Thirunavukkarasu Barathan, Jaswal Sofia, Walia Harsimran S, Batra Y K
Anesthesiology, Max Super Specialty Hospital, Mohali, IND.
Anesthesia and Critical Care, Homi Bhabha Cancer Hospital and Research Center, New Chandigarh, IND.
Cureus. 2025 Feb 11;17(2):e78879. doi: 10.7759/cureus.78879. eCollection 2025 Feb.
Several preoperative predictive factors for difficult visualization of the larynx (DVL) have been identified, and these factors have significant predictive value in the obese population. This prospective observational study was conducted to compare the predictive abilities of different airway predictors between obese and non-obese populations.
Our study included a total of 90 patients, divided into two groups based on body mass index (BMI): group O (obese) with BMI >30 kg/m² and group NO (non-obese) with BMI <30 kg/m². The patients were evaluated using the modified Mallampati grade (MMG), neck circumference at the level of the hyoid (NCh) and thyroid (NCt), thyromental distance (TMD), and hyomental distance (HMD) in both neutral and extended head positions in both groups. The modified Cormack and Lehane (MCL) grading for visualization of the larynx was observed during direct laryngoscopy prior to intubation. MCL grades 2b, 3, and 4 were considered indicative of DVL in this study.
DVL was observed in 41.1% of the population, 46.7% of the obese (O) group, and 35.6% of the non-obese (NO) group. MMG was statistically significant only in the O group for predicting the DVL with a specificity of 85.1%. In the NO group, MMG ≥3 was not significant statistically and showed a specificity of 70.8%. NCh and NCt had no statistically significant difference in differentiating the DVL between obese and non-obese groups. NCt/TMD in the O group with a cut-off value of 5.135 had a sensitivity of 61.9% and a specificity of 58.3% and predicted DVL only in the obese group. Hyomental distance ratio (HMDR) was a statistically significant index in both groups and has a good predictive utility for the DVL. An HMDR ≤1.23 had a sensitivity of 68.8% and a specificity of 72.4% in the non-obese population. An HMDR ≤1.20 in the obese group had a sensitivity of 85.7% and a specificity of 91.7%.
The higher incidence of DVL (MCL grades 2b, 3, and 4) in the obese population when compared to the non-obese population was not statistically significant. NCt and NCh had minimal value as predictors of DVL. This study concludes that HMDR was a reliable airway assessment tool irrespective of BMI, while MMG and NCt/TMD were reliable difficult airway predictors but only in the obese population.
已确定了几种术前预测喉镜视野困难（DVL）的因素，这些因素在肥胖人群中具有显著的预测价值。本前瞻性观察性研究旨在比较肥胖和非肥胖人群中不同气道预测指标的预测能力。
我们的研究共纳入90例患者，根据体重指数（BMI）分为两组：BMI>30 kg/m²的O组（肥胖组）和BMI<30 kg/m²的NO组（非肥胖组）。两组患者均在中立位和头后仰位评估改良Mallampati分级（MMG）、舌骨水平（NCh）和甲状腺水平（NCt）的颈围、甲状颏距离（TMD）和颏下距离（HMD）。在插管前直接喉镜检查期间观察改良Cormack和Lehane（MCL）喉镜视野分级。本研究中，MCL 2b、3和4级被视为DVL的指征。
41.1%的人群、46.7%的肥胖（O）组和35.6%的非肥胖（NO）组观察到DVL。MMG仅在O组中对预测DVL具有统计学意义，特异性为85.1%。在NO组中，MMG≥3无统计学意义，特异性为70.8%。NCh和NCt在区分肥胖和非肥胖组的DVL方面无统计学显著差异。O组中NCt/TMD的截断值为5.135，敏感性为61.9%，特异性为58.3%，仅在肥胖组中预测DVL。颏下距离比（HMDR）在两组中均为统计学显著指标，对DVL具有良好的预测效用。在非肥胖人群中，HMDR≤1.23的敏感性为68.8%，特异性为72.4%。在肥胖组中，HMDR≤1.20的敏感性为85.7%，特异性为91.7%。
与非肥胖人群相比，肥胖人群中DVL（MCL 2b、3和4级）的较高发生率无统计学意义。NCt和NCh作为DVL的预测指标价值极小。本研究得出结论，无论BMI如何，HMDR都是一种可靠的气道评估工具，而MMG和NCt/TMD是可靠的困难气道预测指标，但仅适用于肥胖人群。
