Figure 1914

Approaches for fluid management in continuous renal replacement therapy (CRRT). CRRT techniques are uniquely situated in providing fluid regulation, as fluid management can be achieved with three levels of intervention [16]. In Level 1, the ultrafiltrate (UF) volume obtained is limited to match the anticipated needs for fluid balance. This calls for an estimate of the amount of fluid to be removed over 8 to 24 hours and subsequent calculation of the ultrafiltration rate. This strategy is similar to that commonly used for intermittent hemodialysis and differs only in that the time to remove fluid is 24

hours instead of 3 to 4 hours. In Level 2 the ultrafiltrate volume every hour is deliberately set to be greater than the hourly intake, and net fluid balance is achieved by hourly replacement fluid administration. In this method a greater degree of control is possible and fluid balance can be set to achieve any desired outcome. The success of this method depends on the ability to achieve ultrafiltration rates that always exceed the anticipated intake. This allows flexibility in manipulation of the fluid balance, so that for any given hour the fluid status could be net negative, positive, or balanced. A key advantage of this technique is that the net fluid balance achieved at the end of every hour is truly a reflection of the desired outcome. Level 3 extends the concept of the Level 2 intervention to target the desired net balance every hour to achieve a specific hemody-namic parameter (eg, central venous pressure, pulmonary artery wedge pressure, or mean arterial pressure). Once a desired value for the hemodynamic parameter is determined, fluid balance can be linked to that value. Each level has advantages and disadvantages; in general greater control calls for more effort and consequently results in improved outcomes. SCUF— ultrafiltration; CAVHD/CVVHD—continu-ous arteriovenous/venovenous hemodialy-sis; CAVH/CVVH—continuous arteriove-nous/venovenous hemofiltration; CAVHDF/CVVHDF—continuous arteri-ovenous/venovenous hemodiafiltration.

Replacement Fluid

Investigator Golper [19]

Kierdorf [20]

Lauer[21] F

'aganini [22]

Mehta [11]

Mehta [11]

Na+ 147

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