In order to examine the current endotracheal intubation practice among critically ill patients, a prospective observational multicenter study of adult critically ill patients was conducted from July 2015 to January 2017 involving 20 ICUs. In this study, the primary aim was to describe, through a prospective observational multicenter study, the current intubation practice of adult critically ill patients undergoing endotracheal intubations with a focus on deriving and validating a prediction model for both immediate airway and hemodynamic complications.

Aim 1: To derive and validate a prediction model for difficult airway (three or more attempts at laryngoscopy to place an endotracheal tube and/or the need for another operator among the critically ill) [37].

Aim 2: To derive and validate a prediction model for hemodynamic compromise, i.e., post-intubation hypotension [defined as a decrease at any point in mean arterial pressure less than 65 mmHg; systolic blood pressure less than 80 mm Hg and/or a reduction in systolic blood pressure of 40% from baseline; or the initiation of, or increase in infusion dosage of, any vasopressor medication (bolus or infusion) during the 30 minute period following intubation] [38-39].

Aim3: To derive and validate a predication model for hypoxemia (decrease in pulse oximetry to oxygen saturation less than 88% during the procedure).

Inclusion Criteria:

• Patient age ≥ 18 years
• Surgical and medical intensive care unit adult patients
• Adult patients requiring endotracheal intubation during the time period of study

Exclusion Criteria:

• Patient age < 18 years
• Endotracheal intubations performed outside the ICU (in the operating room, in and outside the hospital) are excluded

Adult patients admitted to 20 participating medical/surgical/mixed ICUs who underwent endotracheal intubation.