Communicating with parents of premature infants: who is the informant?

OBJECTIVES: To determine what sources of information are most helpful for neonatal intensive care unit (NICU) parents, who provides NICU parents with the information, and also what expectations parents have regarding obtaining information. STUDY DESIGN: A 19-item questionnaire was given to the parents of infants 32 weeks or younger prior to discharge from the NICU. RESULTS: Out of the 101 parents who consented, almost all of the parents (96%) felt that 'the medical team gave them the information they needed about their baby' and that the 'neonatologist did a good job of communicating' with them (91%). However, the nurse was chosen as 'the person who spent the most time explaining the baby's condition, 'the best source of information,' and the person who told them 'about important changes in their baby's condition' (P<0.01). CONCLUSION: Although the neonatologist's role in parent education is satisfactory, the parents identified the nurses as the primary source of information.

Milk and blood fatty acid composition during two lactations in the same woman.

Fatty acid composition of colostrum, milk, and serum was studied during two consecutive lactations in the same woman. There were marked differences between milk and serum: medium chain fatty acids (C6:0-C14:0) were higher in milk (8.36-21.37%) than in serum (1.59-9.6%) throughout lactation. The high milk-serum ratio of medium chain fatty acids (up to 28.4, 30.2, and 6.2 for 10:0, 12:0, and 14:0, respectively) indicates synthesis in the mammary gland. Long-chain polyunsaturated fatty acids (C20:1-C22:6) of the n - 3 and n - 6 series were higher in serum (6.76-12.53%) than in milk (1.57-4.42%). With the exception of colostrum, the fatty acid composition of milk and serum changed little during lactation and was similar in two consecutive lactations in the same woman. Comparison of milk and serum fatty acids provides a noninvasive approach for the assessment of the synthetic activity of the human mammary gland.

Prolonged apnea and oxyhemoglobin desaturation in asymptomatic premature infants.

Seventy-eight longitudinal four-channel recordings of heart rate, thoracic impedance, nasal thermistry, and pulse oximetry were performed on 26 asymptomatic premature infants (gestational age, 29.9 +/- 1.58 weeks; birth weight, 1,753 +/- 226 grams; postconceptional age, 34.3 +/- 2.0 weeks; postnatal age, 4.41 +/- 2.40 weeks; all values mean +/- SD). Tracings were scored for central and obstructive apnea, bradycardia, periodic breathing, apnea density, and prolonged apnea. The studies demonstrated 585 episodes (7.41/recording) of oxyhemoglobin desaturation with less than 90%. Recordings had a mean of 16.1 episodes of central apnea, 3.04 episodes of obstructive apnea, and 2.34 episodes of bradycardia. Periodic breathing and short obstructive apneas correlated significantly with the total number of oxyhemoglobin desaturations of less than 80% and 90%. Episodes of prolonged apnea were seen in 20 of 78 recordings. In the latter a significantly higher number of total desaturations (less than 90%), desaturations less than 80% and 90% in association with apnea and with bradycardia, longer desaturations, desaturations during sleep, and isolated bradycardia were observed. Variations in heart rate, thoracic impedance, nasal air flow, and pulse oximetry are associated with episodes of oxyhemoglobin desaturation in asymptomatic premature infants. These infants, although asymptomatic, may be at risk for impaired tissue oxygenation.

Soluble interleukin-2 receptor levels in infants with bronchopulmonary dysplasia.

Soluble interleukin-2 receptors (sIL2R) in plasma have been identified as a marker of lymphocyte activation. Lymphocyte activation as a manifestation of inflammation may be important in the pathogenesis of bronchopulmonary dysplasia (BPD). To test the hypothesis that infants with BPD have higher sIL2R levels, 12 infants with or at risk of developing BPD (GA +/- SD, 27 +/- 5 weeks; BW +/- SD 1,053 +/- 733 g) had plasma sIL2R levels determined and were compared to 20 infants being ventilated for respiratory distress syndrome (RDS) (GA +/- SD, 28 +/- 3.5 weeks; BW +/- SD, 1,133 +/- 390 g: P = NS for both GA and BW, t test). Tracheal aspirates in both groups were also analyzed for sIL2R levels. To control for the effects of postnatal age (PNA) and study weight (SW) on the sIL2R levels, another group of 16 nonventilated babies (NVB) had plasma analyzed for sIL2R (PNA +/- SD: 39 +/- 40 days NVB vs. 48 +/- 36 days BPD; P = NS); (SW +/- SD: 1391 +/- 250 g NVB vs. 1212 +/- 700 g BPD; P = NS). The following data were obtained for the plasma sIL2R levels (mean +/- SEM U/mL): RDS controls, 1,231 +/- 80; BPD infants, 1,790 +/- 120; NVB controls, 1,319 +/- 76; P = 0.0005 RDS vs. BPD and P = 0.002 BPD vs. NVB. There was no significant difference in the sIL2R levels for the infants at risk of developing BPD vs. the infants with established BPD. Also, when analyzed separately, infants at risk of BPD and the infants with established BPD had higher sIL2R levels than the RDS and NVB controls. No differences were noted in the tracheal sIL2R levels in the BPD vs. RDS groups. These data indicate that infants with BPD had significantly higher sIL2R levels in plasma than either RDS or NVB controls. Therefore, lymphocyte activation may play a role in the pathogenesis of BPD.

Effect of fat infusions on platelet concentration in premature infants.

Critically ill premature infants often require lipid emulsions with parenteral nutrition until enteral feedings can be safely initiated. Because thrombocytopenia has been listed as a potential side effect of fat emulsions, we examined the effect of varying doses of intravenous fat infusions on platelet concentrations in premature infants. An initial validation study demonstrated no artifactual effect of fat infusions on the electronic cell counter method of platelet enumeration. We observed no adverse effect of fat emulsions administered at doses of 0.8 to 3.3 g/kg/day on platelet concentration either during short-term (48 hr) or long-term study periods (4 weeks).

The effect of 15-hour fat infusions of varying dosage on bilirubin binding to albumin.

Intravenous fat emulsions (1, 2, and 3 g/kg) were administered over 15 hr to 20 appropriate for gestational age premature infants with physiologic hyperbilirubinemia to determine the effect of fat infusions on the serum free fatty acid:albumin molar ratio (F/A) and on unbound bilirubin. Significant increases (p less than 0.05) in F/A occurred with each increase in lipid dose in infants less than 30 wk gestation, but not in infants greater than or equal to 30 wk gestation. There was a direct linear correlation (r = 0.65, p less than 0.001) between F/A ratio and unbound bilirubin (estimated fluorometrically by the ratio of albumin-bound bilirubin/reserve bilirubin binding capacity, B/R). The largest increases in unbound bilirubin (albumin-bound bilirubin/reserve bilirubin binding capacity) were seen in infants with F/A greater than 4.0. The gestational age of infants with F/A greater than 4.0 was significantly less (p less than 0.01) than infants with F/A less than 4.0 (28.7 +/- 0.47 vs. 31.1 +/- 0.40 wk, mean +/- SEM). In 10/58 infusions there was a fall in unbound bilirubin, unrelated to birthweight, gestational age, postnatal age, however, during these infusions the end-infusion F/A was greater than or equal to 3.0. We conclude that 1 g/kg of lipid emulsion infused over a 15-hr period has minimal risk of decreasing bilirubin binding in premature infants less than 30 wk gestation. As doses of 2 or 3 g/kg are used, these infants may be at risk of decreased bilirubin binding, due to elevations in the F/A ratio. Monitoring of the F/A ratio may identify infants at risk for decreased bilirubin binding during lipid infusion and provide guidelines for determining the appropriate lipid dose.

Human mammary gland function at the onset of lactation: medium-chain fatty acid synthesis.

The onset of medium-chain fatty acid synthesis in the human mammary gland was investigated. Colostrum and serum were collected from 31 healthy women and the fatty acid composition of total lipid was analyzed by gas-liquid chromatography. Although colostrum/serum ratios for most fatty acids range from 0.7-2.4, very low levels of 10:0 and 12:0 were present in serum lipids as compared to much higher concentrations of these fatty acids in colostrum lipids (colostrum/serum ratio 16.23 and 17.11 for 10:0 and 12:0, respectively). We have previously found that medium-chain fatty acid levels are very low in prepartum mammary secretions (6-10 wk before term delivery) but are higher and similar in colostrum of women who deliver preterm (3-14 wk) or at full term. The data indicate that parturition, irrespective of length of pregnancy, is the trigger for medium-chain fatty acid synthesis in the human mammary gland.

Effect of sleep position on apnea and bradycardia in high-risk infants.

OBJECTIVE: The purpose of this investigation was to investigate, in high-risk infants, the occurrence of abnormalities in documented monitor downloads during the side versus prone position. STUDY DESIGN: Forty infants admitted to the A. I. duPont Hospital for Children with diagnoses associated with sudden infant death syndrome were included in this investigation. During an overnight hospitalization, infants were placed on home apnea monitors, with computer memory to capture alarms for apnea > 20 seconds, age-defined bradycardia, and tachycardia. Infants were studied for 12 hours. Each infant was assigned to 6 hours of prone and side during the 12-hour period, with order of position randomly assigned by random number generation. Differences between the two positions in alarm frequency and significant events, as determined by a blinded interpreting physician were analyzed by Fisher exact test, with p < 0.05. Power analysis necessitated 20 patients in each group, with beta error of 0.2. RESULTS: Eleven episodes of apnea occurred in the prone position, and 16 in the side position (p = NS). The mean numbers of apnea events per tracing in the prone position was 0.27 +/- 0.84 and 0.39 +/- 1.1 in the side position (p = 0.58). The mean number of bradycardia events per tracing in the prone position was 0.44 +/- 1.45 and 0.49 +/- 1.94 in the side position (p = 0.9). CONCLUSION: Clinicians need to be cautious when recommending the side or prone position in this group of high-risk infants. The results in this investigation provide support for the Back to Sleep Campaign recommendations to be applied, not only to healthy term infants, but higher risk infants as well. Studies of the high-risk infant in the supine position are warranted.

Recent advances in parenteral nutrition.

With the modifications described in this article, some of the precise elements in parenteral nutrition have been elucidated. With these changes, this form of nutrition has provided the essential calories and trace elements necessary for very-low-birthweight infants, as well as infants who have required surgery. As further research is done in this area, it is anticipated that even more adjustments to parenteral nutrition will be made, in order to provide optimal caloric vitamin, and trace element intake and establish the optimal manner in which these are administered.

Intravenous administration of lipid emulsions to premature infants.

This article describes the mechanisms responsible for hydrolysis and clearance of triglyceride from the circulation and focuses on the factors that affect lipid clearance in the newborn infant. The potential beneficial and adverse effects of IV lipid administration to premature infants are reviewed in detail. Several practical considerations for IV lipid administration are also discussed.

Case report: congenital syphilis associated with persistent pulmonary hypertension of the newborn.

A Newborn infant with prenatally acquired syphilis and persistent pulmonary hypertension is described. The patient had clinical, serologic, and radiologic evidence of syphilis at birth. He demonstrated right to left shunting of blood at the level of the foramen ovale, and responded to hyperventilation. Despite adequate oxygenation with hyperventilation, the patient expired after five days of therapy due to a progressive pneumonia and hypotension. The clinician should be aware of this unusual mode of presentation and anticipate the potential need for early aggressive intervention.

The hematofluorometer: a rapid assay for bilirubin and bilirubin binding.

Serum bilirubin measurement is extremely important to clinicians caring for newborn infants. These infants are at risk for kernicterus (bilirubin staining of brain matter) due to their immature clearance mechanism and increased bilirubin load. The hematofluorometer is a newly available device that uses the fluorescent properties of bilirubin to measure 1) albumin-bound bilirubin, 2) reserve binding capacity, and 3) total whole blood bilirubin. Since it is an easy and rapid assay, it provides the clinician with immediate information regarding the infant's level of unbound bilirubin. This information permits rapid assessment of the patient's risk for bilirubin encephalopathy. Clinicians and researchers could readily use this device in several clinical situations.

Use of [13C]bicarbonate infusion for measurement of CO2 production.

To determine whether infusion of 13C-labeled bicarbonate can be used to measure rates of CO2 production (VCO2), seven healthy adults received 6-h primed continuous intravenous infusions of NaH13CO3 and L-[1-14C]leucine in the post-absorptive state while VCO2 was measured by indirect calorimetry. Indirect calorimetry and the use of specific activity and rate of 14CO2 expired yielded identical values of VCO2: 8.97 +/- 0.82 and 8.80 +/- 0.83 mmol/min, respectively (P = NS). The concentration of NaH13CO3 in the infusates and the 13C enrichment in breath CO2 were determined using gas chromatography-isotope ratio mass spectrometry. The rate of appearance of CO2 measured using the NaH13CO3 infusion rate and the steady-state breath 13CO2 enrichments was 11.41 +/- 1.56 mmol/min, which was higher (P < 0.001) than that determined by either of the other two methods. When corrected for the recovery of labeled CO2 during the infusion of NaH13CO3 by use of published values, rate of appearance of CO2 was 9.24 +/- 0.78 mmol/min, which did not differ from VCO2 determined using the other two methods. We conclude that infusion of NaH13CO3 can be used to determine VCO2. This method should be useful to study the oxidation of substrates in populations such as ventilator-dependent neonates, in whom indirect calorimetry is laborious and inaccurate.

Soluble interleukin-2 receptor as a predictor of neonatal sepsis.

We prospectively measured soluble interleukin-2 receptor levels in 56 premature infants with suspected sepsis and demonstrated significant differences between those with positive results on blood, urine, or cerebrospinal fluid cultures, and those with negative results. Soluble interleukin-2 receptor levels can be used to facilitate the diagnosis of sepsis in premature infants with negative blood culture results.