The Prediction of Difficult Intubation in Elective Surgical Patients by Using Preoperative Bedside Airway Assessment Tools
Keywords:
Airway management; difficult airway; difficult intubation; laryngoscopy; Mallampati test; diagnostic accuracyAbstract
Background: Unexpected difficult tracheal intubation can delay oxygenation and increase perioperative harm. Bedside airway tests are widely used, but individual tests have inconsistent predictive performance. Objective: To evaluate commonly used preoperative bedside airway assessment tools for predicting difficult intubation in adults undergoing elective surgery. Methods: This cross-sectional diagnostic-accuracy study included 133 patients aged 18–65 years undergoing elective surgery under general anaesthesia at Social Security Hospital Lahore between December 2025 and April 2026. Modified Mallampati test (MMT), thyromental distance (TMD), inter-incisor gap (IIG), upper lip bite test (ULBT), LEMON score and atlanto-occipital extension (AOE) were assessed. Categorical data and reported diagnostic-performance measures were summarized using IBM SPSS Statistics version 27.0. Results: Nineteen patients (14.3%) screened positive by MMT, 15 (11.3%) by TMD, 31 (23.3%) by IIG, four (3.0%) by ULBT, 35 (26.3%) by LEMON and 13 (9.8%) by AOE. MMT had the highest reported sensitivity (66%), whereas LEMON had the highest reported specificity (77%). TMD showed the lowest sensitivity (10%); IIG, ULBT and AOE each had sensitivity of 20%. Conclusion: The tests showed heterogeneous performance, and no single bedside assessment provided consistently strong discrimination. MMT was the most sensitive and LEMON the most specific within the reported analysis; multimodal assessment should be considered clinically, while locally validated combination rules require further study.
References
1. Apfelbaum JL, Hagberg CA, Connis RT, Abdelmalak BB, Agarkar M, Dutton RP, et al. 2022 American Society of Anesthesiologists practice guidelines for management of the difficult airway. Anesthesiology. 2022;136(1):31–81. doi:10.1097/ALN.0000000000004002.
2. Cook TM, MacDougall-Davis SR. Complications and failure of airway management. Br J Anaesth. 2012;109 Suppl 1:i68–i85. doi:10.1093/bja/aes393.
3. Frerk C, Mitchell VS, McNarry AF, Mendonca C, Bhagrath R, Patel A, et al. Difficult Airway Society 2015 guidelines for management of unanticipated difficult intubation in adults. Br J Anaesth. 2015;115(6):827–48. doi:10.1093/bja/aev371.
4. Ahmad I, El-Boghdadly K, Bhagrath R, Hodzovic I, McNarry AF, Mir F, et al. Difficult Airway Society guidelines for awake tracheal intubation in adults. Anaesthesia. 2020;75(4):509–28. doi:10.1111/anae.14904.
5. Detsky ME, Jivraj N, Adhikari NKJ, Friedrich JO, Pinto R, Simel DL, et al. Will this patient be difficult to intubate? The Rational Clinical Examination systematic review. JAMA. 2019;321(5):493–503. doi:10.1001/jama.2018.21413.
6. Roth D, Pace NL, Lee A, Hovhannisyan K, Warenits AM, Arrich J, et al. Bedside tests for predicting difficult airways: an abridged Cochrane diagnostic test accuracy systematic review. Anaesthesia. 2019;74(7):915–28. doi:10.1111/anae.14608.
7. Shiga T, Wajima Z, Inoue T, Sakamoto A. Predicting difficult intubation in apparently normal patients: a meta-analysis of bedside screening test performance. Anesthesiology. 2005;103(2):429–37. doi:10.1097/00000542-200508000-00027.
8. Mallampati SR, Gatt SP, Gugino LD, Desai SP, Waraksa B, Freiberger D, et al. A clinical sign to predict difficult tracheal intubation: a prospective study. Can Anaesth Soc J. 1985;32(4):429–34. doi:10.1007/BF03011357.
9. Samsoon GLT, Young JRB. Difficult tracheal intubation: a retrospective study. Anaesthesia. 1987;42(5):487–90. doi:10.1111/j.1365-2044.1987.tb04039.x.
10. Savva D. Prediction of difficult tracheal intubation. Br J Anaesth. 1994;73(2):149–53. doi:10.1093/bja/73.2.149.
11. Wilson ME, Spiegelhalter D, Robertson JA, Lesser P. Predicting difficult intubation. Br J Anaesth. 1988;61(2):211–6. doi:10.1093/bja/61.2.211.
12. Khan ZH, Kashfi A, Ebrahimkhani E. A comparison of the upper lip bite test with modified Mallampati classification in predicting difficulty in endotracheal intubation: a prospective blinded study. Anesth Analg. 2003;96(2):595–9. doi:10.1213/00000539-200302000-00053.
13. Eberhart LHJ, Arndt C, Cierpka T, Schwanekamp J, Wulf H, Putzke C. The reliability and validity of the upper lip bite test compared with the Mallampati classification to predict difficult laryngoscopy: an external prospective evaluation. Anesth Analg. 2005;101(1):284–9. doi:10.1213/01.ANE.0000154535.33429.36.
14. Cormack RS, Lehane J. Difficult tracheal intubation in obstetrics. Anaesthesia. 1984;39(11):1105–11. doi:10.1111/j.1365-2044.1984.tb08932.x.
15. El-Ganzouri AR, McCarthy RJ, Tuman KJ, Tanck EN, Ivankovich AD. Preoperative airway assessment: predictive value of a multivariate risk index. Anesth Analg. 1996;82(6):1197–204. doi:10.1097/00000539-199606000-00017.
16. Reed MJ, Dunn MJG, McKeown DW. Can an airway assessment score predict difficulty at intubation in the emergency department? Emerg Med J. 2005;22(2):99–102. doi:10.1136/emj.2003.008771.
17. Hagiwara Y, Watase H, Okamoto H, Goto T, Hasegawa K. Prospective validation of the modified LEMON criteria to predict difficult intubation in the ED. Am J Emerg Med. 2015;33(10):1492–6. doi:10.1016/j.ajem.2015.06.038.
18. Tse JC, Rimm EB, Hussain A. Predicting difficult endotracheal intubation in surgical patients scheduled for general anesthesia: a prospective blind study. Anesth Analg. 1995;81(2):254–8. doi:10.1097/00000539-199508000-00008.
19. Karkouti K, Rose DK, Wigglesworth D, Cohen MM. Predicting difficult intubation: a multivariable analysis. Can J Anaesth. 2000;47(8):730–9. doi:10.1007/BF03019474.
20. Honarmand A, Safavi M, Yaraghi A, Attari M, Khazaei M, Zamani M. Comparison of five methods in predicting difficult laryngoscopy: neck circumference, neck circumference to thyromental distance ratio, ratio of height to thyromental distance, upper lip bite test and Mallampati test. Adv Biomed Res. 2015;4:122. doi:10.4103/2277-9175.158033.
21. Alemayehu T, Sitot M, Zemedkun A, Tesfaye S. Assessment of predictors for difficult intubation and laryngoscopy in adult elective surgical patients at Tikur Anbessa Specialized Hospital, Ethiopia: a cross-sectional study. Ann Med Surg (Lond). 2022;77:103682. doi:10.1016/j.amsu.2022.103682.
22. Bicalho GP, Borges CR Jr, Cruvinel MGC, Carneiro FS, Castilho JB, Castro CHV. A prospective validation and comparison of three multivariate models for prediction of difficult intubation in adult patients. Braz J Anesthesiol. 2023;73(2):153–8. doi:10.1016/j.bjane.2021.07.028.
23. Chu Y, Tsai MH, Russotto V, Parotto M. Predicting the difficult airway: how useful are preoperative airway tests? Curr Anesthesiol Rep. 2022;12:398–406. doi:10.1007/s40140-022-00525-1.
24. Sotoodehnia M, Khodayar M, Jalali A, Momeni M, Safaie A. Prediction of difficult laryngoscopy/difficult intubation cases using upper airway ultrasound measurements in emergency department: a prospective observational study. BMC Emerg Med. 2023;23:47. doi:10.1186/s12873-023-00811-1.
25. Bossuyt PM, Reitsma JB, Bruns DE, Gatsonis CA, Glasziou PP, Irwig L, et al. STARD 2015: an updated list of essential items for reporting diagnostic accuracy studies. BMJ. 2015;351:h5527. doi:10.1136/bmj.h5527.
26. Cohen JF, Korevaar DA, Altman DG, Bruns DE, Gatsonis CA, Hooft L, et al. STARD 2015 guidelines for reporting diagnostic accuracy studies: explanation and elaboration. BMJ Open. 2016;6(11):e012799. doi:10.1136/bmjopen-2016-012799.
27. Whiting PF, Rutjes AWS, Westwood ME, Mallett S, Deeks JJ, Reitsma JB, et al. QUADAS-2: a revised tool for the quality assessment of diagnostic accuracy studies. Ann Intern Med. 2011;155(8):529–36. doi:10.7326/0003-4819-155-8-201110180-00009.
28. Jaeschke R, Guyatt GH, Sackett DL. Users’ guides to the medical literature. III. How to use an article about a diagnostic test. B. What are the results and will they help me in caring for my patients? JAMA. 1994;271(9):703–7. doi:10.1001/jama.1994.03510330081039.
