Interest in modified techniques for ventilating patients with acute lung injury (ALI) has been driven by an evolving knowledge of the respiratory mechanics of this condition and the potential for ventilator-induced lung damage (VILI). Protracted mechanical ventilation is associated with pulmonary and systemic infections, multisystem organ dysfunction, and increased mortality. Experimentally, high stretching forces applied repeatedly to normal lungs can increase capillary permeability, promote edema formation, and initiate inflammation—even when alveolar gas leaks do not occur.<sup>24 Dreyfuss D., Saumon G. Barotrauma is volutrauma, but which volume is the one responsible? Intensive Care Med 1992 ;  18 : 139-141  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti, 114 Webb H.H., Tierney D.F. Experimental pulmonary edema due to intermittent positive pressure ventilation with high inflation pressures. Protection by positive end-expiratory pressure Am Rev Respir Dis 1974 ;  110 : 556-565

Cliccare qui per andare alla sezione Riferimenti</sup> In view of that fact, investigators and clinicians have begun to reconsider the fundamental objectives of mechanical ventilation and to adopt ventilatory strategies to accomplish the revised clinical goals more effectively.

The basic principles of managing ALI are well accepted. The primary objective is to accomplish effective gas exchange at the least inspired oxygen fraction (F io₂) and pressure cost. The relative hazards of oxygen (O₂) therapy, high-pressure ventilatory patterns, and abnormal values of arterial blood gases and pH, however, are debated vigorously. Similarly, the contribution of vascular pressures and flows to iatrogenic lung injury has not been settled. In this article, the author reviews what he believes should be the basis for concern regarding the traditional approach to ventilatory support in acute respiratory distress syndrome (ARDS). Drawing from the available evidence, a ventilatory strategy is developed that seems consistent with lessons emerging from the admittedly incomplete database currently at hand (Table 1). In the formulation of this strategy, however, it should be kept in mind that many important issues are unresolved. With important exceptions, the great majority of information concerning VILI has been gleaned by experimentation with imperfect animal models of ALI and from clinical reports that lack concurrent controls. However rational newer approaches may be, therefore, and however consistent the experimental evidence may appear, the clinical benefit of altering traditional ventilation practices has not been shown rigorously.