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Therapeutics

Fluid management emphasizing diuresis and fluid restriction reduced extravascular lung water, ventilator-days and ICU days in patients requiring pulmonary artery catheterization

ACP J Club. 1992 Sept-Oct;117:43. doi:10.7326/ACPJC-1992-117-2-043


Source Citation

Mitchell JP, Schuller D, Calandrino FS, Schuster DP. Improved outcome based on fluid management in critically ill patients requiring pulmonary artery catheterization. Am Rev Respir Dis. 1992 May;145: 990-8.


Abstract

Objective

To evaluate the effectiveness of a fluid management strategy based on direct measurement of extravascular lung water (EVLW) instead of wedge pressure (WP) in critically ill patients with pulmonary edema requiring pulmonary artery catheterization.

Design

Randomized controlled trial completed at hospital discharge.

Setting

Medical intensive care unit (ICU) in a university medical center.

Patients

101 critically ill patients (89 with pulmonary edema) requiring pulmonary artery catheterization who were admitted to the ICU. Exclusion criteria included contraindication to arterial catheter placement; lack of notification of investigators within 2 hours of the placement of the catheter; catheterization done for preoperative assessment or for evaluation of hemodynamics after pulmonary embolism; focal pulmonary infiltrate; severe mitral regurgitation; contraindication to iodinated dyes; or pregnancy or lactation.

Intervention

Patients were randomized to an EVLW management group (n = 52) on the basis of bedside indicator-dilution measurements of EVLW, or to a WP management group (n = 49), for which fluid management decisions were guided by WP measurements.

Main outcome measures

Development or resolution of EVLW, time on mechanical ventilation, time in the ICU, and death.

Main results

The mean cumulative input-output of fluid over the median study duration of 54 hours was less in the EVLW-managed patients than in the WP-managed patients (142 mL vs 2239 mL, respectively, P = 0.001). Among the 89 patients with pulmonary edema, EVLW was less at each time point after 24 hours in patients from the EVLW group compared with the initial value (P < 0.05), but this was not observed in the WP group. The median time on mechanical ventilation for the EVLW group was 9 days compared with 22 days for the WP group (P = 0.047). The median ICU stay was 7 days for patients in the EVLW group compared with 16 days for patients in the WP group (P = 0.05).

Conclusion

A fluid management strategy emphasizing diuresis and fluid restriction in critically ill patients with pulmonary edema requiring pulmonary artery catheterization led to a lower positive fluid balance, reduced extravascular lung water, and fewer days on mechanical ventilation and in the intensive care unit.

Source of funding: In part, National Institutes of Health.

Address for article reprint: Dr. D.P. Schuster, Respiratory and Critical Care Medicine Division, Box 8052, 660 South Euclid Avenue, Washington University School of Medicine, St. Louis, MO 63110, USA.


Commentary

Mitchell and colleagues have done a large randomized trial comparing therapy based on a measure of EVLW with standard therapy based on the pulmonary capillary WP. They are the first to confirm that reduced lung water decreases time on mechanical ventilation and length of stay in an ICU. For several reasons, however, it is not certain that measurement of EVLW was superior to WP in guiding fluid management.

First, in the WP group, the algorithm for hypotensive patients called for fluid infusion up to a WP of 18; the normotensive group had diuresis stopped when the WP was less than 10. These high values are conservative and probably magnify the beneficial effect of fluid management based on EVLW measurement. Indeed, animal and human studies have shown that small decreases in WP can result in large decreases in lung water in cases of acute lung injury, and several groups (1-3) have advocated aggressive diuresis to achieve a low WP as long as an adequate cardiac output is maintained. Second, measurement of EVLW requires considerable technical expertise to ensure valid data; and, finally, general applicability is limited because the EVLW computer is no longer commercially available. As the authors state, the important concept is attention to fluid balance. The clinical utility of EVLW measurement has not been clearly defined.

Randolph J. Lipchik, MD
Medical College of WisconsinMilwaukee, Wisconsin, USA

Randolph J. Lipchik, MD
Medical College of Wisconsin
Milwaukee, Wisconsin, USA


References

1. Costello JL, Dorinsky PM, Gadek JE. Edema reduction improves clinical abnormalities in ARDS: a clinical trial of aggressive diuretic therapy [Abstract]. Am Rev Respir Dis. 1987;135:A9.

2. Hall JB, Wood LD. Acute hypoxemic respiratory failure. In: Hall JB, Schmidt GA, Wood LD, eds. Principles of Critical Care. New York: McGraw-Hill; 1992: 1634-58.

3. Broaddus VC, Berthiaume Y, Biondi JW, Matthay MA. Hemodynamic management of the adult respiratory distress syndrome. Journal of Intensive Care Medicine 1987;2:190-213.