Achieved oxygen saturations and retinopathy of prematurity in extreme preterms

OBJECTIVE

To identify achieved oxygen saturations (SpO₂) associated with increased risk of severe retinopathy of prematurity (ROP).

DESIGN

This is a secondary analysis of the Surfactant Positive Airway Pressure and Pulse Oximetry Trial (SUPPORT)randomised controlled trial. SpO₂ was recorded up to 36 weeks' postmenstrual age. Saturations through 9 postnatal weeks were explored graphically, and logistic regression models were created to predict severe ROP.

SETTING

20 centres of the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network.

PATIENTS

984 surviving infants of 24-27 weeks' gestational age born in 2005-2009.

INTERVENTIONS

SUPPORT targeted SpO₂ to a lower (85%-89%) or higher (91%-95%) range through 36 weeks' postmenstrual age or off respiratory support.

MAIN OUTCOME MEASURES

Severe ROP defined as threshold ROP, ophthalmological surgery or bevacizumab treatment.

RESULTS

There were statistically significant interactions between duration of oxygen supplementation and percentage of time in certain achieved saturation ranges. Specifically, for infants who spent at least 2 weeks on oxygen in postnatal weeks 1-5, a higher percentage of time at 91%-96% SpO₂ was associated with increased odds of severe ROP. For infants who spent at least 3 weeks on oxygen in postnatal weeks 6-9, a higher percentage of time at 97%-100% SpO₂ was associated with increased odds of severe ROP. Other significant risk factors were lower gestational age and birth weight, non-Hispanic white versus black race, prospectively defined severe illness, late-onset sepsis or meningitis, and clinical centre.

CONCLUSIONS

Among extremely preterm survivors to discharge, the association between SpO₂ and severe ROP depended on the timing and duration of oxygen supplementation.

Effect of Therapeutic Hypothermia Initiated After 6 Hours of Age on Death or Disability Among Newborns With Hypoxic-Ischemic Encephalopathy: A Randomized Clinical Trial

IMPORTANCE

Hypothermia initiated at less than 6 hours after birth reduces death or disability for infants with hypoxic-ischemic encephalopathy at 36 weeks' or later gestation. To our knowledge, hypothermia trials have not been performed in infants presenting after 6 hours.

OBJECTIVE

To estimate the probability that hypothermia initiated at 6 to 24 hours after birth reduces the risk of death or disability at 18 months among infants with hypoxic-ischemic encephalopathy.

DESIGN, SETTING, AND PARTICIPANTS

A randomized clinical trial was conducted between April 2008 and June 2016 among infants at 36 weeks' or later gestation with moderate or severe hypoxic-ischemic encephalopathy enrolled at 6 to 24 hours after birth. Twenty-one US Neonatal Research Network centers participated. Bayesian analyses were prespecified given the anticipated limited sample size.

INTERVENTIONS

Targeted esophageal temperature was used in 168 infants. Eighty-three hypothermic infants were maintained at 33.5°C (acceptable range, 33°C-34°C) for 96 hours and then rewarmed. Eighty-five noncooled infants were maintained at 37.0°C (acceptable range, 36.5°C-37.3°C).

MAIN OUTCOMES AND MEASURES

The composite of death or disability (moderate or severe) at 18 to 22 months adjusted for level of encephalopathy and age at randomization.

RESULTS

Hypothermic and noncooled infants were term (mean [SD], 39 [2] and 39 [1] weeks' gestation, respectively), and 47 of 83 (57%) and 55 of 85 (65%) were male, respectively. Both groups were acidemic at birth, predominantly transferred to the treating center with moderate encephalopathy, and were randomized at a mean (SD) of 16 (5) and 15 (5) hours for hypothermic and noncooled groups, respectively. The primary outcome occurred in 19 of 78 hypothermic infants (24.4%) and 22 of 79 noncooled infants (27.9%) (absolute difference, 3.5%; 95% CI, -1% to 17%). Bayesian analysis using a neutral prior indicated a 76% posterior probability of reduced death or disability with hypothermia relative to the noncooled group (adjusted posterior risk ratio, 0.86; 95% credible interval, 0.58-1.29). The probability that death or disability in cooled infants was at least 1%, 2%, or 3% less than noncooled infants was 71%, 64%, and 56%, respectively.

CONCLUSIONS AND RELEVANCE

Among term infants with hypoxic-ischemic encephalopathy, hypothermia initiated at 6 to 24 hours after birth compared with noncooling resulted in a 76% probability of any reduction in death or disability, and a 64% probability of at least 2% less death or disability at 18 to 22 months. Hypothermia initiated at 6 to 24 hours after birth may have benefit but there is uncertainty in its effectiveness.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT00614744.

Early blood pressure, antihypotensive therapy and outcomes at 18-22 months' corrected age in extremely preterm infants

OBJECTIVE

To investigate the relationships between early blood pressure (BP) changes, receipt of antihypotensive therapy and 18-22 months' corrected age (CA) outcomes for extremely preterm infants.

DESIGN

Prospective observational study of infants 23(0/7)-26(6/7) weeks' gestational age (GA). Hourly BP values and antihypotensive therapy exposure in the first 24 h were recorded. Four groups were defined: infants who did or did not receive antihypotensive therapy in whom BP did or did not rise at the expected rate (defined as an increase in the mean arterial BP of ≥5 mm Hg/day). Random-intercept logistic modelling controlling for centre clustering, GA and illness severity was used to investigate the relationship between BP, antihypotensive therapies and infant outcomes.

SETTING

Sixteen academic centres of the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network.

MAIN OUTCOME MEASURES

Death or neurodevelopmental impairment/developmental delay (NIDD) at 18-22 months' CA.

RESULTS

Of 367 infants, 203 (55%) received an antihypotensive therapy, 272 (74%) survived to discharge and 331 (90%) had a known outcome at 18-22 months' CA. With logistic regression, there was an increased risk of death/NIDD with antihypotensive therapy versus no treatment (OR 1.836, 95% CI 1.092 to 3.086), but not NIDD alone (OR 1.53, 95% CI 0.708 to 3.307).

CONCLUSIONS

Independent of early BP changes, antihypotensive therapy exposure was associated with an increased risk of death/NIDD at 18-22 months' CA when controlling for risk factors known to affect survival and neurodevelopment.

CLINICAL TRIAL REGISTRATION NUMBER

clinicaltrials.gov #NCT00874393.

Definitions of cardiovascular insufficiency and relation to outcomes in critically ill newborn infants

BACKGROUND

We previously reported on the overall incidence, management, and outcomes in infants with cardiovascular insufficiency (CVI). However, there are limited data on the relationship of the specific different definitions of CVI to short-term outcomes in term and late preterm newborn infants.

OBJECTIVE

This study aims to evaluate how four definitions of CVI relate to short-term outcomes and death.

STUDY DESIGN

The previously reported study was a multicenter, prospective cohort study of 647 infants ≥ 34 weeks gestation admitted to a Neonatal Research Network (NRN) newborn intensive care unit (NICU) and mechanically ventilated (MV) during their first 72 hours. The relationship of five short-term outcomes at discharge and four different definitions of CVI were further analyzed.

RESULTS

All the four definitions were associated with greater number of days on MV and days on O2. The definition using a threshold blood pressure (BP) measurement alone was not associated with days of full feeding, days in the NICU or death. The definition based on the treatment of CVI was associated with all the outcomes including death.

CONCLUSIONS

The definition using a threshold BP alone was not consistently associated with adverse short-term outcomes. Using only a threshold BP to determine therapy may not improve outcomes.

Neuroimaging and neurodevelopmental outcome in extremely preterm infants

BACKGROUND

Extremely preterm infants are at risk for neurodevelopmental impairment (NDI). Early cranial ultrasound (CUS) is usual practice, but near-term brain MRI has been reported to better predict outcomes. We prospectively evaluated MRI white matter abnormality (WMA) and cerebellar lesions, and serial CUS adverse findings as predictors of outcomes at 18 to 22 months' corrected age.

METHODS

Early and late CUS, and brain MRI were read by masked central readers, in a large cohort (n = 480) of infants <28 weeks' gestation surviving to near term in the Neonatal Research Network. Outcomes included NDI or death after neuroimaging, and significant gross motor impairment or death, with NDI defined as cognitive composite score <70, significant gross motor impairment, and severe hearing or visual impairment. Multivariable models evaluated the relative predictive value of neuroimaging while controlling for other factors.

RESULTS

Of 480 infants, 15 died and 20 were lost. Increasing severity of WMA and significant cerebellar lesions on MRI were associated with adverse outcomes. Cerebellar lesions were rarely identified by CUS. In full multivariable models, both late CUS and MRI, but not early CUS, remained independently associated with NDI or death (MRI cerebellar lesions: odds ratio, 3.0 [95% confidence interval: 1.3-6.8]; late CUS: odds ratio, 9.8 [95% confidence interval: 2.8-35]), and significant gross motor impairment or death. In models that did not include late CUS, MRI moderate-severe WMA was independently associated with adverse outcomes.

CONCLUSIONS

Both late CUS and near-term MRI abnormalities were associated with outcomes, independent of early CUS and other factors, underscoring the relative prognostic value of near-term neuroimaging.

Incidence, management, and outcomes of cardiovascular insufficiency in critically ill term and late preterm newborn infants

OBJECTIVE

The objective of this study was to characterize the incidence, management, and short-term outcomes of cardiovascular insufficiency (CVI) in mechanically ventilated newborns, evaluating four separate prespecified definitions.

STUDY DESIGN

Multicenter, prospective cohort study of infants ≥34 weeks gestational age (GA) and on mechanical ventilation during the first 72 hours. CVI was prospectively defined as either (1) mean arterial pressure (MAP) < GA; (2) MAP < GA + signs of inadequate perfusion; (3) any therapy for CVI; or (4) inotropic therapy. Short-term outcomes included death, days on ventilation, oxygen, and to full feedings and discharge.

RESULTS

Of 647 who met inclusion criteria, 419 (65%) met ≥1 definition of CVI. Of these, 98% received fluid boluses, 36% inotropes, and 17% corticosteroids. Of treated infants, 46% did not have CVI as defined by a MAP < GA ± signs of inadequate perfusion. Inotropic therapy was associated with increased mortality (11.1 vs. 1.3%; p < 0.05).

CONCLUSION

More than half of the infants met at least one definition of CVI. However, almost half of the treated infants met none of the definitions. Inotropic therapy was associated with increased mortality. These findings can help guide the design of future studies of CVI in newborns.

Respiratory outcomes of the surfactant positive pressure and oximetry randomized trial (SUPPORT)

OBJECTIVE

To explore the early childhood pulmonary outcomes of infants who participated in the National Institute of Child Health and Human Development's Surfactant Positive Airway Pressure and Pulse Oximetry Randomized Trial (SUPPORT), using a factorial design that randomized extremely preterm infants to lower vs higher oxygen saturation targets and delivery room continuous positive airway pressure (CPAP) vs intubation/surfactant.

STUDY DESIGN

The Breathing Outcomes Study, a prospective secondary study to the Surfactant Positive Airway Pressure and Pulse Oximetry Randomized Trial, assessed respiratory morbidity at 6-month intervals from hospital discharge to 18-22 months corrected age (CA). Two prespecified primary outcomes-wheezing more than twice per week during the worst 2-week period and cough longer than 3 days without a cold-were compared for each randomized intervention.

RESULTS

One or more interviews were completed for 918 of the 922 eligible infants. The incidences of wheezing and cough were 47.9% and 31.0%, respectively, and did not differ between the study arms of either randomized intervention. Infants randomized to lower vs higher oxygen saturation targets had a similar risk of death or respiratory morbidity (except for croup and treatment with oxygen or diuretics at home). Infants randomized to CPAP vs intubation/surfactant had fewer episodes of wheezing without a cold (28.9% vs 36.5%; P<.05), respiratory illnesses diagnosed by a doctor (47.7% vs 55.2%; P<.05), and physician or emergency room visits for breathing problems (68.0% vs 72.9%; P<.05) by 18-22 months CA.

CONCLUSION

Treatment with early CPAP rather than intubation/surfactant is associated with less respiratory morbidity by 18-22 months CA. Longitudinal assessment of pulmonary morbidity is necessary to fully evaluate the potential benefits of respiratory interventions for neonates.

Evaluating retinopathy of prematurity screening guidelines for 24- to 27-week gestational age infants

OBJECTIVE

To determine whether current retinopathy of prematurity (ROP) screening guidelines adequately identify treatable ROP in a contemporary cohort of extremely low gestation infants.

STUDY DESIGN

Data from the Surfactant, Positive Pressure, and Pulse Oximetry Randomized Trial were used. Inborn infants of 24 (0)/7 to 27 (6)/7 weeks gestational age (GA) with consent before delivery were enrolled in 2005 to 2009. Severe ROP (type 1 ROP or treatment with laser, cryotherapy or bevacizumab) or death was the primary outcome for the randomized trial. Examinations followed the then current AAP (American Academy of Pediatrics) screening recommendations, beginning by 31 to 33 weeks postmenstrual age (PMA).

RESULT

One thousand three hundred and sixteen infants were enrolled in the trial. Nine hundred and ninety-seven of the 1121 who survived to first eye exam had final ROP outcome determined. One hundred and thirty-seven (14% of 997) met criteria for severe ROP and 128 (93%) of those had sufficient data (without missing or delayed exams) to determine age of onset of severe ROP. PMA at onset was 32.1 to 53.1 weeks. In this referral center cohort, 1.4% (14/997) developed severe ROP after discharge.

CONCLUSION

Our contemporary data support the 2013 AAP screening guidelines for ROP for infants of 24 (0)/7 to 27 (6)/7 weeks GA. Some infants do not meet treatment criteria until after discharge home. Post-discharge follow-up of infants who are still at risk for severe ROP is crucial for timely detection and treatment.

Mortality and morbidity of VLBW infants with trisomy 13 or trisomy 18

OBJECTIVE

Little is known about how very low birth weight (VLBW) affects survival and morbidities among infants with trisomy 13 (T13) or trisomy 18 (T18). We examined the care plans for VLBW infants with T13 or T18 and compared their risks of mortality and neonatal morbidities with VLBW infants with trisomy 21 and VLBW infants without birth defects.

METHODS

Infants with birth weight 401 to 1500 g born or cared for at a participating center of the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network during the period 1994-2009 were studied. Poisson regression models were used to examine risk of death and neonatal morbidities among infants with T13 or T18.

RESULTS

Of 52,262 VLBW infants, 38 (0.07%) had T13 and 128 (0.24%) had T18. Intensity of care in the delivery room varied depending on whether the trisomy was diagnosed before or after birth. The plan for subsequent care for the majority of the infants was to withdraw care or to provide comfort care. Eleven percent of infants with T13 and 9% of infants with T18 survived to hospital discharge. Survivors with T13 or T18 had significantly increased risk of patent ductus arteriosus and respiratory distress syndrome compared with infants without birth defects. No infant with T13 or T18 developed necrotizing enterocolitis.

CONCLUSIONS

In this cohort of liveborn VLBW infants with T13 or T18, the timing of trisomy diagnosis affected the plan for care, survival was poor, and death usually occurred early.

Neonatal magnesium levels correlate with motor outcomes in premature infants: a long-term retrospective cohort study

OBJECTIVE

Chronic neurological deficits are a significant complication of preterm birth. Magnesium supplementation has been suggested to have neuroprotective function in the developing brain. Our objective was to determine whether higher neonatal serum magnesium levels were associated with better long-term neurodevelopmental outcomes in very-low birth weight infants.

STUDY DESIGN

A retrospective cohort of 75 preterm infants (<1500 g, gestational age <27 weeks) had follow-up for the outcomes of abnormal motor exam and for epilepsy. Average total serum magnesium level in the neonate during the period of prematurity was the main independent variable assessed, tested using a Wilcoxon rank-sum test.

RESULTS

Higher average serum magnesium level was associated with a statistically significant decreased risk for abnormal motor exam (p = 0.037). A lower risk for epilepsy in the group with higher magnesium level did not reach statistical significance (p = 0.06).

CONCLUSION

This study demonstrates a correlation between higher neonatal magnesium levels and decreased risk for long-term abnormal motor exam. Larger studies are needed to evaluate the hypothesis that higher neonatal magnesium levels can improve long-term neurodevelopmental outcomes.

Pharmacokinetics and safety of a single intravenous dose of myo-inositol in preterm infants of 23-29 wk

BACKGROUND

Myo-inositol given to preterm infants with respiratory distress has reduced death, increased survival without bronchopulmonary dysplasia, and reduced severe retinopathy of prematurity in two randomized trials. Pharmacokinetic (PK) studies in extremely preterm infants are needed before efficacy trials.

METHODS

Infants born in 23-29 wk of gestation were randomized to a single intravenous (i.v.) dose of inositol at 60 or 120 mg/kg or placebo. Over 96 h, serum levels (sparse sampling population PK) and urine inositol excretion were determined. Population PK models were fit using a nonlinear mixed-effects approach. Safety outcomes were recorded.

RESULTS

A single-compartment model that included factors for endogenous inositol production, allometric size based on weight, gestational age strata, and creatinine clearance fit the data best. The central volume of distribution was 0.5115 l/kg, the clearance was 0.0679 l/kg/h, endogenous production was 2.67 mg/kg/h, and the half-life was 5.22 h when modeled without the covariates. During the first 12 h, renal inositol excretion quadrupled in the 120 mg/kg group, returning to near-baseline value after 48 h. There was no diuretic side effect. No significant differences in adverse events occurred among the three groups (P > 0.05).

CONCLUSION

A single-compartment model accounting for endogenous production satisfactorily described the PK of i.v. inositol.

Serum tocopherol levels in very preterm infants after a single dose of vitamin E at birth

OBJECTIVE

Our aim was to examine the impact of a single enteral dose of vitamin E on serum tocopherol levels. The study was undertaken to see whether a single dose of vitamin E soon after birth can rapidly increase the low α-tocopherol levels seen in very preterm infants. If so, this intervention could be tested as a means of reducing the risk of intracranial hemorrhage.

METHODS

Ninety-three infants <27 weeks' gestation and <1000 g were randomly assigned to receive a single dose of vitamin E or placebo by gastric tube within 4 hours of birth. The vitamin E group received 50 IU/kg of vitamin E as dl-α-tocopheryl acetate (Aquasol E). The placebo group received sterile water. Blood samples were taken for measurement of serum tocopherol levels by high-performance liquid chromatography before dosing and 24 hours and 7 days after dosing.

RESULTS

Eighty-eight infants received the study drug and were included in the analyses. The α-tocopherol levels were similar between the groups at baseline but higher in the vitamin E group at 24 hours (median 0.63 mg/dL vs. 0.42 mg/dL, P = .003) and 7 days (2.21 mg/dL vs 1.86 mg/dL, P = .04). There were no differences between groups in γ-tocopherol levels. At 24 hours, 30% of vitamin E infants and 62% of placebo infants had α-tocopherol levels <0.5 mg/dL.

CONCLUSIONS

A 50-IU/kg dose of vitamin E raised serum α-tocopherol levels, but to consistently achieve α-tocopherol levels >0.5 mg/dL, a higher dose or several doses of vitamin E may be needed.

Effectiveness of fundoplication at the time of gastrostomy in infants with neurological impairment

IMPORTANCE

Gastrostomy tube (GT) placement is the most common gastrointestinal operation performed on neonates. Concomitant fundoplication is used variably to prevent complications of gastroesophageal reflux, but its effectiveness is unproven.

OBJECTIVE

To compare the effect of fundoplication at the time of GT placement vs GT placement alone on subsequent reflux-related hospitalizations in infants with neurological impairment.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective, observational cohort study, defined by birth between January 1, 2005, and December 31, 2010, at 42 children's hospitals in the United States, with a 1-year follow-up period among 4163 infants with neurological impairment who underwent GT placement with or without fundoplication during their neonatal intensive care unit stay.

INTERVENTION

Fundoplication and GT placement vs. GT placement alone.

MAIN OUTCOMES AND MEASURES

One-year postprocedural reflux-related hospitalization rates, defined as hospitalization for asthma, mechanical ventilation, gastroesophageal reflux disease, and aspiration or other types of pneumonia. Propensity to undergo concomitant fundoplication was modeled using demographics, prior procedures (tracheostomy and mechanical ventilation), and prior diagnoses (eg, pneumonia, gastroesophageal reflux disease, and other comorbidities).

RESULTS

Overall, 4163 of 42,796 infants (9.7%) with neurological impairment admitted to the neonatal intensive care unit underwent GT placement alone or with fundoplication. Infants who concomitantly underwent fundoplication had more reflux-related hospitalizations during the first year than those who underwent GT placement alone (mean, 1.02; 95% CI, 0.93-1.10 vs mean, 0.92; 95% CI, 0.91-1.00). Of 1404 infants who underwent fundoplication, 1027 (73.1%) were matched based on propensity scores. The mean difference of the matched cohort for any reflux-related hospitalizations was -0.05 (95% CI, -0.20 to 0.15) per year.

CONCLUSIONS AND RELEVANCE

Infants with neurological impairment who underwent fundoplication at the time of GT placement did not have a reduced rate of reflux-related hospitalizations during the first year compared with those who underwent GT placement alone, despite propensity score matching. This may be due to a lack of effectiveness of fundoplication in preventing these complications or due to differences in the patient groups that were inadequately accounted for in the matching.

Use of antihypotensive therapies in extremely preterm infants

OBJECTIVE

To investigate the relationships among blood pressure (BP) values, antihypotensive therapies, and in-hospital outcomes to identify a BP threshold below which antihypotensive therapies may be beneficial.

METHODS

Prospective observational study of infants 23(0/7) to 26(6/7) weeks' gestational age. Hourly BP values and antihypotensive therapy use in the first 24 hours were recorded. Low BP was investigated by using 15 definitions. Outcomes were examined by using regression analysis controlling for gestational age, the number of low BP values, and illness severity.

RESULTS

Of 367 infants enrolled, 203 (55%) received at least 1 antihypotensive therapy. Treated infants were more likely to have low BP by any definition (P < .001), but for the 15 definitions of low BP investigated, therapy was not prescribed to 3% to 49% of infants with low BP and, paradoxically, was administered to 28% to 41% of infants without low BP. Treated infants were more likely than untreated infants to develop severe retinopathy of prematurity (15% vs 8%, P = .03) or severe intraventricular hemorrhage (22% vs 11%, P < .01) and less likely to survive (67% vs 78%, P = .02). However, with regression analysis, there were no significant differences between groups in survival or in-hospital morbidity rates.

CONCLUSIONS

Factors other than BP contributed to the decision to use antihypotensive therapies. Infant outcomes were not improved with antihypotensive therapy for any of the 15 definitions of low BP investigated.

Neurodevelopmental outcomes in the early CPAP and pulse oximetry trial

BACKGROUND

Previous results from our trial of early treatment with continuous positive airway pressure (CPAP) versus early surfactant treatment in infants showed no significant difference in the outcome of death or bronchopulmonary dysplasia. A lower (vs. higher) target range of oxygen saturation was associated with a lower rate of severe retinopathy but higher mortality. We now report longer-term results from our prespecified hypotheses.

METHODS

Using a 2-by-2 factorial design, we randomly assigned infants born between 24 weeks 0 days and 27 weeks 6 days of gestation to early CPAP with a limited ventilation strategy or early surfactant administration and to lower or higher target ranges of oxygen saturation (85 to 89% or 91 to 95%). The primary composite outcome for the longer-term analysis was death before assessment at 18 to 22 months or neurodevelopmental impairment at 18 to 22 months of corrected age.

RESULTS

The primary outcome was determined for 1234 of 1316 enrolled infants (93.8%); 990 of the 1058 surviving infants (93.6%) were evaluated at 18 to 22 months of corrected age. Death or neurodevelopmental impairment occurred in 27.9% of the infants in the CPAP group (173 of 621 infants), versus 29.9% of those in the surfactant group (183 of 613) (relative risk, 0.93; 95% confidence interval [CI], 0.78 to 1.10; P=0.38), and in 30.2% of the infants in the lower-oxygen-saturation group (185 of 612), versus 27.5% of those in the higher-oxygen-saturation group (171 of 622) (relative risk, 1.12; 95% CI, 0.94 to 1.32; P=0.21). Mortality was increased with the lower-oxygen-saturation target (22.1%, vs. 18.2% with the higher-oxygen-saturation target; relative risk, 1.25; 95% CI, 1.00 to 1.55; P=0.046).

CONCLUSIONS

We found no significant differences in the composite outcome of death or neurodevelopmental impairment among extremely premature infants randomly assigned to early CPAP or early surfactant administration and to a lower or higher target range of oxygen saturation. (Funded by the Eunice Kennedy Shriver National Institute of Child Health and Human Development and the National Heart, Lung, and Blood Institute; SUPPORT ClinicalTrials.gov number, NCT00233324.).

Feasibility study of early blood pressure management in extremely preterm infants

OBJECTIVE

To assess the feasibility of a randomized placebo controlled trial (RCT) of blood pressure (BP) management for extremely preterm infants.

STUDY DESIGN

This was a prospective pilot RCT of infants 23-0/7 to 26-6/7 weeks gestation who had protocol-defined low BP in the first 24 postnatal hours. Enrolled infants were administered a study infusion (dopamine or placebo) and a study syringe medication (hydrocortisone or placebo).

RESULTS

Of the 366 infants screened, 119 (33%) had low BP, 58 (16%) met all entry criteria, and 10 (3%) were enrolled. A total of 161 infants (44%) were ineligible because they received early indomethacin. Only 17% of eligible infants were enrolled. Problems with consent included insufficient time, parent unavailability, and physician unwillingness to enroll critically ill infants. Two infants were withdrawn from the study because of the potential risk of intestinal perforation with simultaneous administration of hydrocortisone and indomethacin.

CONCLUSIONS

This pilot RCT was not feasible because of low eligibility and consent rates. An RCT of BP management for extremely preterm infants may require a waiver of consent for research in emergency care. The frequent use of early indomethacin and the associated risk of intestinal perforation when used with hydrocortisone may limit future investigations to only inotropic medications.

Enrollment of extremely low birth weight infants in a clinical research study may not be representative

BACKGROUND AND OBJECTIVE

The Surfactant Positive Airway Pressure and Pulse Oximetry Randomized Trial (SUPPORT) antenatal consent study demonstrated that mothers of infants enrolled in the SUPPORT trial had significantly different demographics and exposure to antenatal steroids compared with mothers of eligible, but not enrolled infants. The objective of this analysis was to compare the outcomes of bronchopulmonary dysplasia, severe retinopathy of prematurity, severe intraventricular hemorrhage or periventricular leukomalacia (IVH/PVL), death, and death/severe IVH/PVL for infants enrolled in SUPPORT in comparison with eligible, but not enrolled infants.

METHODS

Perinatal characteristics and neonatal outcomes were compared for enrolled and eligible but not enrolled infants in bivariate analyses. Models were created to test the effect of enrollment in SUPPORT on outcomes, controlling for perinatal characteristics.

RESULTS

There were 1316 infants enrolled in SUPPORT; 3053 infants were eligible, but not enrolled. In unadjusted analyses, enrolled infants had significantly lower rates of death before discharge, severe IVH/PVL, death/severe IVH/PVL (all < 0.001), and bronchopulmonary dysplasia (P = .003) in comparison with eligible, but not enrolled infants. The rate of severe retinopathy of prematurity was not significantly different. After adjustment for perinatal factors, enrollment in the trial was not a significant predictor of any of the tested clinical outcomes.

CONCLUSIONS

The results of this analysis demonstrate significant outcome differences between enrolled and eligible but not enrolled infants in a trial using antenatal consent, which were likely due to enrollment bias resulting from the antenatal consent process. Additional research and regulatory review need to be conducted to ensure that large moderate-risk trials that require antenatal consent can be conducted in such a way as to ensure the generalizability of results.

Association of antenatal corticosteroids with mortality and neurodevelopmental outcomes among infants born at 22 to 25 weeks' gestation

CONTEXT

Current guidelines, initially published in 1995, recommend antenatal corticosteroids for mothers with preterm labor from 24 to 34 weeks' gestational age, but not before 24 weeks due to lack of data. However, many infants born before 24 weeks' gestation are provided intensive care.

OBJECTIVE

To determine if use of antenatal corticosteroids is associated with improvement in major outcomes for infants born at 22 and 23 weeks' gestation.

DESIGN, SETTING, AND PARTICIPANTS

Cohort study of data collected prospectively on inborn infants with a birth weight between 401 g and 1000 g (N = 10,541) born at 22 to 25 weeks' gestation between January 1, 1993, and December 31, 2009, at 23 academic perinatal centers in the United States. Certified examiners unaware of exposure to antenatal corticosteroids performed follow-up examinations on 4924 (86.5%) of the infants born between 1993 and 2008 who survived to 18 to 22 months. Logistic regression models generated adjusted odds ratios (AORs), controlling for maternal and neonatal variables.

MAIN OUTCOME MEASURES

Mortality and neurodevelopmental impairment at 18 to 22 months' corrected age.

RESULTS

Death or neurodevelopmental impairment at 18 to 22 months was significantly lower for infants who had been exposed to antenatal corticosteroids and were born at 23 weeks' gestation (83.4% with exposure to antenatal corticosteroids vs 90.5% without exposure; AOR, 0.58 [95% CI, 0.42-0.80]), at 24 weeks' gestation (68.4% with exposure to antenatal corticosteroids vs 80.3% without exposure; AOR, 0.62 [95% CI, 0.49-0.78]), and at 25 weeks' gestation (52.7% with exposure to antenatal corticosteroids vs 67.9% without exposure; AOR, 0.61 [95% CI, 0.50-0.74]) but not in those infants born at 22 weeks' gestation (90.2% with exposure to antenatal corticosteroids vs 93.1% without exposure; AOR, 0.80 [95% CI, 0.29-2.21]). If the mothers had received antenatal corticosteroids, the following events occurred significantly less in infants born at 23, 24, and 25 weeks' gestation: death by 18 to 22 months; hospital death; death, intraventricular hemorrhage, or periventricular leukomalacia; and death or necrotizing enterocolitis. For infants born at 22 weeks' gestation, the only outcome that occurred significantly less was death or necrotizing enterocolitis (73.5% with exposure to antenatal corticosteroids vs 84.5% without exposure; AOR, 0.54 [95% CI, 0.30-0.97]).

CONCLUSION

Among infants born at 23 to 25 weeks' gestation, antenatal exposure to corticosteroids compared with nonexposure was associated with a lower rate of death or neurodevelopmental impairment at 18 to 22 months.

Early onset neonatal sepsis: the burden of group B Streptococcal and E. coli disease continues

BACKGROUND

Guidelines for prevention of group B streptococcal (GBS) infection have successfully reduced early onset (EO) GBS disease. Study results suggest that Escherichia coli is an important EO pathogen.

OBJECTIVE

To determine EO infection rates, pathogens, morbidity, and mortality in a national network of neonatal centers.

METHODS

Infants with EO infection were identified by prospective surveillance at Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Network centers. Infection was defined by positive culture results for blood and cerebrospinal fluid obtained from infants aged ≤72 hours plus treatment with antibiotic therapy for ≥5 days. Mother and infant characteristics, treatments, and outcomes were studied. Numbers of cases and total live births (LBs) were used to calculate incidence.

RESULTS

Among 396 586 LBs (2006-2009), 389 infants developed EO infection (0.98 cases per 1000 LBs). Infection rates increased with decreasing birth weight. GBS (43%, 0.41 per 1000 LBs) and E coli (29%, 0.28 per 1000 LBs) were most frequently isolated. Most infants with GBS were term (73%); 81% with E coli were preterm. Mothers of 67% of infected term and 58% of infected preterm infants were screened for GBS, and results were positive for 25% of those mothers. Only 76% of mothers with GBS colonization received intrapartum chemoprophylaxis. Although 77% of infected infants required intensive care, 20% of term infants were treated in the normal newborn nursery. Sixteen percent of infected infants died, most commonly with E coli infection (33%).

CONCLUSION

In the era of intrapartum chemoprophylaxis to reduce GBS, rates of EO infection have declined but reflect a continued burden of disease. GBS remains the most frequent pathogen in term infants, and E coli the most significant pathogen in preterm infants. Missed opportunities for GBS prevention continue. Prevention of E coli sepsis, especially among preterm infants, remains a challenge.

Prediction of bronchopulmonary dysplasia by postnatal age in extremely premature infants

RATIONALE

Benefits of identifying risk factors for bronchopulmonary dysplasia in extremely premature infants include providing prognostic information, identifying infants likely to benefit from preventive strategies, and stratifying infants for clinical trial enrollment.

OBJECTIVES

To identify risk factors for bronchopulmonary dysplasia, and the competing outcome of death, by postnatal day; to identify which risk factors improve prediction; and to develop a Web-based estimator using readily available clinical information to predict risk of bronchopulmonary dysplasia or death.

METHODS

We assessed infants of 23-30 weeks' gestation born in 17 centers of the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network and enrolled in the Neonatal Research Network Benchmarking Trial from 2000-2004.

MEASUREMENTS AND MAIN RESULTS

Bronchopulmonary dysplasia was defined as a categorical variable (none, mild, moderate, or severe). We developed and validated models for bronchopulmonary dysplasia risk at six postnatal ages using gestational age, birth weight, race and ethnicity, sex, respiratory support, and Fi(O(2)), and examined the models using a C statistic (area under the curve). A total of 3,636 infants were eligible for this study. Prediction improved with advancing postnatal age, increasing from a C statistic of 0.793 on Day 1 to a maximum of 0.854 on Day 28. On Postnatal Days 1 and 3, gestational age best improved outcome prediction; on Postnatal Days 7, 14, 21, and 28, type of respiratory support did so. A Web-based model providing predicted estimates for bronchopulmonary dysplasia by postnatal day is available at https://neonatal.rti.org.

CONCLUSIONS

The probability of bronchopulmonary dysplasia in extremely premature infants can be determined accurately using a limited amount of readily available clinical information.

Risk factors associated with development of persistent coagulase-negative staphylococci bacteremia in the neonate and associated short-term and discharge morbidities

BACKGROUND

Coagulase-negative staphylococci (CoNS) are the most common cause of late-onset sepsis in neonatal intensive care unit settings. Historically, authors have questioned the clinical significance of these bacteremia episodes. Recently, clusters of CoNS bacteremia associated with significant morbidity have been reported. The frequency and importance of these clusters of bacteremia and their associated morbidity remains unclear.

OBJECTIVE

We studied a prolonged cluster of 52 cases of persistent CoNS bacteremia in a level III neonatal intensive care unit to clarify risk factors, morbidity and outcomes associated with persistent CoNS bacteremia.

STUDY DESIGN

A retrospective case-control study of infants with CoNS bacteremia >48 h after initiation of appropriate antibiotics and gestational age-matched control infants was performed. We reviewed patient characteristics prior to and during bacteremia, and outcomes at discharge or death.

RESULTS

Persistently infected infants were significantly more likely to have greater duration of exposure to parenteral nutrition, hydrocortisone, antibiotics, and mechanical ventilation prior to infection. Persistently infected infants were significantly more likely than controls to experience feeding intolerance and to require inotropic support, increased respiratory support, and blood product transfusion during bacteremia. Infants with persistent CoNS bacteremia took longer to achieve full enteral feeds, had higher rates of chronic lung disease and increased length of stay compared to controls. No significant difference in mortality was noted.

CONCLUSIONS

Persistent CoNS bacteremia is associated with clinically significant morbidity including feeding intolerance, respiratory failure, blood transfusion and chronic lung disease in this patient population. This impacts hospital course, increases length of stay and impacts medical needs after discharge. During this study, CoNS bacteremia was difficult to clinically eradicate despite in vitro antibiotic susceptibility.

A low-sodium solution for airway care: results of a multicenter trial

BACKGROUND

Normal saline is sometimes instilled into the endotracheal tube preparatory to airway suctioning, to assist in removing thick secretions. However, saline can damage the antimicrobial properties of airway secretions. We previously described a low-sodium physiologically based solution for airway care and reported a small (n = 60) randomized trial in neonates, which showed trends toward less ventilator-associated pneumonia (VAP) and less chronic lung disease with the new solution. We now report a multicenter trial of that solution.

METHODS

We conducted a before-and-after study with a parallel control group, in 4 level-3 neonatal intensive care units (NICUs). During year 1, all 4 NICUs used saline for airway care. During year 2, one NICU used the test solution exclusively while the other NICUs used saline exclusively. The 2 study outcomes were VAP (cases/1,000 ventilator days) and chronic lung disease, defined 3 ways: supplemental oxygen at 28 days; supplemental oxygen at 36 weeks gestation; and supplemental oxygen on hospital discharge.

RESULTS

During the study period 1,116 neonates had endotracheal intubation for respiratory management. Of those, 1,029 received the standard saline for airway suctioning, and the 87 in NICU 4 received the test solution. NICU 4 had a decrease in VAP rate, from 4.2 VAPs/1,000 ventilator days with saline, to 1.6 VAPs/1,000 ventilator days with the test solution (P = .04), and also had the lowest prevalence of chronic lung disease (P < .001 for each definition).

CONCLUSIONS

The test solution significantly reduced the VAP and chronic lung disease rates.

Neonatal outcomes of extremely preterm infants from the NICHD Neonatal Research Network

OBJECTIVE

This report presents data from the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network on care of and morbidity and mortality rates for very low birth weight infants, according to gestational age (GA).

METHODS

Perinatal/neonatal data were collected for 9575 infants of extremely low GA (22-28 weeks) and very low birth weight (401-1500 g) who were born at network centers between January 1, 2003, and December 31, 2007.

RESULTS

Rates of survival to discharge increased with increasing GA (6% at 22 weeks and 92% at 28 weeks); 1060 infants died at <or=12 hours, with most early deaths occurring at 22 and 23 weeks (85% and 43%, respectively). Rates of prenatal steroid use (13% and 53%, respectively), cesarean section (7% and 24%, respectively), and delivery room intubation (19% and 68%, respectively) increased markedly between 22 and 23 weeks. Infants at the lowest GAs were at greatest risk for morbidities. Overall, 93% had respiratory distress syndrome, 46% patent ductus arteriosus, 16% severe intraventricular hemorrhage, 11% necrotizing enterocolitis, and 36% late-onset sepsis. The new severity-based definition of bronchopulmonary dysplasia classified more infants as having bronchopulmonary dysplasia than did the traditional definition of supplemental oxygen use at 36 weeks (68%, compared with 42%). More than one-half of infants with extremely low GAs had undetermined retinopathy status at the time of discharge. Center differences in management and outcomes were identified.

CONCLUSION

Although the majority of infants with GAs of >or=24 weeks survive, high rates of morbidity among survivors continue to be observed.

Early CPAP versus surfactant in extremely preterm infants

BACKGROUND

There are limited data to inform the choice between early treatment with continuous positive airway pressure (CPAP) and early surfactant treatment as the initial support for extremely-low-birth-weight infants.

METHODS

We performed a randomized, multicenter trial, with a 2-by-2 factorial design, involving infants who were born between 24 weeks 0 days and 27 weeks 6 days of gestation. Infants were randomly assigned to intubation and surfactant treatment (within 1 hour after birth) or to CPAP treatment initiated in the delivery room, with subsequent use of a protocol-driven limited ventilation strategy. Infants were also randomly assigned to one of two target ranges of oxygen saturation. The primary outcome was death or bronchopulmonary dysplasia as defined by the requirement for supplemental oxygen at 36 weeks (with an attempt at withdrawal of supplemental oxygen in neonates who were receiving less than 30% oxygen).

RESULTS

A total of 1316 infants were enrolled in the study. The rates of the primary outcome did not differ significantly between the CPAP group and the surfactant group (47.8% and 51.0%, respectively; relative risk with CPAP, 0.95; 95% confidence interval [CI], 0.85 to 1.05) after adjustment for gestational age, center, and familial clustering. The results were similar when bronchopulmonary dysplasia was defined according to the need for any supplemental oxygen at 36 weeks (rates of primary outcome, 48.7% and 54.1%, respectively; relative risk with CPAP, 0.91; 95% CI, 0.83 to 1.01). Infants who received CPAP treatment, as compared with infants who received surfactant treatment, less frequently required intubation or postnatal corticosteroids for bronchopulmonary dysplasia (P<0.001), required fewer days of mechanical ventilation (P=0.03), and were more likely to be alive and free from the need for mechanical ventilation by day 7 (P=0.01). The rates of other adverse neonatal outcomes did not differ significantly between the two groups.

CONCLUSIONS

The results of this study support consideration of CPAP as an alternative to intubation and surfactant in preterm infants. (ClinicalTrials.gov number, NCT00233324.)

Target ranges of oxygen saturation in extremely preterm infants

BACKGROUND

Previous studies have suggested that the incidence of retinopathy is lower in preterm infants with exposure to reduced levels of oxygenation than in those exposed to higher levels of oxygenation. However, it is unclear what range of oxygen saturation is appropriate to minimize retinopathy without increasing adverse outcomes.

METHODS

We performed a randomized trial with a 2-by-2 factorial design to compare target ranges of oxygen saturation of 85 to 89% or 91 to 95% among 1316 infants who were born between 24 weeks 0 days and 27 weeks 6 days of gestation. The primary outcome was a composite of severe retinopathy of prematurity (defined as the presence of threshold retinopathy, the need for surgical ophthalmologic intervention, or the use of bevacizumab), death before discharge from the hospital, or both. All infants were also randomly assigned to continuous positive airway pressure or intubation and surfactant.

RESULTS

The rates of severe retinopathy or death did not differ significantly between the lower-oxygen-saturation group and the higher-oxygen-saturation group (28.3% and 32.1%, respectively; relative risk with lower oxygen saturation, 0.90; 95% confidence interval [CI], 0.76 to 1.06; P=0.21). Death before discharge occurred more frequently in the lower-oxygen-saturation group (in 19.9% of infants vs. 16.2%; relative risk, 1.27; 95% CI, 1.01 to 1.60; P=0.04), whereas severe retinopathy among survivors occurred less often in this group (8.6% vs. 17.9%; relative risk, 0.52; 95% CI, 0.37 to 0.73; P<0.001). There were no significant differences in the rates of other adverse events.

CONCLUSIONS

A lower target range of oxygenation (85 to 89%), as compared with a higher range (91 to 95%), did not significantly decrease the composite outcome of severe retinopathy or death, but it resulted in an increase in mortality and a substantial decrease in severe retinopathy among survivors. The increase in mortality is a major concern, since a lower target range of oxygen saturation is increasingly being advocated to prevent retinopathy of prematurity. (ClinicalTrials.gov number, NCT00233324.)

Gestational therapy with an angiotensin II receptor antagonist and transient renal failure in a premature infant

The fetotoxic effects of angiotensin converting enzyme inhibitors when used during the second half of pregnancy are well known. The more recently developed angiotensin II receptor antagonists appear to yield similar fetal abnormalities. We report a premature infant born to a 41-year-old mother with a long history of infertility who had received losartan therapy for hypertension throughout an undetected pregnancy. Ultrasound examination 2 days prior to delivery identified a single fetus at 29 weeks gestation, anhydramnios, and an empty fetal bladder. The neonatal course was complicated by oliguria, hyperkalemia, marked renal dysfunction, respiratory failure, joint contractures, and a large anterior fontanelle with widely separated sutures. Hypotension (mean arterial pressure<25 torr) on day 1 responded to volume expansion, dopamine, and hydrocortisone. Serum creatinine reached a maximum of 2.7 mg/dL on day 6 and decreased to 0.4 by day 56. No formal urinalysis was performed, but the urine was reported to be visually clear throughout the course. Although a renal ultrasound on day 2 was normal, a follow-up study at 7 months revealed bilateral generalized parenchymal echogenicity, consistent with medical renal disease. Since then, weight and length have been at the 5th percentile or less, with apparent renal tubular acidosis necessitating the addition of sodium citrate supplements. This case emphasizes the importance of maintaining a high index of suspicion for potential pregnancy when contemplating the use of a drug of this class, and considering serial testing for pregnancy when using such drugs, even in patients with a longstanding history of infertility.

Large vancomycin overdose in two premature infants with minimal toxicity

Two premature infants received 10-fold overdoses of vancomycin with resulting peak plasma concentrations > 300 microg/mL. Discontinuation of vancomycin and watchful waiting were employed, with no specific intervention to accelerate vancomycin clearance. Plasma vancomycin concentration < 40 microg/mL was attained at < 48 hours in one infant and < 72 hours in the other. Although one infant sustained a transient increase in serum creatinine to 1.4 mg/dL, no further evidence of renal, auditory, or other toxicity was detected in either infant acutely or long term. Contemporary preparations of vancomycin appear much less toxic than earlier formulations. Aggressive and invasive interventions to hasten clearance may be unnecessary following overdose in infants with normal or near-normal basal renal function, although careful surveillance for clearance and toxic effects still appear warranted.

Viral infection and antiviral therapy in the neonatal intensive care unit

Viral diseases are leading causes of mortality and morbidity among infants requiring care in the neonatal intensive care unit (NICU), with ongoing discoveries of new viral pathology likely to add to the burdens posed. Many viral diseases in NICU infants are undiagnosed or appreciated only late in the course because of subtle or asymptomatic presentation, confusion with bacterial disease, and failure to consider viral disease. We present an overview of viral disease in NICU infants, with emphasis on pharmacologic agents currently employed for prophylaxis and treatment of such diseases. Advances in molecular biology and popular demand to develop antiviral agents for viral diseases (eg, human immunodeficiency virus) offer great promise for the future.

Risk Factors Associated With Ampicillin-Resistant Infection in Newborns in the Era of Group B Streptococcal Prophylaxis

OBJECTIVES

To document the trend of ampicillin-resistant infections in newborns weighing at least 1500 g and to determine factors associated with ampicillin-resistant neonatal early-onset infection in the era of routine group B streptococcal prophylaxis.

DESIGN

Case-control study.

SETTING

Referral hospital with level I through level III nurseries.Patients Newborns aged 0 to 7 days with cultures positive for bacterial infection, born from January 1994 to August 2002 (n = 53). Random controls were matched to admission year and nursery level (n = 159).

MAIN OUTCOME MEASURES

Trends of and factors associated with ampicillin-resistant infections.

RESULTS

Trends in our institution were the same as those found in some recent reports, a decrease in group B streptococcal early-onset infections without a concomitant increase in gram-negative early-onset infections. Specifically, when stratified by birth weight, newborns weighing at least 1500 g had no increase in gram-negative pathogens in the eras both before and after group B streptococcal prophylaxis (0.8 per 1000 live births to 0.3 per 1000 live births; incidence ratio, 2.3 [95% confidence interval, 0.5-10.9]). No increase in ampicillin resistance was seen during the same 3 periods (50%, 60%, and 50%, respectively; P =.97). Independent risk factors associated with ampicillin-resistant early-onset infection were intrapartum antibiotics for a 24-hour duration or longer (odds ratio, 4.8 [95% confidence interval, 1.0-23.3]) and clinical chorioamnionitis (odds ratio, 9.2 [95% confidence interval, 2.6-32.9]).

CONCLUSIONS

No increase in early-onset infections with gram-negative or ampicillin-resistant pathogens was detected. Ampicillin-resistant early-onset infection was associated with intrapartum antibiotics given for 24 hours or longer prior to delivery and with clinical chorioamnionitis. Ampicillin sodium and gentamicin sulfate remain appropriate initial antibiotic therapies for early-onset infection in newborns weighing at least 1500 g and without these risk factors.

Invasive neonatal candidiasis: an overview

Until the 1980s, recovery of Candida species from normally sterile body sites in high-risk infants was often dismissed as contamination. Such delay in diagnosis often resulted in death, multifocal disease, or significant morbidity, outcomes that still occur today. Problems establishing the diagnosis of invasive candidiasis persist, while the frequency of this infection in increasingly fragile and smaller premature infants appears to be increasing. Standard culture techniques have limited sensitivity and often take several days for recovery of Candida when positive. Heightened suspicion and improved diagnostic tools are needed. Less toxic antifungal agents with better tissue penetration profiles will help. Better understanding of risk factors and pathogenesis may permit more effective strategies for prophylaxis and appropriately targeted empiric antifungal therapy.

Central nervous system candidiasis in the high-risk neonate

Central nervous system involvement in neonatal candidiasis is not rare, although possibly less frequent than in previous decades. In addition to increasing the potential for neurodevelopmental morbidity, this infection poses major challenges in establishing diagnosis and assuring adequate treatment. In the setting of candidemia or other severe invasive candida disease, suggestive imaging studies or inflammatory changes in cerebrospinal fluid should prompt careful consideration of central nervous system candidiasis even if culture of the fluid is negative. Although delivery of amphotericin to cerebrospinal fluid appears much better in premature infants than in older individuals, the availability of other agents with superior delivery to the central nervous system suggests that strong consideration be given to their use as alternative or adjunct therapy if central nervous system involvement appears likely. Careful surveillance for neurodevelopmental sequelae may permit early detection, timely rehabilitative intervention, and potentially better long-term functional outcomes.

Neonatal early-onset group B streptococcal disease in the era of intrapartum chemoprophylaxis: residual problems

OBJECTIVE

To identify limitations of current strategies for intrapartum prophylaxis of neonatal early-onset group B streptococcal infection.

METHODS

Retrospective review of infants with culture-proven early-onset group B streptococcal infection admitted to two nurseries and their mothers from July 1992, when ACOG and AAP guidelines for intrapartum prophylaxis were first issued, through December 2001. Information was recorded regarding clinical risk factors for early-onset group B streptococcal infection, collection and processing of specimens to assess maternal colonization, delivery of prophylaxis, duration of hospitalization before delivery, and outcome.

RESULTS

Among 92 infants with early-onset group B streptococcal infection admitted from 23 institutions, 68 had received no intrapartum prophylaxis. Of these 68 who received no prophylaxis, 34 had identifiable risk factors before delivery (32 clinical, two positive maternal culture), while 34 had no risk factors. Prenatal culture for group B streptococcal colonization was performed in 22 of these women. Of the 18 cultures that were negative for group B streptococcus, 15 were obtained using suboptimal culture technique or were collected more than 6 weeks before delivery. Of the 68 with no prophylaxis, 14 required extracorporeal membrane oxygenation and three died. Of the 24 who received some intrapartum prophylaxis, nine had received >/=two doses for >/=4 hours immediately before delivery. Among the 24 receiving some intrapartum prophylaxis, two required extracorporeal membrane oxygenation and one died. No deaths occurred in those who received >4 hours of prophylaxis, although one such infant required extracorporeal membrane oxygenation. After the CDC guidelines were issued in May 1996, there was a decrease both in the number of cases of early-onset group B streptococcal infection (56 versus 36) as well as in the number with clinical risk factors but no intrapartum prophylaxis (24/56 (43%) versus 5/28 (18%)).

CONCLUSIONS

The use of clinical risk factors alone will inevitably result in missed opportunity for intrapartum antibiotic prophylaxis. With maternal screening, false-negative results will be reduced but not necessarily eliminated by assuring that specimens are obtained from proper sites using selective media within 6 weeks of delivery. Better strategies are needed to assure timely administration when prophylaxis is indicated. The nine neonates with early-onset group B streptococcal infection despite intrapartum antibiotics for the recommended duration illustrate that disease may occur even when guidelines are implemented appropriately.

Persistent bacteremia and outcome in late onset infection among infants in a neonatal intensive care unit

BACKGROUND

Persistent bacteremia despite antibiotic therapy has been correlated with adverse outcomes, including focal suppurative complications and death. Coagulase-negative staphylococci (CONS) are the most common cause of nosocomial infection in infants requiring neonatal intensive care and might yield more substantial pathology if infection were persistent.

METHODS

To compare the severity and features of persistent infection by CONS with those of other bacteria, we reviewed infants admitted to our neonatal intensive care unit from 1990 through 2001 who developed bacteremia at >5 days of age with recovery of the same bacterial species from blood for >24 h after initiation of antibiotic therapy to which the organism was susceptible. Cases were excluded if a focal complication was already present with the initial positive culture or if the medical record was unavailable. Outcomes of interest included focal suppurative complications, death attributable to infection and duration of hospitalization among survivors.

RESULTS

We identified 62 infants with sustained infection, caused by CONS in 30 and by other organisms in 32 [10 Gram-negative, 22 Gram-positive (16 Staphylococcus aureus)]. Infants with persistent CONS had significantly lower birth weight and gestational age, but no difference was found for multiple other clinical and demographic risk factors. Indwelling vascular catheters were present at diagnosis in 85% of the infants (CONS 26 of 30, non-CONS 27 of 32). Responses of bacteremia to catheter removal vs. in situ treatment did not differ between the groups. No differences were observed for death from all causes (27 vs. 34%), death attributable to infection (6 vs. 12%) or duration of hospitalization among survivors [median (interquartile range): 102 (73 to 167) 107.5 (89 to 130) days]. Focal suppurative complications were significantly more frequent in infants persistently infected with non-CONS (28 vs. 3%; P = 0.01). Duration of persistence correlated with focal complication in non-CONS infants (r = 0.988; P < 0.001).

CONCLUSIONS

Although persistent infection with CONS occurs in significantly smaller and less mature infants than with non-CONS, death is no more frequent and focal complications are significantly less frequent. Infants with persistent infection should undergo aggressive evaluation for focal complications, with the yield expected to be higher in those with non-CONS.

Intraparenchymal brain hemorrhage and remote soft tissue arteriovenous malformation in a newborn infant

Congenital arteriovenous malformations (AVMs) often present with congestive heart failure. Such pathologic vascular structures typically occur in cranial, hepatic, or pulmonary locations and are usually associated with overlying external visible, tactile, or audible abnormalities. These vascular anomalies may also be associated with such complications as thromboembolic events, coagulopathy, and localized hemorrhage. We present a newborn infant with an occult but hemodynamically significant parascapular AVM who presented with an intraparenchymal brain hemorrhage, which we suspect to be a remote complication of the AVM.

Maternal and transplacental pharmacokinetics of cefazolin

OBJECTIVE

To evaluate the intrapartum pharmacokinetics of cefazolin, including delivery to amniotic fluid (AF) and fetal compartments, and to ascertain that adequate cefazolin concentrations are attained to exceed the mean concentration inhibiting 90% (MIC(90)) of group B streptococcus strains.

METHODS

Cefazolin (1 g) was administered intravenously at five separate time intervals (0.5, 1, 2, 4, and 6 hours) before elective cesarean at term to 26 women with intact membranes and with no significant infections or cardiovascular, liver, or renal disease. Samples of maternal blood, cord blood, and AF were obtained at the time of delivery. Exact collection times relative to cefazolin infusion were noted. Amniotic fluid contaminated with blood or meconium was excluded. Cefazolin concentration was measured by high-pressure liquid chromatography.

RESULTS

All maternal and cord plasma cefazolin levels, except one, were above the MIC(90) for Streptococcus agalactiae (group B streptococcus). For AF, all cefazolin levels, except two, were above the MIC(90).

CONCLUSIONS

Cefazolin concentrations greater than or equal to the MIC(90) for group B streptococcus were attained in nearly all maternal, fetal, and AF samples. This information, together with the knowledge that there is rare resistance of group B streptococcus to cefazolin, supports the use of cefazolin as a better alternative than clindamycin or erythromycin for group B streptococcus prophylaxis in patients with a nonanaphylactic penicillin allergy.

Persistently positive cultures and outcome in invasive neonatal candidiasis

BACKGROUND

A persistently positive culture >24 h after starting antibiotic therapy has been correlated with adverse outcome in several invasive bacterial infections, but few reports address persistent positivity and outcome in infections caused by fungi and other pathogens that replicate more slowly and therefore may succumb less quickly to therapy.

METHODS

To assess whether positive culture >24 h after achieving target doses (amphotericin > or =0.5 mg/kg/day or fluconazole > or =6 mg/kg/day) of systemic antifungal therapy predicts focal infectious complication(s) or death from infection, we compared neonatal intensive care unit infants who had persistent (P+) or nonpersistent (P-) positive cultures with invasive candidiasis (clinical signs of infection and recovery of Candida from a normally sterile site) at this center from January 1, 1981, through June 30, 1999. Infants who died < or = 24 h after attaining target dosing, recovered without therapy, had a focal infectious complication already present at the time target dosing was achieved or were diagnosed with invasive candidiasis only postmortem were excluded.

RESULTS

We identified 58 P+ (29, 12 and 7 had positive cultures for >7, >14 and > or =21 days, respectively) and 38 P- infants. No differences were found between P+ and P- for birth weight; gestational age; gender; onset age; central vascular catheters; necrotizing enterocolitis, surgery or bacterial sepsis; or duration of parenteral nutrition, antibiotics, tracheal intubation or postnatal steroids. P+ were more likely to have blood or cerebrospinal fluid involvement (68 vs. 45%, P = 0.03). Distribution of Candida species was similar (albicans in 53 vs. 63% for P+ vs. P-). P+ were significantly more likely to develop later "fungus ball" uropathy (16 of 56 vs. 2 of 32, P = 0.01), to develop renal infiltration (11 of 56 vs. 1 of 32, P = 0.03) and to die from invasive candidiasis (11 of 58 vs. 0 of 38, P = 0.003) than P-. P+ were also more likely to develop endocarditis, abscess, ventriculitis and invasive dermatitis, although P > 0.05. Focal complication increased as duration of P+ increased (48, 55, 67 and 71% at >1, >7, >14 and > or =21 days, P = 0.06). When comparing only those with positive blood and/or cerebrospinal fluid culture, similar patterns were observed, although only death and focal complication or death from invasive candidiasis attained significance.

CONCLUSIONS

These observations suggest that in neonatal invasive candidiasis: (1) cultures usually remain positive >24 h after attaining target antifungal doses; (2) aggressive imaging for focal complications may be reserved for infants with persistently positive cultures after several days of antifungal therapy at target doses or have signs strongly suggestive of focal complication; (3) focal complications and/or death from candidiasis increase with persistence; (4) focal complications increase with duration of persistence; (5) serial culture of infected site(s) helps predict outcome and the need for aggressive surveillance and intervention for focal complications.

Lack of vancomycin-associated nephrotoxicity in newborn infants: a case-control study

OBJECTIVE

The purpose of this study was to compare the incidence of nephrotoxicity, defined as doubling of baseline serum creatinine concentration, in newborn infants with peak vancomycin serum concentrations </=40 microg/mL at steady state to infants with peak vancomycin serum concentrations >40 microg/mL. A secondary objective was to correlate concomitant disease states and potentially nephrotoxic drug therapy with rises in serum creatinine in vancomycin recipients.

METHODS

Newborn infants with culture-proven Staphylococcus aureus or coagulase-negative staphylococcal septicemia who received vancomycin therapy for >3 days between 1985 and 1995 were identified from an existing database and a review of medical record. All 69 patients included in the study had serial serum creatinine determinations, including a baseline value within 48 hours of starting treatment with vancomycin, and serum vancomycin concentrations determined after at least three doses, with peak and trough concentrations determined 1 hour after a 60-minute infusion and 15 to 30 minutes before a dose, respectively. Infants with congenital renal or cardiac anomalies were excluded. Demographic characteristics, vancomycin dosing regimen, serum vancomycin concentrations and sample times, concomitant drug therapy, and disease states were recorded. Patients were divided into group A (peak vancomycin concentration </=40 microg/mL) and group B (peak vancomycin concentration >40 microg/mL). The change in serum creatinine concentration between the start and end of vancomycin therapy was determined. Nephrotoxicity was identified if serum creatinine doubled at any time from the start to the end of vancomycin therapy. Alternative definitions of nephrotoxicity (any rise in serum creatinine to >0.6 mg/dL or new abnormalities of urine sediment) were used in additional analyses.

RESULTS

A total of 69 evaluable patients (gestational age, 28.9 +/- 3.0 weeks; birth weight, 1219 +/- 516 g) were identified, 61 in group A and 8 in group B. Six patients in group A underwent doubling of serum creatinine concentration during vancomycin therapy, whereas none in group B did so. Serum creatinine doubled to >0.6 mg/dL in only 3 infants (all in group A). Any increase in serum creatinine to >0.6 mg/dL was seen in 10 infants, 9 of whom were in group A. No confounding variable, including previous or concomitant underlying disease states associated with renal dysfunction or treatment with other potentially nephrotoxic agents, were associated with a significant rise in serum creatinine.

CONCLUSION

Vancomycin-associated nephrotoxicity is rare in neonates, even with serum peak concentrations >40 microg/mL.

Frequent resistance of clinical group B streptococci isolates to clindamycin and erythromycin

OBJECTIVE

To determine both the frequency of reported penicillin allergy in parturients and the frequency of resistance in vitro of clinical isolates of group B streptococci to clindamycin and erythromycin.

METHODS

One hundred clinical isolates of group B streptococci were tested to determine the frequency of resistance to clindamycin, erythromycin, penicillin G, vancomycin, and cefazolin. The frequency of beta-lactam allergy and reported allergic reaction also were recorded for all consecutive laboring women during the 4-month study.

RESULTS

The frequency of group B streptococcal resistance to clindamycin was 15% and to erythromycin was 16%. No isolates were resistant to penicillin G, vancomycin, or cefazolin. Twelve percent of the 963 women who delivered during the study reported a penicillin allergy, but only 30% of those could describe their allergic reaction.

CONCLUSION

In vitro resistance of group B streptococci to clindamycin and erythromycin occurred frequently in this population. Whereas the importance of this finding in vivo is uncertain, it raises concern about the possibility of inadequate prophylaxis using currently recommended alternatives in penicillin-allergic patients. Artful questioning of women reporting penicillin allergy may lessen the likelihood of using these less desirable agents in the setting of intrapartum antimicrobial prophylaxis.

Successful treatment of neonatal arterial thromboses with recombinant tissue plasminogen activator

Seven newborns were treated with recombinant tissue plasminogen activator for arterial thromboses. Complete lysis occurred in four of seven and partial in two of seven patients. Serious bleeding complications were observed in two of seven patients. This and published experience suggest that successful lysis with recombinant tissue plasminogen activator occurs in most patients and that hemorrhagic complications are unusual but are not.

Ureaplasma urealyticum and chronic lung disease in very low birth weight infants during the exogenous surfactant era

BACKGROUND

An association between recovery of Ureaplasma urealyticum from the respiratory tract of very low birth weight (VLBW) infants (< or =1500 g) and later chronic lung disease (CLD) was reported by several authors before the routine use of exogenous surfactant (SURF). We sought to assess whether this relation persists in the era of routine SURF.

METHODS

We prospectively studied a cohort of 105 VLBW infants who required mechanical ventilation at < 12 h of age. Tracheal aspirates for U. urealyticum culture were obtained before administration of SURF or antibiotics. Clinicians were unaware of U. urealyticum status. Chest radiographs at 28 days were reviewed by a single pediatric radiologist, blinded to U. urealyticum status. Sample size was predetermined to detect a 30% increase in CLD among those with U. urealyticum recovery from tracheal culture (U. urealyticum-positive) with alpha <0.05 and beta <0.20.

RESULTS

Of the study infants 22 were U. urealyticum-positive and 83 were U. urealyticum-negative. No differences were found between the groups for birth weight, gestational age, gender, inborn, antenatal or postnatal steroid use, SURF therapy, non-U. urealyticum infection, necrotizing enterocolitis, patent ductus arteriosus, intraventricular hemorrhage or cystic periventricular leukomalacia. At 28 days U. urealyticum-positive patients were significantly more likely to have CLD than U. urealyticum-negative [15 of 22 (68%) vs. 30 of 83 (36%); P < 0.02]. The U. urealyticum-positive patients also required significantly longer courses of supplemental oxygen and mechanical ventilation. No significant differences were found for CLD at 36 weeks postconception or duration of hospitalization, although type II error could not be excluded for these secondary endpoints.

CONCLUSIONS

Respiratory U. urealyticum at or shortly after birth remains associated with CLD at 28 days despite routine use of SURF. Controlled trials of anti-Ureaplasma therapy in U. urealyticum-positive VLBWs as soon after birth as possible may determine whether CLD, duration of respiratory support and attendant costs can be decreased.

Improving the timing of antibiotic administration to high-risk newborns

OBJECTIVES

To describe the timing of initiation of administration of parenteral antibiotics to infants with suspected sepsis at birth, identify barriers to prompt administration, and assess the effectiveness of subsequent interventions designed to minimize these barriers. The goals were to administer antibiotics within 1 hour of the physician order and within 2 hours of birth with more than 80% compliance for both goals.

STUDY DESIGN

Retrospective chart review and prospective interventions involved 488 infants born at the University of Michigan Medical Center with indications for antibiotic therapy at birth. After an initial audit of the charts of 56 infants and the identification of poor compliance with the goals, unit policies and educational programs were developed to facilitate timely antibiotic administration. After a second audit demonstrated improvement but failure to attain the target compliance rates, review of individual cases with the responsible physician and nurse was initiated. Time intervals between birth, writing the order for antibiotics, noting the order by the nurse, and administration of antibiotics were tracked for an additional 20 months after these interventions.

RESULTS

Before the interventions, antibiotics were administered to 28% of infants within 1 hour of the physician order (mean +/- SEM 1.58 +/- 0.11 hours) and to 19% within 2 hours of birth (3.12 +/- 0.16 hr). By the conclusion of the study, antibiotics were administered to 87% (p < 0.0001) of infants within 1 hour of the physician order (0.79 +/- 0.04 hour; p < 0.001) and to 92% (p < 0.0001) within 2 hours of birth (1.26 +/- 0.06 hours; p < 0.001).

CONCLUSIONS

Administration of the first dose of parenteral antibiotics to newborns with suspected sepsis at birth frequently takes more than 1 hour after the order is written and more than 2 hours after birth. Efforts to identify and minimize common barriers significantly improved the timing of antibiotic administration. Additional improvement was attained by means of continued surveillance and individual feedback to caregivers of infants when timing objectives were not fulfilled.

Group C streptococcal infection in a term newborn infant

Group C streptococci were recovered from the cerebrospinal fluid of a term infant with symptoms whose mother had received intrapartum antibiotic therapy for chorioamnionitis. This case highlights that beta-hemolytic streptococci of Lancefield groups other than A or B can be isolated from a normally sterile site and should be considered as pathogens. It also underscores the potential importance of sampling cerebrospinal fluid in an infant with symptomatic suspected sepsis, especially in the setting of exposure to maternal antimicrobial agents.