Venovenous extracorporeal membrane oxygenation for acute respiratory failure

Abstract

Despite expensive life-sustaining interventions delivered in the ICU, mortality and morbidity in patients with acute respiratory failure (ARF) remain unacceptably high. Extracorporeal membrane oxygenation (ECMO) has emerged as a promising intervention that may provide more efficacious supportive care to these patients. Improvements in technology have made ECMO safer and easier to use, allowing for the potential of more widespread application in patients with ARF. A greater appreciation of the complications associated with the placement of an artificial airway and mechanical ventilation has led clinicians and researchers to seek viable alternatives to providing supportive care in these patients. Thus, this review will summarize the current knowledge regarding the use of venovenous (VV)-ECMO for ARF and describe some of the recent controversies in the field, such as mechanical ventilation, anticoagulation and transfusion therapy, and ethical concerns in patients supported with VV-ECMO.

Do we need randomized clinical trials in extracorporeal respiratory support? No

“…Therefore, a randomized trial would be meaningful (i.e., sufficient biological plausibility) only in severe ARDS patients, where the extracorporeal respiratory support is applied as a complement to mechanical ventilation. In patients with lower probability of VILI, the rationale of applying extracorporeal support is more questionable, as the ECMOrelated complications [7] may outweigh those related to ventilation.…”

Ventilation during extracorporeal support

“…Some centers use prone position during ECMO: it may be however associated with complications such as compression or inadvertent removal of the vascular cannulas which may lead to reduction or interruption of the extracorporeal support [5].…”

Focus on ECMO and ECCO2R in ARDS patients

“…A low haemoglobin (Hb) threshold (7 g/dl) that reduces red blood cells (RBC) exposure and adverse events related to RBC transfusion, appears to be safe [10]. Nonetheless, in cases of persistent severe hypoxia, a higher Hb threshold (10 g/dl) may prevent against severe tissue hypoxia [11]. Although some observational studies suggest that low-dose heparin is safe, thrombotic events are likely to be underdiagnosed and underreported, and the extracorporeal life support organisation recommends therapeutic anticoagulation in these patients.…”