Wednesday, October 12, 2005

Furosemide and albumin administration in acute lung injury

A recent paper in Critical Care Medicine adds another piece to our understanding of the controversy surrounding fluid management in acute lung injury (ALI) and acute respiratory distress syndrome (ARDS). In patients with ALI/ARDS and low total serum protein (<6g/dl) the investigators compared furosemide with albumin to furosemide with placebo. The albumin group had better outcomes in terms of oxygenation and hemodynamic stability. The use of albumin was associated with less shock, the need for fewer fluid boluses, and consequently better ability to maintain negative fluid balance.

Historically the controversy has centered around two related questions, one being whether it’s better to maintain positive or negative fluid balance in ARDS (the “wet vs. dry” debate) and the other issue being the use of albumin in general.

Evidence to date seems to favor the dry school (patients with negative fluid balance and who lost weight did better in this study and those who dropped their wedge pressure did better in this one). The level of evidence in these studies is somewhat low, and better answers await completion of FACTT, an ARDSnet sponsored study prospectively comparing wet and dry strategies. (The study also has arms comparing central venous catheter vs. pulmonary artery catheter monitoring).

The albumin controversy has an interesting history. Used indiscriminately in the past, it fell into disfavor after this meta-analysis of albumin use in a variety of critical illnesses including ARDS. Survival differences in this analysis were not significantly different but the point estimates suggested harm with albumin administration.

I can remember when it was popular to administer albumin with loop diuretics for ARDS based on little more than physiologic plausibility. People began to decry the use of albumin when evidence based medicine came on the scene. This study in Critical Care Medicine suggests an evidentiary basis for albumin, but the authors caution that more studies, looking at more meaningful outcomes, are needed. I look forward to knowing whether patients have fewer days of mechanical ventillation, shorter ICU stays and better survival.

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