High Frequency Oscillation Ventilation In The Treatment Of Newborn Pigs With Severe Meconium Aspiration Syndrome In Experimental Research

Meconium aspiration syndrome (MAS) is one of the main cause of neonatal respiratory failure. About one third of all infants with MAS need mechanical ventilation. Also MAS is the primary lung disease requiring extracorporeal membrane oxygenation(ECMO). Clinical studies reported that severe MAS with diffuse atelectasis and overdistention changes on x-ray treated by conventional mechanical ventilation (CMV) had high mortality rate, nearly 40%. HFOV which provides effective gas exchange at low tidal volume showed benefits for treatment of MAS. However, its routine use as a primary mode of ventilation remains controversial.Airway obstruction was a striking problem in early stage of MAS, can HFOV provide enough gas exchange with vary small tidal volume ? dose it increase intraventricular hemorrhage ? Few report using HFOV for treatment of MAS published in mainland China. It is important to fully understand if HFOV can effectively improve gas exchange in MAS .The newborn infants of MAS with persistent pulmonary hypertension had high mortality rate .vasodilators such as tolazoline are no longer advocated because of severe adverse,which effect, iNO and ECMO have been used to treat severe cases of PPHN ,they are not available in most neonatal centres in China. Magnesium sulphate, a muscle relaxant and sedative can decrease pulmonary pressures is one of our choice. There is no report about using HFOV combined with Magnesium sulphate to treat MAS with PPHThe pathogenesis of pulmonary hypertension in MAS is complicate and uncertain yet. Fewer articles are involved in Endothelin-1(ET-1), angiotensin converting enzyme(ACE) and inducible Nitric Oxide Synthase (iNOS).Our objective was to evaluate of the curative effect of HFOV in the early management of a severe meconium aspiration syndrome of piglet model, the response of HFOV and HFOV plus Magnesium sulphate, the adverse effect of HFOV (including air leak and cerebral hemorrhage ), the influence of magnesium sulphate therapy on systemic arterial pressure (SAP) and serum magnesium concentration. Histologic alterations and the role of ET-1, ACE , iNOS in development of pulmonary hypertension of MAS we(?)also investigated.