|For Patients with Severe Lung Injury, Less Is More
Study Answers Long-Debated Questions on Fluid Management in Critical Care
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.
Investigators from the Fluid and Catheter Treatment Trial (FACTT) presented
the findings May 21 at the American Thoracic Society (ATS) International Conference
in San Diego. The results were also published early online concurrently by the
New England Journal of Medicine (NEJM). The study comparing the use of the longer
pulmonary artery catheter to the shorter central venous catheter for managing
patients will be published in the May 25 print issue of NEJM; the study evaluating
fluid management strategies will appear in the June 15 print issue of NEJM.
Acute lung injury (ALI) and Acute Respiratory Distress Syndrome (ARDS) are life-threatening
lung conditions that affect more than 190,000 people in the United States each
year, based on an estimate published in the October 20, 2005, NEJM. Thirty percent
to 60 percent of cases result in death. ALI/ARDS develops in patients who are
critically ill with other diseases such as pneumonia or sepsis (severe and widespread
bacterial infection), or who have sustained major injuries. Fluid builds up in
the lungs, and as a result, breathing is difficult, and other organs such as
kidneys, liver, heart or brain fail if they do not get enough oxygen from the
blood. There is no specific drug treatment for ALI/ARDS. Patients are placed
in the intensive care unit (ICU) and supported with mechanical ventilators (breathing
machines) and intravenous fluids such as saline (salt water), blood, or drugs
such as dobutamine to improve heart function or diuretics to increase fluid output.
"A key focus of caring for these critically ill patients is management of fluids," said
NHLBI Director Elizabeth G. Nabel, MD. "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."
FACTT was designed to clarify: Is it better to give ALI/ARDS patients more fluids
(liberal fluid management) or smaller amounts of fluids (conservative fluid management)?
Is a pulmonary artery catheter (PAC) superior to a central venous catheter (CVC)
for monitoring these patients? The two studies were conducted simultaneously
at 20 clinical centers, with 1,000 participants randomized to receive either
of the two fluid management strategies with either of the two catheters.
For the fluid management component of the study, approximately one-half (503)
of the participants were assigned to receive a conservative fluid strategy and
the other half (497) received liberal fluid management for 7 days. Patients were
monitored continuously, and treatment was adjusted according to the study protocol
based on the status of key factors measured at least every four hours. Composition
of the fluids and treatments for patients in shock were left to the judgment
of the physician.
At 60 days, FACTT researchers did not detect a difference in the numbers of
deaths between patients receiving conservative fluid management compared to those
on a liberal fluid management strategy. However, compared to the liberal fluid
management approach, the conservative fluid strategy improved lung function and
shortened the time that patients needed mechanical ventilation and intensive
care, without increasing the risk of organ failure, the researchers report.
"Based on these results, we recommend that a conservative fluid management approach
be used in patients with ALI or ARDS," said Herbert P. Wiedemann, M.D., 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
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, MD,
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."
In a separate but interrelated component of FACTT, investigators evaluated the
safety and efficacy of a PAC compared to a CVC to guide management of patients
with ALI and ARDS. Both types of catheters are used to deliver fluids to the
patient and to assess heart and lung function by measuring pressures in specific
blood vessels. With a CVC, a short tube is placed in a large vein. A PAC provides
additional information on heart and lung function, such as the pressures in the
lung and cardiac output, because the catheter passes through the heart and into
a large artery in the lung. Because the PAC is more invasive, concerns had been
raised about whether increased risks for other complications outweigh the benefits
of the device.
In FACTT, PAC-guided therapy did not improve survival or organ function compared
to CVC. After 28 days in the study, the numbers of ventilator-free days and ICU-free
days also were similar between the two groups. However, participants in the PAC
group had twice as many complications related to catheters compared to those
in the CVC group.
"The PAC did not provide any additional benefit over CVC to patients with acute
lung injury," noted Arthur P. Wheeler, MD, Associate Professor of Medicine, Vanderbilt
University Medical Center, and lead author of the FACTT catheter study. "Patients
managed with pulmonary-artery catheters are more likely to have complications
such as disturbances in their heart rhythms, so we do not recommend routine use
of PACs to manage patients with acute lung injury."
FACTT investigators also reported that they found no interaction between the
type of catheter used and the fluid management strategy.
"The fluid management and catheter treatment study represents another key finding
concerning the importance of supportive care for patients with ALI/ARDS," said
Andrea Harabin, PhD, NHLBI project officer for the NHLBI ARDS Clinical Research
Network. "FACTT was a large randomized clinical trial with a highly defined protocol
followed under rigorous monitoring. These results are relevant to ALI patients
and clinicians nationwide."
FACTT is one of six clinical trials conducted by the NHLBI ARDS Clinical Research
Network, which was formed in 1994 to hasten the development of effective therapies
for ALI and ARDS by evaluating new treatments and management practices. The network's
first clinical trial, a ventilator management study, was stopped early in 1999
when data showed that death rates were lowered by approximately 25 percent among
patients receiving small breaths of air from the mechanical ventilator compared
to patients receiving large breaths of air, which were the standard of care at
that time. The results have been heralded as signaling a new era of research
and management of the critically ill. Recently published results from another
ARDS Network study showed that corticosteroids do not improve survival and may
increase complications in patients with late-stage ARDS.
For more information:
Acute Respiratory Distress Syndrome (for patients and the public)
ARDS Clinical Research Network
To interview Dr. Harabin about this study, please contact the NHLBI Communications
Office, (301) 496-4236 or email@example.com. To reach Dr. Wiedemann, please
contact Kate Nagel at Cleveland Clinic’s Department of Media Relations at 216-445-6472
or firstname.lastname@example.org. To reach Dr. Bernard or Dr. Wheeler, please contact John Howser
at the Vanderbilt University Medical School Public Affairs Office at (615) 322-4747.
Part of the National Institutes of Health, the National Heart, Lung, and Blood
Institute (NHLBI) plans, conducts, and supports research related to the causes,
prevention, diagnosis, and treatment of heart, blood vessel, lung, and blood
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