Selective surfactant prophylaxis in preterm infants born at < or =31 weeks' gestation using the stable microbubble test in gastric aspirates.

Objective: To evaluate the stable microbubble test (SMT) ability to select candidates for surfactant prophylaxis for respiratory distress syndrome (RDS).

Study Design: We followed patients treated according to a new routine for surfactant prophylaxis based on the SMT to determine timing of the initial dose of surfactant, proportion of infants using surfactant, and the predictive value of the SMT. Gastric secretions were collected after birth. Newborns with < 25 microbubbles (MB)/mm(2) received prophylactic surfactant. Surfactant was given only after confirmation of RDS (rescue therapy) to newborns with > or =25 MB/mm(2).

Results: Fifty-four (55%) had a low MB count and received prophylactic surfactant. Three out of 44 infants with a high MB count required rescue therapy (negative predictive value 93%; CI:81.3-98.6%). The median interval and interquartile range between surfactant administration and birth in the prophylaxis group was 20 (17-27) minutes. Surfactant was used in 23 of 28 (82%) infants born at < 28 weeks of gestation and in 34 of 70 (49%) infants between 28 and 31 weeks.

Conclusions: The SMT may be useful to determine surfactant prophylaxis (< 30 min after birth). This approach may reduce costs and the number of unnecessary interventions.