UMEM Educational Pearls

The Severely Hypoxemic ED Patient

  • Most define hypoxemia as a PaO2 < 60 mm Hg.
  • Perhaps a better definition of hypoxemia is a PaO2 that is associated with continued tissue hypoxia (rising lactate, low ScvO2), the need for vasopressor medications, or severe metabolic acidosis.
  • For ED patients that remain hypoxemic despite increased FiO2 and high levels of PEEP, consider the following rescue therapies:
    • Recruitment maneuvers - brief periods of high PEEP (35-50 cm H2O) or pressure-controlled breaths to reopen collapsed alveoli
    • High-frequency oscillatory ventilation - employs a high airway pressure to recruit closed alveolar segments
    • Prone positioning - believed to improve oxygenation through a redistribution of ventilation and perfusion
    • Extracorporeal membrane oxygenation


Patroniti N, Isgro S, Zanella A. Clinical management of severely hypoxemic patients. Curr Opin Crit Care 2011; 17:50-56.