Fluid Regulation vs Fluid Removal

Fluid management is an integral component in the management of patients with acute renal failure (ARF) in the ICU setting. In the presence of a failing kidney, fluid removal is often a challenge and requires the use of high dose diuretics with a variable response. It is often necessary in this setting to institute dialysis for volume control rather than metabolic control. CRRT techniques offer a significant advantage over intermittent dialysis for fluid control, however if not carried out appropriately can result in major complications. In order to utilize these therapies for their maximum potential it is necessary to recognize the factors which influence fluid balance and have an understanding of the principles of fluid management with these techniques. Introduction Over the last decade there has been a general trend to use aggressive fluid resuscitation for patients with multi organ failure to achieve supra normal levels of oxygen delivery. This has been largely based on the findings of several studies which have shown that survival in critically ill surgical patients is associated with supra normal levels of cardiac output, oxygen delivery and oxygen utilization ( 56). Although this concept has now been questioned (7,8), it is still an important factor in the management of the ICU patient. The end result is often a markedly edematous patient with fluid sequestration in all organs. Third spacing of fluids is common and fluid removal by glomerular filtration is limited by plasma refilling from the interstitial compartment. Most surgeons and intensivists who believe in the value of supra normal oxygen delivery are willing to accept edema as a side effect of fluid resuscitation, however there is evidence to suggest that fluid overload by itself may be an important factor contributing to an adverse outcome. Lowell et al (9) have shown that in a group of surgical patients mortality was related to the extent of fluid overload with a 100% mortality in patients with more than 20% increase in fluid from baseline. This can be explained if one recognizes that the consequences of fluid excess are not limited to superficial edema but result in myocardial and gut edema thereby compromising vital organ functions and promoting local ischemia. It is therefore essential that the strategy of fluid CRRT The Sixth International Continuous Renal Replacement Therapies Conference San Diego, California