Robert D. Jansen

A multicenter randomized, masked comparison trial of natural versus synthetic surfactant for the treatment of respiratory distress syndrome

OBJECTIVE To compare the efficacy and safety of two surfactant preparations in the treatment of respiratory distress syndrome (RDS). METHODS We conducted a randomized, masked comparison trial at 21 centers. Infants with RDS who were undergoing mechanical ventilation were eligible for treatment with two doses of either a synthetic (Exosurf) or natural (Infasurf) surfactant if the ratio of arterial to alveolar partial pressure of oxygen was less than or equal to 0.22. Crossover treatment was allowed within 96 hours of age if severe respiratory failure (defined as two consecutive arterial/alveolar oxygen tension ratios < or = 0.10) persisted after two doses of the randomly assigned surfactant. Four primary outcome measures of efficacy (the incidence of pulmonary air leak (< or = 7 days); the severity of RDS; the incidence of death from RDS; and the incidence of survival without bronchopulmonary dysplasia (BPD) at 28 days after birth) were compared by means of linear regression techniques. RESULTS The primary analysis of efficacy was performed in 1033 eligible infants and an analysis of safety outcomes in the 1126 infants who received study surfactant. Preentry demographic characteristics and respiratory status were similar for the two treatment groups, except for a small but significant difference in mean gestational age (0.5 week) that favored the infasurf treatment group. Pulmonary air leak (< or = 7 days) occurred in 21% of Exosurf- and 11% of infasurf-treated infants (adjusted relative risk, 0.53; 95% confidence interval, 0.40 to 0.71; p < or = 0.0001). During the 72 hours after the initial surfactant treatment, the average fraction of inspired oxygen (+/-SEM) was 0.47 +/- 0.01 for Exosurf- and 0.39 +/- 0.01 for infasurf-treated infants (difference, 0.08; 95% confidence interval, 0.06 to 0.10; p < 0.0001); the average mean airway pressure (+/-SEM) was 8.6 +/- 0.1 cm H2O; for Exosurf- and 7.2 +/- 0.1 cm H2O for Infasurf-treated infants (difference, 1.4 cm H2O; 95% confidence interval, 1.0 to 1.8 cm H2O; p < 0.0001). The incidences of RDS-related death, total respiratory death, death to discharge, and survival without bronchopulmonary dysplasia at 28 days after birth did not differ. The number of days of more than 30% inspired oxygen and of assisted ventilation, but not the duration of hospitalization, were significantly lower in Infasurf-treated infants. CONCLUSION Compared with Exosurf, Infasurf provided more effective therapy for RDS as assessed by significant reductions in the severity of respiratory disease and in the incidence of air leak complications.

A new look at the neonatal bowel-contrast studies with metrizamide (amipaque)

Metrizamide is the first water-soluble radiographic contrast agent which, because it is nonionic, can be used in isotonic solution and gives good visualization of the desired body structure. Its only major disadvantage is that it is very expensive. Metrizamide can be used to study the neonatal bowel in clinical situations where all the other existing contrast agents are contraindicated. The results of 55 metrizamide studies of the bowel in infants are reviewed. In necrotizing enterocolitis metrizamide aids in confirming or rejecting the diagnosis, identifying patients for surgery, and in evaluating the response to surgery. Metrizamide can identify the etiology in unusual cases of bowel obstruction. Metrizamide correctly identified a thoracic origin of free peritoneal air in four cases and a bowel origin in two cases. It identified bowel perforation in two patients in the absence of pneumoperitoneum. In six patients, the metrizamide study identified the cause for a gasless abdomen. It is concluded that metrizamide has a valuable role to play in evaluating a variety of neonatal bowel disorders.

Cardiopulmonary Resuscitation of the Newborn: An Update

The abrupt transition from intrauterine to extrauterine life represents a series of profound physiologic changes. This process puts the baby at risk for asphyxia. At birth, the newborn is, therefore, more frequently in need of resuscitation than at any other age. This article reviews the rationale for the sequence and process of neonatal resuscitation, emphasizing recent changes in recommendations.

1700 METABOLIC EFFECTS OF GLUCOSE ADMINISTRATION IN THE ASPHYXIATED NEWBORN RAT

Brain injury resulting from birth asphyxia has been correlated with elevated CNS lactate levels. This study investigated the metabolic response of newborn rat pups to a glucose bolus given during normoxic recovery from asphyxia at birth. Three groups were studied: Group A-G, asphyxiated in 5% O2 first 20 min of life, given glucose 1 g/kg at 20 min; Group A-S asphyxiated as group A-G but given saline at 20 min; Group C-G kept in room air from birth, given glucose at 20 min. Blood and brain tissue were obtained at birth, 20, 40, 60, 90, 120, 180, 240 and 300 min. Plasma glucose peaked in all groups at 40 min age (A-G, 230±16; A-S, 100±4; C-G, 156±12 mg/dl; p<.001 for intergroup comparisons); whereas blood lactate was maximum in each group at 20 min (A-G, 18.9±0.7; A-S, 17.4±1.5; C-G, 9.9±1.2 mM/1; p=NS A-G vs A-S, p<.001 A-G or A-S vs C-G). Blood lactate/ pyruvate ratios also peaked at 20 min. Brain lactate and lactate/pyruvate ratios correlated directly with simultaneous blood values, with 20-min brain lactates being A-G 13.9±0.8, A-S 14.4±0.5 and C-G 7.1±0.9 mM/kg tissue; p=NS A-G vs A-S, p<.001 A-G or A-S vs C-G. Brain glucose reserves decreased with asphyxia and increased with glucose administration. Thus provision of glucose after an hypoxic insult increased available glucose but did not adversely affect tissue lactate or lactate/pyruvate ratios.