Abstract
To minimize ventilator-induced lung injury, attention should be directed toward avoidance of alveolar over-distention and cyclical opening and closure of alveoli. The most impressive study of mechanical ventilation to date is the Acute Respiratory Distress Syndrome (ARDS) Network study of higher versus lower tidal volume (VT), which reported a reduction in mortality from 39.8% to 31.0% with 6 mL/kg ideal body weight rather than 12 mL/kg ideal body weight (number-needed-to-treat of 12 patients). To achieve optimal lung protection, the lowest plateau pressure and VT possible should be selected. What is most important is limitation of VT and alveolar distending pressure, regardless of the mode set on the ventilator. Accumulating observational evidence suggests that VT should be limited in all mechanically ventilated patients—even those who do not have ALI/ARDS. Evidence does not support the use of pressure controlled inverse-ratio ventilation. Although zero PEEP is probably injurious, an area of considerable controversy is the optimal setting of PEEP. Available evidence does not support the use of higher PEEP, compared to lower PEEP, in unselected patients with acute lung injury (ALI)/ARDS. However, results of a meta-analysis using individual patients from 3 randomized controlled trials suggest that higher PEEP should be used for ARDS, whereas lower PEEP may be more appropriate in patients with ALI. PEEP should be set to maximize alveolar recruitment while avoiding over-distention. Many approaches for setting PEEP have been described, but evidence is lacking that any one approach is superior to any other. In most, if not all, cases of ALI/ARDS, conventional ventilation strategies can be used effectively to provide lung-protective ventilation strategies.
- acute lung injury
- ALI
- acute respiratory distress syndrome
- ARDS
- lung-protective ventilation strategies
- mechanical ventilation
- PEEP
- ventilator-induced lung injury
Footnotes
- Correspondence: Dean R Hess PhD RRT FAARC, Respiratory Care, Ellison 401, Massachusetts General Hospital, 55 Fruit Street, Boston MA 02114. E-mail: dhess{at}partners.org.
Dr Hess presented a version of this paper at the 26th New Horizons Symposium, “ARDS Update,” at the 56th International Respiratory Congress of the American Association for Respiratory Care, held December 6–9, 2010, in Las Vegas, Nevada.
Dr Hess has disclosed relationships with Philips Respironics, Covidien, ResMed, Pari, and Breathe Technologies.
- Copyright © 2011 by Daedalus Enterprises Inc.