. Subsequently, a combined analysis was performed with these miRNAs and 4297 differentially expressed genes. We identified 33 miRNAs that regulate our mRNAs, and the most relevant biological processes are associated with the immune system and the inflammatory response. CONCLUSIONS: The miRNA profiling in very low birth-weight neonates distinguishes late-onset Gram-positive sepsis versus control neonates.

Preventive bundle approach decreases the incidence of ventilator-associated pneumonia in newborn infants.

OBJECTIVE: We hypothesized that the implementation of evidence-based interventions shaping a bundle approach could significantly reduce the incidence of ventilator-associated pneumonia (VAP) in the neonatal intensive care unit. STUDY DESIGN: We conducted a prospective observational cohort study including neonates undergoing mechanical ventilation >48 h. VAP rate and endotracheal intubation ratio were compared before (pre-period) and after (post-period) applying VAP prevention bundle strategies. RESULT: One hundred seventy-four neonates were included in pre-period (30 months) and 106 in post-period (17 months). Demographic characteristics were comparable and device use ratios were similar. Twenty-eight VAP episodes were diagnosed, 25 in the first period and 3 after the implementation of prevention bundle. This represents a reduction in the incidence rate from 11.79 to 1.93 episodes/1000 ventilator days (p < 0.01). CONCLUSION: The implementation of an educational evidence-based program using a bundle approach to prevent VAP has shown a statistically significant reduction in its incidence density.

Recommendations on the skills profile and standards of the neonatal transport system in Spain.

The first hours of life of a sick or premature newborn are crucial for its prognosis and therefore delivery should take place in a center prepared for that degree of complexity. When this condition is not met, the newborn must be transferred in an optimal and safe way to the center that can offer the necessary care. The training, staffing, organization and coordination of the neonatal transport team are essential to guarantee a safe transfer. Being aware of the interest and the advances that are currently taking place in this area of ​​pediatrics, the Standards Commission and the Neonatal Transport Commission of the Spanish Society of Neonatology have prepared this document. In it, both the provision of human and material resources necessary as well as the bases of clinical stabilization in transport to carry out the neonatal transfer in a safe way and proportionate to the needs of the critical newborn have been exhaustively reviewed and detailed.

Sedoanalgesia in neonatal units.

Pain recognition and management continues to be a challenge for health professionals in Neonatal Intensive Care Units. Many of the patients are routinely exposed to repeated painful experiences with demonstrated short- and long-term consequences. Preterm babies are a vulnerable high-risk population. Despite international recommendations, pain remains poorly assessed and managed in many Neonatal Intensive Care Units. Due to there being no general protocol, there is significant variability as regards the guidelines for the approach and treatment of pain between the different Neonatal Intensive Care Units. The objective of this article is to review and assess the general principles of pain in the initial stages of development, its recognition through the use of standardised scales. It also includes its prevention and management with the combination of pharmacological and non-pharmacological measures, as well as to establish recommendations that help alleviate pain in daily clinical practice by optimising pain and stress control in the Neonatal Intensive Care Units.