Suppression of plasma renin activity in a boy with chronic hyperkalemia

Chronic hyperkalemia (6.8 mmol/L [6.8 mEq/L]) was discovered in a boy, aged 13 years 7 months, with short stature, delayed puberty, and normal blood pressure. Additional studies revealed hyperchloremic metabolic acidosis (serum values: sodium ion, 139 mmol/L [139 mEq/L]; chloride, 113 mmol/L [113 mEq/L]; bicarbonate, 18 mmol/L [18 mEq/L]), a normal glomerular filtration rate, a subnormal renal threshold for bicarbonate reabsorption, and normal serum thyroxine, growth hormone, and cortisol values. Renal excretion of potassium ion was subnormal for the prevailing serum concentration of potassium ion but was increased normally by infusion of sodium sulfate. The serum aldosterone concentration was appropriate for a normokalemic subject, despite marked suppression of plasma renin activity (PRA) (supine/upright: aldosterone, 140/580 pmol/L [5/21 ng/dL]; PRA, 0.0/0.03 ng/L X s [0.0/0.1 ng/mL/h]). Treatment with chlorothiazide and sodium chloride resulted in correction of the abnormal electrolyte concentrations and an increase in linear growth velocity. Serum aldosterone concentrations did not change significantly during treatment, even though the PRA had increased (supine/upright: aldosterone, 110/920 pmol/L [4/33 ng/dL]; PRA, 0.89/2.17 ng/L X s [3.2/7.8 ng/mL/h]). In this patient, we conclude that (1) hyperkalemia was due to inadequate renal excretion of potassium ion; (2) the serum potassium ion concentration was the major stimulus to aldosterone secretion before treatment; (3) suppression of PRA was more likely due to hyperkalemia than to extracellular volume expansion.     

Frequency and significance of electrolyte abnormalities in pneumonia.

To determine the frequency of electrolyte disturbance in pneumonia, we studied 264 hospitalized children with pneumonia for serum sodium and potassium concentration, and plasma osmolality (Posm) on the day of admission. Urine osmalality (Uosm) and urine spot sodium concentration were measured in those who had a serum sodium less than or equal to 130 mEq/L. Hyponatremia was found in 27%, hypernatremia in 3.7%. Hypokalemia (serum potassium less than or equal to 3.5 mEq/L) in 19 and 2% had hyperkalemia (serum potassium greater than or equal to 6.5 mEq/L). Of all the hyponatremia, 68% were secondary to syndrome of inappropriate ADH secretion (SIADH) as suggested by a concomitant lowering of Posm less than or equal to 280 mosm/kg and increased urinary osmolality and sodium excretion. Hyponatremia was associated with 60% longer hospital stay, two fold increase in complications and the 3.5 times higher mortality compared to that of normonatremia. The above variables were affected further, if hypokalemia coexisted with hyponatremia.     

Blood sampling through umbilical catheters.

An in vitro study testing the reliability of chemical determinations on blood samples withdrawn through an umbilical catheter is described. Blood samples were withdrawn through three different sizes of umbilical catheters containing a solution of dextrose, sodium bicarbonate, and potassium. Using either a 5 French or a 3 1/2 French catheter, accurate results were obtained for pH, sodium, potassium, and glucose when measurements were made after an initial 4-ml blood sample was discarded. With an 8 French catheter, accurate results were obtained for pH, sodium, and potassium but plasma glucose determinations remained inaccurate after 6 ml of blood was discarded.     

Sodium homeostasis in infants with biliary drainage procedures

We studied biliary excretion of sodium and chloride in 17 infants with external bile drainage through a "biliostomy" and describe four additional children who became ill from sodium depletion following external biliary drainage procedures for biliary tract anomalies. In the 17 infants, the mean +/- SD bile sodium concentration was 122 +/- 15 mEq/L. The mean +/- SD serum sodium concentration was low (132 +/- 7 mEq/L) (normal, 138 to 145 mEq/L). The mean +/- SD bile volume was 388 +/- 317 mL/day at one year following surgery (range, 40 to 1,000 mL/day). In the four children, clinical manifestations of sodium depletion (lethargy, anorexia, dehydration, and malnutrition) necessitated hospital admission. At that time, the serum sodium concentration ranged from 109 to 129 mEq/L, and the simultaneous urinary sodium concentration ranged from 0 to 5 mEq/L. Although dietary sodium was normal, biliary losses exceeded dietary intake, resulting in salt and water depletion despite renal conservation. Children with biliary drainage procedures are at risk for sodium depletion and should be monitored closely and supplemented accordingly until biliostomy closure is performed.     

Serum ionized calcium concentrations in normal neonates

Adult serum ionized calcium (iCa) concentrations are higher when using the newer, highly sensitive, ion-selective electrodes compared with older electrodes. Currently used neonatal normative ranges were established using older electrodes and not under standardized conditions or age. Thirty term infants, carefully screened to exclude confounding factors that could affect serum iCa concentration, were studied at birth and 2 and 24 hours of age for serum iCa concentrations. Mean concentrations declined from 1.45 mmol/L (5.82 mg/dL) at birth to 1.33 mmol/L (5.34 mg/dL) at 2 hours to 1.23 mmol/L (4.92 mg/dL) at 24 hours. The 95% confidence limits at 24 hours ranged from 1.10 to 1.36 mmol/L (4.40 to 5.44 mg/dL). Using newer ion-selective electrodes, normal neonatal ranges for iCa concentrations during the first 24 hours of age are higher than published references.     

Oral rehydration of infants in a large urban U.S. medical center

A prospective randomized study of 100 well-nourished infants with acute gastroenteritis resulting in dehydration and acidosis was carried out at the Jackson Memorial Hospital, Miami from 1981 to 1983. Patients were randomly assigned to receive either standard intravenous therapy or oral rehydration. Infants in the latter group first received solution A containing 75 mEq/L sodium, 30 mEq/L potassium, 75 mEq/L chloride [corrected], 30 mEq/L bicarbonate, and 2 gm/dL glucose [corrected]. After ad libitum feeding for six hours, solution B containing 50 mEq/L sodium, 30 mEq/L potassium, 50 mEq/L chlorine, 30 mEq/L bicarbonate, and 3 gm/dL [corrected] glucose was given. With three exceptions (6%), oral rehydration was comparable to the intravenous regimen in clinical estimates of improvement, although the oral group had more stools in the first day. The oral group had faster correction of acidosis and a sustained rise in serum potassium concentration, whereas in the intravenous group the potassium concentration showed first a drop with a later increase, but levels were at all times below those in the oral group. Although potassium was given from the beginning of oral rehydration, and at a higher concentration than recommended by the World Health Organization, no hyperkalemia occurred. We concluded that oral therapy is safe, less expensive for patients, and more convenient for the medical and nursing staffs.     

Neonatal ascites and hyponatraemia following umbilical venous catheterization

The complications associated with umbilical venous catheterization in neonates range from pericardial effusion, portal hypertension, and peritoneal perforation with ascites, to Wharton's jelly embolism. The case of a term neonate who developed ascites and severe hyponatraemia (serum sodium 119 mmol/L) most probably following peritoneal perforation by an umbilical venous catheter is reported. The presenting feature was convulsions associated with dilutional hyponatraemia, probably following absorption of a large quantity of ascitic fluid across the peritoneum. Conservative management was associated with gradual recovery over 24 h. The case highlights that, irrespective of the route, excessive administration of salt-free fluids can lead to dilutional hyponatraemia with adverse consequences. The present case illustrates the importance of confirming intravascular positioning of umbilical catheters by ensuring free flow of blood on aspiration, to prevent/detect inadvertent peritoneal perforation. Ideally, echocardiographic confirmation of optimal intravascular placement of such catheters is preferred as radiographic confirmation is reported to be unreliable.     

Concentration of eight trace minerals in milk and sera of mother-infant pairs in northern Nigeria

Breastmilk from 15 healthy lactating women (21-31 years of age) from the hot, semi-arid sahel of Africa were analysed for copper, iron, zinc, magnesium, manganese, sodium, potassium, and phosphorus. Relative to published data from other populations worldwide, the milk of the Jos women appeared to contain adequate levels of magnesium, manganese, sodium, potassium, phosphorus and iron, but relatively low concentrations of zinc (1.07 micrograms/ml) and copper (170 micrograms/l). The sera of the exclusively breastfed infants nursed by these mothers contained levels of all these minerals that are within the international reference range of values. No statistically significant correlation was observed between the level of a particular mineral in the mothers' milk and the sera of their nursing infants.     

Nonoliguric hyperkalemia in the premature infant weighing less than 1000 grams

Eighteen very low birth weight premature infants born before 28 weeks gestation and weighing less than 1000 gm were evaluated prospectively for disturbances in serum electrolyte concentrations and for renal glomerular and tubular functions. Clinically symptomatic hyperkalemia resulting in significant electrocardiographic dysrhythmias developed in eight of these infants; 10 babies remained normokalemic. Peak serum potassium concentration ranged from 6.9 to 9.2 mEq/L in the hyperkalemic group; all potassium values in the normokalemic group were less than 6.6 mEq/L. Indices of renal glomerular function and urine output were similar in both groups; no infant had oliguria. Serum creatinine concentrations were the same in both groups (1.04 +/- 0.16 SD mg/dl in normokalemic vs 1.19 +/- 0.24 mg/dl in hyperkalemic infants, beta less than 0.2 at alpha = 0.05), and glomerular filtration rates did not differ significantly (6.29 +/- 1.78 ml/min/1.73 m2 in normokalemic vs 5.70 +/- 1.94 ml/min/1.73 m2 in hyperkalemic infants, beta less than 0.2 at alpha = 0.05). In contrast, indicators of tubular function revealed a significantly larger fractional excretion of sodium in hyperkalemic infants: 13.9 +/- 5.4% versus 5.6 +/- 0.9% in normokalemic control subjects (p less than 0.001). Hyperkalemic infants also had a tendency toward lower urine concentrations of potassium, although there was no significant difference in their net potassium excretion in comparison with that in the normokalemic group. We speculate that hyperkalemia in the tiny baby is in part the result of immature distal tubule function with a compromise in ability to regulate potassium balance.     

The effect of metoclopramide administration on electrolyte status and activity of renin-angiotensin-aldosterone system in premature infants

The present study has been carried out to define whether endogenous dopamine contributes to the regulation of renal sodium handling and the function of the renin-angiotensin-aldosterone system in low birth weight premature infants. Twelve premature infants with mean birth weight of 1420 g and mean gestational age of 29.2 wk were given metoclopramide (MTC) in a dose of 0.1 mg/kg/day to treat delayed gastric emptying, regurgitation, and abdominal distension at the age of 17-23 days. Infants were kept on either a low (2-3 mEq/kg/day) or high (4-7 mEq/kg/day) sodium diet to modulate activity of RAAS. Prior to and after a 3-day period of MTC administration, blood samples were taken, and in six male infants 24-h urine collections were made to determine plasma and urine electrolytes, plasma renin activity, plasma aldosterone concentration, and urinary aldosterone excretion. We demonstrated that plasma sodium and potassium concentrations and plasma renin activity were not altered by MTC. On the other hand, in response to MTC, there was a significant increase in urinary sodium excretion (1.8 +/- 0.3 versus 2.3 +/- 0.3 mEq/kg/day) and a decrease in potassium excretion (1.2 +/- 0.2 versus 0.8 +/- 0.1 mEq/kg/day); plasma aldosterone concentration and urinary aldosterone excretion decreased significantly from initial values of 2101 +/- 274 pg/ml and 2.91 +/- 0.52 micrograms/day to 1500 +/- 207 pg/ml (p less than 0.01) and 2.21 +/- 0.43 micrograms/day (p less than 0.01), respectively, after MTC. These alterations were independent of the pretreatment hormone levels.(ABSTRACT TRUNCATED AT 250 WORDS)     

Serum Sodium Levels in Patients with Kawasaki Disease

The purpose of this study was to assess the hypothesis that lower serum sodium levels are associated with cardiovascular sequelae in patients with Kawasaki disease (KD). We used the database of the 16th nationwide survey of KD in Japan. We investigated the distribution of serum sodium levels and the relationship between serum sodium levels and cardiovascular sequelae. Of the reported cases, serum sodium levels were reported in 13,569 patients (89%). The proportion of patients with serum sodium levels 130 mEq/L or less, was greater in complete cases than in incomplete cases. The proportion of patients with serum sodium levels 130 mEq/L or less was increased with age. The largest proportion of patients with serum sodium levels 130 mEq/L or less was found in the category of 3–5 days since onset of illness. A serum sodium of level 135 mEq/L or less was an independent risk factor for cardiovascular sequelae (odds ratio, 1.79, 95% confidence interval, 1.42–2.26). Among patients with KD, there are significant differences in serum sodium levels between diagnostic categories, age, and days since the onset of illness. The sodium level may be a simple predictor of cardiovascular sequelae.     

Reduced thrombus formation with silicone elastomere (silastic) umbilical artery catheters.

This report describes clinical experience with a radiopaque silicone elastomere (Silastic) umbilical artery catheter. Twenty infants, ten with polyvinyl chloride (PVC) umbilical artery catheters and ten with Silastic umbilical artery catheters, all positioned at the aortic bifurcation, had aortograms performed at the time of catheter removal. Catheter-associated thrombus formation was observed in nine of the ten infants (90%) with PVC umbilical artery catheters and in one of the ten infants(10%) with Silastic catheters. The incidence of lower extremity vasospasm associated with the two catheters was not significantly different. Aortic pressure tracing recorded through Silastic catheters were accurate, but slightly damped. Autopsies were performed on five additional infants who died with indwelling Silastic umbilical artery catheters. None of the catheters, nor their surrounding tissues, showed evidence of thrombus formation on either gross or microscopic examination. It is our experience that radiopaque silicone elastomere tubing can be used as an umbilical artery catheter and appears to have the advantage of being less thrombogenic than the standard PVC tubing currently in general use.     

Growth Failure in an Infant with Congenital Nephrogenic Diabetes Insipidus During Sodium Restriction

Congenital nephrogenic diabetes insipidus (CNDI) is an inherited disorder characterized by renal tubular insensitivity to antidiuretic hormone, resulting in an inability to concentrate urine. We report on an infant boy with CNDI who showed growth failure during treatment with sodium restriction. At the age of 4 mo, he was diagnosed as having CNDI, judging from fever with hypernatremia (serum Na 153 mEq/L), diluted urine (urine osmolarity 193 mOsm/kg), high antidiuretic hormone (plasma antidiuretic hormone 53 pg/mL), and normal renal function (serum creatinine 0.3 mg/dL). His length and weight were mean +0.4 and –1.1 SD, respectively, at that time. He was treated with sodium restriction (sodium intake; 0.53 mEq/kg/day) using low sodium formula in addition to trichlormethiazide, spironolactone, and mefenamic acid. Growth failure developed: his length and weight were mean –2.4 and –3.3 SD, respectively, at the age of 10 mo. After withdrawal of sodium restriction to 1.5 mEq/kg/day of sodium intake without any change of caloric intake and medication, catch-up growth was observed. At the age of 39 mo, the patient’s height and weight were mean –0.8 and –0.6 SD, respectively. We conclude that excessive sodium restriction can cause growth failure in infants with CNDI.     

Use of double-lumen umbilical vein catheters in a neonatal intensive care unit]

BACKGROUND: The aim of the study was to compare the success/failure rate and complications of insertion into the umbilical vein, of either double-lumen catheters (Charrière diameter 04, length 13 and 30 cm) or single-lumen catheters (Charrière diameter 05, length 40 cm) in a population of neonates admitted to a neonatal intensive care unit. The numbers of insertions of additional peripheral venous catheters were also compared. PATIENTS AND METHODS: The population was divided into two groups according to the severity of the respiratory failure. Group 1 (n = 52): normal hemodynamic parameters and moderate respiratory failure (FiO2 < 0.6): only single-lumen catheters were used. Group 2 (n = 56): low systemic pressure requiring vascular filling and/or inotropic drugs infusion and/or severe respiratory failure (FiO2 > 0.6): in this group, either single-lumen catheters or double-lumen catheters were inserted. RESULTS: The success rate of insertion of double-lumen catheters and of single-lumen catheters were similar (61% vs 71%: P = 0.7). Nineteen double-lumen catheters were inserted in the group 2. The average duration of double-lumen umbilical catheterization was not significantly different from simple-lumen catheterization (4.9 +/- 2.2 vs 4.6 +/- 2.2 days). Complications relating to the umbilical venous catheterization were uncommon: three catheter obstructions (two with single-lumen catheter, one with double-lumen catheters), two nosocomial infections (both with single-lumen catheter), one hydropericardium (with single-lumen catheter). In group 2, more peripheral venous catheters were required during the first 72 hours of life after insertion of single-lumen catheter than after insertion of double-lumen catheters (average number of peripheral venous catheters per infant: 1.6 +/- 0.83 vs 1 +/- 0.35 respectively; P < 0.01). CONCLUSION: Feasibility and complication rate of umbilical double-lumen catheters were similar to those of single-lumen catheters. The use of umbilical double-lumen catheters reduces the need of peripheral venous catheters.     

Sodium restriction versus daily maintenance replacement in very low birth weight premature neonates: a randomized, blind therapeutic trial.

To test the hypothesis that restriction of sodium intake during the first 3 to 5 days of life will prevent the occurrence of hypernatremia and the need for administration of large fluid volumes, we prospectively and randomly assigned 17 babies (mean +/- SD: 850 +/- 120 gm; 27 +/- 1 weeks of gestation) to receive in blind fashion either daily maintenance sodium or salt restriction with physician-prescribed parenteral fluid intake. Maintenance-group infants received 3 to 4 mEq of sodium per kilogram per day; restricted infants received no sodium supplement other than with such treatments as transfusion. Sodium balance studies conducted for 5 days demonstrated that maintenance salt intake resulted in a daily sodium balance near zero, whereas sodium-restricted infants continued to excrete urinary sodium at a high rate, which promoted a more negative balance (average daily sodium balance -0.30 +/- 1.78 SD in maintenance group vs -3.71 +/- 1.47 mEq/kg per day in restriction group; p less than 0.001). Care givers tended to prescribe daily increases in parenteral fluids for the salt-supplemented infants, perhaps because serum sodium concentrations were elevated in these infants after the first day of the study (p less than 0.001). Hypernatremia developed in two sodium-supplemented infants (greater than 150 mEq/L), and hyponatremia developed in two sodium-restricted infants (less than 130 mEq/L); however, the restricted infants were more likely to have normal serum osmolality (p less than 0.05). Both groups of infants produced urine that was neither concentrated nor dilute, with a high fractional excretion of sodium; renal failure was not observed. The mortality rate was not affected, but the incidence of bronchopulmonary dysplasia was significantly less in the sodium-restricted babies (p less than 0.02). We conclude that in tiny premature infants, a fluid regimen that restricts sodium may simplify parenteral fluid therapy targeted to prevent hypernatremia and excessive administration of parenteral fluids.     

Acute pediatric digoxin ingestion. A ten-year experience

A retrospective study conducted in three major pediatric teaching hospitals revealed only 41 cases of acute digoxin ingestion with well-documented serum concentrations. All patients who were symptomatic at presentation (27%) had digoxin concentrations greater than 2 ng/mL (2.6 nmol/L). Only one patient had a transient elevation of the serum potassium concentration. Electrocardiographic (ECG) abnormalities (bradycardia, 1 degree or 2 degrees atrioventricular block, and ST depression) were present in 11 patients. Seven of the 11 patients had ECG abnormalities delayed more than five hours after ingestion. None of these ECG abnormalities were life-threatening. Serum digoxin concentrations ranged from 0.2 to 11.6 ng/mL (0.3 to 14.9 nmol/L). Serum half-lives were rapid (approximately three hours) in an initial phase and longer (approximately 20 hours) in a second phase. Our findings were as follows: acute pediatric digoxin ingestions are not common and are usually not severe; signs and symptoms on presentation predict a digoxin concentration greater than 2 ng/mL (2.6 nmol/L); a correlation between serum potassium and digoxin concentrations was not observed; non-life-threatening bradycardia and conduction disturbances were noted; and a serum digoxin concentration greater than 2 ng/mL (2.6 nmol/L) in the absence of signs or symptoms or ECG abnormalities soon after ingestion does not accurately predict their occurrence later in the course.     

Umbilical vascular catheters: Localization by two-dimensional echocardio/aortography

Summary Umbilical vascular catheters are often necessary in the care of critically ill neonates. Position of the catheter tip is usually determined by roentgenography. Location of the umbilical arterial or venous catheter was determined by 2-dimensional echocardio/aortography in 55 consecutive infants and was compared to localization by thoraco-abdominal roentgenography. Most of the infants (76%) had respiratory distress syndrome or congenital heart disease. Echoaortographic localization of the umbilical arterial catheter correlated very closely (N = 50, r = .90) with roentgenographic determination. For localization of the tip of the umbilical venous catheters, echocardiography was more accurate than roentgenography (employing contrast echocardiography for confirmation of cardiac chamber position). Two-dimensional echocardio/aortographic localization of the tip of indwelling umbilical vascular catheters is as accurate as roentgenography in the arterial system and more accurate than x-ray for umbilical venous catheters. Echocardio/aortography is superior to roentgenography (in localizing the catheter tip) because it 1) avoids ionizing radiation, 2) makes positioning of the patient unnecessary, 3) allows visualization of the catheter in relation to cardiovascular structures, and 4) may allow demonstration of intraarterial thrombo-emboli.     

Fetomaternal potassium relations in the fetal rat on the twentieth day of gestation.

Time-corrected measurements of transplacental and transamniotic potentials were made in the fetal rat on the 20th day of gestation. These averaged 14.3 mV and 18.4 mV, respectively. The measured maternal potassium concentration in plasma of 4.8 mEq/liter and these potential measurements were used in the Nernst equation to predict the fetal concentrations in plasma. The concentration in amniotic fluid was predicted, using the potentials and either the fetal or maternal plasma concentration. The predicted concentrations in fetal plasma and amniotic fluid were 2.8 and 2.5 mEq/liter, respectively. The sampling time-corrected potassium concentration in fetal plasma was 2.9 mEq/liter and the mean in amniotic fluid was 4.6 mEq/liter. The observed concentration in amniotic fluid is significantly higher than the predicted level.     

The effect of draw-up volume on the accuracy of electrolyte measurements from neonatal arterial lines

OBJECTIVES: Contamination by infusate of blood samples withdrawn from arterial lines has been recognized but not well documented for neonates. The aim of this study was to investigate, using in vitro and in vivo studies, the effects of different draw-up volumes (withdrawn from the line prior to the sample being taken) on the concentration of sodium. METHODS: In-vitro study: The tip of an umbilical artery catheter (dead space 0.6 mL), infused with half normal saline containing 1 unit/mL of heparin was placed in a beaker of normal saline. The line was flushed with 1 mL of this infusate just before each sample was taken. Volumes from 0.5 mL to 2.0 mL of infusate/normal saline were withdrawn in 0.1 mL increments from a three-way tap and discarded. A sample was then taken from the line into a blood gas syringe for analysis of the sodium concentration by the 860 Blood Gas Analyzer (Chiron Diagnostics, Bayer, Scoresby). Control samples were taken from the beaker. In-vivo study: A 22 gauge intravenous catheter was inserted into a vein of an adult male volunteer. The dead space was also 0.6 mL. The line was flushed with 5 mL of half-normal saline immediately before sampling. Draw-up volumes of 0.6, 0.9, 1.3, and 1.6 mL were withdrawn and discarded. 10 mL was used as a control. A 0.5-mL blood sample was then taken and the electrolyte concentrations analysed immediately. RESULTS: In-vitro: A minimum draw-up volume of 1.3 mL was required before the sodium concentration was not significantly different from the control samples. In-vivo: A minimum draw-up volume of 1.6 mL was required before the sodium concentration was not significantly different from the control samples. There were similar trends in the effect of draw-up volume for glucose, calcium, potassium, chloride and lactate. CONCLUSION:: A minimum volume of 1.6 mL should be withdrawn from neonatal arterial lines (dead space 0.6 mL) before taking blood for analysis.     

脐血心钠素在监测高危新生儿水钠平衡中的意义

目的：心钠素(ANP)是一种具有多种功能的内分泌激素,其过度分泌可造成低钠血症。该文探讨脐血ANP测定在监测高危新生儿水钠平衡中的作用和临床意义。方法：选择117例高危新生儿依据Apgar评分的不同分为两大组,即单纯窒息组及评分正常组。单纯窒息组又分为轻度窒息组和重度窒息组,评分正常组又分为感染组和非感染组,另设40例正常新生儿为对照组。各组均在新生儿娩出后立即抽取脐血,应用放射免疫法测定ANP水平,同时抽取静脉血测定患儿的血清钠含量,并分别与对照组比较。结果：高危新生儿的脐血ANP水平明显高于正常新生儿,尤以早产儿1.46±0.39 ng/mL、严重感染新生儿1.16±0.35 ng/mL及重度窒息新生儿2.12±0.46 ng/mL增高最为明显(P<0.01)。而与其相对应的则是血清钠水平的下降,两者呈显著负相关。结论：高危新生儿脐血心钠素增高明显,易致低钠血症,早期测定可对新生儿抢救与治疗起到指导作用。