Adverse effects of COVID-19 pandemic on a multicenter randomized controlled trial

OBJECTIVE

Describe the effects of the COVID-19 pandemic on subject enrollment in a multicenter randomized controlled trial.

STUDY DESIGN

We assessed the number of eligible infants approached and consented for enrollment over five separate epochs including baseline, peak pandemic, and gradual but incomplete recovery.

RESULT

The pandemic had a major effect on ability to approach parents for consent. Parents approached dropped from 95.4% baseline to 13.1% in the peak pandemic epoch and has not recovered to baseline even in the just-completed post-pandemic epoch (84.9%). Despite the decrease in subjects approached, there was no significant change in the overall consent rate for the study CONCLUSION: The pandemic has significantly limited ability to approach parents of eligible infants for consent, with only partial recovery. Opportunities for interactions of investigators and study coordinators with parents continue to present challenges limiting full recovery.

Online clinical tool to estimate risk of bronchopulmonary dysplasia in extremely preterm infants

OBJECTIVE

Develop an online estimator that accurately predicts bronchopulmonary dysplasia (BPD) severity or death using readily-available demographic and clinical data.

DESIGN

Retrospective analysis of data entered into a prospective registry.

SETTING

Infants cared for at centres of the United States Neonatal Research Network between 2011 and 2017.

PATIENTS

Infants 501-1250 g birth weight and 23 0/7-28 6/7 weeks' gestation.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Separate multinomial regression models for postnatal days 1, 3, 7, 14 and 28 were developed to estimate the individual probabilities of death or BPD severity (no BPD, grade 1 BPD, grade 2 BPD, grade 3 BPD) defined according to the mode of respiratory support administered at 36 weeks' postmenstrual age.

RESULTS

Among 9181 included infants, birth weight was most predictive of death or BPD severity on postnatal day 1, while mode of respiratory support was the most predictive factor on days 3, 7, 14 and 28. The predictive accuracy of the models increased at each time period from postnatal day 1 (C-statistic: 0.674) to postnatal day 28 (C-statistic 0.741). We used these results to develop a web-based model that provides predicted estimates for BPD by postnatal day.

CONCLUSION

The probability of BPD or death in extremely preterm infants can be estimated with reasonable accuracy using a limited amount of readily available clinical information. This tool may aid clinical prognostication, future research, and center-specific quality improvement surrounding BPD prevention.

TRIAL REGISTRATION NUMBER

NCT00063063.

Pulmonary function tests in extremely low gestational age infants at one year of age

RATIONALE

Identifying neonatal and post-discharge exposures among extremely low gestational age newborns (ELGANs) that drive increased pulmonary morbidity and abnormal lung function at 1 year of age proves challenging.

OBJECTIVE

The NIH-sponsored Prematurity and Respiratory Outcomes Program (PROP), evaluated infant pulmonary function tests (iPFTs) at 1 year corrected age to determine which demographic and clinical factors are associated with abnormal lung function.

METHODS

iPFTs were performed on a PROP subcohort of 135 participants following Institutional Review Board (IRB)-approved written consent. Demographic data, Neonatal Intensive Care Unit (NICU) clinical care, and post-NICU exposures were analyzed for association with iPFTs.

MAIN RESULTS

A significant decrease in forced expiratory volume at 0.5 s (FEV_0.5 ) and/or forced expiratory flows at 75% of forced vital capacity (FEF₇₅ ), were associated with male sex and African American race. Clinical factors including longer duration of ventilatory support, exposure to systemic steroids, and weight less than the 10th percentile at 36 weeks postmenstrual age were also associated with airflow obstruction, whereas supplemental oxygen requirement and bronchopulmonary dysplasia were not. Additionally, the need for respiratory medications, technology, or hospitalizations during the first year, ascertained by a quarterly survey, were the only post-NICU factors associated with decreased FEV_0.5 and FEF₇₅ . Only 7% of infants had reversible airflow obstruction.

CONCLUSIONS

Neonatal demographic factors, respiratory support in the NICU, and a history of greater post-NICU medical utilization for respiratory disease had the strongest association with lower lung function at 1 year in ELGANs.

Effect of high-frequency oscillation on pressure delivered by high flow nasal cannula in a premature infant lung model

OBJECTIVE

This study describes the effect of high-frequency oscillation on airway pressure generated by high flow nasal cannula (HFNC) in a premature infant lung model.

DESIGN/METHODS

A premature in 0.5 or 1.0 mL/cmH ₂ O, respiratory rate (RR) of 40 or 60 breaths per min, and tidal volume of 6 mL. Oscillation was achieved by passing the HFNC supply flow through a 3-way solenoid valve operating at 4, 6, 8, or 10 Hz. Airway pressure at the simulated trachea was recorded following equilibration of end-tidal CO ₂ both with and without oscillation.

RESULTS

Superimposing high-frequency oscillations onto HFNC resulted in an average decrease in mean airway pressure of 17.9% (P = .011). The difference between the maximum and minimum airway pressures, ∆ P _min-max, significantly increased as oscillation frequency decreased ( P < .001). Airway pressure during oscillation was 12.8% greater with the 1.0 vs the 0.5 mL/cmH ₂ O compliance at flows > 4 L/min ( P = .031). CO ₂ clearance was 13.1% greater with the 1.0 vs 0.5 mL/cmH ₂ O compliance at oscillation frequencies less than 8 Hz ( P = .015).

CONCLUSION

In this in-vitro study we demonstrate that delivered mean airway pressure decreases when applying high-frequency oscillation to HFNC, while still improving CO₂ clearance. The combination of improved CO ₂ clearance and reduced pressure delivery of this novel noninvasive modality may prove to be a useful improvement in the respiratory care of infants in respiratory distress.

Effect of high frequency oscillatory high flow nasal cannula on carbon dioxide clearance in a premature infant lung model: A bench study

OBJECTIVE

This study compared CO₂ clearance in a premature infant lung model connected to a high flow nasal cannula (HFNC) system supplied with oscillatory versus non-oscillatory flow.

DESIGN/METHODS

The lung model was set to compliance 1.0 mL/cmH₂ O, RR 60 breaths/min, and 6 mL tidal volume. A 100% CO₂ was injected at a constant 15 mL/min. To create oscillation, HFNC flow was interrupted at rates of 4-6-8 and 10 Hz. equilibrated end-tidal CO₂ (ETCO₂ ) was recorded with and without oscillation at set flows of 2-8 L/min and repeated for each oscillation frequency.

RESULTS

Overall ETCO₂ decreased significantly (P < 0.001) during both non-oscillatory and oscillatory HFNC as set flow increased from 2 to 8 L/min by 26.3% and 60.8%, respectively. Oscillatory ETCO₂ levels decreased linearly compared to non-oscillatory HFNC with negligible difference at 2 L/min and a 48.4% difference at 8 L/min (P < 0.001). There were no differences in ETCO₂ levels between oscillation frequencies at any flow except at 6 Hz for which ETCO₂ was significantly lower (P < 0.01) than at 4, 8, and 10 Hz for 5-8 L/min HFNC flows. Amplitude of volume oscillations increased with increasing flow from 0.5 mL at 2 L/min to 4.0 mL at 8 L/min (P < 0.001), and decreased with increasing oscillation frequency.

CONCLUSION

Oscillatory HFNC as compared to non-oscillatory was associated with significantly improved CO₂ clearance in this premature infant lung model. This simple modification of the HFNC system may prove to be a useful enhancement to this mode of non-invasive respiratory support for preterm infants at high risk for respiratory failure.

Management of Neonates Born at ≤34 6/7 Weeks' Gestation With Suspected or Proven Early-Onset Bacterial Sepsis

Early-onset sepsis (EOS) remains a serious and often fatal illness among infants born preterm, particularly among newborn infants of the lowest gestational age. Currently, most preterm infants with very low birth weight are treated empirically with antibiotics for risk of EOS, often for prolonged periods, in the absence of a culture-confirmed infection. Retrospective studies have revealed that antibiotic exposures after birth are associated with multiple subsequent poor outcomes among preterm infants, making the risk/benefit balance of these antibiotic treatments uncertain. Gestational age is the strongest single predictor of EOS, and the majority of preterm births occur in the setting of other factors associated with risk of EOS, making it difficult to apply risk stratification strategies to preterm infants. Laboratory tests alone have a poor predictive value in preterm EOS. Delivery characteristics of extremely preterm infants present an opportunity to identify those with a lower risk of EOS and may inform decisions to initiate or extend antibiotic therapies. Our purpose for this clinical report is to provide a summary of the current epidemiology of preterm neonatal sepsis and provide guidance for the development of evidence-based approaches to sepsis risk assessment among preterm newborn infants.

Management of Neonates Born at ≥35 0/7 Weeks' Gestation With Suspected or Proven Early-Onset Bacterial Sepsis

The incidence of neonatal early-onset sepsis (EOS) has declined substantially over the last 2 decades, primarily because of the implementation of evidence-based intrapartum antimicrobial therapy. However, EOS remains a serious and potentially fatal illness. Laboratory tests alone are neither sensitive nor specific enough to guide EOS management decisions. Maternal and infant clinical characteristics can help identify newborn infants who are at risk and guide the administration of empirical antibiotic therapy. The incidence of EOS, the prevalence and implications of established risk factors, the predictive value of commonly used laboratory tests, and the uncertainties in the risk/benefit balance of antibiotic exposures all vary significantly with gestational age at birth. Our purpose in this clinical report is to provide a summary of the current epidemiology of neonatal sepsis among infants born at ≥35 0/7 weeks' gestation and a framework for the development of evidence-based approaches to sepsis risk assessment among these infants.

Tidal Breathing Measurements at Discharge and Clinical Outcomes in Extremely Low Gestational Age Neonates

RATIONALE

The relationship between respiratory function at hospital discharge and the severity of later respiratory disease in extremely low gestational age neonates is not well defined.

OBJECTIVES

To test the hypothesis that tidal breathing measurements near the time of hospital discharge differ between extremely premature infants with bronchopulmonary dysplasia (BPD) or respiratory disease in the first year of life and those without these conditions.

METHODS

Study subjects were part of the PROP (Prematurity and Respiratory Outcomes Program) study, a longitudinal cohort study of infants born at less than 29 gestational weeks followed from birth to 1 year of age. Respiratory inductance plethysmography was used for tidal breathing measurements before and after inhaled albuterol 1 week before anticipated hospital discharge. Infants were breathing spontaneously and were receiving less than or equal to 1 L/min nasal cannula flow at 21% to 100% fraction of inspired oxygen. A survey of respiratory morbidity was administered to caregivers at 3, 6, 9, and 12 months corrected age to assess for respiratory disease. We compared tidal breathing measurements in infants with and without BPD (oxygen requirement at 36 wk) and with and without respiratory disease in the first year of life. Measurements were also performed in a comparison cohort of term infants.

RESULTS

A total of 765 infants survived to 36 weeks postmenstrual age, with research-quality tidal breathing data in 452 out of 564 tested (80.1%). Among these 452 infants, the rate of postdischarge respiratory disease was 65.7%. Compared with a group of 18 term infants, PROP infants had abnormal tidal breathing patterns. However, there were no clinically significant differences in tidal breathing measurements in PROP infants who had BPD or who had respiratory disease in the first year of life compared with those without these diagnoses. Bronchodilator response was not significantly associated with respiratory disease in the first year of life.

CONCLUSIONS

Extremely premature infants receiving less than 1 L/min nasal cannula support at 21% to 100% fraction of inspired oxygen have tidal breathing measurements that differ from term infants, but these measurements do not differentiate those preterm infants who have BPD or will have respiratory disease in the first year of life from those who do not. Clinical trial registered with www.clinicaltrials.gov (NCT01435187).

An intervention to improve transitions from NICU to ambulatory care: quasi-experimental study

BACKGROUND

Infants born prematurely or with complex medical problems are surviving to discharge in growing numbers and often require significant monitoring and coordination of care in the ambulatory setting. Using Healthcare Failure Modes and Effects Analysis (HFMEA), we identified a large number of potentially serious error points in this transition of care. PURPOSE To test whether a multifaceted intervention that included a health coach to assist families and an enhanced personal health record to improve the quality of information available to parents and community professionals would decrease adverse events and improve family assessment of the transition.

METHODS

Using a concurrent cohort design, infants in one geographic area (pod) of the intensive care nursery received the intervention; infants in two other pods received routine discharge care. Primary outcomes included deaths, sick visits, unplanned readmissions and missed appointments within 1 month of discharge. The family assessed the transition using a modified version of the Care Transitions Measure.

RESULTS

125 intervention infants (54% boys) and 104 control infants (48% boys) were enrolled over 18 months. The groups were similar in maternal education, insurance status, language spoken and number of adults in the home, birth weight and length of stay. At least one adverse outcome occurred in 63 (50.4%) intervention infants and 56 (53.8%) control infants (p=0.55). At 24–48 h post discharge, caregivers in the intervention group had significantly higher scores on the adapted care transitions measure (3.51 vs 3.27, p<0.0001); however, at 30 days, the difference was no longer significant (3.45 vs 3.40, p=0.27).

CONCLUSIONS

A multicomponent discharge intervention designed to address specific problems identified using HFMEA did not reduce certain adverse outcomes in the post-discharge period.

TRIAL REGISTRATION

NCT01088945.

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.

CSF removal in infantile posthemorrhagic hydrocephalus results in significant improvement in cerebral hemodynamics

Rational intervention in infants with posthemorrhagic hydrocephalus (PHH) would be facilitated greatly by bedside measure of impaired cerebral perfusion, as there is substantial evidence that impaired perfusion and oxidative metabolism contribute to irreversible brain injury in hydrocephalus. Near-infrared spectroscopy (NIRS) measures changes in the cerebral concentration of oxygenated and deoxygenated hemoglobin and oxidized cytochrome oxidase at the bedside of infants continuously and noninvasively. The total hemoglobin and the hemoglobin difference signal are derived from the sum and difference, respectively, of oxygenated and deoxygenated hemoglobin. Changes in total hemoglobin reflect changes in cerebral blood volume; our previous work has shown that changes in hemoglobin difference signal reflect changes in cerebral blood flow. We hypothesized that cerebrospinal fluid (CSF) removal in infants with PHH would result in significant increases in cerebral perfusion, cerebral blood volume, and oxidative metabolism, as measured by NIRS. Continuous NIRS recordings were performed during CSF removal on 16 infants with PHH. There was a statistically significant increase in oxygenated hemoglobin (p < 0.001), total hemoglobin (p = 0.001), and hemoglobin difference signal (p = 0.006), but not oxidized cytochrome oxidase, accompanying CSF removal. There was no significant correlation between either the volume of CSF removed (in milliliters per kilogram body weight) or the opening pressure and the change in any of the measured or calculated NIRS signals. These findings demonstrate the pronounced effect of CSF removal on cerebral perfusion in infants with PHH. NIRS may be a useful technique to detect impending cerebral ischemia in such infants and thereby provide a means to guide the rational management of PHH.

Intrapartum fever and unexplained seizures in term infants

OBJECTIVE

Early-onset neonatal seizures are a strong predictor of later morbidity and mortality in term infants. Although an association of noninfectious intrapartum fever with neonatal seizures in term infants has been reported, it was based on only a small number of neonates with seizures. We therefore conducted a case control study to investigate this association further.

METHODS

All term infants with neonatal seizures born at Brigham and Women's Hospital between 1989 and 1996 were identified. For this study, cases consisted of all term neonates with a confirmed diagnosis of seizure born after a trial of labor for whom no proximal cause of seizure could be identified. Infants with sepsis or meningitis were excluded. Four controls matched by parity and date of birth were identified for each case. The rate of intrapartum maternal temperature >100.4 degrees F was compared for case infants and controls. Potential confounding was controlled in logistic regression analysis.

RESULTS

Cases comprised 38 term infants with unexplained seizures after a trial of labor. We identified 152 controls. Infants with seizures were more likely to be born to mothers who were febrile during labor (31.6% vs 9.2%). In almost all cases, the fever developed during labor (94.7% cases, 97.4% controls). At admission, mothers of infants with seizures were not significantly more likely to have factors associated with concern about infection such as a white blood cell count >15 000/mm(3) (28. 9% vs 19.1%) and premature rupture of the membranes (15.8% vs 17.8%). In a logistic regression analysis controlling for confounding factors, intrapartum fever was associated with a 3.4-fold increase in the risk of unexplained neonatal seizures (odds ratio = 3.4, 95% confidence interval = 1.03-10.9).

CONCLUSION

Our data indicate that intrapartum fever, even when unlikely to be caused by infection, is associated with a fourfold increase in the risk of unexplained, early-onset seizures in term infants.

Cerebral intravascular oxygenation correlates with mean arterial pressure in critically ill premature infants

OBJECTIVES

Premature infants experience brain injury, ie, germinal matrix-intraventricular hemorrhage (GMH-IVH) and periventricular leukomalacia (PVL), in considerable part because of disturbances in cerebral blood flow (CBF). Because such infants are susceptible to major fluctuations in mean arterial blood pressure (MAP), impaired cerebrovascular autoregulation would increase the likelihood for the changes in CBF that could result in GMH-IVH and PVL. The objectives of this study were to determine whether a state of impaired cerebrovascular autoregulation could be identified reliably and conveniently at the bedside, the frequency of any such impairment, and the relation of the impairment to the subsequent occurrence of severe GMH-IVH and PVL.

PATIENTS AND METHODS

To monitor the cerebral circulation continuously and noninvasively, we used near-infrared spectroscopy (NIRS) to determine quantitative changes in cerebral concentrations of oxygenated hemoglobin (HbO(2)) and deoxygenated hemoglobin (Hb) from the first hours of life. Our previous experimental study showed a strong correlation between a measure of cerebral intravascular oxygenation (HbD), ie, HbD = HbO(2) - Hb, determined by NIRS, and volemic CBF, determined by radioactive microspheres. We studied 32 very low birth weight premature infants (gestational age: 23-31 weeks; birth weight: 605-1870 g) requiring mechanical ventilation, supplemental oxygen, and invasive blood pressure monitoring by NIRS from 1 to 3 days of age. MAP measured by arterial catheter pressure transducer and arterial oxygen saturation measured by pulse oximetry were recorded simultaneously. The relationship of MAP to HbD was quantitated by coherence analysis.

RESULTS

Concordant changes (coherence scores >. 5) in HbD and MAP, consistent with impaired cerebrovascular autoregulation, were observed in 17 of the 32 infants (53%). Eight of the 17 infants (47%) developed severe GMH-IVH or PVL or both. Of the 15 infants with apparently intact autoregulation, ie, coherence scores <.5, only 2 (13%) developed severe ultrasonographic lesions. Thus, for the entire study population of 32 infants, 8 of the 10 with severe lesions exhibited coherence scores >.5.

CONCLUSIONS

We conclude that NIRS can be used in a noninvasive manner at the bedside to identify premature infants with impaired cerebrovascular autoregulation, that this impairment is relatively common in such infants, and that the presence of this impairment is associated with a high likelihood of occurrence of severe GMH-IVH/PVL.

Enhancement of neonatal innate defense: effects of adding an N-terminal recombinant fragment of bactericidal/permeability-increasing protein on growth and tumor necrosis factor-inducing activity of gram-negative bacteria tested in neonatal cord blood ex vivo

Innate defense against microbial infection requires the action of neutrophils, which have cytoplasmic granules replete with antibiotic proteins and peptides. Bactericidal/permeability-increasing protein (BPI) is found in the primary granules of adult neutrophils, has a high affinity for lipopolysaccharides (or "endotoxins"), and exerts selective cytotoxic, antiendotoxic, and opsonic activity against gram-negative bacteria. We have previously reported that neutrophils derived from newborn cord blood are deficient in BPI (O. Levy et al., Pediatrics 104:1327-1333, 1999). The relative deficiency in BPI of newborns raised the possibility that supplementing the levels of BPI in plasma might enhance newborn antibacterial defense. Here we determined the effects of addition of recombinant 21-kDa N-terminal BPI fragment (rBPI(21)) on the growth and tumor necrosis factor (TNF)-inducing activity of representative gram-negative clinical isolates. Bacteria were tested in citrated newborn cord blood or adult peripheral blood. Bacterial viability was assessed by plating assay, and TNF-alpha release was measured by enzyme-linked immunosorbent assay. Whereas adult blood limited the growth of all isolates except Klebsiella pneumoniae, cord blood also allowed logarithmic growth of Escherichia coli K1/r and Citrobacter koseri. Bacteria varied in their susceptibility to rBPI(21)'s bactericidal action: E. coli K1/r was relatively susceptible (50% inhibitory concentration [IC(50)], approximately 10 nM), C. koseri was intermediate (IC(50), approximately 1,000 nM), Klebsiella pneumoniae was resistant (IC(50), approximately 10,000 nM), and Enterobacter cloacae and Serratia marcescens were highly resistant (IC(50), >10,000 nM). All isolates were potent inducers of TNF-alpha activity in both adult and newborn cord blood. In contrast to its variable antibacterial activity, rBPI(21) consistently inhibited the TNF-inducing activity of all strains tested (IC(50), 1 to 1,000 nM). The antibacterial effects of rBPI(21) were additive with those of a combination of conventional antibiotics typically used to treat bacteremic newborns (ampicillin and gentamicin). Whereas ampicillin and gentamicin demonstrated little inhibition of bacterially induced TNF release, addition of rBPI(21) either alone or together with ampicillin and gentamicin profoundly inhibited release of this cytokine. Thus, supplementing newborn cord blood with rBPI(21) potently inhibited the TNF-inducing activity of a variety of gram-negative bacterial clinical pathogens and, in some cases, enhanced bactericidal activity. These results suggest that administration of rBPI(21) may be of clinical benefit to neonates suffering from gram-negative bacterial infection and/or endotoxemia.

Impaired innate immunity in the newborn: newborn neutrophils are deficient in bactericidal/permeability-increasing protein

OBJECTIVE

The mechanisms by which newborns are at increased risk for invasive bacterial infections have been incompletely defined. A central element of innate immunity to bacterial infection is the neutrophil-a cell that contains cytoplasmic granules replete with antibiotic proteins and peptides. The activity of adult neutrophils against gram-negative bacteria is believed to depend to a significant degree on the presence in neutrophil primary (azurophilic) granules of the 55-kDa bactericidal/permeability-increasing protein (BPI), which binds with high affinity to bacterial lipopolysaccharides and kills gram-negative bacteria. In light of the importance of BPI to antibacterial host defense and to investigate possible factors underlying the risk of neonatal bacterial infections, we determined the relative content of BPI in the neutrophils of adults and newborns.

DESIGN

The cellular content of BPI was determined by Western blotting of neutrophils derived from full-term newborn cord blood (n = 21; mean gestational age: 38.6 weeks) and from adult peripheral blood (n = 22; mean age: 29 years). Extracellular levels of BPI in adult and newborn plasma were assessed by enzyme-linked immunosorbent assay. Neutrophil content of other azurophil granule markers also was assessed: myeloperoxidase by Western blotting and defensin peptides by acid-urea polyacrylamide gel electrophoresis and Coomassie staining. Acid extracts of newborn and adult neutrophils were analyzed for antibacterial activity against serum-resistant encapsulated isolate Escherichia coli K1/r.

RESULTS

The neutrophils of newborns contain at least threefold to fourfold less BPI per cell than adult neutrophils (67 +/- 13 ng per 10(6) cells vs 234 +/- 27 ng per 10(6) cells). The relative BPI-deficiency of newborn neutrophils apparently was not attributable to perinatal stress-related degranulation of intracellular BPI stores because: 1) newborn and adult neutrophils contained nearly identical amounts of 2 microbicidal constituents derived from the same primary (azurophil) granule compartment as BPI (the enzyme myeloperoxidase as well as defensin peptides), and 2) levels of extracellular BPI in newborn plasma, measured by enzyme-linked immunosorbent assay, represent only approximately 2% of cellular BPI content. As predicted by their lower BPI content, newborn neutrophil acid extracts demonstrated significantly lower antibacterial activity against E coli K1/r than did adult neutrophil acid extracts.

CONCLUSION

These data suggest that the neutrophils of newborns are selectively deficient in BPI, a central effector of antibacterial activity against gram-negative bacteria. BPI deficiency correlates with decreased antibacterial activity of newborn neutrophil extracts against serum-resistant E coli and could contribute to the increased incidence of gram-negative sepsis among newborns relative to healthy adults.neonatal sepsis, gram-negative bacteria, endotoxin, neutrophil, polymorphonuclear leukocyte, innate immunity, bactericidal/permeability-increasing protein, defensin, myeloperoxidase.