Thyromental Height Test as a Method for Predicting Difficult Intubation in Patients with Obesity: A Prospective...

Area of Science:

• Anesthesiology and Perioperative Medicine
• Medical Imaging and Diagnostics
• Obesity Medicine

Background:

• Existing anthropometric tests for predicting difficult intubation in obese patients have limited accuracy.
• The thyromental height test (TMHT) measures the distance between the thyroid cartilage and the mentum.
• Obesity presents unique challenges for airway management, necessitating improved predictive tools.

Purpose of the Study:

• To evaluate the effectiveness of the thyromental height (TMH) measurement in predicting difficult intubation in obese patients undergoing elective surgery.
• To assess the predictive value of various anthropometric measurements, including thyromental distance (TMD), sternomental distance (SMD), modified Mallampati test (MMT), neck circumference (NC), and mouth opening (MO).
• To develop and analyze a composite risk score for difficult intubation in this population.

Main Methods:

• A prospective observational cohort study involving 77 obese adult patients (BMI ≥ 30 kg/m²) scheduled for elective surgery.
• Direct laryngoscopy and intubation were performed under general anesthesia.
• Key measurements included TMH, TMD, SMD, MMT score, NC, and MO. The Cormack-Lehane (CL) grade was also recorded.

Main Results:

• Difficult intubation occurred in 23.38% of patients. Sleep apnea was significantly more prevalent in patients with difficult intubation (50% vs. 23.75%).
• No significant differences were found for TMH, TMD, NC, or MO individually.
• Male sex, TMD ≤ 175 mm, and MO ≤ 60.5 mm were identified as predictors of difficult laryngoscopy. The OPERA Score demonstrated a superior predictive value (AUC = 0.8).

Conclusions:

• Thyromental height (TMH) alone is not a reliable predictor of difficult intubation in obese patients.
• Male sex, TMD ≤ 175 mm, and MO ≤ 60.5 mm are significant predictors of difficult laryngoscopy in this cohort.
• A composite score, like the OPERA Score, integrating multiple factors offers a more effective multifactorial risk assessment for difficult intubation in obese individuals.