Biomedical subjects
Publications and source records attributed to B T Bloom.
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UNLABELLED: Surfactant therapy has become an effective standard therapy for infants with respiratory distress syndrome (RDS). The first dose may be given either as prophylaxis immediately after delivery, or as rescue after an infant has developed RDS. Second and subsequent doses are currently recommended by the manufacturers to be administered at minimal levels of respiratory support. PURPOSE: This study compared the relative efficacy of administering second and subsequent doses of Infasurf surfactant at a low threshold (FIO(2) >30%, still requiring endotracheal intubation) versus a high threshold (FIO(2) >40%, mean airway pressure >7 cm H(2)O) of respiratory support. METHODS: A total of 2484 neonates received a first dose of surfactant; 1267 reached conventional retreatment criteria and were randomized to be retreated according to low- or high-threshold criteria. They were then retreated at a minimum of 6-hour intervals each time they reached their assigned threshold until receiving a maximum of 4 total doses. Subjects were stratified by whether they received their first dose by prophylaxis or rescue and by whether their lung disease was considered complicated (evidence of perinatal compromise or sepsis) or uncomplicated. RESULTS: Among the patients randomized, 33% of prophylaxis and 23% of rescue subjects met criteria for the complicated stratum. Although infants allocated to the high-threshold strategy were receiving slightly more oxygen at 72 hours, there was no difference in the number receiving mechanical ventilation at 72 hours or in the secondary respiratory outcomes (requirement for supplemental oxygen or mechanical ventilation at 28 days, supplemental oxygen at 36 weeks' postconceptional age, inspired oxygen concentration >60% at any time). However, there was a significantly higher mortality for infants with complicated RDS who had received retreatment according to the high-threshold strategy. CONCLUSIONS: We conclude that equal efficacy can be realized by delaying surfactant retreatment of infants with uncomplicated RDS until they have reached a higher level of respiratory support than is the current standard. We speculate that this would result in a substantial cost-saving from less utilization of drug. Conversely, we believe that infants with complicated RDS should continue to be treated by the low-threshold retreatment strategy, which is currently recommended by the manufacturers of the commercially available surfactants.
OBJECTIVE: To compare the relative safety and efficacy of Infasurf (calf lung surfactant extract; ONY, Inc, Amherst, NY, IND #27169) versus Survanta (Beractant, Ross Laboratories, Columbus, OH) in reducing the acute severity of respiratory distress syndrome (RDS) when given at birth and to infants with established RDS. DESIGN: A prospective, randomized, double-blind, multicenter clinical trial. SETTING: Thirteen neonatal intensive care units participated in the treatment arm: seven of these concurrently participated in the prevention arm. PATIENTS: The treatment arm enrolled infants of </=2000 g birth weight with established RDS, and the prevention arm enrolled infants of </=29 weeks' gestation with birth weights <1250 g. INTERVENTION: Infants were randomly assigned to receive Infasurf (n = 303, treatment arm; n = 180, prevention arm) or Survanta (n = 305, treatment arm; n = 194, prevention arm) in accordance with the Survanta package insert instructions. OUTCOME MEASURES: We projected a 25% reduction between groups in the need for a third dose of surfactant for infants with established RDS, and a 25% reduction in the need for a second dose of surfactant for infants who received prophylactic surfactant. Secondary outcomes included the severity of RDS measured by inspired oxygen concentrations and mean airway pressure, air leaks, complications associated with surfactant administration, and survival to 36 weeks' postmenstrual age without the need for oxygen supplementation. RESULTS: In the treatment arm, there was no difference between groups in the number of infants requiring more than two doses of surfactant. The interval between doses was significantly longer for Infasurf, suggesting an increased duration of treatment effect. The inspired oxygen concentration and mean airway pressure were lower in the Infasurf infants during the first 48 hours in the treatment arm. In the prevention arm, there were no differences with respect to the number of surfactant doses. The dosing intervals were longer for Infasurf infants after the second dose. No difference in inspired oxygen or mean airway pressure was noted during the first 72 hours. There were no significant differences in the incidence of air leaks, complications associated with dosing, complications of prematurity, mortality, or survival without chronic lung disease in the prevention or treatment arm. CONCLUSIONS: Infants treated with Infasurf have a modest benefit in the acute phase of RDS. Infasurf seems to produce a longer duration of effect than Survanta.
OBJECTIVE: Although numerous trials have demonstrated the efficacy of exogenous surfactant for prophylaxis or treatment of neonatal respiratory distress syndrome (RDS), optimum timing of administration remains controversial. One previous study showed that administration of calf lung surfactant extract immediately following birth, to neonates born before 30 weeks postconceptional age, was preferable to delaying administration until after development of RDS. The current study was designed to test a similar hypothesis for babies born between 29 and 32 weeks gestational age. DESIGN: One thousand three hundred ninety-eight neonates with obstetric estimates of 29 through 32 weeks' gestation were randomized to receive CLSE at birth or to wait until development of mild RDS. After exclusions for malformations and other factors, data from 1248 were analyzed. RESULTS: Prophylaxis was associated with less development of moderate RDS (7% vs 12%), less need for retreatment (5% vs 9%), less need for mechanical ventilation or supplemental oxygen during the first 4 days, and fewer deaths or less requirement for supplemental oxygen at 28 days (5% vs 9%). Although 1-minute Apgar scores were significantly lower in the prophylaxis group, the difference disappeared by the 5-minute score and there was no difference in the incidence of asphyxia-related complications. Sixty percent of the neonates assigned to early treatment received endotracheal intubation and 43% received calf lung surfactant extract at a median age of 1.5 hours. When data were analyzed by gestational age and birth weight subgroups, most of the differences could be attributable to babies born at 30 weeks or less or weighing less than 1500 g, probably because of the higher incidence of surfactant deficiency in this more immature subgroup.
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An 1180-g infant with esophageal atresia and tracheoesophageal fistula developed life-threatening respiratory distress syndrome. Conventional mechanical ventilation resulted in gastric perforation and pneumoperitoneum. High-frequency ventilation stabilized the infant, permitting distal occlusion of the esophagus with a Silastic band. Fistula ligation was subsequently performed under more optimal physiologic conditions.
Preterm triplets were treated with calf lung surfactant extract (CLSE). Two were treated at birth without development of respiratory distress syndrome (RDS); one was treated after development of RDS, with rapid improvement. These cases demonstrated the efficacy of exogenous surfactant and the potential benefit of prophylaxis (early treatment) over late treatment. Although various exogenous surfactants have been used successfully to treat or prevent RDS in preterm infants, the optimal time of surfactant treatment has not been established. Surfactant therapy at birth results in a reduction in the incidence and severity of RDS, but it could lead to unnecessary treatment in a significant portion of patients. On the other hand, delaying treatment is likely to lessen the benefits of exogenous surfactant by various factors, including barotrauma and oxygen toxicity. The triplets in this report were treated with Infasurf CLSE. Two were treated at birth without development of RDS, but one was treated after development of RDS, with rapid improvement of respiratory status.
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We undertook a randomized, controlled trial to determine whether human surfactant administered endotracheally at birth to very premature infants (gestational age, 24 to 29 weeks) would prevent the respiratory distress syndrome or reduce its severity. Thirty-one treated infants (birth weight, 938 +/- 286 g) were compared in a blinded fashion with 29 control infants (birth weight, 964 +/- 174 g). The lecithin/sphingomyelin ratio was less than 2 in all infants, and phosphatidylglycerol was not present in amniotic fluid or tracheal fluids at birth, indicating a deficiency of surfactant in the lungs. The principal dependent variables were neonatal death, the incidence of bronchopulmonary dysplasia, and the infant's requirement for respiratory support (and its complications). The surfactant-treated group had significantly fewer deaths than the control group (16 percent vs. 52 percent, P less than 0.001), fewer cases of bronchopulmonary dysplasia (16 percent vs. 31 percent), and significantly fewer cases of pulmonary interstitial emphysema (P less than 0.001) and pneumothorax (P less than 0.02). Prophylactic treatment with human surfactant also substantially reduced the period of neonatal intensive care. We conclude that treatment with human surfactant offers promise for improving the survival of very premature infants with a surfactant deficiency and for reducing the pulmonary sequelae of the respiratory distress syndrome.
OBJECTIVE: To compare the effectiveness of a prophylactic surfactant treatment strategy (PRO) to the effectiveness of a rescue (RESC) surfactant treatment strategy in patients at high risk for developing hyaline membrane disease (HMD). STUDY DESIGN: We analyzed data from a retrospective cohort consisting of all patients admitted to the neonatal intensive care units at the centers participating in the recently completed Infasurf-Survanta Comparative Trial. To be in the cohort, a patient had to be admitted during the trial, be <48 hours of age on admission, have a gestational age of <30 weeks, have a birth weight of 501 to 1250 gm, and be free of congenital anomalies. Twelve centers participated in this study. They contributed 1097 patients of whom 381 were treated with a PRO strategy. RESULTS: Survival was significantly higher in the PRO-strategy patients (84% vs 72%, p < 0.05) as was survival without oxygen requirement at a postconceptional age of 36 weeks (60% vs 46%, p < 0.05). In addition, the patients with PRO had a lower prevalence of grade III and IV intraventricular hemorrhage (IVH, 9% vs 14%, p < 0.05). All analyses were controlled for birth weight and type of study center. CONCLUSION: These data support the conclusion that using a PRO treatment strategy results in improved survival in patients at risk for developing HMD. A PRO treatment strategy may also decrease the likelihood of developing a severe IVH.