Renal calcification incidence in very low birth weight infants

Serial ultrasound examinations were performed on 31 neonates with birth weights of less than 1,500 g for the detection of renal calcifications. Renal calcifications occurred in 20 (64%) of the infants at a mean age of 39.3 +/- 26.7 days of life. Infants with renal calcifications had shorter gestations (28.2 +/- 1.8 v 31 +/- 1.4 weeks, P less than .004) and lighter birth weights (924 +/- 195 v 1,338 +/- 100 g, P less than .004) than those infants without renal calcifications (n = 11). Furosemide administration was more common in the infants with renal calcifications (65% v 9.1%, P less than .001). The mean total dose of furosemide administered before renal calcifications were noted was 9.59 +/- 7.25 mg/kg. The 20 neonates with renal calcifications had a mean urine calcium level of 12.0 +/- 6.8 mg/kg/24 hours, mean urine calcium to creatinine ratio of 1.32 +/- 1.03 (range 0.3 to 4.45), and a mean alkaline phosphatase concentration of 961 +/- 327 IU. Initial parathyroid hormone levels were not different between the two groups, and subsequent determinations in infants with renal calcifications did not differ significantly from initial values. Renal calcifications are fairly common among very low birth weight infants, particularly in those receiving supplemental calcium and furosemide therapy. Although long-term implications of such findings are not known, close monitoring of renal function by serial determinations of urine calcium and urine calcium to creatinine ratios may identify those infants at risk for renal calcifications.     

Increased survival of low birth weight infants: impact on the incidence of retinopathy of prematurity

Retinopathy of prematurity is a retinal vascular disease that occurs only in premature infants. Because of concern that the occurrence of this potentially blinding disease is increasing, a retrospective chart review was undertaken to compare the incidence of retinopathy of prematurity at the University of Washington during the years 1981 to 1984 with previously published data collected at the same institution during the years 1968 to 1980. During 1981 to 1984, there was an increase in the annual numbers of admissions and survivors weighing 1750 g at birth; the survival rate increased significantly (P less than .000001). A trend toward an increased risk for proliferative retinopathy of prematurity (P = .057) during 1981 to 1984 period was noted, but the number of "excess cases" was calculated to be only 6 per year. The remainder of the additional cases, 19 annually, were due to increased survival of infants at risk. Thus, the "second epidemic" of retinopathy of prematurity is largely due to improved survival of low birth weight infants rather than to new iatrogenic factors. In infants with proliferative retinopathy of prematurity, there was a previously unreported association between increased severity of disease and lower birth weight (P = .015). There were four children with severe bilateral visual loss due to retinopathy of prematurity identified during the 1981 to 1984 period, whereas only one bilaterally blind infant was noted during the preceding 12.7 years.     

极低及超低出生体重儿的预后因素分析

目的 分析极低及超低出生体重儿（出生体重≤ 1 200 g）的临床资料,为其预后及临床干预提供预警指标。方法 回顾性分析108 例极低及超低出生体重儿的母孕期病史、新生儿出生时情况、诊治经过及预后,采用非条件logistic 回归分析筛选预后的影响因素。结果 108 例极低及超低出生体重儿,出生体重范围在结论 极低及超低出生体重儿的病死率较高,且随着日龄的增加,影响早产儿生存的预后因素不同,临床上应针对这些因素制定合理的管理方案,提高早产儿生存率。     

Hyperkalemia in very low birth weight infants.

PURPOSE: To assess the frequency and pathogenesis of hyperkalemia in the very low birth weight infant. METHODS: Infants who weighed less than 1000 gm at birth were prospectively entered into the study within 12 hours of birth. Potential risk factors for hyperkalemia were assessed. Body weight, fluid and electrolyte balance, serum levels of sodium and potassium, creatinine clearance, fractional sodium excretion, and urine sodium/potassium ratio were measured every 8 hours for 72 hours. Measurements of plasma renin, serum aldosterone, and plasma atrial natriuretic factor were made at study entry and repeated when hyperkalemia (serum potassium greater than 6.5 mmol/L) occurred or at 72 hours. Infants in whom hyperkalemia developed were compared with those in whom it did not. RESULTS: Thirty-one infants completed the study; hyperkalemia developed in 16 (51.6%). The only difference in the occurrence of perinatal complications was the more frequent occurrence of pH less than 7.20 in infants with subsequent development of hyperkalemia. Creatinine clearance, urine output, and potassium excretion were significantly lower in the hyperkalemia group during the first 24 hours. Serum potassium concentration at 24 hours was inversely related to urine output in the prior 24 hours. Fractional sodium excretion, urine sodium/potassium ratio, and levels of renin, aldosterone, and atrial natriuretic factor did not differ between groups. CONCLUSIONS: Hyperkalemia is a frequent complication in very low birth weight infants. Infants with low urinary flow rates during the first few hours after birth are at greatest risk for the development of hyperkalemia.     

Postnatal weight changes in low birth weight infants

Postnatal body weight changes were assessed in 385 surviving infants with birth weights of less than 2,500 g. Body weight was measured daily between birth and 45 days of age. Infants were grouped according to 100-g birth weight categories, and mean body weight changes for each group were compared. Initial postnatal weight loss occurred in each group and ranged between 7.9% and 14.6% of birth weight. Mean postnatal weight loss was greater in the lowest birth weight groups, but considerable variability was observed among individual infants. Duration of postnatal weight loss was similar among all birth weight groups. Weight gain usually began between four and six days of age, and the rate of weight gain expressed as grams per kilogram per day was similar in all birth weight groups.     

Feeding of low birth weight infants

Optimal feeding of low birth weight (LBW) infants improves their immediate survival and subsequent growth and development. Being a heterogeneous group comprising term and preterm neonates, their feeding abilities, fluid and nutritional requirements are quite different from normal birth weight infants. A practical approach to feeding a LBW infant including choice of initial feeding method, progression of oral feeds, and nutritional supplementation based on her oral feeding skills and nutritional requirements is being discussed in this protocol. Growth monitoring, management of feed intolerance, and the essential skills involved in feeding them have also been described in detail.     

Folic acid supplementation in low birth weight infants.

Low birth weight infants (246) entered a trial to folic acid supplementation from 3 weeks to 12 months of age. The folic acid group had significantly higher mean hemoglobin levels at 6 and 9 months of age but the differences were only about 0.5 gm/dl, there was no significant difference in hematocrit, and in both groups of infants the mean hemoglobin levels were higher than those of normal birth weight infants. The differences in hemoglobin, although statistically significant, are of uncertain clinical significance. Median red cell folate levels remained within the normal adult range in both groups of infants. A minority of infants in the untreated group had low red cell folate levels but this was usually temporary, corrected by dietary folate, and not associated with low hemoglobin. Weight gain was not affected by folic acid supplementation. The infants in this trial were fed with a milk preparation containing 3.5 microgram/100 ml of folic acid which is a similar concentration to that of human milk and we recommend that the folate content of milks fed to low birth weight infants should not fall below this level. We do not have sufficient grounds to recommend routine folic acid supplements for all low birth weight infants throughout the first year of life but there is a possibility that their folate intake may sometimes be suboptimal.     

低出生体重儿排尿功能观察

<正>小儿正常膀胱储尿排尿功能在20世纪中期逐渐受到医学专家的关注。国外学者已经进行了一系列小儿排尿研究,但大部分是针对较大儿童(大于3岁)的有创性尿动力学检查[1]。目前缺乏新生儿尤其是低出生体重儿(low birth weight infant,LBWI)     

Postural development in very low birth weight and normal birth weight infants

In this study the seven postural responses selected by Vojta to evaluate neuromotor development were applied to 68 very low birth weight (VLBW) (greater than 1500 g) infants and to 28 healthy infants of normal birth weight (less than 2500 g). Of the 68 VLBW infants, 41 were small for gestational age and 27 appropriate for gestational age. All infants were examined between 37 and 40 weeks postmenstrual age. They were all later assessed on the Griffiths Mental Developmental Scale at 12 and 18 months. There were significant differences in postural reactions between the two groups which confirmed the lower tone and greater extension previously described in very low birth weight infants. An important finding in the study was that poor head and trunk righting noted at four months corrected age in very low birth weight infants, was associated with less developed locomotion at 12 and 18 months as assessed by the Griffiths Mental Developmental Scale. Thus, a delay in maturation in very low birth weight infants which was apparent from the assessment of postural responses in early infancy was still identifiable on the locomotor subscales at 12 and 18 months. Five of Vojta's responses were shown to be useful as part of the neurological assessment of high risk infants.