| Extracorporeal membrane oxygenation(ECMO)is one of the important and effective methods to rescue patients with fulminant myocarditis(FM).But there is a lack of domestic experience.In addition,the reverse blood flow of ECMO increases the cardiac afterload,which leads to the defect of insufficient left ventricular unloading in some patients,which is not conducive to the recovery of myocardium.On the basis of summing up the experience of ECMO in our center,this study explores the deficiency of left ventricular unloading and the scheme to make up for it.Methods: From September 2009 to September 2017,8 patients with FM supported by ECMO were analyzed retrospectively.Results:(1)6 patients were successfully withdrawn from cardiac function,and 2 patients died because of their own cardiac function could not be reversed.(2)2 patients with cardiac arrest underwent emergency extracorporeal cardiopulmonary resuscitation ECPR),all of them were successfully withdrawn from the machine,and no brain dysfunction was found in the follow-up.(3)Femoral arteriovenous catheterization was performed in 4 patients under direct vision,and femoral arteriovenous catheterization was urgently placed under the guidance of ultrasound.Compared with the former,the latter significantly shortened the time(t ≤ 7.908,P < 0.05)and did not increase the complications.(4)Left ventricular unloading deficiency occurred in 6 of 8 patients with ECMO supporting FM.(5)Three of the 6 patients with left ventricular insufficiency showed electrical storm(ES),which could restore spontaneous or pacing rhythm after electrical defibrillation and β blocker maintenance.However,2 cases of ES still had recurrent attacks combined with intra-aortic ballon pumps(IABP).(6)The other 3cases showed the decrease of pulse pressure difference,among which 1 case had obvious increase of lactic acid.immediately combined with IABP,the pulse pressure difference was increased and lactic acid returned to normal.There was no significant change of myocardial enzymes in 6 patients before and after left ventricular unloading deficiency(P > 0.05),which was myocardial stunning.Of the 8 patients,3patients did not use β receptor blockers,ES occurred,β receptor blockers were prevented in 5 patients,and ES did not occur.(9)The pathogenesis of insufficient left ventricular unloading was that the intersection watershed between ECMO reverse blood flow and self-cardiac forward blood flow closed to aortic valve,and even passed over aortic valve to produce left ventricular systolic reflux flow.Reverse blood flow counteracted the efficacy of forward blood flow,left ventricular end-diastolic pressure and systolic wall stress increased,resulting in a series of clinical manifestations.Conclusion: ECMO is an effective mechanical aid method to rescue FM,and ECPR should be performed once cardiac arrest occurs in FM.Mastering the technique of femoral arteriovenous catheterization under the guidance of ultrasound can greatly shorten the intubation time,and the combination of this method with ECPR has a good clinical value.Left ventricular unloading deficiency caused by ECMO can occur at the peak of myocardial edema in some patients with severe FM.The mechanism is caused by the mismatch between forward blood flow and reverse blood flow.The(left ventricular outflow tract velocity time integral(LVOT VTI)can be used to adjust the flow matching,and β receptor blockers can be selected to prevent and terminate the occurrence of ES.Pulsatile perfusion produced by combined IABP can be used to increase pulse pressure difference for left ventricular unloading,termination of ES and improvement of peripheral perfusion.Insufficient left ventricular unloading can be prevented and treated. |
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