A validation study of the intubation difficulty scale for obese patients

Area of Science:

• Anesthesiology
• Critical Care Medicine
• Surgical Innovation

Background:

• The Intubation Difficulty Scale (IDS) is widely used in research to identify difficult intubation in obese patients.
• No prior studies have assessed the performance of the IDS in this population.
• Obesity presents unique challenges for endotracheal intubation.

Purpose of the Study:

• To evaluate the performance of the IDS in obese patients.
• To define difficult tracheal intubation (DI) based on subjective difficulty assessments.
• To determine optimal cutoff points for the IDS in this demographic.

Main Methods:

• A cross-sectional study was conducted in a tertiary care hospital.
• Adult obese Thai patients undergoing conventional endotracheal intubation were included.
• Subjective difficulty assessments from anesthesiologists and IDS scores were collected.

Main Results:

• 552 obese patients were analyzed, with a 14.3% incidence of somewhat difficult intubation and 2.2% of difficult intubation.
• The IDS demonstrated high overall performance, with an Area Under the Curve of 0.99 for somewhat DI and 1.00 for DI.
• Optimal cutoff points were identified: IDS score ≥2 for somewhat DI (100% sensitivity, 92% specificity) and IDS score ≥5 for DI (100% sensitivity, 100% specificity).

Conclusions:

• The IDS is a reliable tool for identifying difficult tracheal intubation in obese patients.
• An IDS score of 2 or higher is recommended to indicate somewhat difficult intubation.
• An IDS score of 5 or higher is recommended to indicate difficult tracheal intubation.