Comparison of the effects of dry and liquid heparin on neonatal arterial blood gases.

We compared the effects of liquid and vaporized dry heparin on neonatal arterial blood gases. A total of 35 paired simultaneously drawn neonatal arterial blood samples were collected. In one of every paired sample, 0.05 cc of liquid heparin was used and in the other sample vaporized heparin syringes were used. Blood was drawn into every syringe to a total volume of 0.2 ml, pH, arterial oxygen tension (PaO2), and arterial carbon dioxide tension (PaCO2) of the paired samples were analyzed using the paired Student t method. There was no statistical difference in pH and PaO2 but the PaCO2 was statistically lower (p less than 0.0005) with liquid heparin. We conclude that the effects of heparin on neonatal arterial blood gases is dilutional in nature and that they are due to mixing heparin with its very low PaCO2 with the blood sample. If by mistake more heparin than necessary is used, the effects can be dramatic. We therefore suggest using syringes with vaporized heparin in obtaining neonatal arterial blood gases to obtain reliable and consistent results.

Biosocial variances and infant survival: a path analysis approach.

This study used path analysis to assess the chances of survival of babies in a neonatal intensive care unit in Lansing, Michigan, USA. Two paths to neonatal survival were identified and the variables accounted for 20% of the variance in gestational age. The first path showed that prior infant losses were negatively correlated with gestational age while in the second path, gestational age showed negative relationships with pre-pregnancy weight and household job worries.

Effect of fluids on life span of peripheral arterial lines.

This study examines the effect of two different fluids to maintain peripheral arterial line patency at 1 to 2 ml/hr in a randomized controlled trial. Sixty sick newborn infants requiring ventilatory support and frequent blood gas monitoring were randomly assigned to receive either heparinized normal saline (HNS) or heparinized 5% dextrose water (HD5W) to maintain peripheral arterial line patency. One unit of heparin was added to each mililiter of both solutions. The duration of functional arterial lines, sodium balance, and number of peripheral punctures for blood glucose monitoring were compared using Student's t test for independent samples. HNS peripheral arterial catheters functioned significantly longer than HD5W without increased risk of hypernatremia. We conclude that HNS in arterial catheters is safe, lasts longer, and saves the infant (1500 gm or more) from the unnecessary stress of multiple peripheral punctures for blood glucose measurements, which can be obtained from the arterial catheter if glucose is not part of the infusate.

Intermamillary indices in premature infants.

The internipple distance and its relationship to gestational age has not been studied in infants born in the United States. One hundred and thirty-three newborns between 25 and 40 weeks gestation showed progressive increase in the internipple distance with increasing gestational age. The internipple index stays constant during various gestational ages. The internipple index greater than 28% (greater than 2 SD) at any gestational age or during immediate postnatal age should be flagged to look into widely spaced nipples. Extrauterine growth of internipple distance is similar to that of intrauterine growth.

Gentamicin dosing in the newborn. Use of a one-compartment open pharmacokinetic model to individualize dosing.

Gentamicin 2.5 mg/kg was given to 60 term and preterm neonates. Serum gentamicin concentrations were determined at 1, 7 and 11 h postinfusion. Linear regression analysis was used to determine half-life and volume of distribution. From these data a new dosing regimen and a predicted steady-state peak and trough gentamicin concentration were determined for each neonate. The predicted peak and trough were compared to a measured peak or trough drawn at least 48 h later. Criteria for successful peaks were met in 93% of the patients, while criteria for successful troughs were met in 83%. Individualized gentamicin dosing in the newborn based on a one-compartment open pharmacokinetic model is a useful clinical tool in predicting peak and trough gentamicin concentrations.

Omphalocele in half-siblings.

A family is described in which half-siblings, a boy and a girl born to unrelated mothers and a phenotypically normal father, were affected with omphalocele. The suggested mode of transmission remains unclear. Prenatal diagnosis to detect an affected fetus should be offered to relatives of omphalocele-affected individuals.

Studies on the formation of phosphoenolpyruvate and citric acid cycle intermediates by neonatal piglet liver mitochondria.

The capacity of mitochondria isolated from livers of 5-day-old piglets to convert pyruvate to phosphoenolpyruvate, malate and citrate has been investigated. These mitochondria have a large capacity to flux pyruvate through the pyruvate carboxylase reaction causing an accumulation of malate, citrate and phosphoenolpyruvate. As much as 70% of the pyruvate utilized during state 3 respiration can flux through the pyruvate carboxylase reaction. The data indicate that phosphoenolpyruvate from mitochondria can contribute a significant fraction of the carbon skeletons of pyruvate converted to glucose by piglet liver (estimated to be 30%).

The use of a crystalline amino acid mixture for parenteral nutrition in low-birth-weight infants.

Thirty-six preterm, sick, low-birth-weight neonates were given either total or partial parenteral nutrition. The patients were divided into three groups according to their birth weights: group A -less than 1,000 gm, 12 patients: group B--between 1,000 and 1,500 gm, 15 patients: group C--more than 1,500 gm, 9 patients. The solution for total parenteral nutrition contained 20% glucose and 2.6% crystalline amino acids plus appropriate amounts of vitamins and minerals. The volume of infusate given was usually 125 ml/kg/day, but varied depending on the clinical condition of the patient; occasionally it was as high as 150 to 175 ml/kg/day. Infusate of one-half strength was administered initially; its concentrations of glucose and amino acids were increased to three quarters and full strength gradually, if tolerated. The solution for total parenteral nutrition was infused into the superior vena cava via a central venous catheter; that for partial parenteral nutrition was given into a peripheral vein to supplement inadequate oral feedings. The period of parenteral nutrition lasted from 5 to 49 days, with an average of 13.2 days. The intake of 500 mg of nitrogen as crystalline amino acids and 100 kcal as glucose was capable of achieving body weight gain. Positive nitrogen balance of various degrees was also observed. Hyperglycemia of a slight to moderate degree was observed in nine patients; only three required insulin therapy. Two patients had thrombotic occlusion of the central venous catheter. The conclusion was reached that total parenteral nutrition or partial parenteral nutrition, when properly managed, is a safe procedure in small, premature infants. The amino acid solution given as a nitrogen source along with adequate calories was effective in promoting weight gain and nitrogen balance; it was apparently well tolerated by low-birth-weight neonates.

Red cell volume measurements and acute blood loss in high-risk newborn infants.

Red cell volume was measured in 259 infants admitted to a high-risk newborn unit. Red cell volume was measured using 50Cr tagging which subsequently was activated to 51Cr for counting. Total blood volume was calculated using the corrected whole body hematocrit. A low red cell volume was frequently associated with a maternal history of vaginal spotting, with placenta previa or placenta abruptio, with nonelective cesarean section, and with deliveries associated with cord compression. Asphyxiated infants without a history suggestive of blood loos often had a low red cell volume. An early central hematocrit below 45% correlated with a low red cell volume, but a normal or high hematocrit was often associated with low red cell measurements. The total blood volume depended largely on whether the tagging was done long enough after the blood loss for plasma volume equilibration to have occurred. Very low red cell volume values were associated with a high mortality rate, but birth weight played a dominant role in survival, even at low red cell volume levels.