Patients admitted to the intensive care unit (ICU) often have acute respiratory failure and/or cardiovascular collapse. In addition, reserves of oxygenation and organ perfusion are limited in ICU patients in contrast to non-critically ill patients. Endotracheal intubation, which is one of the most commonly performed procedures in the ICU, is associated with a high incidence of complications because of the precarious hemodynamic and respiratory status of critically ill patients [1–3]. The incidence of life-threatening complications associated with endotracheal intubation (severe hypoxemia, cardiovascular collapse, cardiac arrest, death) in ICU patients ranges from 25 to 39% [1, 3, 4]. Severe but non life-threatening complications, including cardiac arrhythmia, difficult endotracheal intubation, esophageal and/or traumatic endotracheal intubation, aspiration, and patient agitation [1] generally occur in 10 to 30 % of endotracheal intubations [1, 3, 4].