Anesthesia in the News
  • Incidence and Risks of Serious AEs During Emergency Intubation

    Tracheal intubation is one of the most performed and high-risk interventions in critically ill patients. However, limited information is available on adverse peri-intubation events. Factors such as underlying shock, respiratory failure, metabolic acidosis, and other pathophysiological changes substantially increase the risk of adverse peri-intubation events in critically ill patients compared with patients undergoing intubation in the operating room.

    Recently, a continent-spanning cohort of researchers set out to ascertain how common major adverse events (AEs) are in critically ill patients undergoing tracheal intubation during the peri-intubation period.

    Investigators for this observational study, recently published in the journal JAMA, sought to evaluate the incidence and nature of adverse peri-intubation events and to assess current practice of intubation in critically ill patients. The authors expressed hope that performing a systematic evaluation of routine clinical practice and occurrence of AEs could establish the baseline for investigating higher-priority interventions to reduce patients’ risk.

    The INTUBE study

    The International Observational Study to Understand the Impact and Best Practices of Airway Management in Critically Ill Patients (INTUBE) study was an international, multicenter, prospective cohort study involving consecutive critically ill patients undergoing tracheal intubation in the intensive care units (ICUs), emergency departments, and wards, in a convenience sample of 197 sites from 29 countries across 5 continents.

    The study had 3 objectives:

    • to assess incidence and types of major adverse peri-intubation events in critically ill patients,
    • to examine factors associated with these events, and
    • to determine the association of adverse peri-intubation events with outcomes among critically ill patients.

    The primary outcome of the study, conducted from October 1, 2018, to July 31, 2019 (August 28, 2019, was the final follow-up), was the incidence of major adverse peri-intubation events. These were defined as at least one of the following events occurring within 30 minutes from the start of the intubation procedure: cardiovascular instability (either: systolic pressure <65 mm Hg at least once, <90 mm Hg for >30 minutes; new or increase need of vasopressors or fluid bolus >15 mL/kg), severe hypoxemia (peripheral oxygen saturation <80%) or cardiac arrest. Primary outcome data were available for all patients.

    The secondary outcomes included the incidence of cardiac arrhythmia; difficult intubation; a cannot-intubate or cannot-oxygenate scenario; emergency front-of-neck airway; pulmonary aspiration of gastric contents; esophageal intubation; pneumothorax or pneumomediastinum; airway injury; dental injury; and ICU mortality.  Study investigators calculated 28-day mortality as a post hoc analysis.

    The who, what, and how

    Of 3,659 patients screened, 2,964 were included. The study participants were 62.6% male ranging in age from 49 to 74 years, with a median age of 63 years. The primary reason for intubation was respiratory failure in 1,548 patients (52.3%), followed by neurological impairment in in 902 patients (30.5%), and cardiovascular instability in 277 cases (9.4%).

    The INTUBE researchers found that major adverse peri-intubation events were observed frequently. Of the critically ill patients undergoing tracheal intubation, 1,340 (45.2%) experienced at least one major adverse peri-intubation event. Cardiovascular instability accounted for most of the events, occurring in 42.6% of all patients. Severe hypoxemia was the second most common event, observed in 272 patients (9.3%). Ninety-three patients (3.1%) experienced a cardiac arrest following tracheal intubation. Of these, 49 patients (52.7%) had a sustained return of spontaneous circulation, and 44 (47.3%) died following cardiac arrest. The main reason reported for cardiac arrest was hypovolemia or hemodynamic instability in 34 patients (36.9%), followed by hypoxemia in 23 (25.0%). 

    Of the secondary outcomes, 167 patients (5.6%) had an esophageal intubation; 167 (5.6%), new onset cardiac arrhythmia; 138 (4.7%), difficult intubation; and 116 (3.9%), aspiration of gastric contents.

    A total of 2,943 patients were followed up through ICU discharge. The overall ICU mortality was 32.8%. Of those patients who experienced a major adverse peri-intubation event, 40.7% died versus 26.3% who did not experience an adverse peri-intubation event. 

    Further factors and predictors

    The authors also compared preoxygenation by a bag-valve mask, noninvasive ventilation, and high-flow nasal cannula use as well as administration of various common induction and neuromuscular blocking agents. They also analyzed use of a video laryngoscope as the primary device for tracheal intubation and its value in identifying at least one predictor of difficult airway management prior to intubation. Waveform capnography utilized during intubation was also assessed.

    Additionally, the researchers examined first-pass intubation success rates versus those following a second or subsequent attempts. First-pass intubation success was achieved for 2,360 of 2,958 patients (79.8%). A second attempted intubation was achieved for 460 patients (15.6%), and 133 patients (4.5%) required more than 2 attempts.

    The cut-to-air countdown

    In addition to their key finding that cardiovascular instability is the most frequent adverse event following intubation, the researchers conclude that the study confirms the importance of achieving first-pass intubation success given the higher incidence of adverse events associated with repeated intubation attempts writing, “the need for multiple intubation attempts increased the risk of severe hypoxia and cardiac arrest.”

    Overall, the researchers conclude that the study underscores the critical need for a “high level of expertise in tracheal intubation…[to] reduce the need for repeated intubation attempts. These findings emphasize the importance of experience in airway management and of measures to enhance tracheal intubation skills, along with proficiency in hemodynamic optimization.”

    The full 2021 paper, “Intubation Practices and Adverse Peri-intubation Events in Critically Ill Patients From 29 Countries,” JAMA. ;325(12):1164-1172., is free for your review at