Kenneth Poole

Validation of the National Institutes of Health consensus definition of bronchopulmonary dysplasia.

Objective. A number of definitions of bronchopulmonary dysplasia (BPD), or chronic lung disease, have been used. A June 2000 National Institute of Child Health and Human Development/National Heart, Lung, and Blood Institute Workshop proposed a severity-based definition of BPD for infants <32 weeks’ gestational age (GA). Mild BPD was defined as a need for supplemental oxygen (O2) for ≥28 days but not at 36 weeks’ postmenstrual age (PMA) or discharge, moderate BPD as O2 for ≥28 days plus treatment with <30% O2 at 36 weeks’ PMA, and severe BPD as O2 for ≥28 days plus ≥30% O2 and/or positive pressure at 36 weeks’ PMA. The objective of this study was to determine the predictive validity of the severity-based, consensus definition of BPD. Methods. Data from 4866 infants (birth weight ≤1000 g, GA <32 weeks, alive at 36 weeks’ PMA) who were entered into the National Institute of Child Health and Human Development Neonatal Research Network Very Low Birth weight (VLBW) Infant Registry between January 1, 1995 and December 31, 1999, were linked to data from the Network Extremely Low Birth Weight (ELBW) Follow-up Program, in which surviving ELBW infants have a neurodevelopmental and health assessment at 18 to 22 months’ corrected age. Linked VLBW Registry and Follow-up data were available for 3848 (79%) infants. Selected follow-up outcomes (use of pulmonary medications, rehospitalization for pulmonary causes, receipt of respiratory syncytial virus prophylaxis, and neurodevelopmental abnormalities) were compared among infants who were identified with BPD defined as O2 for 28 days (28 days definition), as O2 at 36 weeks’ PMA (36 weeks’ definition), and with the consensus definition of BPD. Results. A total of 77% of the neonates met the 28-days definition, and 44% met the 36-weeks definition. Using the consensus BPD definition, 77% of the infants had BPD, similar to the cohort identified by the 28-days definition. A total of 46% of the infants met the moderate (30%) or severe (16%) consensus definition criteria, identifying a similar cohort of infants as the 36-weeks definition. Of infants who met the 28-days definition and 36-weeks definition and were seen at follow-up at 18 to 22 months’ corrected age, 40% had been treated with pulmonary medications and 35% had been rehospitalized for pulmonary causes. In contrast, as the severity of BPD identified by the consensus definition worsened, the incidence of those outcomes and of selected adverse neurodevelopmental outcomes increased in the infants who were seen at follow-up. Conclusion. The consensus BPD definition identifies a spectrum of risk for adverse pulmonary and neurodevelopmental outcomes in early infancy more accurately than other definitions.

Neonatal Candidiasis Among Extremely Low Birth Weight Infants: Risk Factors, Mortality Rates, and Neurodevelopmental Outcomes at 18 to 22 Months

BACKGROUND. Neonatal candidiasis is associated with substantial morbidity and mortality rates. Neurodevelopmental follow-up data for a large multicenter cohort have not been reported. METHODS. Data were collected prospectively for neonates born at <1000 g at National Institute of Child Health and Human Development-sponsored Neonatal Research Network sites between September 1, 1998, and December 31, 2001. Uniform follow-up evaluations, including assessments of mental and motor development with the Bayley Scales of Infant Development II, were completed for all survivors at corrected ages of 18 to 22 months. We evaluated risk factors for the development of neonatal candidiasis, responses to antifungal therapy, and the association between candidiasis and subsequent morbidity and death. RESULTS. The cohort consisted of 4579 infants; 320 of 4579 (7%) developed candidiasis; 307 of 320 had Candida isolated from blood, 27 of 320 had Candida isolated from cerebrospinal fluid, and 13 (48%) of 27 of those with meningitis had negative blood cultures. In multivariate analysis of risk factors on day of life 3, birth weight, cephalosporins, gender, and lack of enteral feeding were associated with development of candidiasis. After diagnosis, most neonates had multiple positive cultures despite antifungal therapy, and 10% of neonates had candidemia for ≥14 days. Death or neurodevelopmental impairment (NDI) was observed for 73% of extremely low birth weight infants who developed candidiasis. Death and NDI rates were greater for infants who had delayed removal or replacement of central catheters (>1 day after initiation of antifungal therapy), compared with infants whose catheters were removed or replaced promptly. CONCLUSIONS. Blood cultures were negative for approximately one half of the infants with Candida meningitis. Persistent candidiasis was common. Delayed catheter removal was associated with increased death and NDI rates.

The Association of Third-Generation Cephalosporin Use and Invasive Candidiasis in Extremely Low Birth-Weight Infants

OBJECTIVES. Previous studies have shown that incidence of invasive candidiasis varies substantially among centers, and previous use of broad-spectrum antibiotics is a risk factor for candidiasis in extremely low birth-weight infants. Differences in center practices, such as antibiotic strategies and the effects of these strategies on center incidence of candidiasis, are not reflected in assessments of an individuals risk of candidiasis. We evaluated the relationship between empirical antibiotic practices for extremely low birth-weight infants and center incidence of candidiasis. METHODS. We studied a cohort of extremely low birth-weight infants who survived ≥72 hours and were admitted to 1 of 12 tertiary centers between 1998 and 2001. Multivariable logistic regression was used to validate previous broad-spectrum antibiotics use as a risk factor for subsequent candidiasis in individual infants. We calculated correlation coefficients to assess the relationship between center incidence of candidiasis with antibiotic practice patterns. RESULTS. There were 3702 infants from 12 centers included, and 284 (7.7%) developed invasive candidiasis. Broad-spectrum antibiotics use was associated with candidiasis for individual infants. Center candidiasis incidence ranged from 2.4% to 20.4%. Center incidence of candidiasis was correlated with average broad-spectrum antibiotics use per infant and average use of broad-spectrum antibiotics with negative cultures per infant. CONCLUSIONS. Center incidences of invasive candidiasis differ substantially, and antibiotic practice differences are possible contributors to center variation in candidiasis risk.

A Cluster-Randomized Trial of Benchmarking and Multimodal Quality Improvement to Improve Rates of Survival Free of Bronchopulmonary Dysplasia for Infants With Birth Weights of Less Than 1250 Grams

OBJECTIVE. We tested whether NICU teams trained in benchmarking and quality improvement would change practices and improve rates of survival without bronchopulmonary dysplasia in inborn neonates with birth weights of <1250 g. METHODS. A cluster-randomized trial enrolled 4093 inborn neonates with birth weights of <1250 g at 17 centers of the National Institute of Child Health and Human Development Neonatal Research Network. Three centers were selected as best performers, and the remaining 14 centers were randomized to intervention or control. Changes in rates of survival free of bronchopulmonary dysplasia were compared between study year 1 and year 3. RESULTS. Intervention centers implemented potentially better practices successfully; changes included reduced oxygen saturation targets and reduced exposure to mechanical ventilation. Five of 7 intervention centers and 2 of 7 control centers implemented use of high-saturation alarms to reduce oxygen exposure. Lower oxygen saturation targets reduced oxygen levels in the first week of life. Despite these changes, rates of survival free of bronchopulmonary dysplasia were all similar between intervention and control groups and remained significantly less than the rate achieved in the best-performing centers (73.3%). CONCLUSIONS. In this cluster-randomized trial, benchmarking and multimodal quality improvement changed practices but did not reduce bronchopulmonary dysplasia rates.

Unimpaired Outcomes for Extremely Low Birth Weight Infants at 18 to 22 Months

OBJECTIVE: The goal was to identify, among extremely low birth weight (≤1000 g) live births, the proportion of infants who were unimpaired at 18 to 22 months of corrected age. METHODS: Unimpaired outcome was defined as Bayley Scales of Infant Development II scores of ≥85, normal neurologic examination findings, and normal vision, hearing, swallowing, and walking. Outcomes were determined for 5250 (86%) of 6090 extremely low birth weight inborn infants. RESULTS: Of the 5250 infants whose outcomes were known at 18 months, 850 (16%) were unimpaired, 1153 (22%) had mild impairments, 1147 (22%) had moderate/severe neurodevelopmental impairments, and 2100 (40%) had died. Unimpaired survival rates varied according to birth weight, from <1% for infants ≤500 g to 24% for infants 901 to 1000 g. The regression model to predict unimpaired survival versus death or impairment for live births (N = 5250) indicated that 25.3% of the variance was derived from infant factors present at birth, including female gender, higher birth weight, singleton birth. The regression model to predict unimpaired survival for discharged infants indicated that most of the variance was derived from combined effects of major neonatal morbidities, neonatal interventions, and maternal demographic features (15.7%) and only 8.5% was derived from infant factors present at birth. CONCLUSIONS: Although <1% of live-born infants of ≤500 g survive free of impairment at 18 months, this increases to almost 24% for infants of 901 to 1000 g. Female gender, singleton birth, higher birth weight, absence of neonatal morbidities, private health insurance, and white race increase the likelihood of unimpaired status.

Prediction of Death for Extremely Low Birth Weight Neonates

Objective. To compare multiple logistic regression and neural network models in predicting death for extremely low birth weight neonates at 5 time points with cumulative data sets, as follows: scenario A, limited prenatal data; scenario B, scenario A plus additional prenatal data; scenario C, scenario B plus data from the first 5 minutes after birth; scenario D, scenario C plus data from the first 24 hours after birth; scenario E, scenario D plus data from the first 1 week after birth. Methods. Data for all infants with birth weights of 401 to 1000 g who were born between January 1998 and April 2003 in 19 National Institute of Child Health and Human Development Neonatal Research Network centers were used (n = 8608). Twenty-eight variables were selected for analysis (3 for scenario A, 15 for scenario B, 20 for scenario C, 25 for scenario D, and 28 for scenario E) from those collected routinely. Data sets censored for prior death or missing data were created for each scenario and divided randomly into training (70%) and test (30%) data sets. Logistic regression and neural network models for predicting subsequent death were created with training data sets and evaluated with test data sets. The predictive abilities of the models were evaluated with the area under the curve of the receiver operating characteristic curves. Results. The data sets for scenarios A, B, and C were similar, and prediction was best with scenario C (area under the curve: 0.85 for regression; 0.84 for neural networks), compared with scenarios A and B. The logistic regression and neural network models performed similarly well for scenarios A, B, D, and E, but the regression model was superior for scenario C. Conclusions. Prediction of death is limited even with sophisticated statistical methods such as logistic regression and nonlinear modeling techniques such as neural networks. The difficulty of predicting death should be acknowledged in discussions with families and caregivers about decisions regarding initiation or continuation of care.

Prolonged Hospital Stay for Extremely Premature Infants: Risk Factors, Center Differences, and the Impact of Mortality on Selecting a Best-Performing Center

OBJECTIVE:The first objective was to identify factors associated with prolonged hospital stay (PHS: hospitalized >42 weeks postmenstrual age) in extremely premature (EP: born less than or equal to 28 weeks gestation) infants. The second objective was to identify a PHS best-performing benchmark center.METHODS:This study was a retrospective cohort analysis of infants born ≤28 weeks gestation and admitted to one of 12 tertiary centers between January 1998 and October 2001. Risk-adjusted odds of PHS, defined as hospitalization beyond 42 weeks postmenstrual age, and the competing outcome, mortality, were assessed using logistic regression models.RESULTS:Among 3892 EP survivors who had complete data for multivariable analysis, 685 (18%) had PHS. Variables contributing to PHS included chronic lung disease (oxygen use at discharge home or 36 week postmenstrual age) (OR 6.75; 95% CI: 5.04 to 9.03), necrotizing enterocolitis requiring surgery (OR 13.83; 95% CI: 8.05 to 23.76), and >two episodes of late-onset sepsis (OR 2.39; 95% CI: 1.66 to 3.44). Centers’ risk-adjusted PHS odds differed from the reference center, which had the lowest incidence of PHS and mortality (overall P-value <0.0001). Mortality contributed to PHS, but in an opposite direction compared to other factors. Centers with lowest PHS odds were among those with highest mortality.CONCLUSIONS:These findings suggest that reduction of CLD, surgical NEC, and late onset sepsis could reduce PHS in EP infants. Risk adjusted odds of PHS and mortality are both crucial for selecting a PHS best-performing center.

Does labor influence neonatal and neurodevelopmental outcomes of extremely-low-birth-weight infants who are born by cesarean delivery?

OBJECTIVE The purpose of this study was to examine the influence of labor on extremely-low-birth-weight infants who were born by cesarean delivery with reference to neonatal and neurodevelopmental outcomes. We hypothesized that infants who are born by cesarean delivery without labor will have better outcomes than those infants who are born by cesarean delivery with labor. STUDY DESIGN This was a retrospective cohort study of extremely-low-birth-weight infants (birth weight, 401-1000 g) who were born by cesarean delivery and cared for in the National Institute for Child Health and Human Development Neonatal Network, during calendar years 1995 to 1997. A total of 1606 extremely-low-birth-weight infants were born by cesarean delivery and survived to discharge. Of these, 1273 infants (80.8%) were examined in the network follow-up clinics at 18 to 22 months of corrected age and had a complete data set (667 infants were born without labor, 606 infants were born with labor). Outcome variables that were examined include intraventricular hemorrhage grade 3 to 4, periventricular leukomalacia, and neurodevelopmental impairment. RESULTS Mothers in the cesarean delivery without labor group were older (P<.001), more likely to be married (P<.05), less likely to be supported by Medicaid (P<.01), more likely to have preeclampsia/hypertension (P<.001), more likely to receive prenatal steroids (P<.005), and less likely to have received antibiotics (P<.001). Infants who were born by cesarean delivery without labor had higher gestational age (P<.001), lower birth weight (P<.01), and were less likely to be outborn (P<.001). By univariate analysis, infants who were born by cesarean delivery with labor had a higher incidence of grade 3 to 4 intraventricular hemorrhage (23.3% vs 12.1%, P<.001), periventricular leukomalacia (8.5% vs 4.7%, P<.02), and neurodevelopmental impairment (41.7% vs 34.6%, P<.02). Logistic regression analysis that controlled for all maternal and neonatal demographic and clinical variables that were statistically associated with labor or no labor revealed that the significant differences in grade 3 to 4 intraventricular hemorrhage, periventricular leukomalacia, and neurodevelopmental impairment were no longer evident. CONCLUSION In extremely-low-birth-weight infants who were born by cesarean delivery and after control for other risk factors, labor does not appear to play a significant role in adverse neonatal outcomes and neurodevelopmental impairment at 18 to 22 months of corrected age.

Association between early postnatal weight loss and death or BPD in small and appropriate for gestational age extremely low-birth-weight infants

Objective:To examine the association between weight loss during the first 10 days of life and the incidence of death or bronchopulmonary dysplasia (BPD) in small for gestational age (SGA) and appropriate for gestational age (AGA) extremely low-birth-weight infants.Design/Methods:This is a retrospective analysis of a cohort of ELBW (birth weight <1000 g) infants from the NICHD Neonatal Research Networks database. The cohort consisted of 9461 ELBW infants with gestational age of 24–29 weeks, admitted to Networks participating centers during calendar years 1994–2002 and surviving at least 72 h after birth. The cohort was divided into two groups, 1248 SGA (with birth weight below 10th percentile for gestational age) and 8213 AGA (with birth weight between 10th and 90th percentile) infants. We identified infants with or without weight loss during the first 10 days of life, which we termed as ‘early postnatal weight loss’ (EPWL). Univariate analyses were used to predict whether EPWL was related to the primary outcome, death or BPD, within each birth weight/gestation category (SGA or AGA). BPD and death were also analyzed separately in relation to EPWL. Logistic regression analysis was done to evaluate the risk of death or BPD in SGA and AGA groups, controlling for maternal and neonatal demographic and clinical factors found to be significant by univariate analysis.Results:SGA ELBW infants had a lower prevalence of EPWL as compared with AGA ELBW infants (81.2 vs 93.7%, respectively, P<0.001). In AGA infants, univariate analysis showed that death or BPD rate was lower in the group of infants with EPWL compared with infants without EPWL (53.4 vs 74.3%, respectively, P<0.001). The BPD (47.2 vs 64%, P<0.001) and death (13.8 vs 32.9%, P<0.001) rate were similarly lower in the EPWL group. The risk-adjusted odds ratios (ORs) showed that EPWL was associated with lower rate of death or BPD (OR 0.47, 95% CI: 0.37–0.60). In SGA infants, on univariate analysis, a similar association between EPWL and outcomes was seen as shown in AGA infants: death or BPD (55.9 vs 75.2%, P<0.001), BPD rate (48.3 vs 62.1%, P=0.002) and rate death (19 vs 40.8%, P<0.001) for those with or without EPWL, respectively. Multiple logistic regression showed that as in AGA ELBW infants, EPWL was associated with lower risk for death or BPD (OR 0.60, 95% CI: 0.41–0.89) among SGA infants.Conclusions:SGA infants experienced less EPWL when compared with their AGA counterparts. EPWL was associated with a lower risk of death or BPD in both ELBW AGA and SGA infants. These data suggest that clinicians who consider the association between EPWL and risk of death or BPD should do so independent of gestation/birth weight status.

340 Reduction in Death or Moderate/Severe Disability by Whole Body Hypothermia for Hypoxic-Ischemic Encephalopathy (HIE)

Background: Post-asphyxial hypothermia is protective in experimental animals; however, there have been no RCT evaluating safety and effectiveness of whole body hypothermia in term infants with HIE.Objective: To assess safety and effectiveness of whole body hypothermia in term infants with moderate and severe HIE.Design/Methods: A RCT was conducted of infants 36 weeks GA admitted 6 h of age with either a) a cord or first (<1 hour) pH <7.0 or BD >16 mEq/dl or b) a perinatal event and need for resuscitation, AND evidence of moderate or severe HIE by a certified examiner. Infants were randomized to normothermia (NORMO) or whole body cooling to 33.5 C esophageal (HYPO) for 72 h followed by rewarming by on site-research personnel using the Cincinnati Sub-Zero system. Primary outcome was death or disability at 18 mos: severe disability defined as ANY: Bayley MDI<70, Gross Motor Function (GMF) level 3–5, hearing impairment requiring aids, or blindness or moderate disability defined as MDI 85–70 AND either GMF 2, hearing impairment with no amplification or seizure disorder.Results: Of 798 screened infants, 239 were eligible, and 208 were randomized; 102 to HYPO and 106 to NORMO. Target temperature was achieved in HYPO within 90 min and remained constant throughout 72 h. Adverse events were similar among HYPO infants (n=19) and NORMO (n=15), p=0.38. At 18 mos, primary outcome data were available for 204 of the 208 infants. Death or moderate/severe disability occurred in 45 (45%) infants in HYPO and 64 (62%) in NORMO: Risk Ratio (RR) (95%CI) 0.72 (0.55–0.93) with # needed treat (NNT)=6. The risk of death was 24% in HYPO and 36% in NORMO, RR 0.66 (0.43–1.01). The risk of death or disability after moderate HIE was RR 0.67 (0.44–1.03) and after severe HIE was 0.82 (0.64–1.06). For HYPO and NORMO respectively, the risks of disabling CP was 19.7% and 28.6%, RR 0.69 (0.38–1.26), blindness was 5.5% and 14.3%, RR 0.38(0.12–1.19) and hearing impairment requiring aids was 4.0% and 6.3%, RR 0.64 (0.15–2.75).Conclusions: We have demonstrated the effectiveness and safety of whole body hypothermia in term infants with moderate and severe HIE, defined by rigorous criteria, using certified examiners and trained personnel to implement and monitor the intervention and outcome.