Effect Of ECMO On Respiratory And Hemodynamics Of Patients With ARDS

ARDS is a kind of acute respiratory failure, which resulted by many noncardiogenic malgenic factors. Lung capillary membrane is injured by inflamatory reaction. The clinical manifestation includs of tachypnea, stubborn hypoxemia and some cases will develop into MOF. Traditional mechanical ventilation and other comprehensive therapy sometime are frustrate. Artificial extracorporeal lung which used in cardiac surgery has become a new treatment to ARDS. Since 1972, when. Hill first reported this method, the extracorporeal membrane oxygenation has been practised in rescuing severe acute respiratory failure. The objective of this study is to investigate the effects of ECMO on the mPAP, Pa02/Fio2 and PVR of patients with ARDS.Materials and Methods1. Materials:1. 1 Medicine in study: mizodiazepam, heparin, physiological saline, protamine1.2 One - using materials: intravascular catheter, oropharyn-geal intubator, extracorporeal membrane oxygenator, Swan - Ganz catheter1.3 Instrument in study; blood gas analysor, hemodynamic mo-nitor, SIEMENS-300A ventaator. 2. Methods;2. 1 Objective: 20 cases rescued in ICU from 2001 to 2003 were coincident with the diagnosis standard of ARDS.2.2 Grouping: All patients were divided into 2 groups at random with 10 cases in every group. That is: mechanical ventilation combined with ECMO group and only mechanical ventilation group.2.3 Treatment; Swan - Ganz Catheter and oropharyngeal intu-bator were placed in two group. The patients in MV group were placed with vena profounder femoris catheters and arteria femoris catheters, then linked up to extracorporeal membrane oxygenator.3. Assay indexes: To monitor Pa02/Fio2 mPAP and PVR as the basic data before treating, then to assay these indexes per 10 hours when treatment is beginning.4. Statistics: All data were expressed as x ?s and analysis of t test were taken for testing. The level of significance was taken at p < 0.01.Results1. Pa02/Fio2 in two groups was raised significantly when treatment was beginning along with time, ( p < 0.01).2. mPAP and PVR descended when treatment was beginning a-long with time ( P < 0. 01) . Descent tendency in ECMO + MV group was higher than that in MV group ( p < 0. 01).DiscussionThe parameters of mechanical ventilation in ECMO + MV group : TV4 - 6ml/kg, PEEP 2. 5 - 4. 0 cmH2O. The parameter in MV group: TV7 -9ml/kg, PEEP 8 - 15cm H2O. PaO2/Fio2 assayed in different time points rised signieicantly in two groups. The patients in ECMO + MV group were treated with low flux and low pressure; MV group were treated with high flux and high pressure. Recently, it was reported that mechanical ventilation would result volume - induced lung injury, so the ventilation tactics of low flux and low pressure was adopted to clinical practice, but this ventilation type would induce hy-percarbohemia, intracranial hypertension and amyocardia. The lung with ARDS can be divided into infiltration mutation or collapse parts and normal - compliance parts. High ventilation would facilitate pulmonary alveoli: superdistention , denaturation , ventilation perfusion disturbance and gas diffusion disability. As a result, the descent tendency of mPAP and PVE in MV group was lower than that in group A. The ECMO can partly replace the gas exchange function of human's lung, survive lung can be protect and injured lung has time to rest and recovery.