Interdependence of VA-ECMO output, pulmonary congestion and outcome after cardiac surgery

Abstract

Background: Venoarterial-extracorporeal membrane oxygenation (VA-ECMO) is a life-saving method for patients with low-output failure after cardiac surgery. However, VA-ECMO therapy may increase left ventricular afterload due to retrograde blood flow in the aorta, which may lead to progression of pulmonary congestion. We examined the predictive value of pulmonary congestion in patients that need VA-ECMO support after cardiovascular surgery. Methods: We enrolled a total of 266 adult patients undergoing VA-ECMO support following cardiovascular surgery at a university-affiliated tertiary care centre into our single-center registry. Pulmonary edema was assessed on bedside chest X rays at day 0, 3, 5 after VA-ECMO implantation. Results: Median age was 65 (57-72) years, 69% of patients were male and 30-day survival was 63%. At ICUadmission 20% of patients had mild, 54% had moderate and 26% showed severe pulmonary congestion. Pulmonary congestion at day 0 was not associated with outcome (adjusted HR 1.31; 95%-CI 0.89-1.93;P = 0.18), whereas pulmonary congestion at day 3 (adj. HR 2.81; 95%-CI 1.76-4.46;P<0.001) and day 5 (adj. HR 3.01;95%-CI 1.84-4.93;P<0.001) was significantly associated with survival. Linear regression revealed that out of left ventricular function, cardiac output, central venous saturation, maximum dobutamine and norepinephrine dose as well as fluid balance solely ECMO rotation was associated with the evolution of pulmonary congestion (P = 0.007). Conclusions: Pulmonary edema three and five days after ECMO implantation are associated with poor survival. Interestingly, a high VA-ECMO output was the most important determinant of worsening pulmonary congestion within the first five days.

A large arteriovenous fistula steals a considerable part of systemic blood flow during veno-arterial extracorporeal circulation support in a porcine model

“…In our experiment adding gradually increasing ECMO flow to a healthy circulation led to subsequential decrease of cardiac output, mean arterial pressure, pulmonary artery mean pressure, and both systemic and pulmonary vascular resistance. Venous cannula of the V-A ECMO drains blood from the inferior vena cava and thus decreases the right ventricular preload; the arterial cannula flushes blood into the aorta and increases afterload of the left ventricle ( Distelmaier, Wiedemann et al, 2020 ). This was observed also by Popkova et al ( Popkova, Kuriscak et al, 2020 ).…”

Lung ultrasound to evaluate pulmonary changes in patients with cardiogenic shock undergoing extracorporeal membrane oxygenation:A retrospective study

“…In a study in which researchers evaluated patients following cardiovascular surgery, a strong and independent association between pulmonary oedema at later time points and mortality after ECMO was found. There was no such association for baseline pulmonary oedema [24]. Moreover, the LUS score was used to predict the prognosis of ARDS caused by COVID-19 and paediatric diseases, and indicated that the LUS score was associated with a higher risk of PICU mortality and longer PICU stay days after 72 h of VV-ECMO support [25].…”

The ABCDE approach to difficult weaning from venoarterial extracorporeal membrane oxygenation

“…Although VA ECMO may provide supplementary respiratory support, optimal management of mechanical ventilation remains indispensable and the impact of gas exchange depends on the degree of dual circulation and differential oxygenation present [43][44][45]. This includes appreciating heart-lung interaction, assuring adequate pulmonary mechanics and counteracting hydrostatic pulmonary edema, the latter being a common and serious complication of VA ECMO [46][47][48].…”