Why We Use Low Tidal Volume for Acute Lung Injury

August 12, 2017

On the Shoulders of Giants

Spoon Feed
Low tidal volume ventilation reduced mortality in patients with acute lung injury.  If you want to learn more, see this post on Managing the Vent Like a Pro.

Why does this matter?
This study is a true landmark article.  It changed the way we do mechanical ventilation.  Mechanical ventilation is a modifiable variable that can save lives in critically ill patients.

I miss Art Wheeler.
This was a RCT of low vs. traditional tidal volume ventilation in 861 patients with acute lung injury.  It was done at 10 centers across the US over a 3-year period.  Mechanical ventilation of patients with acute lung injury with a low tidal volume (6mL/kg based on ideal body weight vs. 12mL/kg) reduced mortality. NNT = 11.4.  Enrollment was stopped early due to obvious mortality benefit in the low tidal volume group.  This study completely changed mechanical ventilation in ARDS.  Note, tidal volume was based on ideal body weight, not actual body weight.  Here are the formulas used for ideal body weight calculation: in male patients, 50+ 0.91(centimeters of height – 152.4); in female patients, 45.5+0.91(centimeters of height – 152.4).

Source
Ventilation with lower tidal volumes as compared with traditional tidal volumes for acute lung injury and the acute respiratory distress syndrome. The Acute Respiratory Distress Syndrome Network.  N Engl J Med. 2000 May 4;342(18):1301-8.