Canadian Neonatal Network Database Research Articles

Neonatal outcomes of preterm twins according to mode of birth and presentation

Purpose: To compare neonatal outcomes of twins delivered <33 weeks’ gestation in tertiary centers in Canada according to the mode of birth and presentation.Materials and methods: This retrospective cohort from the Canadian Neonatal Network database studied preterm twins born from 24 + 0 to 32 + 6 weeks’ gestation between 2005 and 2012. Twins were grouped by the mode of birth: both vaginal, combined vaginal/cesarean section (CS), and both CS. Additionally, twins were grouped by the mode of presentation: both vertex, vertex/breech, breech/vertex, and both breech. The primary outcome was a composite of mortality or severe neonatal morbidity (severe neurological injury [intraventricular hemorrhage grade 3/4 or periventricular leukomalacia], bronchopulmonary dysplasia, retinopathy of prematurity, and necrotizing enterocolitis).Results: Of the 6636 twins, 1934 (29%) were delivered vaginally, 418 (6%) by combined vaginal birth/CS, and 4284 (65%) were born by CS. The composite did not differ between the groups. However, severe neurological injury was decreased (adjusted odds ratio [AOR], 0.77; 95% confidence interval [CI], 0.61–0.98) and respiratory distress syndrome (AOR, 1.34; 95%CI, 1.15–1.56) was increased when both the twins were delivered by CS.Conclusions: Preterm twin infants born via CS experienced less severe neurological injury when compared to those delivered vaginally, but had an increase in respiratory distress syndrome.

Neonatal outcomes in very preterm singleton infants conceived using assisted reproductive technologies.

To compare neonatal mortality, severe morbidities and hospital length of stay in very preterm singleton infants conceived using assisted reproductive technologies (ARTs) or spontaneously (SP). Singleton infants born at 23 to 32 weeks gestation during 2010-2012 were retrospectively identified from the Canadian Neonatal Network database. A composite outcome indicating a mortality or severe morbidity (grade ≥ 3 intraventricular hemorrhage, periventricular leukomalacia, stage ≥ 3 retinopathy of prematurity, bronchopulmonary dysplasia, or stage ≥ 2 necrotizing enterocolitis) was compared between ART and SP infants using multivariable logistic regression. Length of stay was examined in multivariable time-to-event analyses adjusting for competing risk of mortality. Eligible subjects included 346 (4.4%) ART and 7,578 (95.6%) SP infants. ART mothers were older, with fewer single parents, higher rates of nulliparity, diabetes, hypertension, antenatal corticosteroids, and prenatal care, but less smoking and substance use than SP mothers. No significant differences were detected in the composite outcome (odds ratio: 0.79; 95% confidence interval: 0.54-1.17) or length of stay (hazard ratio: 0.84; 95% confidence interval: 0.63-1.12) between ART and SP infants after adjustment for potential confounders and risk factors. Among singleton infants born very preterm, mode of conception is not associated with overall mortality/morbidity or length of stay.

95: Neonatal Outcomes in Infants &lt;29 Weeks Gestation in Relation to Maternal Hypertension and Smoking Status

Maternal hypertension and cigarette smoking during pregnancy are associated with adverse neonatal outcomes. Paradoxically, smoking during pregnancy is associated with a reduced incidence of gestational hypertension. However, mothers who smoke during pregnancy and develop hypertension have worse pregnancy outcomes as compared to mothers who only have hypertension or non-smoking normotensive mothers. There is little data on neonatal outcomes of infants born to mothers with hypertension who also smoke. To study the outcomes of infants of mothers with hypertension who smoke. Using the Canadian Neonatal Network Database, we analyzed the outcomes of infants <29 weeks GA admitted to Canadian NICUs from 2003–2012. Infants were divided into four groups. Group 0 comprised infants of hypertensive mothers who smoked, group 1 infants of non-smoking hypertensive mothers, group 2 infants of normotensive mothers who smoked and group 3 infants of normotensive non-smoking mothers. Composite outcome of neonatal mortality or any of the major morbidities {grade 3/4 intraventricular hemorrhage (IVH), periventricular leukomalacia (PVL), retinopathy of prematurity (ROP) > stage 2, late onset sepsis (LOS) or bronchopulmonary dysplasia (BPD) was assessed using a multivariable model. Of the 12,307 eligible infants, 172 were in group 0, 1689 in group 1, 1535 in group 2 and 8911 in group 3. Adjusted ORs with 95% CIs with reference to group 3 (normotensive, non-smokers) are reported in Table 1. Infants of hypertensive mothers, whether smokers or non-smokers, were associated with higher rates of BPD. Smoking cessation campaigns during pregnancy are needed for both maternal and neonatal benefits.

Prediction of Neonatal Outcomes in Extremely Preterm Neonates

To develop and validate a statistical prediction model spanning the severity range of neonatal outcomes in infants born at ≤ 30 weeks' gestation. A national cohort of infants, born at 23 to 30 weeks' gestation and admitted to level III NICUs in Canada in 2010-2011, was identified from the Canadian Neonatal Network database. A multinomial logistic regression model was developed to predict survival without morbidities, mild morbidities, severe morbidities, or mortality, using maternal, obstetric, and infant characteristics available within the first day of NICU admission. Discrimination and calibration were assessed using a concordance C-statistic and the Cg goodness-of-fit test, respectively. Internal validation was performed using a bootstrap approach. Of 6106 eligible infants, 2280 (37%) survived without morbidities, 1964 (32%) and 1251 (21%) survived with mild and severe morbidities, respectively, and 611 (10%) died. Predictors in the model were gestational age, small (<10th percentile) for gestational age, gender, Score for Neonatal Acute Physiology version II >20, outborn status, use of antenatal corticosteroids, and receipt of surfactant and mechanical ventilation on the first day of admission. High model discrimination was confirmed by internal bootstrap validation (bias-corrected C-statistic = 0.899, 95% confidence interval = 0.894-0.903). Predicted probabilities were consistent with the observed outcomes (Cg P value = .96). Neonatal outcomes ranging from mortality to survival without morbidity in extremely preterm infants can be predicted on their first day in the NICU by using a multinomial model with good discrimination and calibration. The prediction model requires additional external validation.

Outcomes of neonatal patent ductus arteriosus ligation in Canadian neonatal units with and without pediatric cardiac surgery programs

Background/PurposePreterm infants needing patent ductus arteriosus (PDA) ligation are transferred to a pediatric cardiac center (CC) unless the operation can be done locally by a pediatric surgeon at a non-cardiac center (NCC). We compared infant outcomes after PDA ligation at CC and NCC. MethodsWe analyzed 990 preterm infants who had PDA ligation between 2005 and 2009 using the Canadian Neonatal Network database. In-hospital mortality and major morbidities were compared between CC (n=18) and NCC (n=9). ResultsSNAP-II-adjusted mortality rates were similar (CC=8.7% vs NCC=10.7%, P=.32). Significant cranial ultrasound abnormalities (CC=24.1% vs NCC=32.1%, P<.01) and culture-proven sepsis (CC=39.7% vs NCC=54.8%, P<.01) were more frequent in infants treated at NCC. Infants transferred to CC had higher rates of cranial ultrasound abnormalities (transferred 31.6% vs non-transferred 20.4%, P<.01). NSAIDs prior to PDA ligation were used more often at NCC (CC 36.6% vs NCC 75.6%, P<.001). ConclusionsMortality rates after PDA ligation were similar at CC and NCC, but cranial ultrasound abnormalities and sepsis rates were higher at NCC. Higher morbidity may be associated with different PDA management strategies, including NSAID use or infant transfer. Further studies are needed to investigate the reasons for these differences in morbidity.

New Reference Curves for Head Circumference at Birth, by Gestational Age

The measurement of head circumference (HC) at birth reflects intrauterine brain development. HC charts currently used in Canada are either dated, mixed-gender, nonrepresentative of lower gestational ages (GAs), or reflective of other populations. To create both birth weight and HC curves, we combined weight and HC data from the Canadian Neonatal Network (CNN) database (admissions in NICUs across Canada) with McGill's Obstetrical Neonatal Database (MOND; all births at a tertiary hospital in Montreal, Canada). We included CNN data for GAs of 23 to 34 weeks (2003-2007) and MOND data for GAs of 35 to 41 weeks (1995-2006). Nonsingletons, congenital anomalies, and measurements greater than ±4 SD from the mean were excluded. Distributions of birth weight and HC at each GA were statistically (penalized spline regression) smoothed. Birth weight curves were compared with recent Canadian reference curves and HC curves with historical and/or frequently used curves. We included 39,896 births (3121 births at <30 weeks' GA) to generate the curves. Current weight curves were similar to Canadian reference charts for both genders. Weight and HC measurements in boys were higher than in girls. When classified according to recent international references, the proportion of CNN-MOND infants at ≥32 weeks' GA with HCs <10th percentile was significantly underestimated. When classified according to historical reference curves, a significant number of CNN-MOND infants of all GAs with HCs <10th and >90th percentiles were misclassified. We developed recent gender-specific reference curves for HC at birth for singletons at 23 to 41 completed weeks' GA, which included a large number of very premature infants, reflecting the current geotemporal Canadian population.

Association between Congenital Anomalies and Area-Level Deprivation among Infants in Neonatal Intensive Care Units

To examine the relationship between area-level material deprivation and the risk of congenital anomalies in infants admitted to neonatal intensive care units (NICUs) across Canada. The Canadian Neonatal Network database was used to identify admitted infants who had congenital anomalies between 2005 and 2009. The association between congenital anomalies and material deprivation quintile was assessed using logistic regression analysis. Of 55,961 infants admitted to participating NICUs during the study period, 6002 (10.7%) had major, 6244 (11.2%) had minor, and 43,715 (78.1%) had no anomalies. There were higher odds of major anomalies (odds ratio [OR] 1.13, 95% confidence interval [CI] 1.03 to 1.24) but not minor anomalies (OR 1.01, 95% CI 0.93 to 1.11) in the highest-deprivation areas as compared with the lowest-deprivation area of maternal residence. Analyses of groups of major anomalies revealed higher odds for chromosomal (OR 1.48, 95% CI 1.05 to 2.10) and multiple-systems (OR 1.40, 95% CI 1.14 to 1.71) anomalies in the highest-deprivation areas compared with the lowest-deprivation areas. There are socioeconomic inequalities in the risk of major congenital anomalies, especially chromosomal and multiple-systems anomalies, in the NICU population with the highest rates in the most socioeconomically deprived areas.

Seasonal variations in healthcare-associated infection in neonates in Canada

ObjectiveTo assess the seasonal pattern of healthcare-associated infections (HCAI) among neonates and to describe the trend of HCAI.DesignSecondary analyses of database.SettingThe Canadian Neonatal Network database (2003–2009).ParticipantsNeonates with HCAI defined as...

Transfusion-associated necrotising enterocolitis in neonates

ObjectiveTo evaluate the association between blood transfusion in previous 2 days and necrotising enterocolitis (NEC) in infants admitted to neonatal intensive care units in Canada.Patients and MethodsUsing the Canadian Neonatal...

Neonatal Intensive Care Unit Characteristics Affect the Incidence of Severe Intraventricular Hemorrhage

The incidence of intraventricular hemorrhage (IVH), adjusted for known risk factors, varies across neonatal intensive care units (NICU)s. The effect of NICU characteristics on this variation is unknown. The objective was to assess IVH attributable risks at both patient and NICU levels. Subjects were <33 weeks' gestation, <4 days old on admission in the Canadian Neonatal Network database (all infants admitted in 1996-97 to 17 NICUs). The variation in severe IVH rates was analyzed using Bayesian hierarchical modeling for patient level and NICU level factors. Of 3772 eligible subjects, the overall crude incidence rates of grade 3-4 IVH was 8.3% (NICU range 2.0-20.5%). Male gender, extreme preterm birth, low Apgar score, vaginal birth, outborn birth, and high admission severity of illness accounted for 30% of the severe IVH rate variation; admission day therapy-related variables (treatment of acidosis and hypotension) accounted for an additional 14%. NICU characteristics, independent of patient level risk factors, accounted for 31% of the variation. NICUs with high patient volume and high neonatologist/staff ratio had lower rates of severe IVH. The incidence of severe IVH is affected by NICU characteristics, suggesting important new strategies to reduce this important adverse outcome.

SNAP-II Predicts Mortality among Infants with Congenital Diaphragmatic Hernia

Outcomes analysis in congenital diaphragmatic hernia (CDH) requires a validated risk-adjustment tool. The purpose of this study was to use the Canadian Neonatal Network (CNN) database to validate the Score for Neonatal Acute Physiology, Version II (SNAP-II) for prediction of mortality among CDH infants admitted to a neonatal intensive care unit (NICU), and to compare this to the predictive equation recently developed by the Congenital Diaphragmatic Hernia Study Group (CDHSG). Infants with CDH in the CNN database were identified. Bivariate and multivariable logistic regression models were used to identify risk factors predictive of mortality. Model predictive performance and calibration were assessed using the area under the receiver operator characteristic curve and the technique of Hosmer-Lemeshow, respectively, and compared with the CDHSG predictive equation. There were 88 patients with CDH among 19,507 admissions to CNN hospitals. The mortality rate among CDH patients surviving to NICU admission was 17%, and 12.5% received extracorporeal membrane oxygenation therapy. Gestational age and admission SNAP-II score predicted mortality. Model predictive performance and calibration were optimized with these variables combined. The CDHSG equation was equally predictive of mortality, but was only marginally calibrated. SNAP-II is highly predictive of mortality among patients with CDH, and can be used to risk-adjust these patients.

4 Outborn Preterm Infants: Outcome Based on Place of Admission – Perinatal Centres vs Free Standing Pediatric Hospitals

A previous report from Canadian Neonatal Network (CNN) revealed that even after adjustments of perinatal risks and admission illness severity, inborn infants had better outcomes compared to out-born infants. It was speculated that lack of availability of specialist support, staffing, expertise and equipment might be related to the poor outcomes in outborn infants. The objective of this study was to examine whether admission hospital type was associated with differences in mortality and morbidity among preterm infants who were born outside the perinatal centres, after adjustment of perinatal risks and admission illness severity (using the Score of Neonatal Acute Physiology, version II). Data was obtained from the Canadian Neonatal Network database. Multiple regression analyses were used to compare the risk-adjusted outcome of 605 outborn singleton infants born at < 32 weeks gestation, admitted to either 13 perinatal centres or 4 free standing pediatric hospitals in Canada during 1996–1997. There was no difference in the gestational age, apgar score, delivery type, prenatal care or SNAP II score between infants admitted to both types of hospitals. Maternal hypertension and administration of complete course of prenatal corticosteroid were more common among infants admitted to free standing pediatric hospitals. Outborn infants admitted to free standing pediatric hospitals were at higher risk of death (adjusted odds ratio [OR] 2.25, 95% confidence interval [CI] 1.20, 4.20), nosocomial infection (adjusted OR 2.48, 95% CI 1.64, 3.73) and oxygen dependency at 28 days of age (adjusted OR 1.77, 95% CI 1.14, 2.75); and at lower risk for developing PDA (adjusted OR 0.46, 95% CI 0.30, 0.69) and lower risk of CPAP dependency at 28 days (adjusted OR 0.66, 95% CI 0.47, 0.93); even after adjustment of perinatal risks and admission illness severity. After adjustment for perinatal risks and admission illness severity, outborn infants had better outcomes if they were admitted to perinatal centres compared to free standing pediatric hospitals. Our results indicate that if in-utero maternal transfers are not possible due to reasons beyond control, efforts should be made to transfer preterm infants to perinatal centres.

Toward evidence-based best practices in neonatal surgical care-I: The Canadian NICU Network

Background/Purpose: The Canadian Neonatal Network collects clinical data prospectively on every admission to each of its 17 tertiary level units in Canada. The purpose of this study was to interrogate the network database to determine case volumes, outcomes, and resource utilization for several neonatal surgical conditions. Methods: The network database was used to measure a population-based, profile of incidence, outcome and resource utilization over a 22-month period for the following International Classification of Diseases, Ninth Revision (ICD-9) diagnostic codes: 741, spina bifida; 748.4, congenital cystic lung disease; 750.3, tracheoesophageal fistula; 751.1, atresia/stenosis of small intestine; 751.2, atresia/stenosis of large intestine/imperforate anus; 751.3, Hirschsprung's disease; 756.6, anomalies of the diaphragm; 756.7, anomalies of the abdominal wall. Also, all infants receiving extracorporeal membrane oxygenation (ECMO) during the study period were identified. Results: Case volumes corresponding to each diagnostic code were as follows: 741 (104), 748.4 (12), 750.3 (124), 751.1 (142), 751.2 (121), 751.3 (67), 756.6 (88), 756.7 (151), ECMO cases (28). As a group, infants in the database who required major surgery consumed a disproportionate share of resources and had poorer outcomes than those who did not require major surgery. Conclusions: The Canadian Neonatal Network database enables population-based outcomes analysis for specific diagnoses, which, if supplemented by additional pre-and postnatal data fields for surgical conditions, could contribute to the determination of evidence-based best practices for these patients. J Pediatr Surg 38:672-677. © 2003 Elsevier Inc. All rights reserved.