PURPOSE: Venovenous extracorporeal membrane oxygenation (VV-ECMO) is a well-known modality of pulmonary support in patients with severe acute respiratory failure, which fails to recover by ventilatory support. During the VV-ECMO support the entire patient circulation is totally dependent on the patient's native cardiac function. This study is aimed to assess cardiac function during VV-ECMO sequentially.
METHODS: It is a prospective observational study done over a year. Trans-thoracic echocardiogram (ECHO) was used to assess the cardiac function. ECHO was performed before the initiation of ECMO. ECHO was repeated within 24 hours, 48 to 72 hours and 72 to 96 hours on ECMO as well as prior to and immediately after withdrawal of ECMO. Evaluation will consist of M-mode, two-dimensional, pulsed, and color flow Doppler echocardiography. ECHO measurements were used to calculate shortening fraction (FS), velocity of circumferential fiber shortening (Vcf) and meridian systolic wall stress. Data regarding the heart rate, mean arterial pressure, ventilator settings, arterial blood gases, hemoglobin level, level of inotropic support, and number of organs supported were also collected.
RESULTS: Totally ten patients were involved in this study. Mean age and Murray score were 39.7 years and 3.35 respectively. 20% of patients (2) had episodes of cardiac arrest before initiation of ECMO support. 60% of patients (6) had impaired left ventricular function (FS: <28%, Vcf: <0.85) before initiation of VV-ECMO. In 80% patients inotropic support were gradually decreased within 48 hours after ECMO support. During this period the heart rate was significantly decreased (p = 0.0034). At the same time positive end expiratory pressure was decreased (p =0.0019) and tidal volume has increased (p <0.0001) significantly. Left ventricular FS, Velocity of circumferential fiber shortening, meridian systolic wall stress and aortic peak flow velocities did not change significantly during ECMO support.
CONCLUSION: Echocardiographically left ventricular function does not change during VV-ECMO support in adult patients with acute respiratory failure.
CLINICAL IMPLICATIONS: VV-ECMO can be safely used even in hemodynamically unstable acute lung injury patients with impaired LV function.
DISCLOSURE: Sendhil Balasubramanian, No Financial Disclosure Information; No Product/Research Disclosure Information