Effect of high calcium and phosphorus intake on mineral retention in very low birth weight infants chronically treated with furosemide

The treatment of premature infants with the diuretic furosemide appears to be a contributory factor in the development of metabolic bone disease presumably because of furosemide-induced hypercalciuria. In this study, we measured calcium and phosphorus balance in furosemide-treated very low birth weight infants (VLBW) infants with bronchopulmonary dysplasia (BPD) who were fed a specialized premature formula containing increased amounts of calcium and phosphorus. Furosemide-treated infants received 166 +/- 37 mg/kg/day and retained 80 +/- 34 mg/kg/day of calcium, and 87 +/- 19 mg/kg/day and retained 52 +/- 14 mg/kg/day of phosphorus. The amounts retained were approximately 65% of the calcium and 72% of the phosphorus requirements for in utero mineral accretion. Compared to a group of similarly fed VLBW infants without BPD and not treated with the diuretic, the furosemide-treated infants excreted a larger percent of the calcium intake in the urine but had similar total urinary calcium and phosphorus losses (mg/kg/day) and serum calcium, phosphorus, alkaline phosphatase, and parathyroid hormone (PTH) levels. From the latter two findings, we suggest that the extra mineral content of the formula may have promoted bone mineralization and prevented the occurrence of secondary hyperparathyroidism.     

低体重出生儿的手术预后因素观察

目的：分析低体重出生儿围手术期的病因、并发症及影响预后的因素。方法：1991－2000年间对40例低体重出生儿进行手术,以消化道疾病占绝大多数（95．0％）。大多为胃壁修补术、食道闭锁根治术、肠切除肠吻合术等。结果：共死亡9例（22．5％）。常见术后并发症为败血症并发感染性休克（12例）。1991－1995年间死亡6例（33．3％）,1996－2000年死亡3例（13．6％）,差异有显著性意义。出生体重越低,病死率越高。未成熟儿病死率28．6％;足月小样儿为8．3％（P＜0．05）。结论：低体重出生儿常见外科疾病为消化道畸形,术后并发症以感染多见。预后及病死率与出生体重、胎儿成熟度有关。     

Cord blood lipid levels in low birth weight newborns

Cord blood cholesterol, triglyceride and FFA levels were estimated in 73 newborns, subdivided into various gestation weight categories (FTAGA, PTAGA, FTSGA and PTSGA). Cholesterol levels were not influenced by birth weight and gestation. Prematurity and growth retardation caused a significant elevation in triglyceride values. FFA levels were not influenced by prematurity, but growth retardation produced a significant increase. Birth weight and gestational age should be taken into consideration before labelling the newborn as hyperlipidemic.     

Glycerokinase in brain and liver of low birth weight newborns.

Glycerokinase activity was measured in brain and liver tissue of decreased low birth weight newborns. No glycerokinase activity was found in the brain. In the liver a relatively high activity of glycerokinase was ascertained even in very immature newborns.     

Antioxidant levels in cord blood of low birth weight newborns

We evaluated the antioxidant status of 82 healthy term low birth weight (LBW) newborns and equal number of gestation and sex matched controls weighing <2500 g by measuring vitamin A and E, superoxide dismutase, catalase and glutathione peroxidase in cord serum. Levels of vitamin A and E, superoxide dismutase and catalase were significantly lower and glutathione peroxidase significantly higher in LBW babies compared to controls, with the lowest levels found in babies showing more severe growth restriction (<2000 g). We conclude that LBW newborns are deficient in several important antioxidants which may predispose them to higher oxidative stress.     

极低出生体重儿血清钙磷碱性磷酸酶变化特点及临床意义

目的 探讨极低出生体重儿(VLBWIs)的骨代谢特点及变化趋势.方法 95例VLBWIs作为观察组,生后3 d内、2,4周检测血清钙、磷、碱性磷酸酶(ALP).30例足月正常体质量儿作为对照组,生后3 d内检测血清钙、磷、ALP.结果 观察组3 d内血清钙为(1.92±0.33)mmol/L,对照组为(2.24±0.19)mmol/L,P<0.001;观察组与对照组血清磷差异无统计学意义;观察组血清ALP为(199.9±90.4)U/L,对照组为(133.0±36.4)U/L,P<0.001.2周时两组血清钙、ALP均呈上升趋势,血清磷水平均呈下降趋势.4周血磷有所回升,血钙保持稳定,ALP继续升高明显;出生体质量、3 d内ALP、3 d内血钙、4周后血磷与4周后血ALP密切相关,为其影响因素.观察组自发性骨折3例.结论 出生体质量是VLBWIs骨营养的影响因素.动态监测血清钙、磷、ALP可以早期评价VLBWIs的骨营养状态.     

Double versus single phototherapy in low birth weight newborns.

Conventional phototherapy systems that simultaneously irradiate the front and the back of the baby lower the serum bilirubin level more rapidly than one-sided systems, but they are impractical. Fiberoptic phototherapy makes it easy to administer conventional phototherapy from above while the infant lies on a fiberoptic phototherapy blanket. Newborns with birth weights less than 2500 g were randomly assigned to receive either single (n = 37) or double (n = 33) phototherapy. The groups were similar in clinical and laboratory characteristics. After 18 hours of therapy the serum bilirubin concentration declined by 31 +/- 11% in the double and 16 +/- 15% in the single phototherapy group (2.9 +/- 1.1 vs 1.6 +/- 1.4 mg/dL), and the difference in the total serum bilirubin levels after 18 hours of therapy was significant (double phototherapy group 7.1 +/- 2.7 mg/dL vs single phototherapy group 8.2 +/- 2.6 mg/dL). After 18 hours of treatment the serum bilirubin level was less than the phototherapy threshold level in 26 of 37 single phototherapy patients vs 32 of 33 double phototherapy patients. Double phototherapy was well tolerated. It is concluded that this type of double phototherapy is more effective than single phototherapy in low birth weight newborns. Double phototherapy may be useful when it is necessary to reduce an elevated serum bilirubin level as rapidly as possible or when the bilirubin level is rising with single phototherapy.     

极低出生体重儿住院期间营养及体重增长状况的观察和分析

极低出生体重儿(Very low birth weight infant．VLBWI）生存率逐年提高,但VLBWI胃肠功能不成熟且常伴随疾病与并发症,而不能得到满意的体重增长。如何给予合适的营养支持促进其生长发育已成NICU的重要问题受到广泛关注。我们总结1999年1月至2003年12月,我院NICU收治的64例VLBWI住院期间的营养及体重增长状况,现分析如下。     

Achievement of in utero retention of calcium and phosphorus accompanied by high calcium excretion in very low birth weight infants fed a fortified formula

Calcium and phosphorus retention was evaluated in 13 very low birth weight infants who were fed an experimental formula designed to deliver quantities of calcium and phosphorus sufficient to meet the intrauterine accretion rates for these minerals. Retention of calcium and phosphorus in slight excess of these rates was achieved without any apparent difficulties for the infants. Biochemical measurements demonstrated normal serum calcium (9.8 +/- 8 mg/dL) and alkaline phosphatase (242 +/- 51.6 IU) values. However, there was evidence of high tubular reabsorption of phosphate (98.1% +/- 3.3%), hypercalciuria (7.2 +/- 3.8 mg/kg/d), and a relatively low serum phosphorus concentration (5.7 +/- 0.6 mg/dL). This biochemical picture is similar to that seen in phosphorus deficiency except for the low alkaline phosphatase activity. The latter finding, in concert with the high retention of calcium and phosphorus in these balance studies, makes such a diagnosis unlikely. We speculate that this biochemical picture is the result of an inappropriately high calcium/phosphorus ratio.     

Histologic chorioamnionitis and severity of illness in very low birth weight newborns.

OBJECTIVE: Estimating the risk of in-hospital mortality in the neonatal intensive care unit provides important information for health care providers, and several neonatal illness severity scores have been developed. Histologic chorioamnionitis (HCA) is a known cause of neonatal morbidity and mortality. To date, the relationship between HCA and neonatal illness severity scores has not been rigorously tested. In this study, the relationships among HCA, initial illness severity, and neonatal outcomes were analyzed in very low birth weight (VLBW) newborns admitted to the neonatal intensive care unit. DESIGN: Prospective. SETTING: Neonatal intensive care unit. PATIENTS: A total of 116 VLBW inborn infants (gestational age, 28.1 +/- 2.82 wks; birth weight, 1009 +/- 312 g) were categorized as HCA-positive (n = 67) and HCA-negative (n = 49). INTERVENTIONS: Placental histology was performed to identify HCA. Illness severity evaluation included several different neonatal illness severity scores-Clinical Risk Index for Babies (CRIB), CRIB-II, Score for Neonatal Acute Physiology-II (SNAP-II), and Score for Neonatal Acute Physiology Perinatal Extension-II (SNAPPE-II)-as well as the recording of severe morbidity and in-hospital mortality. MEASUREMENTS AND MAIN RESULTS: HCA-positive VLBW newborns showed significantly lower gestational age (p < .0001) and birth weight (p = .0010), together with higher CRIB, CRIB-II, SNAP-II, and SNAPPE-II scores at admission to the NICU (p 5 (odds ratio [OR], 21.37; 95% confidence interval [CI], 6.24-73.21); CRIB-II > 10 (OR, 56.17; 95% CI, 6.75-467.2); SNAP-II > 22 (OR, 43.05; 95% CI, 11.9-155.7), and SNAPPE-II > 42 (OR, 48.95; 95% CI, 10.18-235.4) (all p values <.0001). CONCLUSIONS: Our findings indicate that HCA is a major predictor of morbidity and mortality in VLBW newborns.     

Nosocomial infection in small for gestational age newborns with birth weight <1500 g: a multicentre analysis

Objective

To investigate whether preterm newborns who are small for gestational age are at increased risk of nosocomial infections and necrotising enterocolitis.

Design, setting and subjects

The German national surveillance system for nosocomial infection in very low birthweight infants uses the US Centers for Disease Control and Prevention criteria. 2918 newborns (24–28 weeks), born between 2000 and 2004, were selected after application of predefined inclusion criteria to ensure similar proportions of small and appropriate weight for gestational age newborns across gestational age groups.

Main outcome measures

The outcome criterion was at least one episode of nosocomial sepsis, pneumonia or necrotising enterocolitis. Adjusted odds ratios and corresponding 95% CIs were calculated based on general estimating equation models.

Results

The study population consisted of 13% (n = 392) small and 87% (n = 2526) appropriate weight for gestational age infants. 33% (n = 950) of the infants experienced at least one episode of sepsis: 42% (n = 163) of small and 31% (n = 787) of appropriate weight for gestational age newborns (adjusted OR 1.41, 95% CI 1.05 to 1.89). Pneumonia was diagnosed in 6% (n = 171) of infants: 8.4% (n = 33) of small and 5.5% (n = 138) of appropriate weight for gestational age newborns (adjusted OR 1.57, 95% CI 1.19 to 5.57). Necrotising enterocolitis was documented in 5.2% (n = 152) of infants: 7.1% (n = 28) of small and 4.9% of (n = 124) appropriate weight for gestational age newborns (adjusted OR 1.20, 95% confidence interval 0.75 to 1.94).

Conclusions

Growth‐retarded preterm infants seem to be at increased risk of nosocomial infection, irrespective of the responsible pathogen. Future immunological research should elucidate potential causal associations.Very low birthweight (VLBW, <1500 g) newborns are at increased risk of morbidity and mortality. Besides their immaturity, risk profiles can vary due to a multitude of factors. Growth retardation is one factor conferring additional risk. Recent studies have consistently shown an increased mortality risk for small for gestational age (SGA) infants,1,2,3 but results regarding morbidity are conflicting.4,5,6Nosocomial infection has a large impact on neonatal survival and has important cost implications,7,8 affecting up to 40% of babies in neonatal intensive care units (NICUs).9,10,11,12,13 Immunological immaturity (eg, poor phagocytosis or hypogammaglobinaemia), exposure to invasive procedures and prolonged hospitalisation predispose VLBW newborns to nosocomial infection.7,14,15 However, little is known about nosocomial infection in SGA newborns.4,11,16,17,18,19We addressed this issue in a large, multicentre analysis to investigate the association of being SGA and being at increased risk of nosocomial infection—that is, sepsis and pneumonia. In addition, necrotising enterocolitis (NEC) was considered as an outcome criterion.     

Renal aspects of calcium and phosphorus metabolism in preterm infants

The aim of this study is to emphasize renal aspects of calcium and phosphorus metabolism from our data of more than 200 metabolic balance studies carried out in preterm infants. Renal production of 1,25-dihydroxyvitamin D increased rapidly after birth provided the concentration of the substrate, 25-hydroxyvitamin D, is adequate. The gut of preterm infants is able to respond to the active metabolite of vitamin D. Mean plasma phosphate threshold for tubular reabsorption of phosphate is high, about 2.1 mmol/l or 6.5 mg/dl. The low fractional excretion of phosphate cannot be explained by immature parathyroid function nor by renal unresponsiveness to parathormone, at least after the first days of life. It is probably due to regulating factors related to the high rate of growth. Because of reduced glomerular filtration rate, a too high phosphorus intake may result in hyperphosphatemia. Conversely, a too low phosphorus intake will lead to a phosphate depletion syndrome characterized by marked increase in urinary calcium excretion, no urinary phosphate, and hypophosphatemia. Preterm infants with chronic metabolic acidosis are able to acidify urine so that titratable acid is directly related to urinary excretion of phosphate. Clinical implications are that calcium:phosphorus ratio in milk must be adapted according to net bone and soft tissue retention.