RISK FACTORS FOR DIFFICULT INTUBATION IN ADULT PATIENTS UNDERGOING ELECTIVE SURGERIES
Main Article Content
Keywords
Difficult intubation, airway assessment, Mallampati classification, thyromental distance, predictive factors
Abstract
Background: Difficult intubation remains a significant challenge in anaesthesiology with potential for catastrophic outcomes. Identifying reliable predictive factors is crucial for patient safety and optimal resource allocation in elective surgical settings.
Methods: A prospective observational cohort study was conducted at Mahatma Gandhi Medical College and Research Institute, Pondicherry, from January to June 2022. Adult patients (n=450) undergoing elective surgeries requiring general anesthesia with endotracheal intubation were enrolled using consecutive sampling. Comprehensive preoperative airway assessment included Mallampati classification, thyromental distance, inter-incisor gap, neck circumference, neck mobility, and anthropometric measurements. Difficult intubation was defined as requiring more than two attempts, alternative techniques, or experienced personnel. Univariate and multivariate logistic regression analyses were performed to identify independent risk factors, with receiver operating characteristic curve analysis for predictive model performance.
Results: Difficult intubation occurred in 34 patients (7.6%). Independent risk factors identified through multivariate analysis included Mallampati Class III-IV (adjusted OR: 8.45, 95% CI: 3.67-19.46), thyromental distance <6cm (adjusted OR: 6.23, 95% CI: 2.54-15.28), inter-incisor gap <3cm (adjusted OR: 5.67, 95% CI: 2.12-15.18), previous difficult intubation (adjusted OR: 4.78, 95% CI: 1.45-15.76), BMI ≥30 kg/m² (adjusted OR: 3.89, 95% CI: 1.52-9.96), neck circumference >40cm (adjusted OR: 2.98, 95% CI: 1.18-7.53), and limited neck mobility (adjusted OR: 2.67, 95% CI: 1.05-6.79). The combined predictive model demonstrated excellent performance with 85.3% sensitivity, 91.8% specificity, and area under curve of 0.886.
Conclusion: Multiple anatomical and anthropometric factors independently predict difficult intubation. A comprehensive multiparameter assessment approach significantly improves prediction accuracy compared to individual predictors, supporting implementation of standardized preoperative airway evaluation protocols in clinical practice.
References
2. Apfelbaum, J. L., Hagberg, C. A., Caplan, R. A., Blitt, C. D., Connis, R. T., Nickinovich, D. G., ... & American Society of Anesthesiologists Task Force. (2013). Practice guidelines for management of the difficult airway: an updated report by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway. Anesthesiology, 118(2), 251-270. https://doi.org/10.1097/ALN.0b013e31827773b2
3. Cattano, D., Panicucci, E., Paolicchi, A., Forfori, F., Giunta, F., & Hagberg, C. (2004). Risk factors assessment of the difficult airway: an italian survey of 1956 patients. Anesthesia & Analgesia, 99(6), 1774-1779. https://doi.org/10.1213/01.ANE.0000136772.38754.01
4. Cook, T. M., Woodall, N., Harper, J., & Benger, J. (2011). Major complications of airway management in the UK: results of the Fourth National Audit Project of the Royal College of Anaesthetists and the Difficult Airway Society. British Journal of Anaesthesia, 106(5), 617-631. https://doi.org/10.1093/bja/aer058
5. Crosby, E. T., Cooper, R. M., Douglas, M. J., Doyle, D. J., Hung, O. R., Labrecque, P., ... & Preston, R. P. (2006). The unanticipated difficult airway with recommendations for management. Canadian Journal of Anesthesia, 53(2), 207-218. https://doi.org/10.1007/BF03022052
6. Frerk, C., Mitchell, V. S., McNarry, A. F., Mendonca, C., Bhagrath, R., Patel, A., ... & Ahmad, I. (2015). Difficult Airway Society 2015 guidelines for management of unanticipated difficult intubation in adults. British Journal of Anaesthesia, 115(6), 827-848. https://doi.org/10.1093/bja/aev371
7. Fulkerson, J. S., Moore, H. M., Anderson, T. S., & Lowe, R. F. (2014). Ultrasonography in the preoperative difficult airway assessment. Journal of Clinical Medicine, 3(4), 1475-1491. https://doi.org/10.3390/jcm3041475
8. Gonzalez, H., Minville, V., Delanoue, K., Mazerolles, M., Concina, D., & Fourcade, O. (2008). The importance of increased neck circumference to intubation difficulties in obese patients. Anesthesia & Analgesia, 106(4), 1132-1136. https://doi.org/10.1213/ane.0b013e3181679659
9. Iohom, G., Ronayne, M., Cunningham, A. J., & McGrath, D. (2003). Prediction of difficult tracheal intubation. European Journal of Anaesthesiology, 20(1), 31-36. https://doi.org/10.1017/s0265021503000061
10. Lee, A., Fan, L. T., Gin, T., Karmakar, M. K., & Ngan Kee, W. D. (2006). A systematic review (meta-analysis) of the accuracy of the Mallampati tests to predict the difficult airway. Anesthesia & Analgesia, 102(6), 1867-1878. https://doi.org/10.1213/01.ane.0000217211.12232.55
11. Lundstrøm, L. H., Møller, A. M., Rosenstock, C., Astrup, G., & Wetterslev, J. (2009). High body mass index is a weak predictor for difficult and failed tracheal intubation: a cohort study of 91,332 consecutive patients scheduled for direct laryngoscopy registered in the Danish Anesthesia Database. Anesthesiology, 110(2), 266-274. https://doi.org/10.1097/ALN.0b013e318194cac8
12. Mallampati, S. R., Gatt, S. P., Gugino, L. D., Desai, S. P., Waraksa, B., Freiberger, D., & Liu, P. L. (1985). A clinical sign to predict difficult tracheal intubation: a prospective study. Canadian Anaesthetists' Society Journal, 32(4), 429-434. https://doi.org/10.1007/BF03011357
13. Mort, T. C. (2004). Emergency tracheal intubation: complications associated with repeated laryngoscopic attempts. Anesthesia & Analgesia, 99(2), 607-613. https://doi.org/10.1213/01.ANE.0000122825.04923.15
14. Patil, V. U., Stehling, L. C., & Zauder, H. L. (1983). Predicting the difficulty of intubation utilizing an intubation gauge. Anesthesiology, 10(1), 32-33. https://doi.org/10.1097/00000542-198301001-00032
15. Prakash, S., Kumar, A., Bhandari, S., Mullick, P., Singh, R., & Gogia, A. R. (2013). Difficult laryngoscopy and intubation in the Indian population: An assessment of anatomical and clinical risk factors. Indian Journal of Anaesthesia, 57(6), 569-575. https://doi.org/10.4103/0019-5049.123323
16. Reed, M. J., Dunn, M. J., & McKeown, D. W. (2005). Can an airway assessment score predict difficulty at intubation in the emergency department? Emergency Medicine Journal, 22(2), 99-102. https://doi.org/10.1136/emj.2003.012500
17. Roth, D., Pace, N. L., Lee, A., Hovhannisyan, K., Warenits, A. M., Arrich, J., & Herkner, H. (2018). Bedside tests for predicting difficult airways: an abridged Cochrane diagnostic test accuracy systematic review. Anaesthesia, 73(6), 709-719. https://doi.org/10.1111/anae.14177
18. Shiga, T., Wajima, Z., Inoue, T., & Sakamoto, A. (2005). Predicting difficult intubation in apparently normal patients: a meta-analysis of bedside screening test performance. Anesthesiology, 103(2), 429-437. https://doi.org/10.1097/00000542-200508000-00027
19. Tse, J. C., Rimm, E. B., & Hussain, A. (1995). Predicting difficult endotracheal intubation in surgical patients scheduled for general anesthesia: a prospective blind study. Anesthesia & Analgesia, 81(2), 254-258. https://doi.org/10.1097/00000539-199508000-00009
20. Wilson, M. E., Spiegelhalter, D., Robertson, J. A., & Lesser, P. (1988). Predicting difficult intubation. British Journal of Anaesthesia, 61(2), 211-216. https://doi.org/10.1093/bja/61.2.211
21. Yentis, S. M., & Lee, D. J. (1998). Evaluation of an improved scoring system for the grading of direct laryngoscopy. Anaesthesia, 53(11), 1041-1044. https://doi.org/10.1046/j.1365-2044.1998.00605.x
22. Zaouter, C., Calderon, J., Hemmerling, T. M., & Hemmerling, T. M. (2019). Video laryngoscopy as a new standard of care. British Journal of Anaesthesia, 114(2), 181-183. https://doi.org/10.1093/bja/aeu266
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Dr Kamal Kishore Chitara
Assistant Professor, Department of Anaesthesiology, Mahatma Gandhi Medical College and Research Institute, Pondicherry