Effects Of Invasive Mechanical Ventilation On Patients With Acute Cardiogenic Pulmonary Edema

Invasive mechanical ventilation has been used to treat acute pulmonary edema, there has been a great progress and recognition for the treatment, but some studies found that noninvasive positive-pressure ventilation cannot be used for treating acute cardiogenic pulmonary edema. Now the treatment to acute cardiogenic pulmonary edema is still controversial.To evaluate the physiologic response of positive-pressure mechanical ventilation on acute cardiogenic pulmonary edema by observing vital signs and effect of positive airway pressure on valves hemodynamics, especially the relationship of blood flow velocity and respiratory phases. By detecting the variation of plasma Brain natriuretic peptide (BNP)in critically ill patients with acute pulmonary edema(CPE), study the effect of positive pressure ventilation on BNP, analyse prognosis value of BNP among these critically ill patients with CPE.Methods1)82 patients were studied. All patients gave written informed consent before participating. According to APACHEⅢscore, all patients had acute pulmonary edema and whose condition had not improved with aggressive medical therapy and who required mechanical ventilation. After using mechanical ventilation, all vital signs were observed.2)using color echocardiographic and pulse wave Doppler echocardiogram(PWDE) to record blood flow velocity at mitral valve, tricuspid valve, pulmonary valve, and aortic valve orifice under positive-pressure mechanical ventilation.3)Using laboratory procedures to analyze the value of BNP.Results1)With ventilation treatment, all patients showed significant improvement. Invasive ventilation was effective in improving gas exchange and hypoxia,and did not observe rapid hemodynamic changes.2)Blood flow rate reached to the highest level in artery valve and mitral valve at positive end-inhalation pressure and decrease at end expiratory,which means that left ventricle output was highest at end-inhalation point in each respiration cycle and same as in mitral valve. The highest point of E wave appeared at end-inhalation. The results showed that compared to expiratory phase, left cardiac function Was improved.3)Blood BNP level were affected by heart failure; cardiac dysfunction indicated a higher risk of death. After analysing followup data by Cox multivariate regression model, BNP change after invasive mechanical ventilation were indepent predictive factor of adverse cardiovascular events.Conclusion1)Invasive positive-pressure ventilation is a safe and effective means of improving gas exchange in patients with acute cardiogenic pulmonary edema. It has been approved that ventilation treatment call improve oxygenation and cardio function.2)The blood flow rate reaches to the highest level in artery valve at positive end-inhalation pressure and decrease at end—expiratory. Compared to expiratory phase, left cardiac function is improved at inhalation phase. Right ventricular filling increase is one of the most important reasons to improve pump function of left ventricle during an inhalation phase.3)The heart failure patients complicated CPE had a bad prognosis, the first BNP level and BNP change after NIPPV can seine as a prognosis factor of mortality and worsening heart failure among ertically ill patients with acute CPE.