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

P. E. Pepe, J. J. Marini

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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 endo-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 consequence 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.

Original languageEnglish (US)
Pages (from-to)166-170
Number of pages5
JournalAmerican Review of Respiratory Disease
Issue number1
Publication statusPublished - 1982


ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine

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