Different doses of exogenous surfactant for treatment of meconium aspiration syndrome in newborn rabbits.

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Lyra, João Cesar
Mascaretti, Renata S
Precioso, Alexander Roberto
Chang, Yin Chia
Costa, Maria Tereza Zulini da
Vaz, Flávio Adolfo Costa
Okay, Yassuhiko
Rebello, Celso Moura
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OBJECTIVE: To evaluate the effects of 2 different doses of exogenous surfactant on pulmonary mechanics and on the regularity of pulmonary parenchyma inflation in newborn rabbits. METHOD: Newborn rabbits were submitted to tracheostomy and randomized into 4 study groups: the Control group did not receive any material inside the trachea; the MEC group was instilled with meconium, without surfactant treatment; the S100 and S200 groups were instilled with meconium and were treated with 100 and 200 mg/kg of exogenous surfactant (produced by Instituto Butantan) respectively. Animals from the 4 groups were mechanically ventilated during a 25-minute period. Dynamic compliance, ventilatory pressure, tidal volume, and maximum lung volume (P-V curve) were evaluated. Histological analysis was conducted using the mean linear intercept (Lm), and the lung tissue distortion index (SDI) was derived from the standard deviation of the means of the Lm. One-way analysis of variance was used with a = 0.05. RESULTS: After 25 minutes of ventilation, dynamic compliance (mL/cm H2O.kg) was 0.87 +/- 0.07 (Control); 0.49 +/- 0.04 (MEC*); 0.67 +/- 0.06 (S100); and 0.67 +/- 0.08 (S200), and ventilatory pressure (cm H2O) was 9.0 +/- 0.9 (Control); 16.5 +/- 1.7 (MEC*); 12.4 +/- 1.1 (S100); and 12.1 +/- 1.5 (S200). Both treated groups had lower Lm values and more homogeneity in the lung parenchyma compared to the MEC group: SDI = 7.5 +/- 1.9 (Control); 11.3 +/- 2.5 (MEC*), 5.8 +/- 1.9 (S100); and 6.7 +/- 1.7 (S200) (*P < 0.05 versus all the other groups). CONCLUSIONS: Animals treated with surfactant showed significant improvement in pulmonary mechanics and more regularity of the lung parenchyma in comparison to untreated animals. There was no difference in results after treatment with either of the doses used.
lung surfactant, animal, artificial ventilation, breathing mechanics, comparative study, disease model, drug effect, female, human, lung compliance, lung gas exchange, male, meconium aspiration, newborn, rabbit, time, Animals, Animals, Newborn, Disease Models, Animal, Female, Humans, Infant, Newborn, Lung Compliance, Male, Meconium Aspiration Syndrome, Pulmonary Gas Exchange, Pulmonary Surfactants, Rabbits, Respiration, Artificial, Respiratory Mechanics, Time Factors
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Revista do Hospital das Clinicas, v. 59, n. 3, p. 104-112, 2004.