Raveendran Lasya, Singh Satyajeet, Verma Akash, Chandrashekar Manjunatha
Department of Anaesthesiology, Employees' State Insurance Corporation (ESIC) Medical College and Hospital, Hyderabad, IND.
Department of Anaesthesiology, Jai Prakash District Hospital, Bhopal, IND.
Cureus. 2025 Jul 12;17(7):e87779. doi: 10.7759/cureus.87779. eCollection 2025 Jul.
Background Airway management is central to anaesthetic practice, with endotracheal intubation pivotal in both elective and emergency settings. Although various assessment tests aim to predict a difficult airway, their predictive performance varies widely. Comparative evaluation is therefore required to identify the most reliable predictor. Objective The study was conducted to compare the two index ratios, the ratio of neck circumference to thyromental distance (RNTMD) and the ratio of neck circumference to inter-incisor gap (RNCIIG), to determine their effectiveness in predicting difficult intubation. Methods This prospective observational study consisted of 118 participants undergoing elective surgeries under general anaesthesia. Measurements of neck circumference, thyromental distance, and inter-incisor gap were recorded preoperatively. RNTMD and RNCIIG were calculated. Ease of intubation was determined using the Intubation Difficulty Scale (IDS). Predictive indices and diagnostic accuracy were calculated for both indices. Results Both parameters were comparable in terms of specificity, positive and negative predictive values, and diagnostic accuracy. The area under the curve, as calculated from the receiver operating characteristic (ROC), was 0.80 for RNCIIG and 0.96 for RNTMD. However, RNCIIG was found to be more sensitive (80%) than RNTMD (69%). Conclusion We conclude that both airway assessment indices, RNCIIG and RNTMD, are effective predictors of a difficult airway. A ratio of two indices provides superior diagnostic accuracy and reliability than when a single parameter is used alone.
气道管理是麻醉实践的核心，气管插管在择期和急诊情况下都至关重要。尽管各种评估测试旨在预测困难气道，但其预测性能差异很大。因此，需要进行比较评估以确定最可靠的预测指标。目的：本研究旨在比较两个指数比，即颈围与颏下距离之比（RNTMD）和颈围与门齿间距之比（RNCIIG），以确定它们在预测困难插管方面的有效性。方法：这项前瞻性观察性研究包括118名接受全身麻醉下择期手术的参与者。术前记录颈围、颏下距离和门齿间距的测量值。计算RNTMD和RNCIIG。使用插管难度量表（IDS）确定插管的难易程度。计算两个指数的预测指标和诊断准确性。结果：在特异性、阳性和阴性预测值以及诊断准确性方面，两个参数具有可比性。根据受试者工作特征曲线（ROC）计算的曲线下面积，RNCIIG为0.80，RNTMD为0.96。然而，发现RNCIIG比RNTMD更敏感（80%对69%）。结论：我们得出结论，气道评估指数RNCIIG和RNTMD都是困难气道的有效预测指标。两个指数的比值比单独使用单个参数提供了更高的诊断准确性和可靠性。
