Abstract

MANZANARES, Dahís et al. Surfacen: Un surfactante natural para el tratamiento del síndrome del distress respiratorio neonatal. Rev Cubana Pediatr [online]. 1997, vol.69, n.1, pp. 3-10. ISSN 1561-3119.

Surfacen is an organic extract obtained from the pulmonary lavage of pigs. It contains approximately 93 % of phospholipids and 1 % of proteins with a low molecular weight. The preparation has an average of 69 % of phospholydylcholine and less than 1 % of lysophosphatidylcholine in some batches. The surface tension was evaluated by the bubble's maximum pressure method, and in some trials the equilibrium surface tension varies from 25 to 30 nM/m. Each batch of Surfacen was also evaluated through experiments with rabbit fetuses aged 27 days that underwent static curves of pressure and volume, with doses of phospholipids between 45 and 80 mg/kg, with an opening pressure from 15 to 20 cm of H₂O, and a maximum expansion volume of 39 mL/kg. A significant improvement of the pulmonary function has been observed in inmature newborn lambs (135 to 140 days of pregnancy). In 7 animals the product was administered 100 mg/kg and PO₂ increased up to 40 kPa; whereas the inspired oxygen fraction could be reduced from 0,7 to 0,2 in 4,5 hours. Later on, Surfacen was used in 23 preterm human neonates (average weight of 1 368 g and 30.5 weeks of gestational age), with clinical and radiological evidence of severe respiratory distress syndrome. These neonates had an inspired oxygen fraction 0.6, an average pressure of airways 8 cm H₂O, and PaO₂/FiO₂ < 20 kPa. In 16 neonates it was used a dosage of 100 mg/kg; in 6, 2; and in 1, 3. The results were as follows: the arterial pressure of oxygen increased significantly more than 9,3 kPa one hour after the administration of Surfacen, with an average of 19,2 kPa in the whole group; the relationship arterial and alveolar pressure of oxygen rose approximately 2,5 times during the first 72 hours; there was a radiological improvement in all patients; and the inspired oxygen fraction as well as the mean pressure of the airways were markedly reduced in 24 hours. The most frequent complications were: ductus arteriosus, 56.5 %; intraventricular hemorrhage (III-IV), 26.1 %; and bronchopulmonary displasia, 17.4 %. There was no pneumothorax. Mortality during the first month was of 30.4 %. Surfacen is an effective biological product for the treatment of RDS in neonates, and a greater reduction of the complications and of mortality may be attained through a good comprehensive management of these neonates.

Keywords : PULMONARY SURFACTANTS [therapeutic use]; RESPIRATORY DISTRESS SYNDROME [drug therapy]; TREATMENT OUTCOME; PILOT PROJECTS; CLINICAL TRIALS.