Set Positive End-Expiratory Pressure During Protective Ventilation Affects Lung Injury

Anesthesiology. 2002 Sep;97(3):682-92. doi: 10.1097/00000542-200209000-00023.


Background: The most appropriate method of determining positive end-expiratory pressure (PEEP) level during a lung protective ventilatory strategy has not been established.

Methods: In a lavage-injured sheep acute respiratory distress syndrome model, the authors compared the effects of three approaches to determining PEEP level after a recruitment maneuver: (1) 2 cm H(2)O above the lower inflection point on the inflation pressure-volume curve, (2) at the point of maximum curvature on the deflation pressure-volume curve, and (3) at the PEEP level that maintained target arterial oxygen partial pressure at a fraction of inspired oxygen of 0.5.

Results: Positive end-expiratory pressure set 2 cm H(2)O above the lower inflection point resulted in the least injury over the course of the study. PEEP based on adequate arterial oxygen partial pressure/fraction of inspired oxygen ratios had to be increased over time and resulted in higher mRNA levels for interleukin-8 and interleukin-1beta and greater tissue inflammation when compared with the other approaches. PEEP at the point of maximum curvature could not maintain eucapneia even at an increased ventilatory rate.

Conclusion: Although generating higher plateau pressures, PEEP levels based on pressure-volume curve analysis were more effective in maintaining gas exchange and minimizing injury than PEEP based on adequate oxygenation. PEEP at 2 cm H(2)O above the lower inflection point was most effective.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Air Pressure
  • Animals
  • Hemodynamics / physiology
  • Histocytochemistry
  • Lung / pathology
  • Lung / physiopathology
  • Lung Injury*
  • Lung Volume Measurements
  • Oxygen / blood
  • Positive-Pressure Respiration*
  • Respiration, Artificial
  • Respiratory Distress Syndrome, Adult / physiopathology
  • Respiratory Mechanics / physiology
  • Reverse Transcriptase Polymerase Chain Reaction
  • Sheep
  • Therapeutic Irrigation
  • Vascular Resistance / physiology


  • Oxygen