A prospective observational study to evaluate sternomental displacement as a predictor of difficult airway

Endotracheal intubation is a procedure wherein a flexible tube is placed in the trachea in order to maintain an open airway and also a conduit through which certain inhalational agents can be delivered. However, there are certain scenarios in which placing the endotracheal tube can cause difficulty. Problems which may arise due to difficult intubation include hypoxia, aspiration, oesophageal intubation and even cardiac arrest and death. Hence, preoperative assessment plays a crucial role in predicting and managing patients with difficult airway.We need to thoroughly evaluate the airway to avoid last moment inevitable misfortunes. Some of the parameters which could be relatively helpful in assessment of difficult intubation include mouth opening, mallampatti classification (MPC), upper lip bite test (ULBT), thyromental distance (TMD), sternomental displacement (SMD).

Sternomental displacement (SMD) will be measured as follows :-

SMD in extended position : Patient will be asked to sit comfortably and will be asked to extend his head and neck maximally and the distance between the mentum and the sternal notch will be measured.

SMD in neutral position : Patient will be asked to sit comfortably on bed by keeping his head in neutral position and the distance between the mentum and the sternal notch will then be measured.

The SMD will be the difference between SMD extended and SMD neutral. A value of less than 5 cm will be considered as a predictor of difficult intubation.

A thorough pre op history taking will be done.

Patient will be selected based on the inclusion and exclusion criteria.

The patient will be explained about the steps involved in the assessment in a language best understood by them and

The assessment will be done only if the patient is consenting.

The patient will be asked to sit comfortably on the bed and then the following parameters will be checked:

1.Mouth Opening

2.Mallampatti Score

3.Upperlip Bite Test

4.Thyromental Distance

5.sternomental Displacement