Results from the largest controlled clinical trial of fluid management methods in patients with severe lung injury provide important new information on the risks and benefits of patient care strategies currently used in the intensive care unit.

The two studies that comprised the trial showed that for patients with acute lung injury or its more severe form, acute respiratory distress syndrome, less fluid is better than more, and a shorter, less invasive catheter is as helpful as and safer than a longer catheter for monitoring patients.

The trial was conducted by scientists from the Acute Respiratory Distress Syndrome Clinical Research Network of the National Heart, Lung, and Blood Institute (NHLBI), part of the National Institutes of Health.

"A key focus of caring for these critically ill patients is management of fluids," NHLBI director Elizabeth G. Nabel said adding, "Fluid management in patients with ALI/ARDS has been the subject of intense debate for decades. We now have answers to two important questions to help guide critical care specialists on the best ways to support patients with severe lung injury."

"Based on these results, we recommend that a conservative fluid management approach be used in patients with ALI or ARDS," said Herbert P. Wiedemann, chairman of the department of pulmonary, allergy and critical care medicine at Cleveland Clinic, and lead author of the fluid management paper. "Less time on the ventilator and fewer days in the ICU could translate into cost savings and lower risk for patients," he added.

The amount of fluid in the body must be carefully monitored and adjusted to maximize lung and heart function. A conservative fluid approach limits the amount of fluids patients are given in an attempt to decrease the amount of fluid in the lungs. However, limiting fluids can strain the heart and further limit oxygen delivery to kidneys and other organs. Conversely, a more liberal use of fluids might help keep blood and oxygen flowing to other organs, but could further damage lungs by adding to the amount of fluid build-up.

"Fluid management is a complex issue, and, until now, it was not clear whether providing more or less fluids was more beneficial," noted Gordon Bernard, director of the division of allergy, pulmonary and critical care medicine at Vanderbilt University in Nashville, and chair of the NHLBI ARDS Clinical Research Network Steering Committee. "Current trends in usual care appear to more closely resemble the liberal fluid management arm of this study -- the study arm with worse outcomes. This suggests that changing usual practice and adapting more conservative fluid management would better serve ALI and ARDS patients," he added.