Level and volume of neonatal intensive care and mortality in very-low-birth-weight infants.

BACKGROUND: There has been a large increase in both the number of neonatal intensive care units (NICUs) in community hospitals and the complexity of the cases treated in these units. We examined differences in neonatal mortality among infants with very low birth weight (below 1500 g) among NICUs with various levels of care and different volumes of very-low-birth-weight infants. METHODS: We linked birth certificates, hospital discharge abstracts (including interhospital transfers), and fetal and infant death certificates to assess neonatal mortality rates among 48,237 very-low-birth-weight infants who were born in California hospitals between 1991 and 2000. RESULTS: Mortality rates among very-low-birth-weight infants varied according to both the volume of patients and the level of care at the delivery hospital. The effect of volume also varied according to the level of care. As compared with a high level of care and a high volume of very-low-birth-weight infants (more than 100 per year), lower levels of care and lower volumes (except for those of two small groups of hospitals) were associated with significantly higher odds ratios for death, ranging from 1.19 (95% confidence interval [CI], 1.04 to 1.37) to 2.72 (95% CI, 2.37 to 3.12). Less than one quarter of very-low-birth-weight deliveries occurred in facilities with NICUs that offered a high level of care and had a high volume, but 92% of very-low-birth-weight deliveries occurred in urban areas with more than 100 such deliveries. CONCLUSIONS: Mortality among very-low-birth-weight infants was lowest for deliveries that occurred in hospitals with NICUs that had both a high level of care and a high volume of such patients. Our results suggest that increased use of such facilities might reduce mortality among very-low-birth-weight infants.

Inhaled nitric oxide in preterm infants undergoing mechanical ventilation.

BACKGROUND: Bronchopulmonary dysplasia in premature infants is associated with prolonged hospitalization, as well as abnormal pulmonary and neurodevelopmental outcome. In animal models, inhaled nitric oxide improves both gas exchange and lung structural development, but the use of this therapy in infants at risk for bronchopulmonary dysplasia is controversial. METHODS: We conducted a randomized, stratified, double-blind, placebo-controlled trial of inhaled nitric oxide at 21 centers involving infants with a birth weight of 1250 g or less who required ventilatory support between 7 and 21 days of age. Treated infants received decreasing concentrations of nitric oxide, beginning at 20 ppm, for a minimum of 24 days. The primary outcome was survival without bronchopulmonary dysplasia at 36 weeks of postmenstrual age. RESULTS: Among 294 infants receiving nitric oxide and 288 receiving placebo birth weight (766 g and 759 g, respectively), gestational age (26 weeks in both groups), and other characteristics were similar. The rate of survival without bronchopulmonary dysplasia at 36 weeks of postmenstrual age was 43.9 percent in the group receiving nitric oxide and 36.8 percent in the placebo group (P=0.042). The infants who received inhaled nitric oxide were discharged sooner (P=0.04) and received supplemental oxygen therapy for a shorter time (P=0.006). There were no short-term safety concerns. CONCLUSIONS: Inhaled nitric oxide therapy improves the pulmonary outcome for premature infants who are at risk for bronchopulmonary dysplasia when it is started between 7 and 21 days of age and has no apparent short-term adverse effects. (ClinicalTrials.gov number, NCT00000548 [ClinicalTrials.gov] .).

Cesarean delivery rates and neonatal morbidity in a low-risk population.

OBJECTIVE: To estimate the relationship between case-mix adjusted cesarean delivery rates and neonatal morbidity and mortality in infants born to low-risk mothers. METHODS: This retrospective cohort study used vital and administrative data for 748,604 California singletons born without congenital abnormalities in 1998-2000. A total of 282 institutions was classified as average-, low-, or high-cesarean delivery hospitals based on their cesarean delivery rate for mothers without a previous cesarean delivery, in labor at term, with no evidence of maternal, fetal, or placental complications. Neonatal mortality, diagnoses, and therapeutic interventions determined by International Classification of Diseases, 9th Revision, Clinical Modification codes, and neonatal length of stay were compared across these hospital groupings. RESULTS: Compared with average-cesarean delivery-rate hospitals, infants born to low-risk mothers at low-cesarean delivery hospitals had increased fetal hemorrhage, birth asphyxia, meconium aspiration syndrome, feeding problems, and electrolyte abnormalities (P <.02). Infused medication, pressors, transfusion for shock, mechanical ventilation, and length of stay were also increased (P <.001). This suggests that some infants born in low-cesarean delivery hospitals might have benefited from cesarean delivery. Infants delivered at high-cesarean delivery hospitals demonstrated increased fetal hemorrhage, asphyxia, birth trauma, electrolyte abnormalities, and use of mechanical ventilation (P <.001), suggesting that high cesarean delivery rates themselves are not protective. CONCLUSION: Neonatal morbidity is increased in infants born to low-risk women who deliver at both low- and high-cesarean delivery-rate hospitals. The quality of perinatal care should be assessed in these outlier hospitals. LEVEL OF EVIDENCE: III

Trends in mortality and morbidity for very low birth weight infants, 1991-1999.

BACKGROUND: Medical care for very low birth weight (VLBW) infants and their mothers has changed dramatically during the 1990s, yet it is unclear how these changes have affected mortality and morbidity. OBJECTIVE: We used the Vermont Oxford Network Database to identify trends in clinical practice and patient outcomes for VLBW infants born from 1991 to 1999. METHODS: Logistic regression was used to evaluate temporal trends in practices and outcomes while adjusting for patient characteristics and accounting for clustering of cases within hospitals. RESULTS: There were 118 448 infants 501 to 1500 g from 362 neonatal intensive care units enrolled in the Network Database from 1991 to 1999. Prenatal care, cesarean section, multiple births, antenatal steroids, and 1-minute Apgar scores increased during this period, as did the use of nasal continuous positive airway pressure, high-frequency ventilation, surfactant, and postnatal steroids. The proportion of white infants decreased; the proportions of Hispanic infants and those of other races increased. The crude and adjusted rates of mortality, pneumothorax, intraventricular hemorrhage (IVH), and severe IVH declined from 1991 to 1995, whereas from 1995 to 1999, the rates of mortality, IVH, and severe IVH did not change significantly, and pneumothorax increased. CONCLUSIONS: There have been major changes in both obstetric and neonatal care during the 1990s. These changes were associated with decreases in mortality and morbidity for VLBW infants during the first half of the decade. However, since 1995, no additional improvements in mortality or morbidity have been seen, ending a decades-long trend of improving outcomes for these infants.

Mortality in low birth weight infants according to level of neonatal care at hospital of birth.

OBJECTIVE: In 1976, the Committee on Perinatal Health recommended that hospitals with no neonatal intensive care unit (NICU) or intermediate NICUs transfer high-risk mothers and infants that weigh <2000 g to a regional NICU. This standard was based on expert opinion and has not been validated carefully. This study evaluated the effect of NICU level and patient volume at the hospital of birth on neonatal mortality of infants with a birth weight (BW) of <2000 g. METHODS: Birth certificates of 16 732 singleton infants who had a BW of <2000 g and were born in nonfederal hospitals in California in 1992 and 1993 were linked to death certificates and to discharge abstracts. The hospitals were classified by the level of NICU: no NICU, no intensive care; intermediate NICU, intermediate intensive care; community NICU, expanded intermediate intensive care; and regional NICU, tertiary intensive care. A logistic regression model that controlled for demographic risks, diagnoses, transfer, average NICU census, and NICU level was estimated using death within the first 28 days or first year of life if continuously hospitalized as the main outcome measure. RESULTS: Compared with birth in a hospital with a regional NICU, risk-adjusted mortality of infants with BW of <2000 g was higher when birth occurred in hospitals with no NICU (odds ratio [OR]: 2.38; 95% confidence interval [CI]: 1.81-3.13), an intermediate NICU (OR: 1.92; 95% CI: 1.44-2.54), or a small (average census <15) community NICU (OR: 1.42; 95% CI: 1.14-1.76). Risk-adjusted mortality for infants who were born in hospitals with a large (average census > or =15) community NICU was not statistically different compared with those with a regional NICU (OR: 1.11; 95% CI: 0.87-1.43). Except for large community NICUs, all of these ORs are larger when the data are restricted to infants with BW of <1500 g or BW of <1250 g and smaller for BW between 1250 g and 1999 g and 1500 g and 1999 g. For large community NICUs, the results are similar for the smaller BW intervals and significant only for the larger BW interval. CONCLUSIONS: These results support the recommendation that hospitals with no NICU or intermediate NICUs transfer high-risk mothers with estimated fetal weight of <2000 g to a regional NICU. For infants with BW of <2000 g, birth at a hospital with a regional NICU is associated with a lower risk-adjusted mortality than birth at a hospital with no NICU, intermediate NICU of any size, or small community NICU. Subsequent neonatal transfer to a regional NICU only marginally decreases the disadvantage of birth at these hospitals. The evidence for the few hospitals with large community NICUs is mixed. Although the data point to higher mortality in large community NICUs, they are not conclusive and additional study is needed on the mortality effects of large community NICUs. Greater efforts should be made to deliver infants with expected BW of <2000 g at hospitals with regional NICUs.