Elizabeth H. Thilo

Prophylaxis of Early Adrenal Insufficiency to Prevent Bronchopulmonary Dysplasia: A Multicenter Trial

Background. Infants developing bronchopulmonary dysplasia (BPD) show decreased cortisol response to adrenocorticotropic hormone. A pilot study of low-dose hydrocortisone therapy for prophylaxis of early adrenal insufficiency showed improved survival without BPD at 36 weeks’ postmenstrual age, particularly in infants exposed to histologic chorioamnionitis. Methods. Mechanically ventilated infants with birth weights of 500 to 999 g were enrolled into this multicenter, randomized, masked trial between 12 and 48 hours of life. Patients received placebo or hydrocortisone, 1 mg/kg per day for 12 days, then 0.5 mg/kg per day for 3 days. BPD at 36 weeks’ postmenstrual age was defined clinically (receiving supplemental oxygen) and physiologically (supplemental oxygen required for O2 saturation ≥90%). Results. Patient enrollment was stopped at 360 patients because of an increase in spontaneous gastrointestinal perforation in the hydrocortisone-treated group. Survival without BPD was similar, defined clinically or physiologically, as were mortality, head circumference, and weight at 36 weeks. For patients exposed to histologic chorioamnionitis (n = 149), hydrocortisone treatment significantly decreased mortality and increased survival without BPD, defined clinically or physiologically. After treatment, cortisol values and response to adrenocorticotropic hormone were similar between groups. Hydrocortisone-treated infants receiving indomethacin had more gastrointestinal perforations than placebo-treated infants receiving indomethacin, suggesting an interactive effect. Conclusions. Prophylaxis of early adrenal insufficiency did not improve survival without BPD in the overall study population; however, treatment of chorioamnionitis-exposed infants significantly decreased mortality and improved survival without BPD. Low-dose hydrocortisone therapy did not suppress adrenal function or compromise short-term growth. The combination of indomethacin and hydrocortisone should be avoided.

Arterial oxygenation and pulmonary arterial pressure in healthy neonates and infants at high altitude

We sought to document arterial oxygen saturation relative to changes in the right ventricular pressure/left ventricular pressure ratio (RVP/LVP ratio), an index of pulmonary arterial pressure, in infants born at high altitude. We performed pulse oximetry and echocardiography in 15 healthy infants born in Leadville, Colo. (3100 m), at 6 to 24 hours, 24 to 48 hours, 1 week, 2 months, and 4 months of age. Pulse oximetry was done under conditions of wakefulness, feeding, and active and quiet sleep. All infants received supplemental O2 at delivery and during postnatal transition; all oximetry measurements were performed with infants breathing room air. The mean arterial O2 saturation ranged from 80.6% +/- 5.3% to 91.1% +/- 1.7% during the 4 months. Values fell during the first week after birth and then rose gradually to attain near-birth values at 2 and 4 months of age. Arterial O2 saturation was uniform among behavioral states at 6 to 24 hours and 24 to 48 hours of age. After 1 week of age, values were highest during wakefulness, intermediate during feeding and active sleep, and lowest during quiet sleep. The RVP/LVP ratio remained in the normal or mildly elevated range throughout the study period. We conclude that the RVP/LVP ratio promptly becomes normal at high altitude, and despite low arterial O2 saturation in the first weeks to months after birth, healthy newborn infants at 3100 m show little evidence of acute pulmonary hypertension.

Saturation by pulse oximetry: Comparison of the results obtained by instruments of different brands

We noticed that arterial oxygen saturation by pulse oximetry (SpO2) was generally lower when determined by the Ohmeda Biox 3700 pulse oximeter than when determined by the Nellcor N-100 pulse oximeter, and we investigated whether this finding was consistent and the reason for the discrepancy. We placed both oximeters simultaneously on 30 infants with indwelling arterial catheters and measured arterial partial pressure of oxygen (PaO2), percentage of fetal hemoglobin, and complete cooximetry, including arterial oxygen saturation (SaO2) with a Radiometer OSM-3 cooximeter, with and without correction for fetal hemoglobin levels, in four samples of blood from each infant during a 12-hour period for a total of 120 samples. The Nellcor SpO2 was consistently higher than the Ohmeda SpO2 by a mean (+/- SD) of 1.61% +/- 2.69% (p < 0.001). The Nellcor SpO2 correlated best with functional SaO2 (oxyhemoglobin (HbO2)/(HbO2 + reduced hemoglobin)) x 100); Ohmeda SpO2 correlated best with fractional SaO2 (HbO2/(HbO2 + reduced hemoglobin + carboxyhemoglobin + methemoglobin)) x 100), reflecting a fundamental difference in the calibration algorithms used in the two instruments. A desired PaO2 of 50 to 100 mm Hg, is maintained when the range of SpO2 is 90% to 96% for Ohmeda SpO2 and 92% to 98% for Nellcor SpO2 in the neonate, giving a positive predictive value in this study of 94% to 95%. We conclude that SpO2 determined by pulse oximeters of different brands is not interchangeable, and this may be of clinical importance in predicting PaO2 on the basis of SpO2.

Comparison of continuous infusion of fentanyl to bolus dosing in neonates after surgery

OBJECTIVE Concern about respiratory depression may lead to underuse of postoperative narcotic analgesia in neonates. The authors compared continuous infusion of fentanyl with bolus dosing in infants after surgery to determine whether continuous infusion is associated with less respiratory depression. STUDY DESIGN In the first phase of the study, 16 patients were randomly assigned to receive fentanyl by continuous infusion (C) or bolus dosing every 2 hours (B) in a double-blinded trial. Respiratory events were recorded. An observational pain score and saliva for cortisol concentration were obtained 2, 8, and 24 hours after beginning treatment to compare efficacy of pain control. In the second phase, 20 additional patients received fentanyl by continuous infusion in an unblinded fashion, with the same data collection, to more accurately determine the incidence of respiratory events. RESULTS In phase 1, apnea occurred in eight of nine B patients (89%) compared with one of seven C patients (14%; P < .009), prompting termination of the randomized trial. The incidence of apnea or significant respiratory depression in the next 20 patients (phase 2) who received fentanyl by continuous infusion was 25% (5 of 20; P < .01 v B). Episodes of apnea in B patients required significantly more intervention than episodes in C patients (P < .01). However, in phase 2, more patients remained intubated and ventilated than in phase 1. Pain scores and salivary cortisol concentrations decreased over the 24-hour study period and were similar in B and C patients during both phases of the study. CONCLUSION Continuous infusion of fentanyl at the doses studied is associated with pain control similar to that with bolus dosing at regular intervals. Although episodes of respiratory depression were less severe and less frequent for C patients, there may be an increased need for ventilator support with continuous infusion of fentanyl to achieve acceptable pain control. Providing adequate pain control to neonates in the immediate postoperative period remains a challenge.

Normal macrophage function in infants receiving intralipid by low-dose intermittent administration

The effect of soybean oil emulsion (Intralipid) therapy on serum complement levels was determined in infants who received Intralipid therapeutically (1 gm/kg over 12 hours, every other day). The effect of Intralipid on macrophage priming for increased superoxide anion production was studied in a mouse model. Intralipid administration did not affect either macrophage function. Serum levels of C2 and C4, complement components synthesized and secreted exclusively in macrophages, were not decreased either during the week the infants received Intralipid or in the week following administration. Macrophages from mice that had received Intralipid produced similar amounts of superoxide anion, as did macrophages from mice that had received saline solution. Our data suggest that macrophages in infants receiving Intralipid in this regimen will function normally.

Early Treatment With Inhaled Steroids Does Not Improve Outcome in Extremely Premature Infants With Respiratory Distress † 1763

Early Treatment With Inhaled Steroids Does Not Improve Outcome in Extremely Premature Infants With Respiratory Distress † 1763

A Single Large Dose of Dexamethasone (Dex) Improves Outcome of Sepsis Syndrome in Term Neonates. † 1155

A Single Large Dose of Dexamethasone (Dex) Improves Outcome of Sepsis Syndrome in Term Neonates. † 1155

DECREASED HEAD ULTRASOUND SCREENING IN LARGER PRETERM INFANTS: REDUCED COST OR REDUCED QUALITY? † 1256

DECREASED HEAD ULTRASOUND SCREENING IN LARGER PRETERM INFANTS: REDUCED COST OR REDUCED QUALITY? † 1256