Impact of Early Postnatal Weight Gain on Retinopathy of Prematurity in Very Preterm Infants in Southwestern Ontario.

PURPOSE: To examine the relationship between post-natal growth and development of retinopathy of prematurity (ROP) among preterm infants in southwestern Ontario. METHODS: The medical records of 431 preterm infants, born between January 1, 2008, and June 1, 2015, with a gestational age (GA) of less than 31 weeks or birth weight (BW) of less than 1,250 g were reviewed. Information collected included pregnancy and birth history, neonatal characteristics, ROP status, comorbidities, and postnatal weight measurements at specified intervals. Infants diagnosed as having ROP and no ROP were compared. RESULTS: Low weight velocity from day 7 to day 28 (P < .001), high weight velocity from birth to first day of full enteral feeding (FEF) (P < .001), long duration from birth to FEF (P < .001), and long duration from FEF to discharge/transfer (P < .001) were associated with ROP. After controlling for GA and BW, the durations, birth to FEF, and FEF to discharge/transfer remained significant (P < .05). In a multivariable logistic regression analysis adjusting for GA, bronchopulmonary dysplasia, and surgical ligation for patent ductus arteriosus, the only independent risk factor of ROP was duration from FEF to discharge/transfer (P < .05). CONCLUSIONS: Low weight velocity from day 7 to day 28 may be a useful predictor for the development of ROP but is dependent on GA and BW. A delay to reach FEF, which is associated with comorbidities of ROP, appears to be a risk factor for ROP that is independent of GA and BW. [J Pediatr Ophthalmol Strabismus. 2019;56(3):168-172.].

Quantitative 3-D head ultrasound measurements of ventricle volume to determine thresholds for preterm neonates requiring interventional therapies following posthemorrhagic ventricle dilatation.

Dilatation of the cerebral ventricles is a common condition in preterm neonates with intraventricular hemorrhage. This posthemorrhagic ventricle dilatation (PHVD) can lead to lifelong neurological impairment through ischemic injury due to increased intracranial pressure, and without treatment can lead to death. Two-dimensional ultrasound (US) through the fontanelles of the patients is serially acquired to monitor the progression of PHVD. These images are used in conjunction with clinical experience and physical exams to determine when interventional therapies such as needle aspiration of the built up cerebrospinal fluid (ventricle tap, VT) might be indicated for a patient; however, quantitative measurements of the ventricles size are often not performed. We describe the potential utility of the quantitative three-dimensional (3-D) US measurements of ventricle volumes (VVs) in 38 preterm neonates to monitor and manage PHVD. Specifically, we determined 3-D US VV thresholds for patients who received VT in comparison to patients with PHVD who resolve without intervention. In addition, since many patients who have an initial VT will receive subsequent interventions, we determined which PHVD patients will receive additional VT after the initial one has been performed.

Disruption to functional networks in neonates with perinatal brain injury predicts motor skills at 8 months.

Objective: Functional connectivity magnetic resonance imaging (fcMRI) of neonates with perinatal brain injury could improve prediction of motor impairment before symptoms manifest, and establish how early brain organization relates to subsequent development. This cohort study is the first to describe and quantitatively assess functional brain networks and their relation to later motor skills in neonates with a diverse range of perinatal brain injuries. Methods: Infants (n = 65, included in final analyses: n = 53) were recruited from the neonatal intensive care unit (NICU) and were stratified based on their age at birth (premature vs. term), and on whether neuropathology was diagnosed from structural MRI. Functional brain networks and a measure of disruption to functional connectivity were obtained from 14 min of fcMRI acquired during natural sleep at term-equivalent age. Results: Disruption to connectivity of the somatomotor and frontoparietal executive networks predicted motor impairment at 4 and 8 months. This disruption in functional connectivity was not found to be driven by differences between clinical groups, or by any of the specific measures we captured to describe the clinical course. Conclusion: fcMRI was predictive over and above other clinical measures available at discharge from the NICU, including structural MRI. Motor learning was affected by disruption to somatomotor networks, but also frontoparietal executive networks, which supports the functional importance of these networks in early development. Disruption to these two networks might be best addressed by distinct intervention strategies.

Auditory structural connectivity in preterm and healthy term infants during the first postnatal year.

Assessing language development in the first postnatal year is difficult, as receptive and expressive skills are rudimentary. Although outward manifestations of change are limited, the auditory language system is thought to undergo critical development at this age, as the foundations are laid for the rapid onset of spoken language in the second and third years. We recruited 11 infants, 7 healthy controls (gestational age = 40.69 ± 0.56; range from 40 to 41.43) and preterm babies (gestational age = 28.04 ± 0.95; range from 27.43 to 29.43) who underwent a Magnetic Resonance Imaging study during the first postnatal year (age at scan = 194.18 ± 97.98). We assessed white matter tracts using diffusion-weighted magnetic resonance imaging with probabilistic tractography. Fractional anisotropy was found to be largely mature even at one month, although there was a little further increase during the first postnatal year in both the acoustic radiation and the direct brainstem-Heschl's pathway.

Using Functional Magnetic Resonance Imaging to Detect Preserved Function in a Preterm Infant with Brain Injury.

We studied developmental plasticity using functional magnetic resonance imaging (fMRI) in a preterm infant with brain injury on structural MRI. fMRI showed preserved brain function and subsequent neurodevelopment was within the normal range. Multimodal neuroimaging including fMRI can improve understanding of neural plasticity after preterm birth and brain injury.

Adult-like processing of naturalistic sounds in auditory cortex by 3- and 9-month old infants.

Functional neuroimaging has been used to show that the developing auditory cortex of very young human infants responds, in some way, to sound. However, impoverished stimuli and uncontrolled designs have made it difficult to attribute brain responses to specific auditory features, and thus made it difficult to assess the maturity of feature tuning in auditory cortex. To address this, we used functional magnetic resonance imaging (fMRI) to measure the brain activity evoked by naturalistic sounds (a series of sung lullabies) in two groups of infants (3 and 9 months) and adults. We developed a novel analysis method - inter-subject regression (ISR) - to quantify the similarity of cortical responses between infants and adults, and to decompose components of the response due to different auditory features. We found that the temporal pattern of activity in infant auditory cortex shared similarity with adults. Some of this shared response could be attributed to simple acoustic features, such as frequency, pitch, envelope, but other parts were not, suggesting that even more complex adult-like features are represented in auditory cortex in early infancy.

Investigating the effects of cerebrospinal fluid removal on cerebral blood flow and oxidative metabolism in infants with post-hemorrhagic ventricular dilatation.

BackgroundPost-hemorrhagic ventricular dilatation (PHVD) is predictive of mortality and morbidity among very-low-birth-weight preterm infants. Impaired cerebral blood flow (CBF) due to elevated intracranial pressure (ICP) is believed to be a contributing factor.MethodsA hyperspectral near-infrared spectroscopy (NIRS) method of measuring CBF and the cerebral metabolic rate of oxygen (CMRO2) was used to investigate perfusion and metabolism changes in patients receiving a ventricular tap (VT) based on clinical management. To improve measurement accuracy, the spectral analysis was modified to account for compression of the cortical mantle caused by PHVD and the possible presence of blood breakdown products.ResultsFrom nine patients (27 VTs), a significant CBF increase was measured (15.6%) following VT (14.6±4.2 to 16.9±6.6 ml/100 g/min), but with no corresponding change in CMRO2 (1.02±0.41 ml O2/100 g/min). Post-VT CBF was in good agreement with a control group of 13 patients with patent ductus arteriosus but no major cerebral pathology (16.5±7.7 ml/100 g/min), whereas tissue oxygen saturation (StO2) was significantly lower (58.9±12.1% vs. 70.5±9.1% for controls).ConclusionCBF was impeded in PHVD infants requiring a clinical intervention, but the effect is not large enough to alter CMRO2.

Brainstem shape is affected by clinical course in the neonatal intensive care unit.

The brainstem, critical for motor function, autonomic regulation, and many neurocognitive functions, undergoes rapid development from the third trimester. Accordingly, we hypothesized it would be vulnerable to insult during this period, and that a difficult clinical course in the neonatal intensive care unit (NICU) would affect development, and be reflected through atypical shape. Our study population consisted of 66 neonates - all inpatients from the NICU at Victoria Hospital, London Health Sciences Centre, ON, Canada, of which 45 entered the final analysis. The cohort varied in gestational age (GA) and ranged from neurologically healthy to severely brain-injured. Structural MRI was used to quantify brainstem shape at term-equivalent age. From these images, brainstems were semi-automatically segmented and co-registered across subjects. The anterior-posterior dimensions on a sagittal maximum intensity projection were used as the basis for shape comparison. Factor analysis was used to summarize variation in shape and in clinical course to determine three shape factors and three clinical factors, and their relationship assessed using correlation. A factor driven by low GA and associated complications correlated with alterations in the posterior medulla, while a factor driven by complications independent of GA correlated with alterations in the midbrain. Additionally, single clinical measures most representative of their respective clinical factor (days in NICU; days on ventilation) predicted the changes. Thus, different clinical courses in the NICU may have different effects on the shape of the brainstem, and may mediate some of the distinct neurodevelopmental profiles observed in premature and brain-injured neonates.

Preterm neonatal lateral ventricle volume from three-dimensional ultrasound is not strongly correlated to two-dimensional ultrasound measurements.

The aim of this study is to compare longitudinal two-dimensional (2-D) and three-dimensional (3-D) ultrasound (US) estimates of ventricle size in preterm neonates with posthemorrhagic ventricular dilatation (PHVD) using quantitative measurements of the lateral ventricles. Cranial 2-D US and 3-D US images were acquired from neonatal patients with diagnosed PHVD within 10 min of each other one to two times per week and analyzed offline. Ventricle index, anterior horn width, third ventricle width, and thalamo-occipital distance were measured on the 2-D images and ventricle volume (VV) was measured from 3-D US images. Changes in the measurements between successive image sets were also recorded. No strong correlations were found between VV and 2-D US measurements ([Formula: see text] between 0.69 and 0.36). Additionally, weak correlations were found between changes in 2-D US measurements and 3-D US VV ([Formula: see text] between 0.13 and 0.02). A trend was found between increasing 2-D US measurements and 3-D US-based VV, but this was not the case when comparing changes between 3-D US VV and 2-D US measurements. If 3-D US-based VV provides a more accurate estimate of ventricle size than 2-D US measurements, moderate-weak correlations with 3-D US suggest that monitoring preterm patients with PHVD using 2-D US measurements alone might not accurately represent whether the ventricles are progressively dilating. A volumetric measure (3-D US or MRI) could be used instead to more accurately represent changes.

In Vivo Validation of a 3-D Ultrasound System for Imaging the Lateral Ventricles of Neonates.

Intra-ventricular hemorrhage, with the resultant cerebral ventricle dilation, is a common cause of brain injury in preterm neonates. Clinically, monitoring is performed using 2-D ultrasound (US); however, its clinical utility in dilation is limited because it cannot provide accurate measurements of irregular volumes such as those of the ventricles, and this might delay treatment until the patient's condition deteriorates severely. We have developed a 3-D US system to image the lateral ventricles of neonates within the confines of incubators. We describe an in vivo ventricle volume validation study in two parts: (i) comparisons between ventricle volumes derived from 3-D US and magnetic resonance images obtained within 24 h; and (ii) the difference between 3-D US ventricle volumes before and after clinically necessary interventions (ventricle taps), which remove cerebral spinal fluid. Magnetic resonance imaging ventricle volumes were found to be 13% greater than 3-D US ventricle volumes; however, we observed high correlations (R(2) = 0.99) when comparing the two modalities. Differences in ventricle volume pre- and post-intervention compared with the reported volume of cerebrospinal fluid removed also were highly correlated (R(2) = 0.93); the slope was not found to be statistically significantly different from 1 (p < 0.05), and the y-intercept was not found to be statistically different from 0 (p < 0.05). Comparison between 3-D US images can detect the volume change after neonatal intra-ventricular hemorrhage. This could be used to determine which patients will have progressive ventricle dilation and allow for more timely surgical interventions. However, 3-D US ventricle volumes should not be directly compared with magnetic resonance imaging ventricle volumes.

Development of a combined broadband near-infrared and diffusion correlation system for monitoring cerebral blood flow and oxidative metabolism in preterm infants.

Neonatal neuromonitoring is a major clinical focus of near-infrared spectroscopy (NIRS) and there is an increasing interest in measuring cerebral blood flow (CBF) and oxidative metabolism (CMRO2) in addition to the classic tissue oxygenation saturation (StO2). The purpose of this study was to assess the ability of broadband NIRS combined with diffusion correlation spectroscopy (DCS) to measured changes in StO2, CBF and CMRO2 in preterm infants undergoing pharmaceutical treatment of patent ductus arteriosus. CBF was measured by both DCS and contrast-enhanced NIRS for comparison. No significant difference in the treatment-induced CBF decrease was found between DCS (27.9 ± 2.2%) and NIRS (26.5 ± 4.3%). A reduction in StO2 (70.5 ± 2.4% to 63.7 ± 2.9%) was measured by broadband NIRS, reflecting the increase in oxygen extraction required to maintain CMRO2. This study demonstrates the applicability of broadband NIRS combined with DCS for neuromonitoring in this patient population.

Optimizing stimulation and analysis protocols for neonatal fMRI.

The development of brain function in young infants is poorly understood. The core challenge is that infants have a limited behavioral repertoire through which brain function can be expressed. Neuroimaging with fMRI has great potential as a way of characterizing typical development, and detecting abnormal development early. But, a number of methodological challenges must first be tackled to improve the robustness and sensitivity of neonatal fMRI. A critical one of these, addressed here, is that the hemodynamic response function (HRF) in pre-term and term neonates differs from that in adults, which has a number of implications for fMRI. We created a realistic model of noise in fMRI data, using resting-state fMRI data from infants and adults, and then conducted simulations to assess the effect of HRF of the power of different stimulation protocols and analysis assumptions (HRF modeling). We found that neonatal fMRI is most powerful if block-durations are kept at the lower range of those typically used in adults (full on/off cycle duration 25-30s). Furthermore, we show that it is important to use the age-appropriate HRF during analysis, as mismatches can lead to reduced power or even inverted signal. Where the appropriate HRF is not known (for example due to potential developmental delay), a flexible basis set performs well, and allows accurate post-hoc estimation of the HRF.

Preservation of the metabolic rate of oxygen in preterm infants during indomethacin therapy for closure of the ductus arteriosus.

BACKGROUND: The aim of this study was to assess and quantify the effects of indomethacin on cerebral blood flow (CBF), oxygen extraction fraction (OEF), and cerebral metabolic rate of oxygen (CMRO2) in preterm infants undergoing treatment for a patent ductus arteriosus (PDA). METHODS: CBF and CMRO2 were measured before and after the first dose of a 3-d course of indomethacin to close hemodynamically significant PDA in preterm neonates. Indocyanine-green (ICG) concentration curves were acquired before and after indomethacin injection to quantify CBF and CMRO2. RESULTS: Eight preterm neonates (gestational age, 27.6 ± 0.5 wk; birth weight, 992 ± 109 g; 6 males:2 females) were treated at a median age of 4.5 d (range, 4-21 d). Indomethacin resulted in an average CBF decrease of 18% (pre- and post-CBF = 12.9 ± 1.3 and 10.6 ± 0.8 ml/100 g/min, respectively) and an OEF increase of 11% (pre- and post-OEF = 0.38 ± 0.02 and 0.42 ± 0.02, respectively) but no significant change in CMRO2 (pre- and post-CMRO2 = 0.83 ± 0.07 and 0.76 ± 0.07 ml O2/100 g/min, respectively). Corresponding mean blood pressure (BP), arterial oxygen saturation (SaO2), heart rate, and end-tidal carbon dioxide tension levels remained unchanged. CONCLUSION: Indomethacin resulted in significant reduction in CBF but did not alter CMRO2 because of a compensatory increase in OEF.

Mothers' "liquid gold": a quality improvement initiative to support early colostrum delivery via oral immune therapy (OIT) to premature and critically ill newborns.

Early breast milk, known as colostrum ("liquid gold") provides immune benefits to infants, offering potential risk reduction for nosocomial infection (NI) and necrotizing enterocolitis (NEC), a serious gastrointestinal emergency. Provision of colostrum is recognized as oral immune therapy (OIT) and is valuable to all NICU infants unable to feed orally. A quality improvement project was initiated by the multidisciplinary NICU Quality Care Council at London Health Sciences Centres-Victoria (LHSC-VH) to obtain mothers' colostrum for early OIT. The initiative was driven by the Canadian EPIQ (Evidence-based Practice for Improving Quality) group as a means of reducing the rates of NEC and NI, two major morbidities in the NICU. The overall aim was to facilitate the availability of OIT to preterm and critically ill neonates as soon as possible after birth.

Opioid infusions in the neonatal intensive care unit.

OBJECTIVES: The primary objective of this study was to compare the use of opioid infusions to that proposed in guidelines published in an in-house medication handbook. Secondary objectives were to assess the documented use of a standardized neonatal pain assessment tool and to describe the supplemental use of opioids concurrent with an opioid infusion. METHODS: A retrospective chart review was performed for all patients in the NICU who received opioid infusions between November 1, 2005, and November 30, 2006. Data collected included patient characteristics, opioid infusion dosing and duration, supplemental opioid use, and pain assessment documentation. RESULTS: Of the110 neonates who received morphine or fentanyl during the study period, 65 patients met inclusion criteria. Reasons for starting an opioid infusion included nonsurgical sedation and/or analgesia (51%), postoperative pain (17%), and procedural pain (1%). No reason was documented for 31% of patients. Thirtyeight percent of neonates received a loading dose of opioid before initiation of the infusion. The median dose was 100 mcg/kg (IQR=48.2) for morphine and and 1 mcg/kg (IQR=0.8) for fentanyl. The mean ± SD starting rates of morphine and fentanyl infusions were 12.3 ± 4.7 mcg/kg/hr and 1.5 ± 1.7 mcg/kg/hr, respectively. Supplemental opioid doses were given to 46% of neonates during the infusion period. Supplemental doses were given for procedures (69%) and pain/agitation/sedation (26%). No reason was documented for 5% of patients. The Neonatal Pain, Agitation and Sedation Scale scores were only documented 9% of the time for each day that the patient received an opioid infusion. CONCLUSIONS: Dosing of opioids generally was within the recommendations that are described in the in-house medication handbook. A substantial percentage of neonates received supplemental opioid doses while on opioid infusions, mostly for procedural pain management. Documentation of the reason for using opioid infusions and the assessment of neonatal pain was poor.

Improving the quality of care for infants: a cluster randomized controlled trial.

BACKGROUND: We developed and tested a new method, called the Evidence-based Practice for Improving Quality method, for continuous quality improvement. METHODS: We used cluster randomization to assign 6 neonatal intensive care units (ICUs) to reduce nosocomial infection (infection group) and 6 ICUs to reduce bronchopulmonary dysplasia (pulmonary group). We included all infants born at 32 or fewer weeks gestation. We collected baseline data for 1 year. Practice change interventions were implemented using rapid-change cycles for 2 years. RESULTS: The difference in incidence trends (slopes of trend lines) between the ICUs in the infection and pulmonary groups was - 0.0020 (95% confidence interval [CI] - 0.0007 to 0.0004) for nosocomial infection and - 0.0006 (95% CI - 0.0011 to - 0.0001) for bronchopulmonary dysplasia. INTERPRETATION: The results suggest that the Evidence-based Practice for Improving Quality method reduced bronchopulmonary dysplasia in the neonatal ICU and that it may reduce nosocomial infection.

Enoxaparin for neonatal thrombosis: a call for a higher dose for neonates.

INTRODUCTION: Enoxaparin is the current anticoagulant of choice for neonatal thrombosis. Present neonatal treatment guidelines of 1.5 mg/kg every 12 hours (q12 h) are extrapolated primarily from an earlier study with 9 infants less than 2 months of age. More recent studies indicate an increased dose requirement for neonates. MATERIALS AND METHODS: Relevant data from articles and abstracts were identified by searching MEDLINE and pediatric and hematology conference proceedings. RESULTS: Publications between 1996 and 2007 included 8 papers, 4 abstracts and 1 review article with primary research documenting enoxaparin use in 240 neonates. The mean maintenance dose of enoxaparin ranged from 1.48 to 2.27 mg/kg q12 h for all infants, but was higher for preterm neonates at 1.9-2.27 mg/kg q12 h. The efficacy of enoxaparin, causing either complete or partial resolution was between 59 and 100%. Minor side effects were common and adverse events (major bleeding) occurred in 12 patients (0-19%). CONCLUSIONS: Increased experience with enoxaparin use in neonates in the past decade has indicated higher doses to achieve accepted target anti-factor Xa values. The long-term use of indwelling catheters (Insuflon catheter) for enoxaparin administration may need to be reevaluated in ELBW infants. Suggested starting doses of enoxaparin are 1.7 mg/kg q12 h for term neonates and 2.0 mg/kg q12 h for preterm neonates if there is no considerable bleeding risk. However, further prospective studies are needed to validate an increased initial dose of enoxaparin.

Enoxaparin use in the neonatal intensive care unit: experience over 8 years.

STUDY OBJECTIVE: To evaluate the effectiveness and safety of enoxaparin therapy in a neonatal intensive care unit (NICU). DESIGN: Retrospective chart review. SETTING: Level III NICU in a Canadian academic center. PATIENTS: All neonates treated with enoxaparin while in the NICU between January 1, 1998, and June 1, 2006. MEASUREMENTS AND MAIN RESULTS: Data abstracted included patient demographics, diagnosis of thrombosis and its progression, enoxaparin dosages with corresponding antifactor Xa levels, and adverse events. Sixteen neonates (four term, 12 preterm) were treated with enoxaparin at a mean +/- SD initial subcutaneous dose of 1.41 +/- 0.15 mg/kg every 12 hours. The target therapeutic range (antifactor Xa level 0.5-1.0 U/ml) was achieved by 12 infants at a mean +/- SD dose of 1.92 +/- 0.43 mg/kg every 12 hours, after a mean of 5.6 days (range 1-15 days). Preterm infants required a higher dose (per kilogram) compared with term infants to maintain therapeutic antifactor Xa levels (mean +/- SD 1.94 +/- 0.39 vs 1.65 +/- 0.14 mg/kg every 12 hrs, p<0.001). Enoxaparin doses were more strongly correlated to antifactor Xa levels in term infants (r(2)=0.51, p<0.001) compared with preterm infants (r(2)=0.20, p<0.001). Ten (71%) of 14 thromboembolic events resolved, either partially or completely, at a mean of 39 days (range 8-61 days) of enoxaparin therapy. Nine infants (56%) experienced minor local adverse effects at the site of the indwelling subcutaneous catheter (induration, bruises, hematomas, or leakage). Systemic adverse events that were possibly related to enoxaparin therapy included osteopenia (one infant), scleral hemorrhage (one), and minor gastrointestinal tract bleeding (three) found in gastric feeding tubes. No adverse effects were associated with antifactor Xa levels greater than 1.0 U/ml. CONCLUSION: Enoxaparin may be effective in the treatment of neonatal thrombosis. An initial dosage of 1.5 mg/kg every 12 hours is likely inadequate to obtain therapeutic antifactor Xa levels rapidly and differs for term and preterm neonates. Therapeutic levels in preterm infants may be more variable, and the pharmacokinetics of this drug in preterm infants requires further evaluation. Future studies in neonates should prospectively evaluate a higher starting dose of enoxaparin to document effectiveness, acceptance, compliance with treatment guidelines, and adverse effects.

Variations in incidence of necrotizing enterocolitis in Canadian neonatal intensive care units.

OBJECTIVES: Necrotizing enterocolitis (NEC) is the most common acquired intestinal disease of neonates. Previous reports on incidence have generally examined small cohorts of extremely low-birth-weight infants and have not examined risk-adjusted variations among neonatal intensive care units (NICUs). The authors examined risk-adjusted variations in the incidence of NEC in a large group of Canadian NICUs and explored possible therapy-related risks. METHODS: The authors obtained data on 18,234 infants admitted to 17 tertiary level Canadian NICUs from January 1996 to October 1997. They used multivariate logistic regression analysis to examine the inter-NICU variation in incidence of NEC, with adjustment for population risk factors and admission illness severity, and explored therapy-related variables. RESULTS: The incidence of NEC was 6.6% (n = 238) among 3,628 infants with birth weight < or = 1,500 g (VLBW), and 0.7% (n = 98) among 14,606 infants with birth weight > 1,500 g (HBW). Multivariate logistic regression analysis showed that for VLBW infants, NEC was associated with lower gestational age and treatment for hypotension and patent ductus arteriosus. Among HBW infants, NEC was associated with lower gestational age, presence of congenital anomalies (cardiovascular, digestive, musculoskeletal, multiple systems) and need for assisted ventilation. There was no significant variation in the risk-adjusted incidence of NEC among NICUs, with the exception of one NICU reporting no cases of NEC. CONCLUSIONS: Risk factors for NEC were different in VLBW and HBW infants. There was no significant variation in the risk-adjusted incidence of NEC among Canadian NICUs, with one possible exception.

The Pediatric Investigators Collaborative Network on Infections in Canada study of predictors of hospitalization for respiratory syncytial virus infection for infants born at 33 through 35 completed weeks of gestation.

BACKGROUND: Infants born at 33 through 35 completed weeks of gestation (33-35GA) are at risk for severe respiratory syncytial virus (RSV) infection, and palivizumab prophylaxis lowers hospitalizations for RSV infection by as much as 80%. The 33-35GA cohort comprises 3-5% of annual births; thus expert panels recommend limiting prophylaxis to situations in which frequency or health care impact of RSV infection is high. This study sought to identify independent risk factors for hospitalization for RSV infection. METHODS: This was a multicenter, prospective, observational cohort study of 33-35GA infants followed through their first RSV season (2001/2002 or 2002/2003). Baseline data were collected by interview with parents and review of medical records. Respiratory tract illnesses were identified by monthly phone calls, and medical records were reviewed for emergency room visits or hospitalizations. Risk factors were determined by stepwise logistic regression. RESULTS: Of 1,860 enrolled subjects, 1,832 (98.5%) were followed for at least 1 month, and 1,760 (94.6%) completed all follow-ups. Of 140 (7.6%) subjects hospitalized for respiratory tract illnesses, 66 infants had proven RSV infection. Independent predictors for hospitalization for RSV infection were: day-care attendance (odds ratio, 12.32; 95% confidence interval, 2.56, 59.34); November through January birth (odds ratio, 4.89; 95% confidence interval, 2.57, 9.29); preschool age sibling(s) (odds ratio, 2.76; 95% confidence interval, 1.51, 5.03); birth weight <10th percentile (odds ratio, 2.19; 95% confidence interval, 1.14, 4.22); male gender (odds ratio, 1.91; 95% confidence interval, 1.10, 3.31); > or = 2 smokers in the home (odds ratio, 1.87; 95% confidence interval, 1.07, 3.26); and households with >5 people, counting the subject (odds ratio, 1.79; 95% confidence interval, 1.02, 3.16). Family history of eczema (odds ratio, 0.42; 95% confidence interval, 0.18, 0.996) was protective. CONCLUSIONS: Specific host/environmental factors can be used to identify which 33-35GA infants are at greatest risk of hospitalization for RSV infection and likely to benefit from palivizumab prophylaxis.