Focus on ECMO and ECCO2R in ARDS patients

Abstract

The technical aspects of veno-venous extracorporeal membrane oxygenation (vv-ECMO) are still improving, permitting the treatment of ARDS patients with very severe hypoxaemia. A recent German survey showed that the incidence of vv-ECMO in the population increased from 1.0:100,000 inhabitants/year in 2007 to a maximum of 3.0:100,000 in 2012, and then stabilised at 2.4:100,000 in 2014 [1]. The in-hospital mortality slightly decreased over time but remained high, at 58.1% in 2014. This real-life mortality rates in an unselected population of patients undergoing ECMO for ARDS is even higher than previously reported. The extracorporeal CO 2 -removal (ECCO 2 -R) is a modification of ECMO characterised by a reduction in extracorporeal blood and sweep gas flow. The aims of ECCO 2 -R are: (1) the management of acute 'isolated' hypercapnic respiratory failure, (2) the reduction of tidal volume (3-4 ml/kg) and the control of hypercapnia, and (3) the avoidance of intubation in exacerbated chronic obstructive lung disease. While in the latter situation a number of small observational studies or case reports exerted promising results, the scientific evidence for the use and benefit of ECCO 2 -R in ARDS patients is limited [2].The prospective observational study by Hermann et al. [3], investigating the efficacy and safety of a novel pumpdriven ECCO2-R-system demonstrated a significant, but 'intensity'-dependent, amount of CO 2 removal between 40 and 70 ml/min. The CO 2 transfer was dependent on the amount of blood flow (0.5-2.0 l/min) and sweep gas flow. A rapid normalisation of hypercapnia secondary to higher blood flows (>1.0 l/min) and a moderate increase in oxygenation were found. However, very high sweep gas flows (higher than 10 l/min) were associated with a deterioration in O 2 and CO 2 transfer. Based on these study results, it is recommended to use ECCO 2 -R settings that combine moderate blood flow (1-1.5 l/min) and sweep gas flow (2-8 l/min) to achieve the best clinical effect and to avoid adverse effects. The combination of ECCO 2 -R and renal replacement therapy was investigated in 11 patients with ARDS and acute renal failure [4]. A membrane oxygenator was inserted in a continuous RRT system, resulting in an average CO 2 removal rate of 80 ml/ min (corresponds to a reduction of ≈20% of the arterial PaCO 2 level). Consequently, the tidal volume was lowered from 6 to 4 ml/kg and the plateau pressure could be reduced from 25 to 21 cm H 2 O (p < 0.01); no adverse events were reported. It is concluded that the combination of ECCO 2 -R with renal replacement therapy allows a safe and adequate blood 'purification' of renal-and pulmonary-associated substances together while enhancing lung protective ventilation in critically ill patients. The trend towards a 'personalised medicine' has reached intensive care medicine and the management of ARDS patients should be revisited accordingly [5]. ECCO 2 -R could become an important part of such a project in a 'balanced' portfolio of extracorporeal lung support. Although vv-ECMO r...

Individualizing mechanical ventilation: titration of driving pressure to pulmonary elastance through Young’s modulus in an acute respiratory distress syndrome animal model

“…The calculus of the individualized DP allows us to determine the maximum DP that would deliver the maximum TV to be applied without worsening the established lung injury. Another benefit is that we would always know the top of DP to apply, and in case a patient would need higher levels of DP to maintain oxygenation or to maintain PaCO 2 in a reasonable range, perhaps other therapies could be considered (ECMO, ECCO 2 R), as recent studies suggest [ 17 , 18 ], to avoid severe hypercarbia while applying individualized protective ventilation according to the daily physical properties of the lung, but this should a matter of future studies. In addition, given that during ARDS, the lung may evolve from an inflammatory phenotype to a fibrotic form (especially in SARS-CoV-2 ARDS [19] ), daily analysis of the individualized DP and elastic limit may characterize the lung phenotype, providing knowledge of the evolutive tendency of the lung injury.…”

Extracorporeal Carbon Dioxide Removal in Patients with Acute Respiratory Distress Syndrome or Chronic Obstructive Pulmonary Disease: A Systematic Review and Meta-Analysis

“…The benefit of ECCO 2 R is not related only to excess CO 2 removal but also to spare work of breathing in spontaneously breathing COPD patients, to diminish dynamic hyperinflation (which can lead to barotrauma and volutrauma) in IMV COPD patients, and to achieve ultraprotective mechanical ventilation in moderate ARDS patients while diminishing tidal volume to 3-4 mL/kg predicted body weight, diminishing respiratory rate, and increasing positive end-expiratory pressure. The previous studies indicated that ECCO 2 R could significantly reduce carbon dioxide partial pressure (PaCO 2 ) in all treated patients than baseline values, including uncontrolled case series or case reports [1,[18][19][20][21][22][23][24][25][26][27][28]. It has been suggested that ECCO 2 R can avoid the need for IMV in 90% of the patients [29].…”

Extracorporeal membrane oxygenation combined with continuous renal replacement therapy for the treatment of severe burns: current status and challenges

“…Extracorporeal membrane oxygenation (ECMO) originated from extracorporeal circulation technology, which provides days to weeks of life support for patients with respiratory failure and/or heart failure [ 3 ]. Early ECMO technology was mainly used as supportive care for acute respiratory distress syndrome (ARDS) in adults and for critical neonatal conditions [ 4 , 5 ]. With technological advancements, ECMO has become safer and more widely applied, with applications including perioperative bridging therapy in critical cardiothoracic surgical patients, supportive care for cardiogenic shock associated with cardiac emergencies (such as fulminant myocarditis and acute myocardial infarction) and auxiliary care for cardiopulmonary resuscitation [ 6–8 ].…”