Nonventilatory treatments for acute lung injury and ARDS

Abstract

Over the past decade, advances in the ventilatory management of acute lung injury (ALI) and ARDS have improved outcomes; however, until recently the search for other therapies has been less fruitful. Recently, the Acute Respiratory Distress Syndrome Network Fluid and Catheter Treatment Trial reported that a conservative fluid management strategy, compared with a fluid liberal strategy, increased the mean (+/- SE) number of ventilator-free days in patients with ALI (14.6 +/- 0.5 vs 12.1 +/- 0.5 days, respectively; p < 0.001). In addition to this beneficial effect on outcomes, the study found that the conservative fluid strategy did not increase the incidence of renal failure or the development of shock. Other studies have demonstrated that albumin and furosemide therapy may be beneficial in hypoproteinemic patients with lung injury, though data on outcomes is still lacking. Although several pharmacologic therapies, such as corticosteroids, surfactant, and nitric oxide, have been demonstrated to be ineffective in improving outcomes, several promising new treatments are being investigated in ongoing or upcoming clinical trials. This article reviews these developments and other recent research on the optimal nonventilatory management of patients with ALI.

FIGURE 1

Relationship between pulmonary hydrostatic pressure and lung edema formation under normal conditions and increased permeability. Even under normal conditions, an increase in pulmonary hydrostatic pressure results in increased lung edema formation. This relationship, however, is dramatically accentuated under conditions of increased lung permeability. Adapted with permission from Staub.

FIGURE 2

Cumulative fluid balance in patients enrolled in the FACTT compared to patients in prior Acute Respiratory Distress Syndrome Network studies. Fluid administration in the liberal fluid management arm of the FACTT mimicked that in two prior Acute Respiratory Distress Syndrome Network studies of ventilator management strategy and resulted in a gain of approximately 1 L/d. In contrast, fluid administration in the conservative fluid management arm resulted in a net even fluid balance. ARMA = Acute Respiratory Distress Syndrome Network trial of 6 vs 12 mL/kg tidal volume ventilation; ALVEOLI = Acute Respiratory Distress Syndrome Network trial of low vs high positive end-expiratory pressure. Adapted with permission from the Acute Respiratory Distress Syndrome Network. Copyright 2006 Massachusetts Medical Society. All rights reserved.