Journal: Cleve Clin J Med 75(1):42-48, 2008. 9 References
Reprint: Dept of Pulmonary, Allergy, and Critical Care Medicine, A90, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195 (HP Wiedemann, MD) LE.15 SP0820/260 ©2008
Faculty Disclosure: Abstracted by L. Easley, who has nothing to disclose.
Although most clinicians tend to manage acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) by giving more rather than less fluid, patients may actually fare better under a strategy of limited fluid intake and increased fluid excretion. This article discusses the basis for the Fluids and Catheters Treatment Trial (FACTT) researchers' con¬clusion that a conservative fluid strategy is preferable to a "wet" or liberal fluid strategy in ALI/ARDS. Enrolled in this study were 1,000 patients, randomized into one of four roughly equal groups based on the type of fluid-management strategy—conservative or liberal—and the type of catheter that was placed—pulmonary artery or central venous. Ventilation according to a low tidal volume strategy was initiated within 1 hour after randomization. The pulmonary artery catheter or central venous catheter was inserted within 4 hours of randomization, and fluid management was started within 2 hours after catheter insertion.
In the conservative-strategy group, the target filling pressures were low—a pulmonary artery occlusion pressure less than 8 mmHg for those randomized to receive a pulmonary artery catheter, and a central venous pressure less than 4 mmHg for those randomized to receive a central venous catheter. In the liberal-strategy group, the target pressures were in the high-to-normal range—14 to 18 mmHg for those with a pulmonary artery catheter and 10 to 14 mmHg for those with a central venous catheter. Patients were monitored once every 4 hours for four variables: pulmonary artery occlusion pressure or central venous pressure, shock, oliguria, and ineffective circulation.
The primary end-point was the mortality rate at 60 days. The secondary end-points were the number of ICU-free and ventilator-free days and the number of organ failure-free days at day 28. Clinicians adhered to the protocol instructions during approximately 90% of the time. At 60 days, the mortality rate was 25.5% in the conservative-strategy treatment group and 28.4% in the liberal-strategy group. Through day 7, the average patient in the conservative-strategy group experienced significantly more ICU-free days and more days free of central nervous system (CNS) failure.
One concern the authors had with the conservative strategy was that it might induce shock more frequently, but this did not occur. Overall, lung func¬tion was considerably better in the conservative-strategy group. The stroke volume index and the cardiac index were slightly lower in the conservative-strategy group at day 7, but not significantly so. At day 7, the conservative-strategy group had a signifi¬cantly higher blood urea nitrogen level. There was no difference in the number of renal failure-free days at either day 7 or day 28. At day 7, the conservative-strategy group had significantly higher hemoglobin and albumin levels and capillary osmotic pressure, even though significantly more patients in the liberal-strategy group received transfusions through day 7. Although the number of adverse events, particularly metabolic alkalosis and electrolyte imbalance, was significantly higher in the conservative-strategy group, the overall incidence was low.
The two fluid-management protocols used in this study were designed to be prudent yet distinctly different. The conservative strategy improved lung function and shortened the duration of mechanical ventilation and ICU stay without increasing nonpul¬monary organ failures or increasing the risk of death within 60 days. The authors recommend the conservative strategy for patients with ALI/ARDS. |
