Nitric Oxide In Persistent Pulmonary Hypertension Of Newborn

Objective:Peadiatrics have tried to treat persistent pulmonary hypertension of newborn(PPHN) with inhaled nitric oxide (iNO). In China,applications of orthodox mechanical ventilation with iNO is very common. Foreigh studies have found that high-frequency oscillatory ventilation(HFOV) with iNO can be better than individual use any kind of therapy to improve oxygenation.And it can reduce the demand of extracorporeal membrane oxygenation(ECMO). To study the therapeutic effects of inhaled intric oxide(iNO) and high-frequencey oscillatory ventilation in neonatal perisistent pulmonary hypertension (PPHN).Material and Methods:August2007to august201136cases of PPHN were dignosed by echocardiography in our hospital neonatal unit.20cases wre males and16were females;10cases were preterm children.24cases were full-term children,and2cases were post-term infants. The gestational age were31+5～42+4weeks,the average was38.2±3.4weeks. The weight were1740-4100g.the average was (3073.9±832.2)g。 At birth.16cases were asphyxia.8cases’s mothers were pregnancy induced hypertension.and3cases’s mothers were diabetes.The primary disease:13cases were meconium aspiration syndrome;10cases were intrauterine infection of pneumonia:4cases were respiratory distress syndrome with pulmonary hemorrhage.6cases have congenital heart disease(1case was single ventricle;1case was great vessels transposition;1case was anomalous pulmonary venous drainage;3cases were pulmonary stenosis).3cases were unknown cause.30neonates with pulmonary angiospasm and6patients with anatomic vascular obstruction were thrapied.During high-frequencey oscillatory ventilation.NO was added into ventilator circle. Ventilator was SLE5000(made in British), and NOSYS SLE360—Inhaled Nitric Oxide System was used to monitor NO and NO2concentrations. Oxygenation indes(OI), blood gas analysis, blood pressure, pulmonary arterial systolic pressure(PASP), heart rate.mean airway pressure(MAP), saturation of blood oxygen per cutem(TcSaO2).methaemoglobin (MetHb).and nitrogen dioxide (NO2)30minutes and24hours after NO therapy were monitored.The concentration of iNO started with8to10ppm, if it was ineffective an increase of5ppm every15to30mintues(the maxium amount is20ppm).the application time was less than96hours.If the oxygen was stable above12hours,inhaled NO concentration is reduced by5ppm each every15-30minutes.If the arterial PaO2could maintain desired lovel, the demand for oxygen was less than50%,and the concentration was3-5ppm, inhalation of NO could be stoped.SPSS17.0software for statistical analysis was applied.data was expressed as mean±standard deviation.using paired-samples t test to analyze.The difference was statistically significant(P<0.05).Results:In group Ⅰ.significant decrease in MAP,OI and PASP,significant increase in TcSaO2were found following30minutes and24hours.And24hour after NO therapy,heart rate decreased (P<0.01). In group Ⅱ,there were no remarkable changes (P>0.05).Twenty-six neonates survived.two neonates died and six neonates were resigned.26cases were cured:6cases were preterm,20cases were full-term neonate.4cases were dead:1case was32+2w,the primary disease was the respiratory distress syndrome with pulmonary hemorrhage;1case was33-2w with intrauterine infection pneumonia, and was succumbed to the systemic severe infections.septic shock with cardiac dysfunction.1case was42+2with meconium aspiration syndrome, and was succumbed to the tension pneumothorax.1case was abandon due to economic difficulties.MetHb concentraton were <3%,NO2concentration were <1×10-6mg/L in group Ⅰ, it was safe.Conclusion:The constant mean airway pressure of HFO could be better to keep the alveoli open and reduce pulmonary vascular resistance.improve the ventilation/perfusion ratio.and reduce intrapulmonary right to left shunt.If the alveolar were opened more.the NO reached the pathway of vascular smooth muscle cells was more.So the pulmonary blood flow was improved and the oxygenation was improved.If the preterm (≥34W) with mechanical ventilation were ineffective.inhaling low doses of NO can improve oxygenation,reduce the oxygen concentration.and reduce long-term complications.The dose was lower and the toxicity was smaller.In order to avoid these side effects,it was best use the lowest effective dose of inhaled NO. Inhaling minimum effective dosage NO in PPHN with pulmonary angiospam was beneficial as soon as possible. Premature infants(≥34W)who was treated with high-frequencey oscillatory ventilation and Inhaling minimum effective dosage NO were effective.