Clinical Research On The Safety And Effectiveness Of Nebulized Iloprost Used To Control Pulmonary Arterial Hypertension In Perioperative Patients With Congenital Heart Disease

【Background】Severe pulmonary arterial hypertension is the most important cause leading to perioperative right heart failure.The clinical effects of infused vasodilator agents were quite limited because of lack the selectivety to the pulmonary vascular.As an analogue of prostacyclin,nebulized iloprost have the favorable effect of selective vasodilation and may be a prospective agent to control the residual pulmonary arterial hypertension after the corrected operation had been performed.【Objectives】The main objectives of our study are to investigate the feasibility and the effects of nebulized iloprost used in the patients with residual pulmonary arterial hypertension after the repaired operation have been employed.【Methods】Twenty-eight patients suffered with residual pulmonary arterial pressure(mean pulmonary arterial pressure＞25mm Hg) after the CPB were enrolled in our study.Standard hemodynamics in cardiac operation were monitored in all patients.After wean off from the CPB about 10-20 minutes,2.5 microgram iloprost were nebulized by a jet nebulizer and inhaled to ventilation circuit.The hemodynamics and blood gas were recorded at pre-inhalation(T0),post-inhalation(T1),5 minutes(T2),15 minutes(T3),30 minutes(T4) and 60 minutes(T5) after inhalation.The mechanical ventilated parameters were also monitored during inhalation. Furthermore,the use of cardiovascular drugs,the extubation time and the chest blood drainage within 12 hours after the operations were compared between the patients administrated with iloprost and the control patients. Additional,the levels of cAMP and cGMP in plasma at pre-inhalation,30 minutes,4 and 6 hours after inhalation were tested by ELISA methods.【Results】After iloprost inhalation,the mean pulmonary arterial pressure(mPAP) and pulmonary vascular resistance(PVR) were both significantly declined from 38.54±11.15 mm Hg to 31.54±9.35 mm Hg (p＜0.001) and from 7.58±3.61 woods to 5.14±2.50 woods(p＜0.001).One hour after the iloprost inhalation,the pulmonary vascular resistance was still marked lower than that of baseline.Despite mean systemic arterial pressure(mSAP) and systemic vascular resistance(SVR) was statistically decreased from 70.82±9.99 mm Hg to 68.93±10.34 mm Hg(p=0.01) and from 15.8±5.08 woods to 13.54±4.09 woods(p＜0.001) separately,the ratios of mPAP/mSAP and PVR/SVR were all significantly reduced from 0.55±0.16 to 0.47±0.16(p＜0.001) and from 0.48±0.17 to 0.39±0.18(p＜0.001) respectively.The cardiac output was significantly increased frmo4.45±1.09 L/min to 4.95±0.97 L/min(p＜0.001) after the iloprost inhalation.The SvO₂ was significantly increased from 77.07±3.80%to 80.14±3.77%(p＜0.001) and the intrapulmonary shunt fraction were profounded reduced from 11.38±2.66%to 10.16±2.21%(p＜0.01).The use of cardiovascular drugs,the extubation time and the chest blood drainage after the operation were all had no significant differences with the control group.The levels of cAMP in plasma were significantly elevated from 0.99±0.48 ng/L to 2.29±0.02 ng/L(p=0.001) 30 minutes after iloprost inhalation,remained increased at 4 h(1.86±0.57 ng/L,p=0.001) and at 6h(1.44±0.49 ng/L,p=0.003).In contrast,the levels of cGMP had no significant changes after iloprost inhalation. 【Conclusions】The nebulized iloprost could decrease the residual pulmonary arterial hypertension safely and effectively after the repair of defects of congenital heart disease and improve the hemodynamics and oxygenation without increase the dangerous of postoperative bleeding and facilitated the management of the early postoperative periods...