Difficult Airway in the Bariatric Patient: The BARINTUBE Cohort Study

Cumulative incidence (expressed as a percentage), according to the American Society of Anesthesiologists 2022 definition of difficult airway (anticipated or unanticipated difficulty or failure is experienced by a physician trained in anesthesia care, including but not limited to one or more of the following: facemask ventilation, laryngoscopy, ventilation using a supraglottic airway, tracheal intubation, extubation, or invasive airway).

Cumulative incidence (expressed as percentage) of severe hypoxia, defined as a peripheral blood oxygen saturation (SpO2) lower than 80% during advanced airway management.

Cumulative incidence (expressed as percentage) of cardiovascular collapse, defined as any of the following events within 30 minutes from induction to surgical incision:

• Systolic blood pressure lower than 65 mmHg.
• Dyastolic blood pressure ower than 90 mmHg for more than 15 minutes
• Unplanned need for vasopressors or fluid loading greater than; 15 ml/kg to maintain target blood pressure.

Cumulative incidence (expressed as percentage) of minor adverse events, including:

• Moderate hypoxia (SpO2 lower than 93%),
• Airway injury,
• Clinically relevant bleeding,
• Oral aspiration of gastric contents,
• Dental injury,
• Lip injury.

Cumulative incidence (expressed as a percentage), according to the American Society of Anesthesiologists 2022 definition of Difficult Facemask Ventilation (It is not possible to provide adequate ventilation, because of one or more of the following problems: inadequate mask seal, excessive gas leak, or excessive resistance to the ingress or egress of gas.). For operationalization, successful face mask ventilation with 2 hands will be consigned as the reference (No difficult face mask ventilation), whereas face mask ventilation attempts with 4 or 6 hands will be considered as the presence of difficult face mask ventilation.

Cumulative incidence (expressed as a percentage), according to the American Society of Anesthesiologists 2022 definition of Difficult or Failed Tracheal Intubation (Tracheal intubation requires multiple attempts or tracheal intubation fails after multiple attempts.). For operationalization, more than 1 attempt will be considered as Difficult or Failed Tracheal Intubation.

Predictors of difficult airway will be identified through a multivariable generalized linear regression model.

Predictors of greater number of intubation attempts will be identified through a multivariable generalized linear regression model.

Participants will be grouped according to the laryngoscopy method (direct laryngoscopy vs videolaryngoscopy) and the cumulative incidence of successful intubation (expressed as proportion) will be calculated for each group. The risk difference and an appropriate measure of association (i.e., risk ratio, odds ratio) will be estimated.