title: Extracorporeal Membrane Oxygenation and the Kidney.
abstract: BACKGROUND
  Extracorporeal membrane oxygenation (ECMO) is an effective therapy for patients with reversible cardiac and/or respiratory failure. Acute kidney injury (AKI) often occurs in patients supported with ECMO; it frequently evolves into chronic kidney damage or end-stage renal disease and is associated with a reported 4-fold increase in mortality rate. Although AKI is generally due to the hemodynamic alterations associated with the baseline disease, ECMO itself may contribute to maintaining kidney dysfunction through several mechanisms.
  
  
  CONCLUSIONS
  AKI may be related to conditions derived from or associated with extracorporeal therapy, leading to a reduction in renal oxygen delivery and/or to inflammatory damage. In particular, during pathological conditions requiring ECMO, the biological defense mechanisms maintaining central perfusion by a reduction of perfusion to peripheral organs (such as the kidney) have been identified as pretreatment and patient-related risk factors for AKI. Hormonal pathways are also impaired in patients supported with ECMO, leading to failures in mechanisms of renal homeostasis and worsening fluid overload. Finally, inflammatory damage, due to the primary disease, heart and lung crosstalk with the kidney or associated with extracorporeal therapy itself, may further increase the susceptibility to AKI. Renal replacement therapy can be integrated into the main extracorporeal circuit during ECMO to provide for optimal fluid management and removal of inflammatory mediators.
  
  
  CONCLUSIONS
  AKI is frequently observed in patients supported with ECMO. The pathophysiology of the associated AKI is chiefly related to a reduction in renal oxygen delivery and/or to inflammatory damage. Risk factors for AKI are associated with a patient's underlying disease and ECMO-related conditions.
authors.affiliation: Section of Anesthesiology and Intensive Care, Department of Health Sciences, University of Florence, Florence, Vicenza, Italy; Department of Nephrology, Dialysis and Transplantation, International Renal Research Institute, San Bortolo Hospital, Vicenza, Italy.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Villa
authors.affiliation: Division of Cardiac Surgery, Johns Hopkins University, Baltimore, Md., USA.
authors.forename: Nevin
authors.initials: N
authors.lastname: Katz
authors.affiliation: Department of Nephrology, Dialysis and Transplantation, International Renal Research Institute, San Bortolo Hospital, Vicenza, Italy.
authors.forename: Claudio
authors.initials: C
authors.lastname: Ronco
keywords: Acute kidney injury; Carbon dioxide removal; Extracorporeal membrane oxygenation; Renal replacement therapy; Systemic inflammation