Resumo

MARTELL, Miguel et al. Evaluate the effect of inhaled nitric oxide on hemodynamic response to hypoxia and acidosis in newborn pigs. Rev. bol. ped. [online]. 2011, vol.50, n.2, pp.113-120. ISSN 1024-0675.

Pulmonary hypertension (HTP) is a frequently pathological situation of maladaptation to the extratuerine life in newborns. Hypoxia and acidosis are key factors capable of evoking the referred situation and can also act as a perpetuator factor of it. Objectives: To evaluate the effect of inhaled nitric oxide (iNO) on pulmonary vascular response to hypoxia and acidosis in newborn pigs. Material and methods: we performed a series of experimental interventions in newborn pigs, sedated, anesthetized and mechanical ventilation. The experimental protocol was to induce hypoxia in a controlled and progressive (FiO₂ from 0.21 (baseline) to 0.14, 0.10 or 0.08, mixing nitrogen with air), between 6 and 10 minutes, evaluating the hemodynamic response. Stabilized response to hypoxia plateau elevation in pulmonary artery pressure (PAP) and systemic administered iNO at 20 ppm. By infusión of HC1 0.1 N i/v was stable at different pH valúes which were reiterated in this series of experiments. Results: we found that the decrease in FiO₂ (below 0,21) produces a fall in saturation and an immediate increase in PAP at different pH and an ERA of iNO for the PAP down near 70%. However, at lower pH, the presence of acidosis produces a basal level of PAP high relative to pH 7.4, which does not descend iNO. As PH developed at different FiO₂ was confirmed that the elevation of the PAP is gradually higher. Conclusion: experimental research in newborn pigs shows that the short-term hypoxic events genérate HTP and instability on systemic hemodynamics. Similarly acidosis induces an increase in baseline PAP in this experimental model. Under these conditions the application of iNO decreases the PAP effectively without altering systemic hemodynamics. Its action is more effective than normal pH in acidosis.

Palavras-chave : hemodynamics; nitric oxide; anoxia; acidosis; hypertension; pulmonary; animals newborn.

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