Preoxygenation for tracheal intubation in critically ill patients: one technique does not fit all

Tracheal intubation is a common procedure in critically ill patients (1). Despite its frequent occurrence, tracheal intubation in this setting remains a risky procedure (2,3), mainly due to the combination of two synergistic and negative factors: the unique respiratory and hemodynamic instability of critically ill patients, and the high incidence of difficult airway in this population (4). Intubation-related life-threatening hypoxemia, hypotension, arrythmia, cardiac arrest and death are frequently reported (2,3). Recently, a multicenter retrospective trial on tracheal intubation in Intensive Care Unit (ICU) observed a 2.7% rate of cardiac arrest (strongly predicted by hypoxemia prior to intubation and lack of preoxygenation), with a high 28-day mortality in patients who had experienced an intubation-related cardiac arrest (5).