Can Timely ECMO Initiation Mitigate Pre-ECMO Risk Factors for Acute Kidney Injury?

Abstract

Hsiao and colleagues [1Hsiao C.C. Chang C.H. Fan P.C. et al.Prognosis of patients with acute respiratory distress syndrome on extracorporeal membrane oxygenation: the impact of urine output on mortality.Ann Thorac Surg. 2014; 97: 1939-1944Abstract Full Text Full Text PDF PubMed Scopus (23) Google Scholar] report increased mortality in patients with acute respiratory distress syndrome (ARDS) and who had lower urine output on the first day of extracorporeal membrane oxygenation (ECMO) support. The nonsurvivors in this study were also older and exhibited greater severity of illness and extrapulmonary organ involvement. The use of venoarterial ECMO in 25% of the patients could indicate greater disease severity or a delay in initiation of venovenous ECMO. Equally, data regarding pre-ECMO diuretic use, fluid balance, and ultra-filtration, if any, would have provided more clarity to the urine output data. Acute kidney injury (AKI) during ECMO significantly increases mortality [2Askenazi D.J. Selewski D.T. Paden M.L. et al.Renal replacement therapy in critically ill patients receiving extracorporeal membrane oxygenation.Clin J Am Soc Nephrol. 2012; 7: 1328-1336Crossref PubMed Scopus (139) Google Scholar]. Although the pathophysiology of AKI in this population is complex, it appears that pre-ECMO factors play a significant role. An isolated respiratory failure upon presentation can transform into multiorgan failure because of complex interactions of the pulmonary system with cardiovascular [3Bronicki R.A. Anas N.G. Cardiopulmonary interaction.Pediatr Crit Care Med. 2009; 10: 313-322Crossref PubMed Scopus (50) Google Scholar] and renal systems [4Ricci Z. Ronco C. Pulmonary/renal interaction.Curr Opin Crit Care. 2010; 16: 13-18Crossref PubMed Scopus (30) Google Scholar] and partly because of interventions directed at optimizing the pulmonary system. Lung protective ventilation results in hypercapnia, which can significantly influence hemodynamics and renal blood flow [4Ricci Z. Ronco C. Pulmonary/renal interaction.Curr Opin Crit Care. 2010; 16: 13-18Crossref PubMed Scopus (30) Google Scholar]. Hypercapnia and resulting acidosis, hypoxia, and poor pulmonary compliance can result in progressive right ventricular failure, shock, and organ dysfunction. The primary disease process and ongoing ventilator induced lung injury both can further exacerbate organ injury. Use of diuretic drugs or preemptive hemofiltration in such patients who are already taking high dose vasoactive agents in an attempt to minimize extravascular lung water and to improve gas exchange and pulmonary compliance can further exacerbate AKI [5Zwiers A.J. Cransberg K. van Rosmalen J. Wildschut E.D. Tibboel D. de Wildt S.N. Loop diuretics are an independent risk factor for acute kidney injury in children on extracorporeal membrane oxygenation with pre-emptive continuous hemofiltration.Intensive Care Med. 2014; 40: 627-628Crossref PubMed Scopus (5) Google Scholar]. Given the effects of AKI on ECMO outcomes, the pre-ECMO risk factors need scrutiny. The use of ECMO to salvage patients with multiple organ failure results in poor outcomes. ECMO technology has evolved significantly, and current outcomes are promising despite its use as salvage therapy. Timely extracorporeal respiratory support in ARDS may restitute physiology and minimize the risks of AKI. Although prospective clinical studies might answer this question in future, studies in animal models [6Shekar K. Fung Y.L. Diab S. et al.Development of simulated and ovine models of extracorporeal life support to improve understanding of circuit-host interactions.Crit Care Resusc. 2012; 14: 105-111PubMed Google Scholar] could provide mechanistic insights into the pathophysiology of AKI in ECMO. Prognosis of Patients With Acute Respiratory Distress Syndrome on Extracorporeal Membrane Oxygenation: the Impact of Urine Output on MortalityThe Annals of Thoracic SurgeryVol. 97Issue 6PreviewExtracorporeal membrane oxygenation (ECMO) has been utilized for patients in critical condition, including life-threatening respiratory failure and postcardiotomy cardiogenic shock. This study analyzed the outcomes of patients with acute respiratory distress syndrome (ARDS) treated by ECMO and identified the relationship between prognosis and urine output (UO) obtained on the first day of ECMO support. Full-Text PDF ReplyThe Annals of Thoracic SurgeryVol. 98Issue 4PreviewWe are pleased to have received the expert opinions from Dr Shekar and colleagues [1] from Prince Charles Hospital, Queensland, Australia. In a previous study by our group, Chang and colleagues [2] reviewed the medical records of 119 critically ill patients who were successfully weaned from extracorporeal membrane oxygenation (ECMO). Successful weaning was defined as weaning from ECMO support followed by survival longer than 48 hours. The overall rate of in-hospital mortality was 26%. The most common condition requiring ECMO support was cardiogenic shock. Full-Text PDF