From the Guidelines
The Total Airway Score is not explicitly defined in the provided evidence, but it can be inferred to include assessments such as the Mallampati score, interincisor distance, and neck movement, among others. When evaluating a patient's airway, it is essential to consider multiple factors that contribute to the difficulty of intubation, as no single test is highly sensitive or specific for predicting difficult intubation 1. The assessment of the airway should include evaluations of:
- Mouth opening
- Thyromental distance
- Mallampati classification
- Neck mobility
- Ability to prognath
- Body weight
- History of difficult intubation These factors can help clinicians anticipate potential difficulties and prepare appropriate equipment and backup plans. According to the Canadian Airway Focus Group, a ‘difficult airway’ encompasses problems encountered with facemask ventilation, insertion of supraglottic airway devices, laryngoscopy, tracheal intubation, and front-of-neck airway access 1. In the general obstetric population, factors associated with difficult intubation include high Mallampati score, short neck, receding mandible, protruding maxillary incisors, and increased neck circumference 1. A comprehensive airway assessment is crucial to reduce complications and ensure patient safety during airway management procedures. Anesthesiologists and emergency physicians should routinely perform this assessment before intubation, considering the complex combination of factors involving the patient, anaesthetist, equipment, and environment that can affect the course of events 1.
From the Research
Total Airway Score
The total airway score is not explicitly defined in the provided studies. However, the studies mention various scoring systems used to predict difficult airways, such as:
- Mallampati classification 2, 3, 4, 5
- Thyromental distance 2, 4, 5
- Cormack and Lehane grade 2, 4, 5
- M-TAC score (combination of modified Mallampati score, thyromental distance, anatomical abnormality, and cervical mobility) 4
- ARNE score 6
Scoring Systems
The studies evaluate the accuracy and reliability of these scoring systems in predicting difficult airways. For example:
- The M-TAC score was found to have a higher sensitivity and specificity in predicting difficult laryngoscopy compared to the Mallampati classification 4
- The ARNE score was found to have limited accuracy in predicting difficult intubation in patients with laryngeal pathology, but its accuracy improved when combined with flexible laryngoscopy 6
- The combination of Mallampati test and thyromental distance was found to be a good predictor of difficult laryngoscopy in a Thai population 5
Key Findings
Some key findings from the studies include:
- The Mallampati score is not reliably assessed and lacks accuracy, reliability, and feasibility in predicting difficult airways 3
- The M-TAC score has a higher sensitivity and specificity in predicting difficult laryngoscopy compared to the Mallampati classification 4
- Flexible laryngoscopy improves the prediction model of the ARNE score in patients with laryngeal pathology 6
- The combination of Mallampati test and thyromental distance is a good predictor of difficult laryngoscopy in a Thai population 5