Comparison of two gentamicin dosing schedules in very low birth weight infants

BACKGROUND: Several dosing schedules for gentamicin have been recommended for very low birth weight infants during the early neonatal period. We conducted a prospective, randomized, controlled trial to compare efficacy and pharmacokinetics of two dosing schedules in preterm neonates. METHODS: Fifty-eight very low birth weight infants (600 to 1500 g), prescribed gentamicin for treatment of suspected sepsis during the first week after birth, were randomized to receive either the new dosing schedule [every 48 h (q48h)] or the existing dosing schedule [every 24 h (q24h)]. Infants in the "q48h" group received gentamicin at 5.0 or 4.5 mg/kg/dose q48h depending on weight group and infants in the "q24h" group received 2.5 or 3.0 mg/kg/dose q24h. Peak and trough serum gentamicin concentrations were monitored. RESULTS: Peak serum gentamicin concentrations after the first dose were significantly higher in the q48h infants than in q24h infants (8.19 +/- 1.3 vs. 6.04 +/- 2.2, P = 0.00001). Ninety percent of all peak serum gentamicin concentrations in the q48h group were in a higher therapeutic range of 6 to 12 microg/ml as compared with 55% of q24h (P = 0.0005). None of the q48h infants had subtherapeutic serum gentamicin concentrations immediately after administration of the first dose as compared with 36% of q24h infants (P < 0.005). Eighteen percent of q24h infants continued to have peak serum gentamicin concentrations in subtherapeutic range even after the third dose at 48 h. Trough serum gentamicin concentrations were significantly lower in q48h infants than in q24h infants. However, 9 of 30 (30%) q48h infants had trough serum gentamicin concentrations of < or = 0.5 microg/ml before the dose at 48 h and 4 of the 9 had serum gentamicin concentrations of <1 microg/ml at 24 h after the first dose. CONCLUSIONS: The q48h dosing schedule of gentamicin given to very low birth weight infants during the first week after birth achieved therapeutic serum gentamicin concentrations and potentially higher peak to MIC ratios for microorganisms in all infants. However, nearly one-third of the infants had extremely low serum gentamicin concentrations before the next dose. A dosing interval of 36 h might be optimal for bactericidal activity and avoid bacterial growth during prolonged periods of extremely low serum gentamicin concentrations; this dosing interval warrants study.     

Growth and mineral metabolism in very low birth weight infants. II. Effects of calcium supplementation on growth and divalent cations.

Infants of two groups, one of 16, one of 14 infants, who weighed less than 1.3 kg at birth (mean 1.01 +/- 0.05 kg), were studied from age 14 days until they reached 1.8 kg body weight. Infants were pair-matched for gestational age and birth weight and one member was randomly allocated to two treatment groups. Infants in group A received no calcium supplement and those in group B received calcium lactate, 800 mg/kg/24 hr hr, in divided doses with each feed. All were fed "Improved" SMA, 200 ml/kg/24 hr, 160 cal/kg/24 hr, and were given a multivitamin preparation containing 500 IU vitamin D2/dose. The infants' weekly length gain did not differ between groups (1.08 +/- 0.04 cm/week vs 1.11 +/- 0.04 cm/week; mean +/- SEM). Mean weight and head cercumference increments also were similar (group A, 163 +/- 6 g/week; 1.12 +/- 0.03 cm/week; group B, 170 +/- 6 g/week and 1.18 +/- 0.03 cm/week). An increase in blood pH from 7.33 +/- 0.01 to 7.41 +/- 0.01 (P less than 0.01) in group A babies was associated with a decrease in PCO2 from 44.2 +/- 1.0 to 38.9 +/- 1.4 mm Hg. Values remained unchanged with age in group B babies...     

Growth and very low birth weight.

Information on the likelihood of catch up growth in poorly grown very low birthweight children is sparse. The centiles for weight, height, and head circumference were recorded at both 2 and 5 years of age for 135 very low birthweight children and 42 normal birthweight children. At both ages significantly more children of very low birth weight were under the 10th centile for weight and height. Children of birth weight under 1000 g were more often under the 10th centile for weight at 5 years compared with those of birth weight 1000-1500 g. Mean incremental weight gain between 2 and 5 years was significantly less for very low birthweight children. Mean increment in weight from 2 to 5 years was less for very low birthweight children who had been under the 10th centile for weight at 2 years; children who had been under the 10th centile for height also had lower mean height increments. The growth centiles achieved by 2 years of age were useful predictors of poor growth at 5 years, with perinatal data of marginal importance. Only six of 43 (14%) children with a weight at 5 years of age under the 10th centile were small for gestational age at birth. Very low birthweight children who had a weight or height under the 10th centile at 2 years of age usually remained in this category at 5 years with no evidence of catch up growth.     

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.     

极低出生体重儿贫血的防治

极低出生体重 (ＶＬＢＷ )儿贫血是常见的现象 ,所有ＶＬＢＷ儿生后几周均有血红蛋白 (Ｈｂ)下降 ,而且出生体重越低 ,贫血出现越早 ,程度越严重 ,持续时间也越长。足月儿生后 10～ 12周时Ｈｂ很少 <90 ｇ/Ｌ ,但ＶＬＢＷ儿Ｈｂ生理性降低发生更早、更严重 :出生体重 1 0～ 1 5     

Bone growth with low bone mineral content in very low birth weight premature infants

We report serial measurements of bone mineral content (BMC), bone width (BW, a measure of appositional bone growth), and the ratio of BMC:BW by photon absorptiometry of the left radius through the first 10 wk of life in 38 very low birth weight premature infants (birth weight less than 1300 g, gestational age less than 32 wk). Fifteen of 38 infants developed bronchopulmonary dysplasia (BPD) and as a group they could not be distinguished from the 23 infants without BPD, despite the high association between BPD and metabolic bone disease. As BPD occurred in the smaller patients, the BPD group had a significantly lower mean birth weight and mean gestational age as compared to controls (950 +/- 125 g versus 1119 +/- 149, and 28.0 +/- 0.8 versus 29.0 +/- 1.3 wk). For both control and BPD groups, BMCs did not differ and remained relatively unchanged throughout the first 10 wk of life, lagging significantly behind the intrauterine rate as defined by measuring BMC in 175 infants of varying gestational ages during the first few days of life. BW also did not differ during this period between groups. BW did increase significantly in both groups (from 3.2 +/- 0.3 to 3.9 +/- 0.4 mm in the controls and from 3.0 +/- 0.3 to 3.8 +/- 0.4 mm in the BPD group), but remained significantly delayed compared to the intrauterine rate. In both groups, BMC remained relatively constant despite increasing BW and thus BMC/BW decreased during the first 10 wk of life (from 11.5 +/- 1.3 to 10.2 +/- 1.9 in the controls and from 11.0 +/- 1.3 to 8.6 +/- 2.2 in the BPD group).(ABSTRACT TRUNCATED AT 250 WORDS)     

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.     

Improved mineral balance in very low birth weight infants fed fortified human milk

Enhanced calcium and phosphorus retention was achieved in 16 very low birth weight infants (birth weight 1117 +/- 42 g, gestation 29 +/- 0.2 weeks) fed a preparation of fortified human milk augmented with calcium lactate and monobasic and dibasic phosphate salts. Measurements of growth and macronutrient utilization were similar to those obtained in a previous study of infants fed a preparation of fortified human milk that contained lower levels of calcium and phosphorus. However, unlike the relative hypophosphatemia, hypophosphaturia, and hypercalciuria noted in the infants in our earlier study, normal serum and urine phosphorus and urine calcium values were observed in this study. Postnatal calcium and phosphorus retentions correlated significantly with respective intakes, the absorption of fat, and the retention of nitrogen. The relationships among calcium and phosphorus intake and retention predict that 160 mg/kg/d and 94 mg/kg/d, respectively, must be fed to achieve retention equivalent to intrauterine estimates. Although postnatal retention of calcium and phosphorus may be increased to levels accumulated by the fetus, technical considerations for the preparation of a formula with sufficiently high levels of calcium and phosphorus must be resolved.     

Trace elements and mineral requirements for very low birth weight infants in rickets of prematurity.

To establish mineral and trace element requirements for very low birth it is important to prevent bone mineral disorder. Those infants fed mother's milk only are thought to be at higher risk of this disorder. Both calcium and phosphorus supplementation were thought to be needed to prevent it. Copper and zinc are important as cofactors of major enzymes involved in the synthesis of collagen. These trace elements especially zinc may not be enough for very low birth weight infants fed mother's milk. At present however the relationship between these trace elements and minerals, and bone metabolic disease in preterm infants is not completely clear.     

Severe pre-eclampsia and infants of very low birth weight.

The effect of severe pre-eclampsia on the outcome of infants of very low birth weight was studied in a prospective case control study of 35 pairs of infants of comparable gestation. Significantly more infants were delivered before the onset of labour and by caesarean section in the group with pre-eclampsia. These babies tended to be smaller and had a higher incidence of hyaline membrane disease, patent ductus arteriosus, pulmonary air leak, and hypotension. They also required more intensive treatment with oxygen and mechanical ventilation. The significant difference in birth weight was still apparent at 2 years of age. Although the mean psychomotor developmental index and the incidence of specific neurodevelopmental impairments were not significantly different between the two groups, survivors in the group born to pre-eclamptic mothers had a significantly lower mean mental developmental index, and significantly more of these children had one or more impairments compared with the control group at 2 years of age.     

极低出生体重儿母乳喂养与配方乳喂养的比较

目的探讨极低出生体重儿在进行母乳喂养、早产儿配方乳喂养条件下黄疸消退、体重增长、耐受全胃肠营养的时间及常见并发症的区别。方法对2002年10月至2005年4月我科收治的111例极低出生体重儿提供母乳喂养的39例,另72例采用早产儿配方乳喂养,观察两组在黄疸消退日龄、回升到出生体重日龄、过渡到全胃肠道营养日龄、住院天数等的差别,并比较两组在喂养不耐受、新生儿坏死性小肠结肠炎、酸中毒的发生率方面的不同。结果两组过渡到全胃肠道营养日龄的差异有统计学意义(t=15.06,P<0.01);两组在喂养不耐受和酸中毒发生率的差异也有统计学意义(χ2分别为4.203和4.811,P<0.05);黄疸消退日龄、回升到出生体重日龄差异两组无统计学意义(t值分别为0.70和0.27,P>0.05);新生儿坏死性小肠结肠炎发生率的两组差异也无统计学意义(χ2=0.01,P>0.05)。结论在极低出生体重儿应积极进行母乳喂养,这对于早日过渡到全胃肠道营养、减少喂养不耐受发生率、缩短住院天数、降低酸中毒发生率均有积极作用。     

极低出生体重儿母乳喂养与配方乳喂养的比较

目的 探讨极低出生体重儿在进行母乳喂养、早产儿配方乳喂养条件下黄疸消退、体重增长、耐受全胃肠营养的时间及常见并发症的区别.方法 对2002年10月至2005年4月我科收治的111例极低出生体重儿提供母乳喂养的39例,另72例采用早产儿配方乳喂养,观察两组在黄疸消退日龄、回升到出生体重日龄、过渡到全胃肠道营养日龄、住院天数等的差别,并比较两组在喂养不耐受、新生儿坏死性小肠结肠炎、酸中毒的发生率方面的不同.结果 两组过渡到全胃肠道营养日龄的差异有统计学意义（t=15.06,P＜0.01）;两组在喂养不耐受和酸中毒发生率的差异也有统计学意义（χ2分别为4.203和4.811,P＜0.05）;黄疸消退日龄、回升到出生体重日龄差异两组无统计学意义（t值分别为0.70和0.27, P＞0.05）;新生儿坏死性小肠结肠炎发生率的两组差异也无统计学意义（χ^2=0.01,P＞0.05）.结论 在极低出生体重儿应积极进行母乳喂养,这对于早日过渡到全胃肠道营养、减少喂养不耐受发生率、缩短住院天数、降低酸中毒发生率均有积极作用.     

238例极低出生体重早产儿的生长速率和影响因素

目的 观察极低出生体重早产儿住院期问的生长速度及营养支持情况,研究影响其生长的因素.方法 采用回顾性调查的方法,收集2005年1月1日至2006年6月30日我国不同地区10所三甲医院檄低出生体重早产儿的临床资料,对影响早产儿生长的因素进行分析.结果 共有238例符合条件的极低出生体重早产儿,出生胎龄为(30.9±1.9)周,出生体重(1313±129)g.生后第1周～第6周平均体重生长速率分别为-7.2、14.2、13.6、13.7、14.2、14.8 g/(kg·d).肠内、外营养开始平均时间分别为(3.4±2,3)d和(3.1±1.7)d,总热卡达120 kcal/(kg·d)平均时间为(21.3±11.6)d,喂养奶量达150 ml/(kg·d)平均时间为(23.4±10.8)d.恢复出生体重后平均生长速率为(13.8±3.5)g/(kg·d),平均住院时间(39.8±13.9)d.出生时小于胎龄者较适于胎龄者恢复出生体重后的平均生长速率快[14.4 vs 13.2 g/(kg·d),t=2.703,P<0.05].结论 平均生长速率较快组[≥15 g/(kg·d)]与较慢组[<15g/(kg·d)]相比,出生胎龄差异无显著性,但出生体重低、接受肠内肠外营养早.大多数极低出生体重早产儿在住院期间不能达到正常胎儿在官内的生长速率.更积极的肠内肠外营养,可能有利于极低出生体重儿生后的早期牛长.     

经外周静脉置人中心静脉导管在极低出生体质量儿中的应用

目的 评估经外周静脉置人中心静脉导管(PICC)在极低出生体质量儿(VLBWI)救治中的作用.方法 选取2004年6月至2008年5月入住我院的VLBWI 86例,分为PICC 46例和外周静脉穿刺(PIV)组40例,观察患儿住院期间静脉穿刺次数、呼吸暂停发生次数、体质量增长情况、低血糖持续时间和感染指标.结果 PICC组静脉穿刺次数为1.4±0.2,呼吸暂停发生次数为61.2±8.7,恢复到出生体质量的时间为(12.8±2.8)d,低血糖持续时间为(1.9±1.4)h,与PIV组比较均明显减少,差异有显著性(P＜0.05);而感染指标阳性率和静脉炎发生率两组差异无显著性(P＞0.05).结论 PICC是一种安全可靠的静脉置管术,是有效地应用于VLBWI的长期通畅的静脉通道.     

Amino acids, glutamine, and protein metabolism in very low birth weight infants

Glutamine has been proposed to be conditionally essential for premature infants, and the currently used parenteral nutrient mixtures do not contain glutamine. De novo glutamine synthesis (DGln) is linked to inflow of carbon into and out of the tricarboxylic acid (TCA) cycle. We hypothesized that a higher supply of parenteral amino acids by increasing the influx of amino acid carbon into the TCA cycle will enhance the rate of DGln. Very low birth weight infants were randomized to receive parenteral amino acids either 1.5 g/kg/d for 20 h followed by 3.0 g/kg/d for 5 h (AA1.5) or 3.0 g/kg/d for 20 h followed by 1.5 g/kg/d for 5 h (AA3.0). A third group of babies received amino acids 1.5 g/kg/d for 20 h followed by 3.0 g/kg/d for 20 h (AA-Ext). Glutamine and protein/nitrogen kinetics were examined using [5-(15)N]glutamine, [2H5]phenylalanine, [1-(13)C,15N]leucine, and [15N2]urea tracers. An acute increase in parenteral amino acid infusion for 5 h (AA1.5) resulted in decrease in rate of appearance (Ra) of phenylalanine and urea, but had no effect on glutamine Ra. Infusion of amino acids at 3.0 g/kg/d for 20 h resulted in increase in DGln, leucine transamination, and urea synthesis, but had no effect on Ra phenylalanine (AA-Ext). These data show an acute increase in parenteral amino acid-suppressed proteolysis, however, such an effect was not seen when amino acids were infused for 20 h and resulted in an increase in glutamine synthesis.     

极低出生体重儿早期救治结局的影响因素分析

目的 分析极低出生体重儿(VLBWI)临床特点及影响早期救治结局的相关因素.方法 对2008年1月至2013年1月我院新生儿重症监护室(NICU)住院的VLBWI临床资料进行回顾性分析,对影响早期救治结局的相关因素进行Logistic回归分析.结果 VLBWI主要分布在1250 ～ 1499 g(57.1％),胎龄29～32周(72.3％).新生儿呼吸窘迫综合征(RDS)在＜1000 g组、胎龄25～28周的发生率明显高于其他组;喂养不耐受在1250～1499 g组的发生率明显高于其他组;肺炎在33～ 36周的发生率明显高于其他组;贫血在1250～1499 g的发生率明显高于其他组.临床转归差108例(38.6％),转归好172例(61.4％).多因素Logistic回归分析显示,胎龄越大VLBWI的转归越好(OR=0.979,95％CI0.955 ～ 0.997),RDS(OR=3.739,95％ CI1.955～7.007)、肺炎(OR =2.315,95％CI1.097 ～4.677)是其危险因素.结论 对VLBWI可根据胎龄及出生体重不同,有目的的预防及治疗并发症,可以提高存活率.     

影响极低出生体重儿体重增长的多因素分析

目的探讨影响极低出生体重儿(VLBW)体重增长的相关因素。方法对1998年7月—2004年3月重庆医科大学儿童医院新生儿病房收治的51例VLBW进行回顾性分析。结果单因素分析发现,早开奶、热卡摄入量和蛋白质摄入量对体重增长有显著性影响(P<0·05)。多元逐步回归分析结果示,热卡摄入量和蛋白质摄入量是影响体重增长的显著因素,回归方程为Y(体重增长)=-6·426+0·120X1(热卡摄入量)+3·737X2(蛋白质摄入量)(P<0·01)。达到体重增长目标对象中单纯胃肠内营养组和部分胃肠外营养组热卡摄入量分别为(520·62±21·59)kJ/(kg·d)[(124·43±5·16)kcal/(kg·d)]、(451·49±68·41)kJ/(kg·d)[(107·98±16·35)kcal/(kg·d)],差异有统计学意义(P<0·05)。早开奶组出生体重恢复时间、住院时间和胃肠外营养液体量占总液量比例>75%时间平均秩分别为18·58、20·24、20·11,晚开奶组分别为33·00、32·48、31·83,差异有统计学意义(P<0·05)。结论VLBW在生后应保证足量热卡和蛋白质的供给,对于小于胎龄儿和有严重并发症的患儿更应该加强营养的补充,对VLBW应尽早喂养,同时需要胃肠外营养作为肠内营养的补充。