Selenium status of preterm infants: the effect of postnatal age and method of feeding

Indicators of selenium (Se) status were measured in a longitudinal study of 63 preterm and 46 term infants. Se levels in both groups were similar in the first few days of life. Preterm infants fed parenteral nutrition (PN) for several weeks developed very low plasma Se levels (<10/μg/l). In those receiving either breast milk or formula in conjunction with PN, plasma Se also declined over the first 6 weeks. In the breastfed term infants plasma levels increased by 50%, but there was no increase in the term formula-fed group. In healthy preterm infants who received mainly breast milk, plasma Se concentrations remained constant at newborn levels and were below those of breastfed term infants at 6 weeks. Erythrocyte GSHPx activity did not reflect plasma Se or Se intake. In conclusion, the type of feeding, and hence Se intake, influenced plasma Se concentration in preterm infants. Provision of enteral feeding in conjunction with PN was unable to prevent a decline in plasma Se and at 6 weeks levels were well below those of the reference breastfed term infants.     

Selenium status of New Zealand infants fed either a selenium supplemented or a standard formula

Objective: New Zealand soils are deficient in the essential micronutrient, selenium. New Zealand infants have low selenium levels at birth and experience a further decline if fed cows milk based formula. This study examined the selenium status of infants fed with a new commercially available selenium supplemented formula.
Methodology Forty-four newborn infants, whose mothers wished to formula feed, were randomized in an open controlled trial to be fed a commercially available selenium supplemented cows milk formula (containing 17 μg Se/L) or an unsupplemented formula (containing 4.6 μg Se/L). Cord, 1 and 3 month blood samples were obtained for selenium status (plasma and red cell selenium and glutathione peroxidase) and thyroid function.
Results Mean plasma selenium and glutathione peroxidase values were significantly higher in supplemented than unsupplemented infants at 1 month (unpaired t -tests; P <0.0001 and P = 0.001 respectively) and 3 months ( P <0.0001 and P = 0.0005). Analysis within treatment groups between time points (paired t -tests) showed that selenium supplementation prevented the fall in plasma selenium from birth to 1 month seen in unsupplemented infants and was associated with a rise in levels between 1 and 3 months ( P = 0.002).
Conclusions Supplementing cows milk formula with selenium to replicate the levels found in breast milk is nutritionally sound. Feeding from a few days of age with a formula containing 17 μg Se/L in infants with low selenium status at birth is sufficient to cause a rise to 80% of adult levels at 3 months of age.     

The selenium status of children with phenylketonuria: Results of selenium supplementation

The selenium status of children with phenylketonuria on a synthetic low phenylalanine diet was assessed. Correlation between blood selenium and red cell glutathione peroxidase was unsatisfactory ( r = 0.65) due to the poor discrimination of red cell glutathione peroxidase with a low selenium diet. No symptoms of deficiency were observed. Supplementation with 50 μg per week of selenium as brewers yeast tablets over a period of 6 months significantly increased the blood selenium of the phenylketonuric children. Plasma Vitamin E levels were within normal limits. The supplementation effectively doubled their selenium intake to 15–17 μg per day, which is probably sufficient for this group with an adequate Vitamin E status, though considerably lower than the recommended minimum intake of 50 μg per day.     

Inguinal hernia in extremely preterm infants

The prevalence of inguinal hernia during primary hospitalization was determined in 250 infants with gestational age 24–29 weeks. Fourteen per cent developed hernia, with prevalence significantly higher in boys than girls. Infants with respiratory distress syndrome and those requiring prolonged mechanical ventilation were significantly predisposed to the development of hernia. Male infants, especially those who required prolonged ventilatory assistance, were at greatest risk. This information may be used when counselling parents regarding complications of very preterm infants.     

Lipoproteins in preterm and small-for-gestational-age infants during the first week of life

Plasma lipoprotein levels and composition have been determined in preterm and small-for-gestational-age (SGA) infants, and compared to full-term infants, during the first week of life. Significantly lower levels of HDL and higher levels of VLDL were found in both preterm and SGA infants in comparison to full-term healthy infants. These results suggest a low capacity to metabolize VLDL. Preterm infants showed a behaviour similar to full-term infants with regard to the changes in lipoprotein composition. Small-for-gestational-age infants showed a higher lipoprotein lipid content than preterm infants. A low ratio of cholesteryl ester to free cholesterol (CE/FC) was found in both preterm and SGA infants suggesting a reduced lecithin: cholesterol acyl transferase (LCAT) activity. In preterm infants we observed no changes in the CE/FC ratio during the first week of life, whereas in SGA infants this ratio increased after birth.     

极/超早产儿的生存现状和呼吸管理进展

极/超早产儿由于肺发育不成熟,病死率和支气管肺发育不良的发生率较高,呼吸管理和患儿的生存率及生存质量密切相关.合理的产前皮质激素促肺成熟、肺表面活性物质(pulmonary surfactant,PS)的应用和机械通气策略有助于改善极/超早产儿的预后.采用无创技术进行呼吸支持,特别是生后立即给予持续气道正压通气而后根据病情选择性给予PS作为预防性给予PS的替代呼吸支持策略已受到普遍推荐.新的机械通气策略与模式如高频振荡通气、神经调节辅助呼吸和目标容量通气是否具有更大的优势仍需要进一步的研究证实.     

Clinical and laboratory impact of coagulase-negative staphylococci bacteremia in preterm infants

A retrospective evaluation of the clinical and laboratory impact of coagulase-negative staphylococci (CONS) bacteremia in preterm infants was carried out. The study population included all preterm infants (n = 31) in whom two or more blood cultures were positive for CONS within a period of 4 d, with negative blood cultures 1 wk before and 1 wk after the CONS bacteremia. Clinical manifestations and the results of laboratory tests 7 d before and after the positive blood cultures, and on the first day of sepsis, were recorded and compared. During CONS bacteremia, the infants demonstrated apnoea and bradycardia (88%) and a need for oxygen (59%) and ventilatory support (69%). Significant laboratory findings were leukopenia below 5000 cells/mm³ (12%), leukocytosis above 30,000 cells/mm³ (39%), and thrombocytopenia below 150,000/mm³ (25%). These clinical and laboratory manifestations differed significantly during the bacteremia infection compared with the week before and after. Conclusion: CONS bacteremia is a clinically significant infection in preterm infants, causing episodes of apnoea and bradycardia, and a need for ventilatory support.     

Longitudinal changes in milk composition of mothers delivering preterm and term infants

The concentrations of protein nitrogen (PN), non-protein nitrogen (NPN), energy, fat, sodium (Na), calcium (Ca), phosphorus (P), magnesium (Mg), and zinc (Zn) were determined in human milk from mothers giving birth to full-term (n = 13) and preterm infants (n = 8). Milk samples were collected under controlled conditions at two-week intervals for 12 weeks postpartum. Statistically significant differences in PN, Ca, and P concentrations were detected between the milk from mothers of preterm and term infants. The mean PN concentration in the preterm milk was statistically higher than that of term milk (198 vs. 164 mg N/dl), in contrast to the lower mean Ca (220 vs. 261 mg/1) and P (125 vs. 153 mg/1) concentrations detected in the preterm milk. No other differences in mean nutrient concentration were observed between the two groups. Concentrations of PN, NPN, Na, P, and Zn decreased over time. The concentration of Mg increased slightly. The content of fat, energy, and Ca did not change.     

Morphine increases synchronous ventilation in preterm infants

Objectives: To examine the short-term cardiorespiratory effects of intravenous morphine infusion in ventilated preterm infants.
Methodology A randomized double-blind placebo-controlled trial in a neonatal intensive care unit. Twenty-six preterm infants (29-36 weeks gestation) with hyaline membrane disease requiring ventilatory assistance on the first day after birth were included in the study. A loading dose of morphine 100 μg/kg over 30 min followed by a continuous intravenous infusion at 10 μg/kg per hour was given. Primary measures were heart rate, blood pressure, respiratory rate and interaction of spontaneous respiration with mechanical ventilation. Secondary measures were durations of oxygen therapy, ventilator therapy and hospitalization as well as incidence of bronchopuimonary dysplasia, periventricular haemorrhage and pneumothorax.
Results Morphine-treated infants spent a significantly greater percentage of total ventilated time breathing in synchrony with their ventilators (median [IQ]= 72[58-87] vs 31 [17-51]%; P = 0.0008). Heart rate and respiratory rate, but not blood pressure, were reduced in morphine-treated infants. Duration of oxygen therapy was reduced (median [IQ]= 4.5[3-7] vs 8[4.75-12.5] days; P = 0.046).
Conclusions Intravenous morphine infusion increases synchronicity of spontaneous and ventilator-delivered breaths in preterm infants. Morphine reduces heart rate and respiratory rate without reducing blood pressure, and may help to reduce duration of oxygen therapy in preterm infants with hyaline membrane disease.     

Focal intestinal perforation in preterm infants is an emerging disease

In order to elicit the pathogenesis of focal intestinal perforation in preterm infants we contrasted 8 infants who developed this disease with 16 gestation-matched controls. The cases were found to have lower birthweights for gestation (median standard deviation score of −1.02 in cases versus −0.08 in controls), and more frequently had preexisting patent ductus arteriosus and intraventricular haemorrhage (88 and 63% in cases versus 25 and 6% in controls, respectively). There were similar rates of other perinatal variables in the two groups, including indomethacin and umbilical arterial catheter use. Conditions associated with fetal or neonatal hypoxia are important antecedents for this emerging distinct clinical entity.     

Diagnosis and management of gastro-oesophageal reflux in preterm infants in neonatal intensive care units

Aim: There is relatively little published information regarding gastro-oesophageal reflux (GOR) in preterm infants, therefore the aim of this study was to elucidate the incidence of GOR and management regimes employed for this condition in major neonatal intensive care units (NICUs). Methods: A standard questionnaire was sent to consultants in 77 level II (or secondary) and III (or tertiary) NICUs. Results: Seventy-eight percent of consultants responded. Of babies born in these units, 40% were less than 34 wk gestational age and the estimated incidence of GOR in this group was 22%. GOR was diagnosed on a clinical basis alone in 42% of units, 8% used clinical features and/or investigations, and 50% used clinical features plus investigations and/or therapeutic trials. Intra-oesophageal pH monitoring was available in 93% of units but used regularly in only 32% of suspected cases. Common treatment strategies for diagnosed GOR included non-drug options—body positioning (98%) and placement on a slope (96%); and drugs—H ₂ -receptor antagonists (100%), feed thickeners (98%), antacids (96%), prokinetic agents (79%), proton-pump inhibitors (65%) and dopamine-receptor antagonists (53%). However, the frequency with which all of these treatments were used varied widely between units. Surgery was required in only 1% of cases.

Conclusions: GOR is perceived to be a common condition in preterm infants but the lack of published evidence relating to the management of GOR in preterm infants is reflected in the wide variation in diagnostic and treatment strategies used in major NICUs. It is clear that randomized, controlled trials to evaluate appropriate and effective treatments are needed.     

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目的 探讨早期、晚期早产儿与足月儿呼吸窘迫综合征(RDS)的发病趋势和临床特征的差异,为临床合理诊治提供依据。方法 2006年1月至2010年12月在郑州大学第三附属医院住院的963例RDS患儿根据胎龄不同分为早期早产儿组(<34周)679例,晚期早产儿组(34～<37周)204例,足月儿组(≥37周)80例,分别对各组患儿的发病率、入院情况、高危因素、临床诊治、预后及并发症进行比较。结果 RDS的发病率逐年增加,均以早期早产儿占多数,晚期早产儿和足月儿RDS比例有增多趋势;RDS患儿男婴超过女婴(P<0.05),且胎龄和体重越大,男婴比例越高;足月儿RDS组产前糖皮质激素使用率明显低于早产儿组;早产儿发生RDS的高危因素主要有胎膜早破、胎盘异常、母亲妊娠高血压疾病,足月儿发生RDS的高危因素主要是择期剖宫产与感染;晚期早产儿与足月儿RDS的临床诊断和应用肺泡表面活性物质(PS)时间均晚于早期早产儿;足月儿RDS应用机械通气比例明显高于早产儿,其临床治愈率高(P<0.05),在死亡率方面与早产儿组无差别;但并发气胸的比例高于早产儿组(P<0.05)。结论 新生儿呼吸窘迫综合征(NRDS)发病率逐年增高,晚期早产儿和足月儿RDS比例有增多趋势;早期、晚期早产儿与足月儿RDS在性别比例、高危因素、起病特点、治疗反应与并发症方面均存在差异,RDS的诊治需要考虑胎龄因素。足月儿RDS多与择期剖宫产、感染有关,发病相对较晚,容易合并气胸,应引起足够重视。     

早产儿支气管肺发育不良的表型演变

支气管肺发育不良(bronchopulmonary dysplasia,BPD)是早产儿最常见的慢性肺部疾病,与婴儿死亡率、呼吸系统发病率增加有关。随着新生儿重症医学取得进展的同时,BPD的表型已从主要影响晚期早产儿、肺纤维囊性变演变为主要影响胎龄小于28周的超早产儿、肺实质受损和血管生长失调。文章评估了BPD定义演变、病理生理演变、影像演变及临床表型的演变特点,以期寻找新的循证预防和管理策略,改善疾病表型分类,早期识别高危早产儿的临床特点,以改善其预后。     

Nutrition and early growth of preterm infants

Recent studies have renewed the controversy over what should constitute the best milk for preterm infants. While pooled human breast milk continues to be widely recommended it seems for reasons poorly understood not to allow adequate early post-natal growth. In view of possible programming of later growth and neuropsychological development by early nutritional experiences there is a need to further research the question of what should consitute optimum nutrition for preterm infants. We suggest that modifying or finding natural modifications in human milk rather than further altering cow's milk might provide some of the answers. Particular attention also needs to be given to long-term neurological, anthropometric and psychological assessment to relate functional outcome to early nutritional experiences.     

Circulating levels of adiponectin in preterm infants

OBJECTIVE: To determine circulating levels of adiponectin in preterm infants and examine possible associations with anthropometric measurements, weight gain, and leptin and insulin levels. DESIGN: Prospective study. SETTING: A university hospital neonatal care unit. Study population: 62 preterm (mean (SD) gestational age 32.0 (2.1) weeks) and 15 full-term infants (reference group). INTERVENTIONS: Blood samples taken at discharge (40.9 (14.8) days of life) from the preterm infants and at a comparable postnatal age in full-term infants. All infants were fed the same commercial formula, but in nine preterms the formula contained long-chain polyunsaturated fatty acids (LCPUFAs). MAIN OUTCOME MEASURES: Serum levels of adiponectin, leptin and insulin. Associations of adiponectin levels were tested only in the preterm group. RESULTS: Serum levels of adiponectin were lower in preterm (40.9 (14.8) microg/ml) than full-term infants (53.1 (16.0) microg/ml, p<0.01). However, after adjustment for body weight, the influence of prematurity on adiponectin levels was no longer significant. In preterm infants, adiponectin levels independently correlated with being born small for gestational age (SGA) (beta=-0.35, p=0.01), weight gain (beta=0.28, p=0.03) and LCPUFA-supplemented formula (beta=0.34, p=0.009). Serum adiponectin levels did not correlate with insulin or leptin levels. However, insulin levels were higher in preterm than in full-term infants after adjustment for body weight. CONCLUSIONS: Adiponectin levels are lower in preterm infants at discharge than full-term infants probably due to decreased adiposity. The levels are influenced by being born SGA, weight gain and, possibly, by dietary LCPUFAs. The importance of these findings in the development of insulin or leptin resistance in children born prematurely needs to be further studied.     

Reducing hypothermia in preterm infants with polyethylene wrap

Background: Occlusive plastic applied immediately after birth to reduce evaporative heat loss has been proven effective in preterm infants <28 weeks' gestation. However its effectiveness on preterm infants >28 weeks' gestation has not been shown. This study aimed to determine the effect of occlusive wrap at birth on the temperature at neonatal intensive care unit (NICU) admission among infants of greater than or equal to 24 weeks' and less than 34 weeks' gestation. Methods: Study infants were randomly assigned to “wrap” or “control” groups. Newborns in the wrap group were wrapped with polyethylene plastic sheets within the first min after birth. Infants randomized to the control group were dried immediately after birth with warmed towels under a warmer, according to the guidelines of Neonatal Resuscitation. Infants' axillary temperatures were measured on admission to the NICU, and after having been stabilized in incubators in the NICU. Results: A total of 110 infants were recruited into the study. The mean admission temperature was significantly higher in the wrap group (35.8 vs 34.8°C, P < 0.01). Admission hypothermia (axillary temperature <36.5°C) was present in 38 (78%) and 58 (98%) infants in the wrap and control groups, respectively. Among infants of <28 weeks' gestation, the post‐stabilization temperature was significantly higher in the wrap group. Conclusions: Wrapping premature infants with gestational age <34 weeks in polyethylene plastics immediately after birth is associated with lower incidence of hypothermia.     

Nitric oxide metabolites in the urine of full-term and preterm infants

BACKGROUND: In newborn full-term and preterm infants the urine nitrites and nitrates (NOx) were measured, in order to investigate the effects of different pathological conditions (infection, hypoxia) on systemic nitric oxide production. METHODS: Urine nitrites and nitrates were determined by means of the Griess reaction, after reduction of nitrates to nitrites with nitrate reductase. RESULTS: The NOx level was higher in preterm (278 nmol/mL) than full-term (176 nmol/mL) infants. Low NOx (115 nmol/mL) levels accompanied generalized infections, while its high contents (650 nmol/mL) was found in cytomegalovirus and one case of Pneumocystis carinii infection. Moderate increase of NOx production was observed in infants with local pulmonary infections and encephalopathies. CONCLUSIONS: The results indicate urinary NOx level is lowered in infants with life-threatening generalized infection. A possibility of a rapid test based on newborn urinary NOx level determination is considered.     

早产儿喂养不耐受治疗进展

生长受限和发育迟缓近来已成为早产儿尤其是极低体重儿的主要问题.达到完全肠内喂养时间的延长,也与矫正年龄2岁时的心理发育落后有明显关系.不增加坏死性小肠结肠炎(NEC)危险的肠内喂养已成为优先选择,阻止或减少早产儿喂养不耐受的喂养策略,反映了其定义的困难以及对NEC的担忧.文章讨论了目前早产儿喂养不耐受的喂养策略和治疗方法,但尚需进行大规模实用性的临床研究,以发展更为科学的干预方法.     

Calcium and phosphorus nutrition in preterm infants

Metabolic bone disease is a common event in preterm infants. Between 24 wk gestation and term, the fetus accrues approximately 80% of body Ca, P and Mg. Consequently, preterm infants miss in part or completely the period of greatest mineral accretion. Ca and P requirements in preterm infants are based on demands for matching intrauterine bone mineral accretion rates and on maintenance of normal serum Ca and P concentrations. Daily physical therapy may be a useful adjunct, as it is associated with a significant increase in bone mineral density and content. Osteopenia/rickets of prematurity seems to be a self-resolving disease. However, this does not imply that a period of demineralization is acceptable. While the potential long-term consequences on peak bone mass are unclear at the moment, the short-term benefits include the avoidance of fractures, less marked dolicocephaly and improved linear growth.