Title: Modified Mallampati Test, Sternomental Distance, and Thyromental Distance for Prediction of Difficult Intubation in Patients Undergoing General Anaesthesia

Authors: Dr Aswini B, Dr Madhusoodanan Pillai .C, Dr Rajani Gandha

 DOI:  https://dx.doi.org/10.18535/jmscr/v5i10.169

Abstract

Background and Objectives: Airway management is the fundamental responsibility of every anesthesia-logist. Difficult intubation is one of the major causes of anesthesia-related morbidity and mortality. The risk and complications related to difficult intubation can be reduced if difficult airway is anticipated preoperatively. There are many simple bed side tests to predict difficult intubation preoperatively. There are several studies comparing the different preoperative bedside tests in predicting difficult intubation with varying results. However, limited information is available on effect of combining these parameters in enhancing the preoperative prediction of a difficult airway

Aim: To assess the validity and efficacy of modified Mallampati test (MMT), sternomental distance (SMD), Thyromental distance (TMD) individually and in combination in predicting difficult intubation.

Methodology: This is an observational study, conducted in the department of Anaesthesiology Government Medical College Thiruvananthapuram, a tertiary care centre . 305 Patients aged between 18 to 65 years, undergoing elective major surgeries in Govt: Medical College Hospital, Thiruvananthapuram, Kerala, were selected as the study population. The airway was assessed by Modified Mallampati test (MMT), class III & IV were considered as difficult intubation. Thyromental distance (TMD) of every patient was recorded. A measurement of less than 6.5 cm was considered to be a predictor of difficult intubation. Sternomental distance (SMD) was measured and a measurement of less than 12.5cms was considered to be a predictor of difficult intubation.

A senior anesthesiologist with more than three years of experience assessed the laryngeal view by direct laryngoscopy using Cormack &Lehane grading during intubation. Grade 3 and 4 was considered difficult laryngoscopy and intubation.

The validity parameters such as sensitivity, specificity, false positive and negative values, positive predictive value (PPV) and negative predictive value (NPV) were calculated. The effect of combining different measurements on the validity was also studie

References

  1. Ali MA, Qamar-ul-Hoda M, Samad K. Comparison of upper lip bite test with Mallampati test in the prediction of difficult intubation at a tertiary care hospital of Pakistan. J Pak Med Assoc. 2012; 62:1012–5.
  2. Jonathan L. Benumof. Management of the difficult adult airway. With special emphasis on awake tracheal intubation. Anesthesiology 75:1087-1110, 1991.
  3. Cobley M, Vaughan R.S. Recognition and management of difficult airway problems. BJA 68: 90-97, 1992.
  4. Fasting S, Gisvold SE: Serious intraoperative problems—A five-year review of 83,844 anesthetics. Can J Anaesth 2002; 49:545.
  5. Bellhouse CP: An angulated laryngoscope for routine and difficult tracheal intubation. Anesthesiology 1988; 69:126.
  6. Benumof JL, Scheller MS: The importance of transtracheal jet ventilation in the management of the difficult airway. Anesthesiology 1989; 71:769.
  7. Samsoon GLT, Young JRB: Difficult tracheal intubation: A retrospective study. Anaesthesia 1987; 42:487.
  8. D. L. Oates, A. D. Macleod, P. D. Oates, F. J. Pearsall, J. C. Howie and G. D. Murray. Comparison of two methods for predicting difficult intubation. Br J Anaesth. 1991; 66(3):305-9..
  9. Cobley M, Vaughan R.S. Recognition and management of difficult airway problems. BJA 68: 90-97, 1992.
  10. Randell T, ― Prediction of difficult intubation, Acta Anaesthesiol Scand 1996; 40:1016-23‖
  11. Patel B,Khandekar R, Diwan R, Shah A.Validation of modified Mallampati test with addition of thyromental distance and sternomental distance to predict difficult endotracheal intubation in adults. Indian J Anaesth. 2014 Mar;58(2):171-5.
  12. Sheff S R,May MC, Carlisle SE,Kallies KJ, Mathiason MA, Kothari SN. Predictors of difficult intubation in the bariatric patient: Does Body Mass Index matter?. Surg Obes Relat Dis 2013:29: 183-6
  13. D. L. Oates, A. D. Macleod, P. D. Oates, F. J. Pearsall, J. C. Howie and G. D. Murray. Comparison of two methods for predicting difficult intubation. Br J Anaesth. 1991;66(3):305-9.
  14. Nkihu A. Merah ,David T. Wong ,Dorothy J. F foulkes-Crabbe ,Olusola T. Kushimo , Christopher O. Bode. Modified Mallampati test, thyromental distance and inter-incisor gap are the best predictors of difficult laryngoscopy in West Africans. Can. J Anesth 2005 / 52: 3 / pp 291–296             
  15. D Prediction of difficult tracheal intubation. British journal of anaesthesia 1994;73 149-153  
  16. A.L .Ramdhani , L A Mohammed , D A Roche, and E. Gouws . Sternomental distance as the solepredictor of difficult laryngoscopy in obstetric anaesthesia. Br J Anaesth 1996; 77: 312-316.
  17. Frerk  C M   Prediction difficult intuba-tion. Anaesthesia 1991; 46: 1005-1008.

Corresponding Author

Dr Madhusoodanan Pillai

Additional Professor, Department of Anaesthesiology,

Government Medical College Thiruvananthapuram