Invited commentary

Abstract

Listen

Translate article

Validation of scoring systems for specific clinical situations is valuable because it may guide decisions regarding the initiation of advanced invasive cardiac or respiratory support in addition to providing early prognostic information for realistic discussions with patients and families. Lin and colleagues [1Lin C.-Y. Tsai F.-C. Tian Y.-C. et al.Evaluation of outcome scoring systems for patients on extracorporeal membrane oxygenation.Ann Thorac Surg. 2007; 84: 1256-1263Abstract Full Text Full Text PDF PubMed Scopus (79) Google Scholar] compare the precision of five scoring systems in predicting hospital mortality in adult patients treated with extracorporeal membrane oxygenation (ECMO): (1) APACHE IV, (2) APACHE III, (3) APACHE II, (4) RIFLE, and (5) SOFA). Cardiogenic shock was the most common indication for the institution of ECMO, although some patients with adult respiratory distress syndrome were also included. The high mortality rate (71%) among the 48 patients treated with ECMO for postcardiotomy cardiogenic shock suggests that alternative modalities of assistance are needed for these patients. Although the data on ventricular assist devices (VADs) as a bridge-to-recovery in chronic heart failure is variable, the favorable cardiac remodeling seen with ventricular unloading may be beneficial and remains to be examined specifically in adults with cardiogenic shock [2Maybaum S. Mancini D. Xydas S. et al.Cardiac improvement during mechanical circulatory support: A prospective multicenter study of the LVAD working group.Circulation. 2007; 115: 2497-2505Crossref PubMed Scopus (323) Google Scholar, 3Birks E.J. Tansley P.D. Hardy J. et al.Left ventricular assist device and drug therapy for the reversal of heart failure.N Engl J Med. 2006; 355: 1873-1884Crossref PubMed Scopus (723) Google Scholar]. With the exception of patients with myocarditis, all groups had high mortality rates and no other diagnosis seems particularly amenable to the use of ECMO for cardiopulmonary support. All of the prognostic scores had good predictive ability. However, the APACHE IV score was the most accurate. At a cutoff of 49%, the APACHE IV score had a positive predictive value of 96% for subsequent hospital mortality, and although the exact number is not given, based on the survival curve it seems that approximately 50% of the patients fell into this high-risk group. As the authors note, McCarthy [4McCarthy J.T. Prognosis of patients with acute renal failure in the intensive-care unit: a tale of two eras.Mayo Clin Proc. 1996; 71: 117-126Abstract Full Text Full Text PDF PubMed Scopus (172) Google Scholar] has argued that prognostic scores should not be used as arbitrary criteria to withhold potentially lifesaving treatments in the intensive care unit [4McCarthy J.T. Prognosis of patients with acute renal failure in the intensive-care unit: a tale of two eras.Mayo Clin Proc. 1996; 71: 117-126Abstract Full Text Full Text PDF PubMed Scopus (172) Google Scholar]. However, given the accurate prediction of mortality in these patients and the invasiveness and expense associated with ECMO, we must ask ourselves whether or not these patients benefit from its use. Although perhaps not exclusion criteria on its own, when taken with other factors, based on these data (in approximately 40 patients) an APACHE IV score of less than 49% should be a relative contraindication for the use of ECMO. Whether or not the APACHE IV scores are used to guide decisions regarding device implantation, the data presented by Lin and colleagues [1Lin C.-Y. Tsai F.-C. Tian Y.-C. et al.Evaluation of outcome scoring systems for patients on extracorporeal membrane oxygenation.Ann Thorac Surg. 2007; 84: 1256-1263Abstract Full Text Full Text PDF PubMed Scopus (79) Google Scholar] will be valuable as a guide to discussions with patients and their families and as an indication of which patient populations might benefit from further research into new treatment modalities. Evaluation of Outcome Scoring Systems for Patients on Extracorporeal Membrane OxygenationThe Annals of Thoracic SurgeryVol. 84Issue 4PreviewExtracorporeal membrane oxygenation (ECMO) has been used in critical conditions such as life-threatening respiratory failure or postcardiotomy cardiogenic shock. This investigation compares the predictive value of Acute Physiology, Age and Chronic Health Evaluation IV (APACHE IV), earlier APACHE models, Sequential Organ Failure Assessment (SOFA), and the risk of renal failure, injury to the kidney, failure of kidney function, loss of kidney function, and end-stage renal failure (RIFLE) classification obtained on the first day of ECMO support for hospital mortality in critically ill patients. Full-Text PDF