Surfactant proteins (SP-A and SP-BC), albumin (ALB), and stable microbubble (SM) count were measured in tracheal aspirates from infants with respiratory distress syndrome (RDS) receiving single-dose Surfactant-TA (surfactant group, n = 32) or no surfactant (control group, n = 12), and those without RDS (non-RDS group, n = 8) to determine biochemical and biophysical status of surfactant in the course of RDS after surfactant replacement. Surfactant therapy resulted in immediate and sustained elevations of SP-BC/ALB and SM count with a rapid fall in ventilatory index to levels measured in the non-RDS group, whereas these indices improved slowly in the control group. The SP-A/ALB was initially low in both RDS groups and increased to levels measured in the non-RDS group by age 48 h. Multiple regression analysis showed that SP-BC/ALB, postnatal age, SM count, SM count/SP-A plus SP-BC, and surfactant therapy were independently associated with the severity of RDS as assessed by ventilatory index (r = 0.75, P < 0.0001; number of samples = 256). Infants with a relapse response to surfactant (n = 9) had levels of SP-A/ALB and SP-BC/ALB similar to those measured in the sustained group (n = 23), but had significantly lower SM count and SM count/SP-A plus SP-BC between 24 and 96 h of age.
Conclusion Surfactant therapy normalizes the sur factant and respiratory status of infants with RDS. Surfactant dysfunction rather than depletion may explain the relapse response seen in some surfactant recipients.
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Received: 23 October 1995 / Accepted: 20 May 1996
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Chida, S., Fujiwara, T., Konishi, M. et al. Surfactant proteins and stable microbubbles in tracheal aspirates of infants with respiratory distress syndrome: relation to the degree of respiratory failure and response to exogenous surfactant. Eur J Pediatr 156, 131–138 (1997). https://doi.org/10.1007/s004310050571
- Key words Pulmonary surfactant
- Respiratory distress syndrome
- Tracheal aspirate