Eleanor J. Molloy

Performance of an Automated Immature Granulocyte Count as a Predictor of Neonatal Sepsis

Neonatologists use immature granulocytes (IG) in manual differential counts as an indicator of sepsis. This study was designed to compare the predictive ability of automated vs manual IG counts for neonatal sepsis. Infants undergoing sepsis evaluation were identified prospectively for study if a CBC count was obtained in temporal proximity to the blood culture. Automated IG counts were obtained from the research software of the Sysmex XE-2100 (Sysmex, Kobe, Japan). Manual average IG counts were obtained from two 100-cell manual differential counts independently performed by a technologist and a hematopathology resident. A comparative analysis of manual and automated IG counts showed considerable overlap of ranges. The highest positive blood culture rate occurred in the nonneutropenic preterm subset of infant older than 7 days (21/55 [38%]). For these infants, elevated IG counts by manual and automated methods were associated significantly with positive blood culture results (odds ratio, manual, 3.74; odds ratio, automated, 3.63), albeit with low sensitivity.

Are B-type natriuretic peptide (BNP) and N-terminal-pro-BNP useful in neonates?

B-type natriuretic peptide (BNP) and N-terminal-pro-BNP (NTpBNP) have a major role in screening and diagnosis of cardiac disease and monitoring of the treatment response in children and adults. This review discusses the evidence underpinning the potential benefits of these natriuretic peptides in neonatology. They may serve as a useful adjunct to echocardiography in the diagnosis of patent ductus arteriosus and its response to treatment and the diagnosis of persistent pulmonary hypertension of the newborn. However, more work is needed to explore the possible roles of BNP/NTpBNP in the management of sepsis and monitoring of cardiac performance in neonates.

Vitamin D nutritional status in preterm infants and response to supplementation.

Little is known about vitamin D status in preterm infants and their response to supplementation. To investigate this, we assessed serum 25-hydroxyvitamin D (25OHD) levels using RIA in a consecutive sample of stable preterm very low birth weight (VLBW) infants (born ≤ 32 weeks gestation or birth weight ≤ 1·5 kg), and we explored associated factors. Serum 25OHD level was first assessed once infants were tolerating feeds (n 274). If this first 25OHD level was below 50 nmol/l (20 ng/ml), which is the level associated with covering requirements in terms of skeletal health in the majority, then we recommended prolonged augmented vitamin D intake ( ≥ 10 μg (400 IU) daily) from a combination of fortified feeds and vitamin supplements and follow-up re-assessment at approximately 6 weeks corrected age (n 148). The first assessment, conducted at a median for chronological age of 18 (interquartile range (IQR) 11-28) d, found that 78 % had serum 25OHD levels below 50 nmol/l. Multivariable analysis demonstrated that the determinants of serum 25OHD levels were duration of vitamin D supplementation and gestational age at birth (r 2 0·215; P< 0·001). At follow-up, after a median of 104 (IQR 78-127) d, 87 % achieved levels ≥ 50 nmol/l and 8 % had levels >125 nmol/l, a level associated with potential risk of harm. We conclude that low 25OHD levels are an issue for preterm VLBW infants, warranting early nutritional intervention. In infants with serum 25OHD levels < 50 nmol/l, a vitamin D intake of ≥ 10 μg (400 IU) daily achieves target levels in the majority; however, further work is needed to determine the exact dose to safely meet target levels without overcorrection.

Patent ductus arteriosus evaluation by serial echocardiography in preterm infants

Background: Patent ductus arteriosus (PDA) is associated with morbidity and mortality in premature neonates.

Does Gastroesophageal Reflux Cause Apnea in Preterm Infants

Gastroesophageal reflux (GER) and apnea are both common occurrences in premature infants but their relationship is controversial. We present the evidence for and against an association between GER and apnea and discuss the merits and limitations of the various methodologies employed in characterizing such a relationship. Overall, GER and apnea do not appear temporally related in preterm infants, despite strong physiologic evidence that stimulation of laryngeal afferents elicits central apnea and laryngeal adduction. In a subpopulation of infants with neurodevelopmental compromise, there may be an increased incidence of both apnea and GER, although the direct association between GER and apnea in this population is unclear. Therefore, we believe there is no evidence to support widespread use of anti-reflux medications in the treatment of apnea in preterm infants. Further studies are needed to clarify the existence of a small subpopulation of infants who may have GER-induced apnea, to identify potential triggering mechanisms, and to document benefit from newer pharmacological approaches.

Are carbon dioxide detectors useful in neonates

Maintenance of neonatal normocarbia may prevent chronic lung disease and periventricular leucomalacia, but this requires frequent arterial sampling, which has risks. Alternative methods for measuring CO2 are therefore desirable. These include end tidal CO2, capillary sampling, and transcutaneous measurements. CO2 detectors have also proved effective and rapid indicators of endotracheal intubation. However, this method relies on the presence of exhaled CO2, which may be reduced in certain situations, such as cardiopulmonary arrest. Colorimetric CO2 detectors are therefore valuable adjuncts for airway management, especially during resuscitation, but Paco2 is still the best measure of CO2 in neonatal practice.

Troponin T, N-terminal pro natriuretic peptide and a patent ductus arteriosus scoring system predict death before discharge or neurodevelopmental outcome at 2 years in preterm infants

Background There is little consensus regarding the use of echocardiography in patent ductus arteriosus (PDA) treatment in preterm infants. The use of troponin T (cTnT) and N-terminal Pro-BNP (NTpBNP) in combination with echocardiography assessment may facilitate the development of a superior predictive model. Objective To investigate the ability of cTnT, NTpBNP and a PDA scoring system applied at 48 h of life to predict death before discharge and neurodevelopmental outcome at 2 years of age. Design/Methods Infants <32 weeks and <1500 g were prospectively enrolled. Echocardiography evaluation coupled with cTnT and NTpBNP measurements were done at 48 h. The ductus arteriosus was scored (0–6) according to echocardiography markers of haemodynamic significance. Infants were assessed at 2 years using the Bayley scales and categorised into two groups: Severe Disability/Death before discharge or Normal/Mild Disability. Results Sixty infants with a median gestation of 27.7 weeks (26.2–29.4) and a median birth weight of 1.01 kg (0.86–1.22) were followed up to 2 years of age. Plasma cTnT and NTpBNP were higher in the Severe Disability/Death compared to the Normal/Mild Disability group (2.30 μg/l vs 0.19 μg/l, p<0.001; 9209 pmol/l vs 1664 pmol/l, p<0.001, respectively). The severe group had a higher PDA score compared to the mild and normal groups (5 vs 2, p<0.001). Conclusion Blood cTnT, NTpBNP and a PDA scoring system at 48 h may facilitate the identification of those infants with a PDA, who are at greatest risk of poor neurodevelopmental outcome at 2 years of age.

Granulocyte Colony-Stimulating Factor and Granulocyte-Macrophage Colony-Stimulating Factor Have Differential Effects on Neonatal and Adult Neutrophil Survival and Function

Neutropenia is a common sequela of neonatal sepsis. Recent clinical trials have shown the beneficial effects of colony-stimulating factors (CSFs) on outcome in this group, but the exact mechanism remains unknown. Neonates and mothers who were at high-risk for infection were recruited for cord blood sampling in a university tertiary referral maternity hospital. Neonatal and adult neutrophils were evaluated for their ability to combat bacterial infection by examining their functional activity (CD11b and reactive oxygen intermediates) and their persistence at inflammatory sites (apoptosis). The mechanism for altered apoptotic responses was assessed by caspase activation assays, X chromosome–linked inhibitor of apoptosis protein expression, and cytosolic cytochrome c release. Although granulocyte colony-stimulating factor (G-CSF) and granulocyte-macrophage colony-stimulating factor (GM-CSF) significantly delayed neutrophil apoptosis in normal adults, only G-CSF had a similar effect in normal neonates. Neutrophils from neonates who are at high risk for infection are unresponsive to the antiapoptotic effects of G-CSF or GM-CSF, unlike maternal neutrophils, which have delayed apoptosis in response to GM-CSF. However, CD11b expression and reactive oxygen intermediate production were significantly increased in normal neonatal neutrophils that were incubated with GM-CSF versus controls but not G-CSF or lipopolysaccharide. Decreased cytosolic cytochrome c release and caspases 3 and 9 activity are associated with the CSF-mediated delay in apoptosis in adults but not in newborns. The antiapoptotic X chromosome–linked inhibitor of apoptosis protein is up-regulated in neonates compared with adults and may mediate their differential spontaneous apoptosis. These results have important implications for the use of CSFs in neonatal sepsis, as responses differ from those seen in adults. Further delineation of neonatal neutrophil responses to CSFs may improve their therapeutic potential.

Intensive enteral nutrition support in paediatric bone marrow transplantation

This study retrospectively analyses the experience with an intensive enteral feeding protocol in children undergoing BMT at the National Paediatric BMT Centre, Our Ladys Hospital for Sick Children, Crumlin, Dublin. Fifty-three patients were transplanted between January 1996 and December 1998; 42 patients received allogeneic transplants, (19 unrelated) and 11 were autologous. Indications included ALL (21), ANLL (3), CML (3), JCML (1), MPS (5), WAS (2), AA/FA (6), NHL/HD (3) and solid tumours (9). Nasogastric (NG) tubes were inserted electively either during conditioning or within the first week when voluntary oral intake had decreased. Nineteen patients were commenced on a whole protein-based formula, 28 on a semi-elemental preparation and two were commenced on an elemental feed. All were maintained on an elemental formula during the period of maximal gut toxicity. Tubes which were vomited were promptly replaced and morphine infusions were routinely employed until mucositis had resolved. Of 49 evaluable patients, 42 (86%) were maintained exclusively on enteral nutrition and seven required parenteral nutrition. Seven patients weighed <85% ideal body weight (IBW) at discharge (range 75–84), only one of whom was <85% IBW at 3 months. Twenty-two patients continued on NG feeds following discharge (median 41 days). No patient had veno-occlusive disease. The programme was overwhelmingly endorsed by patients and/or parents but required intensive multidisciplinary counselling to ensure success. Bone Marrow Transplantation (2001) 27, 741–746.

A Randomized Trial of Exothermic Mattresses for Preterm Newborns in Polyethylene Bags

BACKGROUND AND OBJECTIVE: Hypothermia on admission to the NICU is associated with increased mortality in preterm infants. Many newborns are hypothermic on admission despite using polyethylene bags (PBs). Using exothermic mattresses (EMs) in addition to PBs may reduce hypothermia but increase hyperthermia. We wished to determine whether placing preterm newborns in PBs on EMs in the DR results in more infants with rectal temperature outside the range 36.5 to 37.5°C on NICU admission. METHODS: Infants <31 weeks were randomly assigned before birth to treatment with or without an EM. All infants were placed in a PB and under radiant heat immediately after birth and brought to NICU in a transport incubator. Infants randomly assigned to EM were placed on a mattress immediately after delivery and remained on it until admission. Randomization was stratified by gestational age. Rectal temperature was measured with a digital thermometer on NICU admission. RESULTS: The data safety monitoring committee recommended stopping for efficacy after analyzing data from half the planned sample. We report data for 72 infants enrolled at this time. Fewer infants in PBs on EMs had temperatures within the target range (15/37 [41%] vs 27/35 [77%], P = .002) and more had temperatures >37.5°C (17/37 [46%] vs 6/35 [17%], P = .009). CONCLUSIONS: In very preterm newborns, using EMs in addition to PBs in the DR resulted in more infants with temperatures outside the normal range and more hyperthermia on NICU admission.