Management of patients to achieve a negative fluid balance may improve mortality outcomes in patients with acute lung injury/acute respiratory distress syndrome (ALI/ARDS), according to a retrospective review of the ARDSNet ARMA Trials Cohort.

Pauline K. Park, MD, from the University of Michigan, Ann Arbor, presented the findings here at the Society of Critical Care Medicine 37th Critical Care Congress.

"The results of this study reinforce the findings of the National Heart, Lung, and Blood Institute's [NHLBI] Fluid and Catheter Treatment Trial [FACTT] in that more conservative fluid management in patients with ALI was associated with improved outcomes," Dr. Park told Medscape Critical Care. The FACTT trial, published in July 2006 in the New England Journal of Medicine, found that ALI/ARDS patients given smaller amounts of fluids (ie, conservative fluid management) fared better than those given fluids more liberally.

The current study reviewed data from 844 patients for whom fluid balance data had been collected in the NHLBI ARDSNet ARMA 6 vs 12 mL/kg ventilator tidal volume trial.

Patients received fluid management according to physician preference. The cumulative fluid balance during the first 4 days was compared with the outcomes of ventilator-free days, intensive care unit (ICU)–free days, and death during hospitalization.

At baseline, 683 patients had an average of more than 3.5 L in positive fluid balance, and 161 patients had a negative fluid balance. A negative cumulative fluid balance at day 4 was associated with lower hospital mortality after taking into account illness severity; 20% of patients in the negative fluid balance group died vs 37% of those with a positive fluid balance, with an odds ratio of 0.51 (95% confidence interval, 0.27 – 0.96; P = .001). Patients with a negative fluid balance also achieved more ventilator-free days (15 vs 10 days; P =.001), more ICU-free days (13 vs 9 days; P = .009), and fewer days on mechanical ventilation (11 vs 13 days; P = .015).

"Since this is a retrospective analysis, we must be careful not to jump to the conclusion that lower fluid administration itself was responsible for the improved outcomes or that it always represents better treatment," Dr. Park told Medscape Critical Care. "In our practice, however, we try to avoid significant positive cumulative fluid balance in ALI patients."

According to Dr. Park, further studies are needed to determine better markers for fluid status, the best way to manage fluid, and whether timing to achieve appropriate fluid balance is important.

"It is often observed that as patients recover from ALI/ARDS, urine output increases, and they are more responsive to diuretics," noted session moderator Bruce Greenwald, MD, from Cornell University's Weill Medical College, Ithaca, New York. "These findings do support the maintenance of a negative fluid balance in ALI/ARDS; however, it should be kept in mind that it may not have been clinical management that brought patients into negative fluid balance, but just that patients in the recovery phase of their illnesses had greater urine output," he told Medscape Critical Care. "Additional prospective studies are needed to clarify whether or not net fluid balance is simply a predictor of recovery or should it be a therapeutic goal," he added.

The study was funded by the National Institutes of Health NHLBI ARDSNetwork and the University of Michigan Health System. The commentators have disclosed no relevant financial relationships.

Society of Critical Care Medicine 37th Critical Care Congress: Abstract 54. Presented February 3, 2008.

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