Water, Sodium and Acid-Base Balance in Premature Infants: Therapeutical Aspects

ABSTRACT. One of the main targets of fluid therapy in premature infants is to avoid variations in osmolality, which mainly means providing a stable sodium, glucose, and acid-base balance. Water, sodium, and acid-base balance were measured in 20 infants appropriate-for-gestational age with a gestational age 34 weeks. The infants were randomly assigned to one of two treatment groups. Fluid intake was restricted and air humidity in the incubator was high in order to minimize insensible water loss. Sodium intake in Group 1 was 2 mmol/kg/day and consisted of sodium chloride. Sodium intake in Group 2 was 4 mmol/kg/day and consisted of both sodium chloride and acetate. Weight loss was appropriate in both groups. In the high sodium intake group there was a tendency towards a more stable plasma sodium concentration than in the low sodium intake group. The use of sodium acetate was efficient and practical as normal acid-base balance was maintained. The protocol with restricted fluid intake (1st day 50 ml/kg, 2nd day 70 ml/kg, 3rd day 90 ml/kg, and 4th day 110 ml/kg), high air humidity, a sodium supply of 3 to 4 mmol/kg/day, and a slow correction of metabolic acidosis with sodium acetate, yields suitable guidelines in planning fluid and electrolyte therapy in premature infants 34 weeks' gestation.     

Influence of Behavioural State on Blood Pressure in Preterm Infants during the First 5 Days of Life

ABSTRACT. The influence of behavioural state on neonatal blood pressure was studied in 19 healthy preterm infants. During the first five days of life every three hours a series of oscillometric blood pressure measurements was made. During the measurements the behavioural state was scored. The predominant states were quiet and active sleep. We confirmed the age-dependency of blood pressure with a steep increase during the first day of life. After the first day blood pressure and heart rate were slightly higher when the infant was awake than when asleep. Paired comparison ( t -test) before and after spontaneous state transitions showed significant differences in median heart rate and ranges of heart rate and blood pressure, but not in median blood pressure. We conclude that especially movements influence oscillometric determination of blood pressure and heart rate.     

血浆渗透压、血气、血糖变化与早产儿脑室周围-脑室内出血的相关性

目的　研究血浆渗透压、血气和血糖变化与早产儿脑室周围 脑室内出血 (PIVH)的相关性 ,为临床防治提供参考依据。方法　PIVH患儿 173例入院后常规作血生化检测和血气分析 ,并与无PIVH的 164例早产儿比较。结果　低血糖、酸中毒、高碳酸血症和缺氧均与早产儿PIVH密切相关 (P均 <0 .0 5 ) ,两组早产儿血浆渗透压差异不显著 (P >0 .0 5 )。结论　早产儿血浆渗透压与PIVH无相关关系 ,对早产儿要重视纠正低血糖、酸中毒、高碳酸血症和缺氧 ,以降低早产儿颅内出血发生率 ,减少伤残。     

Free Urinary Cortisol Immunoreactive Levels in Premature and Full Term Infants

ABSTRACT. Urinary free immunoreactive Cortisol excretion was measured in 20 full term, 20 premature and 20 premature newborns of mothers who had been treated with 12 mg betamethasone 48 hours before delivery. In 10 full term newborns delivered normally, values were 40 ±20 nmol/mmol creatinine on the first, 23±8 on the second and 21±6 on the third day of life. In 10 full term newborns with stressful delivery, the corresponding values were 63±39, 44±33 and 32±17 nmol/mmol creatinine in the first three days of life. The levels of urinary free immunoreactive Cortisol of 10 premature newborns delivered without stress were 170±116, 91±75 and 70±61 nmol/mmol creatinine respectively, on days one, two and three of life. Ten premature infants with respiratory distress syndrome had values of 471 ± 187, 526±465 and 636±906 nmol/mmol creatinine, respectively. The 10 premature newborns whose mothers had received betamethasone, had urinary free immunoreactive Cortisol levels of 109±120, 55±42 and 66±84 nmol/mmol creatinine, lower than the other premature infants. This difference, however, was not statistically significant. We conclude that premature infants regardless of stress or normal labor have high urinary free immunoreactive Cortisol excretion, suggesting that prematurity per se is a potent stress.     

早产儿脑病相关危险因素回顾性分析

目的 探讨早产儿脑病的发生情况,并分析其相关危险因素,以降低其发病率,改善神经发育预后.方法 对2009年11月1日-2010年10月31日青岛大学医学院附属医院NICU收治的胎龄≤32周的186例早产儿行头颅MRI检查,分析早产儿脑病的发生率,根据头颅MRI表现分为颅内出血组和无颅内出血组、缺血性脑损伤组和无缺血性脑损伤组,头颅MRI未发现异常者设为对照组,详细统计临床资料,应用SPSS 17.0软件进行数据分析,比较2组基本情况、产科病理、生后并发症及治疗措施方面的差异;对相关因素进行Logistic回归分析,筛选出早产儿脑病的高危因素.结果 1.早产儿脑病发生率为36.0%(67/186例),出血性脑损伤发生率为29.0%(54/186例);缺血性脑损伤发生率23.1%(43/186例);缺血性脑损伤中局灶性损伤20例,弥散性损伤23例;67例患儿中同时表现出血及缺血性损伤的发生率16.1%(30/186例);43例缺血患儿中11例表现为神经元轴突损伤.2.脑病组与对照组出生胎龄及第1次MRI检查时间的差异均无统计学意义(Pa>0.05),出生体质量的差异有统计学意义(P<0.05).3.Logistic回归分析:母孕期感染、产道分娩、脓毒症、机械通气是出血性脑损伤的独立危险因素,出生体质量为其保护因素;机械通气、脓毒症、低碳酸血症是缺血性脑损伤的独立危险因素,出生体质量、产前激素为其保护因素.结论 早产儿脑病是多种因素相互作用的复杂结果,母孕期感染等宫内暴露因素、围生期缺氧及出生后感染均为早产儿脑病的危险因素.     

谷氨酰胺及低乳糖配方乳对早产儿坏死性小肠结肠炎的预防

目的观察谷氨酰胺及低乳糖配方乳对早产儿坏死性小肠结肠炎(NEC)的预防效果。方法选取新生儿科病房收治的早产极低出生体质量儿90例按不同营养方式分为3组。A组:予常规静脉营养及母乳或配方乳喂养;B组:静脉营养及喂养方法与A组相同,另外胃肠喂养开始即添加谷氨酰胺口服(0.25 g.kg-1,2次.d-1);C组:静脉营养方法与A组相同,胃肠喂养采用低乳糖配方乳,另外添加谷氨酰胺口服(0.25 g.kg-1,2次.d-1)。3组患儿均于出生24 h内、出生5 d、10 d后取静脉血测定其胱抑素C(CysC)和超敏C反应蛋白(hsCRP),出生10 d取2 g左右患儿大便定性测定乳糖水平,并在出生30 d内分别计算各组患儿NEC的发生率。结果经过不同营养方法处理后,3组患儿hsCRP均逐渐升高,但喂养5 d及10 d后C组升高不明显,与A、B组比较差异有统计学意义;各组CysC逐渐升高,A组升高明显,C组升高不明显,在出生10 d时最低,与A、B组比较差异有统计学意义。3组患儿大便乳糖分析显示A组阳性率较高,C组最低。患儿NEC发生率A组为6.7%,B、C组发生率相同为3.3%,A组与B、C组比较差异有统计学意义。结论早产儿喂养谷氨酰胺联合低乳糖配方乳可以减轻炎性反应,增加乳糖吸收,降低NEC的发生,对NEC的发生起到一定预防作用。     

Hyponatraemia in Premature Babies and Following Surgery in Older Children

ABSTRACT. Hyponatraemia implies water retention in excess of sodium with or without increased loss of sodium from the body; extracellular fluid volume may be increased, normal or reduced. It has many causes which are briefly reviewed. Among these is the rare syndrome of inappropriate secretion of antidiuretic hormone (SIADH). It is suggested that SIADH is often diagnosed incorrectly because the raised ADH levels are appropriate for the volume status of the child. Precision in the diagnosis is important because whilst water restriction is necessary for the treatment of SIADH, other measures including the administration of extra fluid are often required if the raised ADH is appropriate. Hyponatraemia in the newborn may be caused by prerenal failure, renal failure or renal sodium wasting which is common in premature infants. Careful control of sodium intake as well as water intake is vital in this age group. Surgery is associated with water retention, but recent studies suggest that ADH levels are raised post-operatively because of volume depletion and that present recommendations for fluid therapy during and following surgery are inadequate. The use of electrolyte-free dextrose solutions should be abandoned and more liberal use of physiological saline or colloid is recommended.     

早产儿脑室周围白质软化与脐血一氧化氮的关系

目的探讨早产儿脑室周围白质软化(PVL)的高危因素、发病机制及其早期诊断方法。方法采集PVL早产儿宫内缺氧缺血病史;采用ELISA检测PVL早产儿脐血TORCH-IgM抗体;应用硝酸还原酶法检测脐血一氧化氮(NO)水平。结果PVL组52例早产儿中39例有宫内缺氧缺血病史且脐血TORCH-IgM抗体阳性率明显高于对照组(P<0.05);PVL组脐血NO水平明显高于对照组(P<0.05)。结论宫内缺氧缺血和感染是早产儿PVL的高危因素。过量NO可能在PVL发生机制中起重要作用;脐血NO水平检测对早产儿PVL有早期诊断价值。     

胃肠功能障碍早产儿胃液表皮生长因子水平变化及意义

目的研究不同胎龄早产儿发生胃肠功能障碍后胃液中表皮生长因子(EGF)水平变化,探讨其在胃肠功能障碍的病理生理过程中的作用,为寻找早期预测早产儿胃肠功能的客观指标提供理论依据。方法本院新生儿监护室2006年1月-2009年6月收治160例不同胎龄早产儿,随机分为胃肠功能障碍组80例(观察组)和非胃肠功能障碍组80例(对照组),采用ELISA方法检测其胃液中EGF水平变化,观察组收集样本时间均为症状表现12 h内,对照组为入院3 d内。结果观察组及对照组均按不同胎龄分为4组:28～30周组,30+1～32周组,32+1～34周组,34+1～36+6周组,每组20例,观察组胃液EGF质量浓度(ng.L-1)分别为68.2±11.4,172.0±34.4,284.8±30.6,444.4±82.4,对照组胃液EGF质量浓度(ng.L-1)分别为:343.0±45.2,494.4±29.4,703.3±118.1,947.8±158.1,EGF随胎龄不同,分泌水平随之变化,胎龄越大,其表达水平越高。胃肠道EGF的分泌水平与胎龄呈正相关。结论早产儿胃肠衰竭时EGF分泌水平明显降低,反映了胃肠道功能的损害程度。     

High Total and Free 1,25-Dihydroxyvitamin D Concentrations in Serum of Premature Infants

ABSTRACT. We investigated the relationship between serum total and free 1,25-dihydroxyvitamin D (1,25-OH₂D) and the biochemical regulation of 1,25-OH₂D production in premature infants. We measured 1,25-OH₂D, vitamin D binding protein and related biochemical parameters and calculated the free 1,25-OH₂D index in serum of 17 premature infants (birthweight 810–1700 g; gestational age 31–36 weeks) on two different occasions defined by body weight (Study A: 1750–1850 g, Study B: 2100–2200 g). Dietary calcium (Ca) intake was 1,5 or 2,6 mmol/kg/d, phosphorus (P) intake 1,7 mmol/kg/d and vitamin D intake 1000 IU/d. Biochemical results were similar in infants with different Ca intakes and all were within reference ranges. Concentrations of vitamin D binding protein (Study A 0.15±0.03 g/1, Study B 0.14±0.03 g/1; ± SD) were lower, concentrations of 1,25(OH)₂D (Study A 180±67 pmol/1, Study B 216±53 pmol/1) were higher, and consequently the free 1,25-OH₂D index (Study A 6.6±2.7, Study B 8.8±2.6) was 4 to 6 times higher than in previously studied term infants. 1,25-OH₂D and the free 1,25-OH₂D index increased significantly with age and were not correlated with serum P or parathyroid hormone. The data indicate that in premature infants with normal biochemical parameters of Ca and P metabolism elevated concentrations of 1,25-OH₂D signify an increased fraction of free 1,25-OH₂D and that increased production of 1,25-OH₂D is not due to hypophosphatemia or hyperparathyroidism.     

Serial Measurements of Cerebral Blood Flow Velocity in Preterm Infants during the First 72 Hours of Life

ABSTRACT. Serial measurements of cerebral blood flow velocity (CBFV) were made in 29 preterm infants, using continuous wave Doppler ultrasound. CBFV was measured in both anterior cerebral arteries and quantitative measurements of CBFV were determined using the area under the velocity curve. In all ventilated infants, CBFV increased significantly during the first 6 hours of life and continued to increase until 16 hours of age. Thereafter, CBFV remained relatively constant. This increase in CBFV was primarily the result of increased diastolic flow. Three infants who had evidence of intraventricular haemorrhage on cranial ultrasound, had similar CBFV compared with the infants with no evidence of haemorrhage. Two infants died and both demonstrated areas of periventricular leukomalacia at autopsy. These infants had a prolonged period of low CBFV. These measurements provide normal data for ventilated, preterm infants. As previously suggested in term infants, the initial rise in CBFV may be secondary to closure of the ductus although a generalized decrease in peripheral vascular resistance could also be a contributing factor. Fluctuations in CBFV rather than individual readings are probably more important in the genesis of IVH. An episode of significantly reduced CBFV is a poor prognostic sign.     

Regulation of Serum Sodium in Dehydrated and Orally Rehydrated Infants

ABSTRACT. We have examined the control of serum sodium concentration (S-Na) in 60 male infants with acute diarrheal disease, moderate dehydration, but without the presence of fever, vomiting or other conditions. The infants were studied on admission and during oral rehydration therapy (ORT). We examined the effect of rapid reduction of the purging rate on the control of S-Na by adding pulverized rice and pulses (dal moong) to the rehydration solution. On admission S-Na was significantly inversely related to age. This correlation could not only be attributed to difference in stool sodium losses. Changes in S-Na and urinary K/Na ratio during oral rehydration therapy (ORT), were analyzed seperately in infants below and above 4 month of age. During the first six hours of ORT, there was an increase in S-Na in all groups. During the following 18 hours, S-Na tended to normalize around 138 mmol/1. Normalization occrred faster if purging rate was reduced. In all groups urinary K/Na ratio (index of aldosterone production and, inversely, of sodium balance), was high at admission and fell during ORT. In the youngest infants (below 4 month of age) the fall was significantly more pronounced if the purging was reduced. We conclude that it is important to consider age when prescribing ORT. The capacity to correct distrubances in S-Na becomes more efficient during maintenance stage of ORT. Correction of S-Na and sodium balance is enhanced by rapid reduction of abnormal intestinal losses.     

Sodium, potassium and chloride needs in low-birth-weight infants

A review of the daily requirements of sodium, potassium and chloride in preterm infants with particular emphasis on very low-birth-weight (VLBW) infants is given against the background of our present knowledge of the homeostatic regulation of these electrolytes during early postnatal life. Particular attention has been given to the importance of balanced fluid and electrolyte homeostasis in the control of compartment volumes and tonicity. The risk of rapid changes of extracellular fluid osmolality for many organs, and particularly for the brain, has been stressed. In order to obtain an adequate sodium and fluid balance during the first postnatal weeks in preterm infants of varying gestational age, recommendations for sodium intake during the first 4-5 postnatal weeks are given.     

Changes in Plasma Concentrations of Atrial Natriuretic Peptide during Exchange Transfusion in Premature Infants

ABSTRACT. Plasma concentrations of atrial natriuretic peptide (ANP) and hemodynamic parameters were investigated in five premature infants undergoing exchange transfusion. Baseline values of ANP were 51.7 ± 21.2 fmol/ml. Volume depletion by withdrawal of 10 ml blood did not cause changes in systolic blood pressure (79.4 ± 4.3 vs. 71.4 ± 5.6 mmHg) and heart rate (115 ± 5.2 vs. 115 ± 2.4 b/min). ANP levels in plasma remained unaltered (53.4 ± 24.9 fmol/ml). Replacement of 10 ml blood increased central venous pressure by 33% and ANP concentration in the plasma by nearly 30%, while heart rate and blood pressure remained unchanged. Our data indicate that the heart of the premature infant responded to acute blood replacement with increased ANP-release, while blood removal appeared not to influence hormone regulation.     

Relationship between Protein and Energy in the Feeding of Preterm Infants during the First Month of Life

ABSTRACT. Energy and protein quantity and quality in the diet are factors regulating the rate of growth in the preterm infant. In the present study twenty infants 31–36 weeks of gestational age were fed with two identical test formulas which vried only in the content of energy. One formula (F-81) contained 3.1 g protein (60 bovine whey: 40 bovine caseins) and 81 kcal per dl. The second formula (F-94) contained the same amount of protein but 94 kcal per dl. At an intake of 150 ml/kg/d the infants received 4.6 g protein/kg/d and either 121 or 141 kcal/kg/d. The infants on F-94 had a significantly higher rate of weight gain, but growth of length and head circumference was equal in the two groups. Significant differences were found in the plasma concentrations of glutamine and alanine between the two feeding groups. The other plasma amino acids were not statistically different in the two groups of infants. Urine excretion of threonine, serine, glycine, alanine, histidine, tyrosine, glutamine and cystathionine was significantly increased in the high caloric, F-94-group. The results indicate that increasing the caloric intake above 120 kcal/kg/d in preterm infants on a relatively high protein intake does not increase linear growth but does produce increased weight gain. The biochemical results provide indirect evidence that this weight increase is the result of increased fat accretion.     

Cerebral Blood Flow in Preterm Infants during the First Week of Life

ABSTRACT. Forty-two preterm infants of 28–33 weeks of gestation were studied once during the first week of life by 133-Xenon clearance after intravenous injection to estimate global cerebral blood flow. Count rates detected over the chest were corrected for chest wall contribution and used as arterial input function. A neonatal blood-brain partition coefficient of Xenon was used for the calculation of a mean flow estimator (CBF-∞). The techique was internally validated by use of differently obtained arterial input functions. In 11 infants wihout respiratory distress, CBF-∞ was 19.8 ml/100 g/min ±5.3 SD. In 24 infants treated with mechanical ventilation CBF-∞ was 11.8 ml/100 g/min ±3.2 SD. In 7 infants treated with continous positive airway pressure CBF-∞ was 21.3 ml/100 g/min ±12.0 SD. When the reduction of CBF-∞ associated with mechanical ventilation was taken into account, the 9 infants with subependymal/intraventricular haemorrhage had increased CBF-∞. The effects of gestational age, birthweight, mode of delivery, postnatal age, mean arterial blood pressure, PaCO2, blood haemoglobin and phenobarbitone medication were also analysed and found inconsistent. In conclusion, CBF was lower than expected and in infants requring mechanical ventilation the values were lower still.     

早产儿间断鼻十二指肠喂养和鼻胃管喂养时血清前白蛋白的变化

目的：早产儿存活率逐年提高,其生后早期经肠道喂养日益受到关注,目前国内普遍采用鼻胃管喂养。鼻十二指肠喂养有争议。该文比较早产儿生后早期间断鼻胃管喂养和鼻十二指肠喂养营养摄入量、生长情况、喂养相关并发症及血清前白蛋白的变化。方法：40例早产儿(出生体重1050g～1920g)随机分为间断鼻胃管喂养组和鼻十二指肠喂养组,用同一种配方乳喂养。记录喂养1周的入液量、热能、蛋白质摄入量;体格生长指标(体重、身长、头围)的变化;大便性状;喂养相关并发症。喂养前和喂养后1周用ELISA法测血清前白蛋白(PA)。结果：喂养后1周鼻十二指肠喂养组较鼻胃管喂养组平均进奶量、热能、蛋白质摄入量均显著增加(P＜0.01＝。肠道营养热能每日达 418.4 kJ/kg 的时间、恢复出生体重的时间明显缩短(P＜0.05＝;两组早产儿喂养前及1周后身长、头围的差异均无显著性(P＞0.05)。喂养前两组PA差异无显著性(P＞0.05);喂养1周后胃十二指肠喂养组的PA明显增加(P＜0.05＝。两组均无腹泻、坏死性小肠结肠炎发生;鼻十二指肠喂养组吸入性肺炎、呕吐、残留的发生率与鼻胃管喂养组比较差异无显著性(P>0.05),高胆红素血症发生率较后者显著减少(P＜0.01＝。结论：生后早期鼻十二指肠喂养儿营养摄入量显著增加,喂养相关并发症减少,营养状态优于鼻胃管喂养儿。     

微量喂养及机械通气对早产儿血促胃液素水平的影响

目的研究机械通气和微量喂养对早产儿血促胃液素(MTL)的影响和提高早产儿特别是危重儿胃肠动力途径,促进早产儿营养发育。方法将2004年11月~2006年1月西安市儿童医院NICU收治早产儿60例,随机分为微量喂养和常规喂养组,所有早产儿根据病情进行机械通气与非机械通气,分别测定生后1d后(开奶前)、3、7d空腹血浆MTL水平,喂养和通气对激素水平影响,采用析因分析,同时比较2种喂养方法胃肠动力的差异;激素测定采用放射免疫分析法。结果机械通气对MTL水平无影响,而微量喂养能显著增加MTL的分泌(P<0.05);2种干预因素之间互相无交互作用;微量喂养组过渡正常便时间、恢复到出生体质量时间及达全量肠内营养时间[(7.66±2.33)、(6.03±1.18)、(13.11±4.05)d],较常规喂养组[(9.96±2.48)、(8.08±1.18)、(19.21±5.58)d],均明显缩短(Pa<0.05);喂养不耐受率分别为13.9%和12.89%,无显著差异(χ2=0.47P>0.05);患儿无1例发生坏死性小肠结肠炎。结论微量喂养能显著提高早产儿胃肠动力,即使对机械通气早产儿施行也是安全有利的。