Introduction: Meconium aspiration produces airway obstruction and surfactant inhibition. Bronchoalveolar lavage (BAL) and surfactant replacement have been proposed as treatments for the syndrome. Objective: To evaluate the effect of BAL with normal saline followed by a supplementary dose of surfactant in a piglet model of meconium aspiration syndrome. Methods: 15 newborn piglets were used in the study. The animals were ventilated with fixed settings. After inhalation of 4 ml/kg of diluted meconium, the piglets were randomized into three groups: group I (n = 5) – tracheal aspiration without BAL; group II (n = 5) – BAL with normal saline (15 ml/kg), and group III (n = 5) – BAL with normal saline (15 ml/kg) followed by a supplementary dose of surfactant (Curosurf® 100 mg/kg). Arterial blood gas samples were obtained 30 min and 6 h after the inhalation of meconium. Results: A significant increase of PaO₂ values at 6 h after treatment was only observed in group III (from 51 ± 13 to 189 ± 115 mm Hg; p = 0.04). At this time, PaO₂ in group III was significantly higher compared to group II (189 ± 115 and 37 ± 11 mm Hg, respectively; p = 0.023) and showed a borderline significance when compared to group I (p = 0.066). Conclusion: BAL with normal saline followed by a supplementary dose of surfactant may improve oxygenation in an experimental piglet model of meconium aspiration syndrome.

In a newborn animal model of acute pulmonary hypertension, oral tadalafil administration reduces pulmonary vascular resistance and increases arterial oxygenation by increasing cardiac output and reducing the lung shunt fraction. This previously untested compound deserves additional investigation in laboratory models of persistent pulmonary hypertension of the newborn.

OBJETIVOS: revisar a literatura sobre a síndrome de aspiração de mecônio (SAM), enfocando aspectos clínicos, fisiopatológicos e abordagem terapêutica, com destaque ao uso do surfactante e lavado broncoalveolar. MÉTODOS: revisão baseada em artigos publicados na MEDLINE, SCIELO e resumos de congressos internacionais de 1988 a 2004, incluindo ensaios randomizados ou quasi-randomizados, estudos caso-controle e metanálises. RESULTADOS: devido à comprovação da inibição do surfactante na SAM, houve modificações em sua abordagem terapêutica. O manejo atual consiste na aspiração das vias aéreas na sala de parto, seguida de suporte ventilatório necessário para manter a oxigenação arterial adequada, e tratamento das complicações. Tendo em vista a obstrução mecânica do mecônio e seu efeito inibitório sobre o surfactante, a reposição e lavado broncoalveolar com surfactante estão sendo estudados atualmente. CONCLUSÕES: estudos em animais e em recém-nascidos apresentam resultados controversos quanto aos benefícios do uso de surfactante e lavado broncoalveolar na SAM. Torna-se importante a realização de mais estudos para avaliar novas estratégias ventilatórias e se existem vantagens no uso do surfactante e lavado broncoalveolar com surfactante na SAM.

Introduction: Aerosol therapy using a metered‐dose inhaler (MDI) coupled to a spacer chamber is the most widely used long‐term treatment modality for chronic lung disease of prematurity. However, its use in neonates is based on data obtained from other age groups. Proper use of maintenance treatment is essential for the long‐term stability of these patients. Objective: To ascertain whether newborns are capable of generating negative pressure during the use of a spacer with face mask for aerosol therapy. Patients and methods: Total of 117 low‐risk newborns (age 12‐48 hours), with no congenital malformations or any detectable clinical symptoms, were included. Inspiratory pressure was measured with a respiratory pressure meter, at each respiratory cycle, during a 10‐second period, for three sequential measurements. The meter was connected to the inner chamber of the spacer through a noncollapsible silicone tube. Suitably sized masks were used. Results: Only 43 participants (36.8%) generated a negative pressure capable of opening the spacer valve, as verified by the respiratory pressure meter. In 25 patients, all three measurements were within the expected range. Weight, gestational age, and mode of delivery were in no way associated with the ability to generate a detectable negative pressure. Conclusion: In neonates, the MDI therapy with a spacer chamber and face mask is susceptible to failure due to the inability of most patients in this age range to generate a negative inspiratory pressure sufficient to open the spacer valve.