Preoperative Assessment and Mallampati Scores

A preoperative assessment by anaesthetic staff should include the Mallampati Score, as there is a direct correlation between the amount of space in the pharynx and the laryngoscopic view during intubation which has been refined by Cormack and Lehane (1984).

This can assist in predicting patients who may have a difficult intubation and preparation with additional equipment. It is important to note, regardless of the Mallampati Score, that difficult intubation can occur without warning, and access to a difficult airway trolley is essential in operating theatres.

To assess the patient for their Mallampati Score, ask them to sit upright and open their mouth fully with their tongue protruding.

The structures that can be visualised classify the patient’s score. The less pharyngeal structures that can be seen results in a higher score or classification, which in turn predicts increasing difficulty in achieving intubation, however in another study conducted by Lee et al. (2000), the Mallampati score did not predict difficult bag-valve-mask ventilation.  Interestingly, the Mallampati Score can also be used to assess a patient’s risk of Obstructive Sleep Apnoea (Wickramasinghe, 2020).

The scoring classification is as follows with visualisation of: 

Class 1: soft palate, uvula and faucial pillars

Class 2: soft palate, majority of uvula and part of faucial pillars 

Class 3: part of soft palate, base of uvula

Class 4: hard palate only

If you are interested in learning more, our suite of Anaesthesia and Recovery Nursing courses cover a wide range of topics. Our 2021 courses include:

• Anaesthesia and Recovery Nursing: The Essentials
• Anaesthesia and Recovery Nursing in the Day Surgery Environment
• Anaesthesia and PACU Nursing (topics change every 12 months)

 
By Crystal Smith and Ken Hambrecht.  

 
References:

Cormack, R.S.; Lehane, J. (1984). Difficult tracheal intubation in obstetrics. Anaesthesia. 39 (11): 1105–11. doi:10.1111/j.1365-2044.1984.tb08932.x. PMID 6507827.

Lee, A; Fan, LT; Gin, T; Karmakar, MK; Ngan Kee, WD (Jun 2006). A systematic review (meta-analysis) of the accuracy of the Mallampati tests to predict the difficult airway. Anesthesia and Analgesia. 102 (6): 1867–78. doi:10.1213/01.ane.0000217211.12232.55. PMID 16717341.

Mallampati, SR, Gatt, SP, Gugino, LD, Desai, SP, Waraksa, B, Freiberger, D & Liu, PL. 1985. A clinical sign to predict difficult tracheal intubation: a propensity study. Can Anaesth Soc J; 32 (4) July, doi:10.1007/FB03011357.

Shehzad, A & Cadogan, M. 2020. Mallampati Score.  Life in the Fast Lane; 3 November. Wickramasingh, H & Rowley, JA. 2020. How is the Mallampati score used in the evaluation of obstructive sleep apnea (OSA)? Medscape, 15 September.