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Correspondence |

Nonventilatory Treatments for ARDS? Response: Future Directions FREE TO VIEW

William S. Lyons, MD
Author and Funding Information

Affiliations: INOVA Fairfax, Fairfax, VA,  University of California at San Francisco, San Francisco, CA

Correspondence to: William S. Lyons, MD, INOVA Fairfax, Surgery, 3300 Gallows Rd, Fairfax, VA 22042; e-mail: lyonsmd@msn.com



Chest. 2008;133(2):586-587. doi:10.1378/chest.07-2333
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Published online

The “Contemporary Review” of acute lung injury (ALI)/ARDS by Calfee and Matthay1 in the March 2007 issue of CHEST is a good one. But there are no known specific or effective treatments for ALI/ARDS, pharmacologic or physical, other than the obvious necessity of oxygen and mechanical ventilatory support.

The most substantive portion of the review considers the significance of the large and long-awaited National Heart, Lung, and Blood Institute Fluids and Catheter Treatment Trial.2The authors summarized the importance of the fluids portion of the Fluids and Catheter Treatment Trial by noting the clear benefit demonstrated by fluids restriction in ARDS patients. Not emphasized by the authors is the fact that both study cohorts, liberal fluids and restricted fluids, were necessarily, by definition, fluid-overloaded to begin the study. This can be deduced from the weight data available on ARDS patients from the ARDS Net itself. The estimated overweight condition is 20%!3 Twenty percent in the average 150-lb patient is 30 lbs, 30 pints, 15 quarts, nearly 4 gallons of retained fluid! It is further remarkable that merely holding the fluid balance “neutral” in the fluids-restricted (but overloaded) cohort resulted in statistically significant and practical benefits. These improvements were consistent with the concept of ARDS as a condition of serious overloading of the extracellular fluid space with isotonic crystalloid.

Calfee and Matthay1 confront, with uncertainty, the risks of the “balancing” act in fluids management in ARDS patients: the obvious edema of too much fluid vs the reduced organ perfusion and lower vascular pressure of too little fluid. Straightforward logic resolves this conundrum, with the use of isooncotic fluid for intravascular volume and small volumes of hypotonic crystalloid for renal function and insensible losses.

The authors’ discussion of the “goal-directed therapy” of Rivers et al4 for cases of “severe sepsis” and “septic shock” is not appropriate in the context of ALI/ARDS. As Rivers et al4 clearly stated in their article, the cases were all diagnosed in the emergency department, and all surgical, cardiac, and trauma cases were excluded.

The authors concluded that fluids restriction is appropriate in the management of established ARDS and that furosamide may be the only helpful pharmacologic agent in treatment. If true, excepting colloids, fluids restriction would likewise be the principle in the prevention of ARDS as well.

The author has reported to the ACCP that no significant conflicts of interest exist with any companies/organizations whose products or services may be discussed in this article.

The authors have reported to the ACCP that no significant conflicts of interest exist with any companies/organizations whose products or services may be discussed in this article.

Calfee, GS, Matthay, MA (2007) Nonventilatory treatments for acute lung injury and ARDS.Chest131,913-920. [PubMed] [CrossRef]
 
National Heart Lung and Blood Institute ARDS Clinical Trials Network, Wiedemann HP, Wheeler AP, et al.. Comparison of two fluid-management strategies in acute lung injury.N Engl J Med2006;254,2564-2575
 
Writing Committee of the Acute Respiratory Distress Network.. Ventilation with lower tidal volumes as compared with traditional tidal volumes for acute lung injury and the acute respiratory distress syndrome.N Engl J Med2000;342,1301-1308. [PubMed]
 
Rivers, E, Nguyen, B, Havstad, S, et al Early goal directed therapy in the treatment of severe sepsis and septic shock.N Engl J Med2001;345,1368-1376. [PubMed]
 
To the Editor:

We agree with Dr. Lyons that fluid overload is a widespread and important problem in critically ill patients, including patients with acute lung injury (ALI) and ARDS. We also agree that holding the net fluid balance at zero, as the fluid conservative strategy did over the first 7 days of the Fluid and Catheter Treatment Trial,1 is a practical means of implementing a fluid conservative approach.

Several points made by Dr. Lyons merit further discussion. First, while measured body weight differed from predicted body weight by an average of 20% in the ARDS Network trial of lower tidal volume ventilation,2not all of that difference is attributable to volume overload. Rather, some of the weight difference is certainly due to obesity and/or excess muscle mass. Second, we question the description of ALI/ARDS as “a condition of serious overloading of the extracellular fluid space with isotonic crystalloid.” While increased hydrostatic pressure and volume overload clearly increase edema formation in ALI/ARDS patients,3the primary problem in this syndrome is not one of volume overload but of increased lung epithelial and endothelial permeability.4Third, we would like to clarify our rationale for discussing the study by Rivers et al5 on early goal-directed therapy in sepsis. We certainly concur with Dr. Lyons that the patient population studied by Rivers et al5 differs substantially from those patients with ALI/ARDS studied in the Fluid and Catheter Treatment Trial1; it was this difference that we were attempting to highlight in our review,6 particularly since sepsis is the most common cause of ALI/ARDS, and since approximately 40% of patients with sepsis will either present with or go on to have ALI/ARDS develop.4 The distinction we wish to emphasize is that patients with shock who meet the criteria for early goal-directed therapy should be treated as such, regardless of the presence of ALI; fluid-conservative therapy should be reserved for ALI/ARDS patients who are no longer in shock.

References
The Acute Respiratory Distress Syndrome Network.. Comparison of two fluid-management strategies in acute lung injury.N Engl J Med2006;254,2564-2575
 
The Acute Respiratory Distress Syndrome Network.. Ventilation with lower tidal volumes as compared with traditional tidal volumes for acute lung injury and the acute respiratory distress syndrome.N Engl J Med2000;342,1301-1308. [PubMed] [CrossRef]
 
Staub, NC Pulmonary edema: physiologic approaches to management.Chest1978;74,559-564. [PubMed]
 
Ware, LB, Matthay, MA The acute respiratory distress syndrome.N Engl J Med2000;342,1334-1349. [PubMed]
 
Rivers, E, Nguyen, B, Havstad, S, et al Early goal-directed therapy in the treatment of severe sepsis and septic shock.N Engl J Med2001;345,1368-1377. [PubMed]
 
Calfee, CS, Matthay, MA Non-ventilatory management of acute lung injury and the acute respiratory distress syndrome.Chest2007;131,913-920. [PubMed]
 

Figures

Tables

References

Calfee, GS, Matthay, MA (2007) Nonventilatory treatments for acute lung injury and ARDS.Chest131,913-920. [PubMed] [CrossRef]
 
National Heart Lung and Blood Institute ARDS Clinical Trials Network, Wiedemann HP, Wheeler AP, et al.. Comparison of two fluid-management strategies in acute lung injury.N Engl J Med2006;254,2564-2575
 
Writing Committee of the Acute Respiratory Distress Network.. Ventilation with lower tidal volumes as compared with traditional tidal volumes for acute lung injury and the acute respiratory distress syndrome.N Engl J Med2000;342,1301-1308. [PubMed]
 
Rivers, E, Nguyen, B, Havstad, S, et al Early goal directed therapy in the treatment of severe sepsis and septic shock.N Engl J Med2001;345,1368-1376. [PubMed]
 
The Acute Respiratory Distress Syndrome Network.. Comparison of two fluid-management strategies in acute lung injury.N Engl J Med2006;254,2564-2575
 
The Acute Respiratory Distress Syndrome Network.. Ventilation with lower tidal volumes as compared with traditional tidal volumes for acute lung injury and the acute respiratory distress syndrome.N Engl J Med2000;342,1301-1308. [PubMed] [CrossRef]
 
Staub, NC Pulmonary edema: physiologic approaches to management.Chest1978;74,559-564. [PubMed]
 
Ware, LB, Matthay, MA The acute respiratory distress syndrome.N Engl J Med2000;342,1334-1349. [PubMed]
 
Rivers, E, Nguyen, B, Havstad, S, et al Early goal-directed therapy in the treatment of severe sepsis and septic shock.N Engl J Med2001;345,1368-1377. [PubMed]
 
Calfee, CS, Matthay, MA Non-ventilatory management of acute lung injury and the acute respiratory distress syndrome.Chest2007;131,913-920. [PubMed]
 
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