Occult positive end-expiratory pressure in mechanically ventilated patients with airflow obstruction: the auto-PEEP effect

Am Rev Respir Dis. 1982 Jul;126(1):166-70. doi: 10.1164/arrd.1982.126.1.166.


Alveolar pressure can remain positive throughout the ventilatory cycle of mechanically-ventilated patients with airflow obstruction, even when positive end-expiratory pressure (PEEP) is not applied intentionally. The increase of intrathoracic pressure associated with this "auto-PEEP" phenomenon can severely depress cardiac output as well as elevate the end-expiratory pulmonary artery wedge pressure. Such effects may be exaggerated in patients with chronic obstructive pulmonary disease because abnormally compliant lungs transmit a high fraction of alveolar pressure to intrathoracic vessels. Failure to recognize the hemodynamic consequences of auto-PEEP may lead to inappropriate fluid restriction or unnecessary vasopressor therapy. Although not apparent during normal ventilator operation, the auto-PEEP effect can be detected and quantified by a simple bedside maneuver: expiratory port occlusion at the end of the set exhalation period.

Publication types

  • Case Reports

MeSH terms

  • Female
  • Hemodynamics
  • Humans
  • Intermittent Positive-Pressure Ventilation / adverse effects*
  • Intermittent Positive-Pressure Ventilation / methods
  • Lung Diseases, Obstructive / physiopathology*
  • Lung Diseases, Obstructive / therapy
  • Male
  • Middle Aged
  • Positive-Pressure Respiration / adverse effects*
  • Pressure
  • Pulmonary Alveoli / physiopathology*
  • Respiration, Artificial / methods