Ann Thorac Surg 2001;71:837
© 2001 The Society of Thoracic Surgeons
Invited commentary
Ernst Wolner, MDa
a Department of Cardio-Thoracic Surgery, University of Vienna, Wahringer Gurtel 18-20, 1090 Vienna, Austria
e-mail: ernst.wolner{at}kh-wien.ac.at
More than 20 years ago hemofiltration was introduced as a form of treatment for acute renal failure [1]. In the early stages, this method was performed arteriovenously. Improvements in venous access made it possible to perform this method venovenously. As opposed to conventional dialysis, this form of renal substitution therapy does not strain the circulatory system and therefore can be performed in hemodynamic unstable patients with acute renal failure after cardiac surgical intervention. A series of studies revealed that continuous intra- and postoperative venovenous hemofiltration improves heart and lung functions in patients with acute renal failure and cardiac shock after heart surgery [2–4]. Additionally, the need for inotropic drugs can be reduced, which also contributes to the survival of the patient. As opposed to conventional dialysis, this method provides better control of the fluid status, improves uremia, and also ultrafiltrates toxic proteins such as the myocardial depressant factor. These positive effects of ultrafiltration were observed recently in pediatric cardiac surgery. As a result of the so-called modified ultrafiltration, the need for inotropic drugs, blood transfusion, and blood loss could be decreased in pediatric heart surgery [5].
The article by Bent and colleagues confirms these recent findings and attempts to prove a decrease in the mortality of patients with acute renal failure and cardiac shock after heart surgery [6]. However, this study, as many others, was performed in a nonrandomized fashion. Therefore, the conclusion needs to be cautiously interpreted. The scoring system used in this report remains questionable for predicting the success of renal therapy after cardiac surgery. It is hard to imagine that one can withhold ultrafiltration in a patient with acute renal failure and cardiac shock after a heart operation as a result of this scoring method. Despite these limitations, the article shows once again that continuous venovenous hemofiltration is the method of choice in acute renal failure after cardiac intervention.
References
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Draaisma A.A., Hazekamp M.G., Frank M., Anes N., Schoof P.H., Huysmans H.A. Modified ultrafiltration after cardiopulmonary bypass in pediatric cardiac surgery. Ann Thorac Surg 1997;64:521-525.[Abstract/Free Full Text]
