The Weaning Method of inhaled Nitric Oxide

Lee, Hyun Woo; Lee, Jae Woong; Hyun, Sung Yeul; Lee, Ha Chang; Park, Chul Hyun; Park, Kook Yang; Yoo, Hyeon Su; Lee, Kyung Cheon; Jang, Young Jin

Abstract

PURPOSE: inhaled nitric oxide(iNO) is an excellent method for the postoperative pulmonary hypertension in congenital heart disease. But more detailed care is needed because of the development of rebound pulmonary hypertension after NO Withdrawal. We performed this study in order to discontinue the iNO successfully by way of presenting the adequate weaning and supplying methods.
METHODS
Between January, 1998 and August, 1999 we sudied 10 patients who had rebound pulmonary hypertension(RPH) after iNO withdrawal. We completed the iNO in these patween the first the second trial of the weaning process. We tried to discover the differences between the first and second weaning process. We measured NO concentration at the start and just before NO withdrawal and during the period of weaning process. Moreover, to identify the iNO effects during the weaning of the iNO, we counted the degree of the change of PaO2/FiO2and mean PAP/SAP beween initial and at half of the initial NO concentration.
RESULTS
Second weaning had a longer duration weaning process(11+/-0 cersus 5+/- hours, P<0.05), lower NO concentration just before NO withdrawal(2+/-.6 versus 4+/-ppm, P<0.05). In the change of the mean PAP/SAP and PaO2/FiO2as iNO was weaning from the initial iNO concentration to a half of the initial iNO concentration, the degree of increase in mean PAP/SAP(0.026+/-.07 versus 0.054+/-.07, P<0.05) and the degree of decrease in PaO2/FiO2(49+/-4 versus 65+/-2, P<0.05) were smaller in the second in the second weaning process than the first weaning process.
CONCLUSION
A successful weaning of iNO can be performed with a low iNO concentration at the start and just before withdrawal and with the long duration iNO weaning process. Moreover, We speculate that the degree of change in the mean PAP/SAP and PaO2/FiO2at the half of the iNO weaning process are an indicator for the development of RPH.