Protocol for the development of a core outcome set for neonatal sepsis (NESCOS)

Neonatal sepsis is a serious public health problem; however, there is substantial heterogeneity in the outcomes measured and reported in research evaluating the effectiveness of the treatments. Therefore, we aim to develop a Core Outcome Set (COS) for studies evaluating the effectiveness of treatments for neonatal sepsis. Since a systematic review of key outcomes from randomised trials of therapeutic interventions in neonatal sepsis was published recently, we will complement this with a qualitative systematic review of the key outcomes of neonatal sepsis identified by parents, other family members, parent representatives, healthcare providers, policymakers, and researchers. We will interpret the outcomes of both studies using a previously established framework. Stakeholders across three different groups i.e., (1) researchers, (2) healthcare providers, and (3) patients' parents/family members and parent representatives will rate the importance of the outcomes in an online Real-Time Delphi Survey. Afterwards, consensus meetings will be held to agree on the final COS through online discussions with key stakeholders. This COS is expected to minimize outcome heterogeneity in measurements and publications, improve comparability and synthesis, and decrease research waste.

A physiological approach to applying CPAP in the preterm infant

Nasal continuous positive airway pressure (CPAP) is increasingly used for respiratory support in preterm infants with respiratory distress syndrome at birth and after extubation from mechanical ventilation. Controversies with CPAP use still exists due to non-uniformity of devices and interfaces used, equivalence of testing conditions for different CPAP systems, differences in study designs, and short study periods that may be insufficient to detect important and relevant clinical outcomes. Compared with ventilator-derived constant-pressure flow-opposition CPAP, variable fluidic flow-opposition CPAP systems may be advantageous and offer some clinical benefits. The distinction between constant-flow fluid-sealed bubble CPAP and variable-flow fluidic flow-opposition systems is less clear. Appropriately designed randomized clinical trials that separately address the controversies with CPAP use in various clinical settings, are necessary to determine which CPAP system results in best outcomes.

Sequential organ failure assessment scores to predict outcomes: from adults to neonates

PURPOSE OF REVIEW

Organ dysfunction severity scores (sequential organ failure assessment or SOFA) are commonly used in the adult and pediatric populations when assessing risk of mortality and adverse outcomes from sepsis. In contrast to sepsis definition in adults and children, clinical and laboratory criteria for defining neonatal sepsis have been inconclusive. More recently, studies have attempted to better understand the clinical progression of neonatal sepsis and associated mortality. This data has guided the development of a neonatal SOFA (nSOFA) score, based on common patterns of organ dysfunction observed in this population.

RECENT FINDINGS

Although SOFA scores in the adult and pediatric populations have their limitations with moderate sensitivities and specificities depending on the clinical setting, the nSOFA score has been validated in predicting sepsis attributable mortality in very low birth weight (VLBW) infants across several patient cohorts. Furthermore, the nSOFA score has been adapted for use in neonatal disease states, other than sepsis, with similar prognostic utility.

SUMMARY

Utilizing an nSOFA scoring system for prediction of sepsis attributable mortality in preterm infants allows for targeted interventions based on risk stratification, as well as better delineation of neonatal sepsis with subsequent improvements in research and patient safety outcomes.

What's new in the management of neonatal early-onset sepsis?

The expert guidelines highlighted in this review provide an evidence-based framework for approaching at-risk infants and allow for a more limited and standardised approach to antibiotic use. While these guidelines have significantly reduced antibiotic utilisation worldwide, optimally each unit would individualise their approach to early onset sepsis (EOS) based on the neonatal population they serve and available resources. As advancements in EOS research continue and limitations with sepsis prediction tools are addressed, it is inevitable that our risk stratification and management guidelines will become more precise.

The NICU Antibiotics and Outcomes (NANO) trial: a randomized multicenter clinical trial assessing empiric antibiotics and clinical outcomes in newborn preterm infants

Background

Early-onset sepsis is an important cause of neonatal morbidity and mortality in the preterm population. Infants perceived to be at increased risk for early-onset sepsis are often treated empirically with broad-spectrum antibiotics while awaiting confirmatory blood cultures, despite an overall incidence of early-onset sepsis of 2–3% among extremely-low-birthweight (ELBW) infants. Recent observational studies associate perinatal antibiotic use with an increased incidence of necrotizing enterocolitis, late-onset sepsis, and mortality among ELBW infants. Given currently available data and variability in clinical practice, we designed a prospective multi-institutional randomized controlled trial to determine the safety of early antibiotic use in ELBW infants.

Methods

The NICU Antibiotics and Outcomes (NANO) trial is a multicenter, double-blinded, randomized controlled trial. A sample of 802 ELBW preterm infants will undergo web-based stratified block randomization to receive empiric antibiotics (EA; ampicillin and gentamicin) or placebo during routine evaluation for early-onset sepsis. Participating sites will use preexisting institutional protocols for antibiotic dosage and duration. Infants born at participating sites with a gestational age of 29 weeks or less are eligible for enrollment. Exclusion criteria include maternal intrauterine infection, hemodynamic or respiratory instability, delivery by caesarean section for maternal indications without labor or prolonged rupture of membranes, and prior administration of antibiotics. The primary outcome is the composite incidence of necrotizing enterocolitis, late-onset sepsis, or death during participants’ index hospitalization. Maternal and infant samples will be collected longitudinally and assessed for differences in microbiome composition and diversity.

Discussion

The NANO trial is designed to compare the rate of adverse outcomes of EA use at birth versus placebo in ELBW preterm infants. If EA at birth worsens clinical outcomes, then the results of the trial may help providers decrease antibiotic utilization in the NICU and subsequently decrease the incidence of complications associated with early antibiotic use in ELBW infants. If we instead find that EA improve outcomes, then the trial will validate a longstanding clinical practice that has not previously been supported by high-quality data. Future studies will assess long-term clinical and microbial outcomes in infants who received empiric antibiotics following delivery.

Trial registration

Trial registration data: June 25, 2019 NCT03997266.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13063-022-06352-3.

Can we back off using antibiotics in the NICU?

Antibiotics are extensively and inconsistently prescribed in neonatal ICUs, and usage does not correlate with rates of culture positive sepsis. There is mounting data describing the short and long-term adverse effects associated with antibiotic overuse in neonates, including the increased burden of multi-drug resistant organisms. Currently there is considerable variation in antibiotic prescribing practice among neonatologists. Applying the practice of antibiotic stewardship in the NICU is crucial for standardizing antibiotic use and improving outcomes in this population. Several approaches have been proposed to identify neonatal sepsis, with the hope of reducing antibiotic utilization. These strategies all have their limitations, and often include laboratory testing and treatment of well-appearing, non-septic, infants. A conservative "watch and wait" algorithm is suggested as an alternative method for when to initiate antibiotics. This observational approach relies on availability of trained personnel able to examine infants at specified intervals, without delaying antibiotics, should signs of sepsis arise.

Routine Early Antibiotic Use in SymptOmatic Preterm Neonates: A Pilot Randomized Controlled Trial

We enrolled 98 infants (gestational age <33 weeks) in a pilot randomized trial of antibiotics vs no antibiotics; 55 were randomized (lower maternal infectious risk; symptoms expected for gestation). Adverse events did not differ significantly between the randomization arms. This trial establishes a framework for a larger multicentered trial.

Evaluation of the Neonatal Sequential Organ Failure Assessment and Mortality Risk in Preterm Infants With Late-Onset Infection

IMPORTANCE

Infection in neonates remains a substantial problem. Advances for this population are hindered by the absence of a consensus definition for sepsis. In adults, the Sequential Organ Failure Assessment (SOFA) operationalizes mortality risk with infection and defines sepsis. The generalizability of the neonatal SOFA (nSOFA) for neonatal late-onset infection-related mortality remains unknown.

OBJECTIVE

To determine the generalizability of the nSOFA for neonatal late-onset infection-related mortality across multiple sites.

DESIGN, SETTING, AND PARTICIPANTS

A multicenter retrospective cohort study was conducted at 7 academic neonatal intensive care units between January 1, 2010, and December 31, 2019. Participants included 653 preterm (<33 weeks) very low-birth-weight infants.

EXPOSURES

Late-onset (>72 hours of life) infection including bacteremia, fungemia, or surgical peritonitis.

MAIN OUTCOMES AND MEASURES

The primary outcome was late-onset infection episode mortality. The nSOFA scores from survivors and nonsurvivors with confirmed late-onset infection were compared at 9 time points (T) preceding and following event onset.

RESULTS

In the 653 infants who met inclusion criteria, median gestational age was 25.5 weeks (interquartile range, 24-27 weeks) and median birth weight was 780 g (interquartile range, 638-960 g). A total of 366 infants (56%) were male. Late-onset infection episode mortality occurred in 97 infants (15%). Area under the receiver operating characteristic curves for mortality in the total cohort ranged across study centers from 0.71 to 0.95 (T0 hours), 0.77 to 0.96 (T6 hours), and 0.78 to 0.96 (T12 hours), with utility noted at all centers and in aggregate. Using the maximum nSOFA score at T0 or T6, the area under the receiver operating characteristic curve for mortality was 0.88 (95% CI, 0.84-0.91). Analyses stratified by sex or Gram-stain identification of pathogen class or restricted to infants born at less than 25 weeks' completed gestation did not reduce the association of the nSOFA score with infection-related mortality.

CONCLUSIONS AND RELEVANCE

The nSOFA score was associated with late-onset infection mortality in preterm infants at the time of evaluation both in aggregate and in each center. These findings suggest that the nSOFA may serve as the foundation for a consensus definition of sepsis in this population.

Antibiotics and the developing intestinal microbiome, metabolome and inflammatory environment in a randomized trial of preterm infants

Antibiotic use in neonates can have detrimental effects on the developing gut microbiome, increasing the risk of morbidity. A majority of preterm neonates receive antibiotics after birth without clear evidence to guide this practice. Here microbiome, metabolomic, and immune marker results from the routine early antibiotic use in symptomatic preterm Neonates (REASON) study are presented. The REASON study is the first trial to randomize symptomatic preterm neonates to receive or not receive antibiotics in the first 48 h after birth. Using 16S rRNA sequencing of stool samples collected longitudinally for 91 neonates, the effect of such antibiotic use on microbiome diversity is assessed. The results illustrate that type of nutrition shapes the early infant gut microbiome. By integrating data for the gut microbiome, stool metabolites, stool immune markers, and inferred metabolic pathways, an association was discovered between Veillonella and the neurotransmitter gamma-aminobutyric acid (GABA). These results suggest early antibiotic use may impact the gut-brain axis with the potential for consequences in early life development, a finding that needs to be validated in a larger cohort.Trial Registration This project is registered at clinicaltrials.gov under the name "Antibiotic 'Dysbiosis' in Preterm Infants" with trial number NCT02784821.

Antibiotics Effects on the Fecal Metabolome in Preterm Infants

Within a randomized prospective pilot study of preterm infants born at less than 33 weeks' gestation, weekly fecal samples from 19 infants were collected and metabolomic analysis was performed. The objective was to evaluate for differences in fecal metabolites in infants exposed to antibiotics vs. not exposed to antibiotics in the first 48 h after birth. Metabolomics analysis was performed on 123 stool samples. Significant differences were seen in the antibiotics vs. no antibiotics groups, including pathways related to vitamin biosynthesis, bile acids, amino acid metabolism, and neurotransmitters. Early antibiotic exposure in preterm infants may alter metabolites in the intestinal tract of preterm infants. Broader multi-omic studies that address mechanisms will guide more prudent antibiotic use in this population.

Preventing Continuous Positive Airway Pressure Failure: Evidence-Based and Physiologically Sound Practices from Delivery Room to the Neonatal Intensive Care Unit

Routine use of continuous positive airway pressure (CPAP) to support preterm infants with respiratory distress is an evidenced-based strategy to decrease incidence of bronchopulmonary dysplasia. However, rates of CPAP failure remain unacceptably high in very premature neonates, who are at high risk for developing bronchopulmonary dysplasia. Using the GRADE framework to assess the quality of available evidence, this article reviews strategies aimed at decreasing CPAP failure, starting with delivery room interventions and followed through to system-based efforts in the neonatal intensive care unit. Despite best efforts, some very premature neonates fail CPAP. Also reviewed are predictors of CPAP failure in this vulnerable population.

Pneumonia

Neonatal pneumonia may occur in isolation or as one component of a larger infectious process. Bacteria, viruses, fungi, and parasites are all potential causes of neonatal pneumonia, and may be transmitted vertically from the mother or acquired from the postnatal environment. The patient's age at the time of disease onset may help narrow the differential diagnosis, as different pathogens are associated with congenital, early-onset, and late-onset pneumonia. Supportive care and rationally selected antimicrobial therapy are the mainstays of treatment for neonatal pneumonia. The challenges involved in microbiological testing of the lower airways may prevent definitive identification of a causative organism. In this case, secondary data must guide selection of empiric therapy, and the response to treatment must be closely monitored.

Noninvasive Support: Does It Really Decrease Bronchopulmonary Dysplasia?

Noninvasive support of preterm infants with respiratory distress is an evidenced-based strategy to decrease the incidence of bronchopulmonary dysplasia. Continuous positive airway pressure (CPAP) is the only noninvasive strategy with sufficient evidence to support its use in acute respiratory distress syndrome. It is unclear if one method for delivering CPAP is superior to another. Future research will focus on strategies (eg, sustained lung inflation, and administration of surfactant using a thin plastic catheter) that increase the likelihood of success with CPAP, especially in infants with a gestational age of less than 26 weeks.

Oxygen Targeting in Extremely Low Birth Weight Infants

The use of supplemental oxygen plays a vital role in the care of the critically ill preterm infant, but the unrestricted use of oxygen can lead to unintended harms, such as chronic lung disease and retinopathy of prematurity. An overly restricted use of supplemental oxygen may have adverse effects as well. Ideally, continuous monitoring of tissue and cellular oxygen delivery would allow clinicians to better titrate the use of supplemental oxygen, but such monitoring is not currently feasible in the clinical setting. The introduction of pulse oximetry has greatly aided the clinician by providing a relatively easy and continuous estimate of arterial oxygen saturation, but pulse oximetry has several practical, technical, and physiologic limitations. Recent randomized clinical trials comparing different pulse oximetry targets have been conducted to better inform the practice of supplemental oxygen use. This clinical report discusses the benefits and limitations of pulse oximetry for assessing oxygenation, summarizes randomized clinical trials of oxygen saturation targeting, and addresses implications for practice.

Strategies for the prevention of continuous positive airway pressure failure

Progress in neonatal intensive care is closely linked to improvements in the management of respiratory failure in preterm infants. Current modalities of respiratory support range from the more benign continuous positive airway pressure (CPAP) to various modes of mechanical ventilation. Data from recent randomized control trials suggest that the use of nasal (n)CPAP as the initial mode of respiratory support in critically ill very low birth weight infants is associated with a lower incidence of chronic lung disease. The practice of early initiation of nasal-prong CPAP in all spontaneously breathing infants at Columbia University has resulted in very low rates of chronic lung disease for decades. Many institutions have attempted to replicate the practices and results at Columbia University. However, success rates with nCPAP are highly variable, which may in part be attributable to how well it is utilized. With recent renewed interest in non-invasive respiratory support, particularly bubble nCPAP, it is essential to evaluate strategies for the prevention of CPAP failure. This review discusses strategies that address these issues and shares the practical aspects for replicating success with bubble nCPAP. In addition, it reviews desirable features, major components, and physiological consequences of various bubble CPAP systems along with clinical experience of CPAP use.

Noninvasive Respiratory Support

Mechanical ventilation is associated with increased survival of preterm infants but is also associated with an increased incidence of chronic lung disease (bronchopulmonary dysplasia) in survivors. Nasal continuous positive airway pressure (nCPAP) is a form of noninvasive ventilation that reduces the need for mechanical ventilation and decreases the combined outcome of death or bronchopulmonary dysplasia. Other modes of noninvasive ventilation, including nasal intermittent positive pressure ventilation, biphasic positive airway pressure, and high-flow nasal cannula, have recently been introduced into the NICU setting as potential alternatives to mechanical ventilation or nCPAP. Randomized controlled trials suggest that these newer modalities may be effective alternatives to nCPAP and may offer some advantages over nCPAP, but efficacy and safety data are limited.

Reappraisal of guidelines for management of neonates with suspected early-onset sepsis

Since 1992, professional societies or public health agencies in the United States^– and elsewhere^– have issued several generations of recommendations for prevention or management of early-onset neonatal sepsis (EOS). Despite those efforts, recommendations remain inconsistent, clarifications are necessary, local adaptations are common, and compliance rates are low. We postulate that lack of consensus, especially regarding postnatal management of the neonate, is largely a result of two sets of factors. First, obstetrical prevention strategies have substantially reduced incidence of EOS, potentially changing the utility of predictive strategies based on risk factors. Second, recent data better delineate relationships among risk factors, clinical signs, and EOS, suggesting that risk predictors may have different utilities in different groups. The purpose of this commentary is to explore these questions and to suggest new approaches to management of newborns who may be at risk for EOS.

Pulse oximetry in very low birth weight infants

Pulse oximetry has become ubiquitous and is used routinely during neonatal care. Emerging evidence highlights the continued uncertainty regarding definition of the optimal range to target pulse oximetry oxygen saturation levels in very low birth weight infants. Furthermore, maintaining optimal oxygen saturation targets is a demanding and tedious task because of the frequency with which oxygenation changes, especially in these small infants receiving prolonged respiratory support. This article addresses the historical perspective, basic physiologic principles behind pulse oximetry operation, and the use of pulse oximetry in targeting different oxygen ranges at various time-points throughout the neonatal period.

Hypothermia and neonatal encephalopathy

Data from large randomized clinical trials indicate that therapeutic hypothermia, using either selective head cooling or systemic cooling, is an effective therapy for neonatal encephalopathy. Infants selected for cooling must meet the criteria outlined in published clinical trials. The implementation of cooling needs to be performed at centers that have the capability to manage medically complex infants. Because the majority of infants who have neonatal encephalopathy are born at community hospitals, centers that perform cooling should work with their referring hospitals to implement education programs focused on increasing the awareness and identification of infants at risk for encephalopathy, and the initial clinical management of affected infants.

Healthcare-associated infections in the hospitalized neonate: a review

Healthcare-associated infections in the neonatal intensive care unit add considerably to hospital stays and costs, and contribute to numerous adverse outcomes, including death. The relatively high prevalence of healthcare-associated infections among neonates is secondary to the newborn's underdeveloped immune system, the need for frequent invasive procedures, and generally prolonged hospitalization. Central line associated bloodstream infections (CLABSI) are the most common form of healthcare-associated infection, with coagulase-negative Staphylococcus species (CONS) being the most commonly cultured microorganism. Interpretation of culture results in the setting of any suspected healthcare-associated infection can be made difficult by the possibility that a recovered organism represents a commensal contaminant, rather than an actual cause of infection. This is especially true in the case of a blood culture that grows CONS during evaluation for suspected CLABSI. This article provides an overview of the epidemiology, diagnosis, prevention, and treatment of healthcare-associated infections in the NICU.

Surfactant replacement therapy for preterm and term neonates with respiratory distress

Respiratory failure secondary to surfactant deficiency is a major cause of morbidity and mortality in preterm infants. Surfactant therapy substantially reduces mortality and respiratory morbidity for this population. Secondary surfactant deficiency also contributes to acute respiratory morbidity in late-preterm and term neonates with meconium aspiration syndrome, pneumonia/sepsis, and perhaps pulmonary hemorrhage; surfactant replacement may be beneficial for these infants. This statement summarizes the evidence regarding indications, administration, formulations, and outcomes for surfactant-replacement therapy. The clinical strategy of intubation, surfactant administration, and extubation to continuous positive airway pressure and the effect of continuous positive airway pressure on outcomes and surfactant use in preterm infants are also reviewed.

Physiologic underpinnings for clinical problems in moderately preterm and late preterm infants

This article highlights some of the important developmental characteristics that underpin common problems seen in moderate and late preterm infants. Preterm birth is associated with an increased prevalence of clinical problems caused by functional immaturities in a wide variety of organ systems, acquired problems, and problems associated with inadequate monitoring and/or follow-up plans. There are variations in the degree of maturation among infants of similar gestational ages because the developmental process is nonlinear. Therefore, different organ systems mature at rates and trajectories that are specific to their functions. A better understanding of these principles can help guide optimal treatment strategies.

Randomized controlled trial of slow vs rapid enteral feeding advancements on the clinical outcomes of preterm infants with birth weight 750-1250 g

OBJECTIVE

To evaluate the effect of slow vs rapid rates of advancement of enteral feed volumes on the clinical outcomes in preterm infants with 750-1250 g birth weight.

STUDY DESIGN

A total of 92 stable neonates 750-1250 g and gestational age <32 weeks were randomly allocated to enteral feeding advancement of 20 mL/kg/d (n = 46) or 30 mL/kg/d (n = 46). The primary outcome was days to reach full enteral feeding, defined as 180 mL/kg/d. Secondary outcomes included rates of necrotizing enterocolitis (NEC) and culture-proven sepsis, days of parenteral nutrition (PN), length of hospital stay, and growth end points.

RESULTS

Neonates in the rapid-feeding advancement group achieved full enteral volume of feedings earlier than the slower advancement group. They received significantly fewer days of PN, exhibited a shorter time to regain birth weight, and had a shorter duration of hospital stay. The incidence of NEC and the number of episodes of feeding intolerance were not significantly different between the groups, whereas the incidence of culture-proven late-onset sepsis was significantly less in infants receiving a rapid feeding advancement. Excluding infants who were small for gestational age at birth, the incidence of extrauterine growth restriction was significantly reduced in the rapid-advancement group at 28 days and at hospital discharge.

CONCLUSION

Rapid enteral feeding advancements in 750-1250 g birth weight infants reduce the time to reach full enteral feeding and the use of PN administration. Rapid-advancement enteral feed also decreases extrauterine growth restriction with improved short-term outcomes for these high-risk infants.

Management of neonates with suspected or proven early-onset bacterial sepsis

With improved obstetrical management and evidence-based use of intrapartum antimicrobial therapy, early-onset neonatal sepsis is becoming less frequent. However, early-onset sepsis remains one of the most common causes of neonatal morbidity and mortality in the preterm population. The identification of neonates at risk for early-onset sepsis is frequently based on a constellation of perinatal risk factors that are neither sensitive nor specific. Furthermore, diagnostic tests for neonatal sepsis have a poor positive predictive accuracy. As a result, clinicians often treat well-appearing infants for extended periods of time, even when bacterial cultures are negative. The optimal treatment of infants with suspected early-onset sepsis is broad-spectrum antimicrobial agents (ampicillin and an aminoglycoside). Once a pathogen is identified, antimicrobial therapy should be narrowed (unless synergism is needed). Recent data suggest an association between prolonged empirical treatment of preterm infants (≥5 days) with broad-spectrum antibiotics and higher risks of late onset sepsis, necrotizing enterocolitis, and mortality. To reduce these risks, antimicrobial therapy should be discontinued at 48 hours in clinical situations in which the probability of sepsis is low. The purpose of this clinical report is to provide a practical and, when possible, evidence-based approach to the management of infants with suspected or proven early-onset sepsis.

Epidemiology and diagnosis of health care-associated infections in the NICU

Health care-associated infections in the NICU are a major clinical problem resulting in increased morbidity and mortality, prolonged length of hospital stays, and increased medical costs. Neonates are at high risk for health care-associated infections because of impaired host defense mechanisms, limited amounts of protective endogenous flora on skin and mucosal surfaces at time of birth, reduced barrier function of neonatal skin, the use of invasive procedures and devices, and frequent exposure to broad-spectrum antibiotics. This statement will review the epidemiology and diagnosis of health care-associated infections in newborn infants.

Strategies for prevention of health care-associated infections in the NICU

Health care-associated infections in the NICU result in increased morbidity and mortality, prolonged lengths of stay, and increased medical costs. Neonates are at high risk of acquiring health care-associated infections because of impaired host-defense mechanisms, limited amounts of protective endogenous flora on skin and mucosal surfaces at time of birth, reduced barrier function of their skin, use of invasive procedures and devices, and frequent exposure to broad-spectrum antibiotic agents. This clinical report reviews management and prevention of health care-associated infections in newborn infants.

Policy statement—Recommendations for the prevention of perinatal group B streptococcal (GBS) disease

The Centers for Disease Control and Prevention (CDC) guidelines for the prevention of perinatal group B streptococcal (GBS) disease were initially published in 1996. The American Academy of Pediatrics (AAP) also published a policy statement on this topic in 1997. In 2002, the CDC published revised guidelines that recommended universal antenatal GBS screening; the AAP endorsed these guidelines and published recommendations based on them in the 2003 Red Book. Since then, the incidence of early-onset GBS disease in neonates has decreased by an estimated 80%. However, in 2010, GBS disease remained the leading cause of early-onset neonatal sepsis. The CDC issued revised guidelines in 2010 based on evaluation of data generated after 2002. These revised and comprehensive guidelines, which have been endorsed by the AAP, reaffirm the major prevention strategy--universal antenatal GBS screening and intrapartum antibiotic prophylaxis for culture-positive and high-risk women--and include new recommendations for laboratory methods for identification of GBS colonization during pregnancy, algorithms for screening and intrapartum prophylaxis for women with preterm labor and premature rupture of membranes, updated prophylaxis recommendations for women with a penicillin allergy, and a revised algorithm for the care of newborn infants. The purpose of this policy statement is to review and discuss the differences between the 2002 and 2010 CDC guidelines that are most relevant for the practice of pediatrics.

Aerosol delivery to ventilated newborn infants: historical challenges and new directions

There are several aerosolized drugs which have been used in the treatment of neonatal respiratory illnesses, such as bronchodilators, diuretics, and surfactants. Preclinical in vitro and in vivo studies identified a number of variables that affect aerosol efficiency, including particle size, aerosol flows, nebulizer choice, and placement. Nevertheless, an optimized aerosol drug delivery system for mechanically ventilated infants still does not exist. Increasing interest in this form of drug delivery requires more controlled and focused research of drug/device combinations appropriate for the neonatal population. In the present article, we review the research that has been conducted thus far and discuss the next steps in developing the optimal aerosol delivery system for use in mechanically ventilated neonates.

Biomarkers for late-onset neonatal sepsis

The diagnosis of healthcare-associated infections is problematic because of the overlap between clinical signs associated with 'normal' physiological disturbances and those of bacteremia or fungemia. Earlier diagnosis of sepsis in critically ill infants would enable timely administration of antibiotics and discontinuation of treatment in infants with a low probability of sepsis. A recent study by Ng et al. identified two novel biomarkers for late-onset neonatal sepsis: the des-arginine variant of serum amyloid A and apolipoprotein C-II. These markers may be of value in the identification of neonates with bacteremia or fungemia.

The state of systemic circulation, collapsed or preserved defines the need for hyperoxic or normoxic resuscitation in neonatal mice with hypoxia-ischemia

BACKGROUND

The return of spontaneous circulation (ROSC) is a primary goal of resuscitation. For neonatal resuscitation the International Liaison Committee on Resuscitation (ILCOR) recommends oxygen concentrations ranging from 21% to 100%.

AIMS AND METHODS

This study (a) compared the efficacy of resuscitation with room air (RA) or 100% O(2) in achieving ROSC in 46 neonatal mice with circulatory collapse induced by lethal hypoxia-ischemia (HI) and (b) determined whether re-oxygenation with RA or 100% O(2) alters the extent of HI cerebral injury in mice with preserved systemic circulation (n=31). We also compared changes in generation of reactive oxygen species (ROS) in cerebral mitochondria in response to re-oxygenation with RA or 100% O(2).

RESULT

In HI-mice with collapsed circulation re-oxygenation with 100% O(2) versus RA resulted in significantly greater rate of ROSC. In HI-mice with preserved systemic circulation and regional (unilateral) cerebral ischemia the restoration of cerebral blood flow was significantly faster upon re-oxygenation with 100% O(2), than RA. However, no difference in the extent of brain injury was detected. Regardless of the mode of re-oxygenation, reperfusion in these mice was associated with markedly accelerated ROS production in brain mitochondria.

CONCLUSION

In murine HI associated with circulatory collapse the resuscitation limited to re-oxygenation with 100% O(2) is superior to the use of RA in achievement of the ROSC. However, in HI-mice with preserved systemic circulation hyperoxic re-oxygenation has no benefit over the normoxic brain recovery.

Does head cooling with mild systemic hypothermia affect requirement for blood pressure support?

OBJECTIVE

Our goal was to evaluate whether head cooling with mild systemic hypothermia for neonatal encephalopathy is associated with greater requirement for volume or inotrope support.

PATIENTS AND METHODS

We studied term infants (>/=36 weeks) with moderate-to-severe neonatal encephalopathy plus abnormal amplitude integrated electroencephalography, randomly assigned to head cooling for 72 hours starting within 6 hours of birth, with the rectal temperature maintained at 34.5 degrees C +/- 0.5 degrees C (n = 112), or conventional care (n = 118).

DESIGN

This was a multicenter randomized, controlled study (the CoolCap trial). The primary outcome was the time relationship between mean arterial blood pressure and subsequent administration of inotropes or volume administration.

RESULTS

Pooled data from 0 to 76 hours after randomization revealed no difference in mean arterial blood pressure between groups and significantly lower mean heart rate during cooling. The use of inotropes or volume was related to preceding mean arterial blood pressure and not to treatment group in the first 24 hours. In contrast, from 24 to 76 hours, there was no effect of mean arterial blood pressure, but there was an overall reduction in pressure support over time and significantly more frequent pressure support in the cooled group than in controls.

CONCLUSIONS

Mild systemic hypothermia did not affect arterial blood pressure or initial treatment with inotropes or volume in infants with moderate-to-severe encephalopathy but was associated with an apparent change in physician behavior, with slower withdrawal of therapy in cooled infants.

Mitochondrial dysfunction contributes to alveolar developmental arrest in hyperoxia-exposed mice

This study investigated whether mitochondrial dysfunction contributes to alveolar developmental arrest in a mouse model of bronchopulmonary dysplasia (BPD). To induce BPD, 3-day-old mice were exposed to 75% O2. Mice were studied at two time points of hyperoxia (72 h or 2 wk) and after 3 weeks of recovery in room air (RA). A separate cohort of mice was exposed to pyridaben, a complex-I (C-I) inhibitor, for 72 hours or 2 weeks. Alveolarization was quantified by radial alveolar count and mean linear intercept methods. Pulmonary mitochondrial function was defined by respiration rates, ATP-production rate, and C-I activity. At 72 hours, hyperoxic mice demonstrated significant inhibition of C-I activity, reduced respiration and ATP production rates, and significantly decreased radial alveolar count compared with controls. Exposure to pyridaben for 72 hours, as expected, caused significant inhibition of C-I and ADP-phosphorylating respiration. Similar to hyperoxic littermates, these pyridaben-exposed mice exhibited significantly delayed alveolarization compared with controls. At 2 weeks of exposure to hyperoxia or pyridaben, mitochondrial respiration was inhibited and associated with alveolar developmental arrest. However, after 3 weeks of recovery from hyperoxia or 2 weeks after 72 hours of exposure to pyridaben alveolarization significantly improved. In addition, there was marked normalization of C-I and mitochondrial respiration. The degree of hyperoxia-induced pulmonary simplification and recovery strongly (r(2) = 0.76) correlated with C-I activity in lung mitochondria. Thus, the arrest of alveolar development induced by either hyperoxia or direct inhibition of mitochondrial oxidative phosphorylation indicates that bioenergetic failure to maintain normal alveolar development is one of the fundamental mechanisms responsible for BPD.

Hypoxic stress exacerbates hyperoxia-induced lung injury in a neonatal mouse model of bronchopulmonary dysplasia

BACKGROUND

Premature infants with lung injury often experience intermittent episodes of hypoxemia.

OBJECTIVE

This study investigates whether intermittent hypoxemia exacerbates oxidative stress and lung injury in neonatal mice in a hyperoxia-induced model of bronchopulmonary dysplasia (BPD).

METHODS

For the BPD model, 3-day-old C57Bl/6J mice were exposed to hyperoxia (65% O(2)) for 4 weeks (O(2) group) or to hyperoxia and intermittent (10 min daily) hypoxia (O(2) + H group). Upon completion of O(2) or O(2) + H exposure, the degree of pulmonary alveolarization and granulocytic infiltration were examined. The severity of oxidative injury in lungs was defined by tissue glutathione and protein carbonyl content. Data were compared to those in naïve mice and mice subjected only to intermittent hypoxia.

RESULTS

Hyperoxia-exposed mice exhibited a dramatic (p < 0.0001) decrease of alveolarization, significantly increased granulocytic infiltration (p < 0.0001) and increased protein carbonyl content (p = 0.04) compared to naïve mice. However, O(2) + H mice demonstrated significantly (p = 0.03) fewer alveoli compared to their O(2) counterparts. This was associated with a significantly (p = 0.02) decreased pulmonary total/oxidized glutathione ratio and a significant (p = 0.03) elevation of protein carbonyl content.

CONCLUSIONS

Thus, intermittent hypoxic stress during hyperoxic induction of BPD in mice potentiates oxidative stress in lung tissue and exacerbates alveolar developmental arrest.

The ductus arteriosus rarely requires treatment in infants > 1000 grams

We sought to determine the rate of spontaneous closure of the ductus arteriosus (DA) in very-low-birth-weight infants. This prospective observational study included 65 infants whose birth weight (BW) < 1500 g. Echocardiograms were done on day of life (DOL) 3 and 7, weekly for the first month, and bimonthly until ligation, discharge, or death. Treatment was reserved for infants with heart failure, acute renal impairment, or those with significant persistent or escalating respiratory support. Chi-square tests, Student T tests, and logistic regression models were used to identify possible associations between spontaneous ductal closure by DOL 7 and predictor variables. Patterns of spontaneous DA closure over time were examined using Kaplan-Meier survival analysis. The DA closed spontaneously in 49% infants by DOL 7. Rates of spontaneous closure by DOL 7 differed significantly by BW strata: 67% for BW > 1000 g, 31% for BW <or= 1000 g ( P < 0.01). Ninety-seven percent of infants > 1000 g did not require intervention, and the DA closed spontaneously prior to discharge in 94%. In a logistic regression model, only BW > 1000 g and male gender were significantly associated with spontaneous closure by 1 week of life. The median time to spontaneous closure differed significantly between infants in the two BW strata: 7 days for > 1000 g versus 56 days for <or= 1000 g ( P < 0.001). Intervention for the patent DA in infants > 1000 g BW is rarely indicated. In infants <or= 1000 g BW, deferring treatment decisions until at least 1 week of life may avoid unnecessary treatment exposure.

Systemic inflammation following hind-limb ischemia-reperfusion affects brain in neonatal mice

Antenatal and postnatal infection and inflammation are associated with neurological injury in neonates. However, no direct role for systemic inflammation in mediating neurodamage has been shown. The study was aimed to determine whether systemic inflammation following ischemia-reperfusion (IR) of an organ remotely located from the brain results in cerebral injury. Neonatal mice were subjected to 2 h of hind-limb IR. At 48 h of reperfusion, brains were examined for activation of microglia and caspase-3. Lungs were assessed for pulmonary edema and granulocyte infiltration. The levels of circulating inflammatory mediators were measured at 24 h of reperfusion. In a separate cohort of mice, changes in the cerebral and hind-limb blood flow were measured. All data were compared to that in sham mice. Compared to shams the degree of pulmonary edema in IR mice was 33% (p = 0.04) greater. This was associated with significantly (p = 0.0006) greater granulocytic infiltration and a markedly increased level of circulating cytokines. The brains of these same mice exhibited significantly (p = 0.02) greater numbers of caspase-3-immunopositive cells and activation of microglia compared to sham mice. These data indicate that systemic inflammation following IR in the organ remote from the brain can induce neuroinflammation and cerebral proapoptotic changes.