Validity of certain bedside tests in predicting difficult endotracheal intubation

Abstract EN

Unexpected difficult endotracheal intubation remains the main concern of anesthesiologists.

This study aimed to compare validity and role of 7 bedside techniques of assessment used in predicting difficult intubation.

This prospective study included 80 patients scheduled for surgery.

Before induction of anesthesia, bedside tests for predicting difficult intubation were done, these tests are: Prayer sign, Thyromental distance, Mallampati test, The inter incisor distance, Palm print test, Upper lip bite test, and Wilson scoring system.

During induction of anesthesia, laryngoscopic view was evaluated.

Values for each test were calculated and compared.

The results showed that, the highest sensitivity (62.5%) was for Mallampati and thyromental distance but despite that, they differed in their specificity and predictive values.

Upper lip bite was 12.5% sensitive but had one of the highest specificity alongside with Mallampati test.

Thyromental distance was 34.7% specific.

Mallampati classes of more than class I was strongly associated with difficult intubation.

The mouth gap of more than 4 cm was marginally associated with difficult intubation.

The predictor Wilson showed a significant association with difficult intubation if the score exceeded 3.5.

The upper lip bite of more than class I was slightly associated with difficult intubation.

In conclusion, Mallampati classification and thyromental distance are superior to other available tests to predict difficult intubation, performing these two tests alone is relatively adequate to predict intubation difficulty.