Evaluation of ultrasound measured tongue thickness, tongue thickness- thyromental distance ratio and skin to epiglottis distance in predicting difficult laryngoscopy.

Endotracheal intubation is one of the most important skills for anesthesiologists in

securing the airway during general anesthesia and resuscitation. Difficulties in handling airways optimally can lead to

severe adverse effects and failure can also lead to mortality. Many clinical screening tests have been used to classify

patients at risk of difficult laryngoscopy, but non have been shown to predict this complication with adequate sensitivity

and specificity. Airway sonography is a noninvasive diagnostic device for bedside visualization and measurement of

dimensions that may be linked to prediction of difficult airway management. Aims and objectives: Primary outcome

measure: Prediction of difficult laryngoscopy with ultrasound measured tongue thickness, tongue thickness- thyromental

distance ratio and skin to epiglottis distance. Secondary outcome measure: • Successful intubation • use of Adjuvants •

Time of intubation till confirmation of ETT by capnography. Material and Methods Inclusion Criteria 1. ASA I and II patients

2. Both male and female patients of age >18 years of age 3. Patients undergoing elective surgeries under GA with ETT

Exclusion Criteria Nonconsenting patients, BMI >35kg/m2 H/o difficult airway in the past surgeries Thyromental distance <

5 cm, inter incisor distance less than 2 cm, restricted neck movements. Maxillofacial anomalies/anatomical

deformities/post burn contracture/neck deformities H/o trauma, surgery to upper airway Change in anaesthetic technique.

All patients will undergo a detailed preoperative airway evaluation on the day before surgery. The modified Mallam Patti

class, mouth opening, thyromental distance, inter incisor distance will be recorded during PAC. All patients will also View undergo a detailed prospective sonographic assessment by the same anesthesiologist and Tongue thickness will be File recorded. For sonographic assessment, the patient will be made to lie in a supine position. Mouth should be closed and tip

of tongue should slightly touch incisors. Tongue should be relaxed and patient should not phonate during assessment. Curvilinear USG probe (high frequency 6-14mHz) is placed under chin in median sagittal plane and view is adjusted to visualize entire tongue clearly on screen. Maximum vertical dimension from surface of tongue to submental skin is measured and this is defined as tongue thickness. After measuring tongue thickness, skin to epiglottis distance will be measured. (method n view to be decided). The next day, the patient will be shifted to the operating room, baseline monitors of electrocardiogram, noninvasive blood pressure and pulse oximetry will be connected and values noted. direct laryngoscopy will be performed by an experienced anaesthesiologist using a curved Macintosh Blade and the Cormack- Lehane grading of Laryngoscopic view will be noted. In this study, laryngoscopy will be defined as easy if Cormack Lehane grading on Laryngoscopy was 1 or 2 and it will be defined as difficult if Cormack Lehane grading was 3 or 4. All laryngoscopies will done by a single experienced anaesthesiologist who will not be privy to preoperative ultrasound airway examination. Patients will then be intubated with an appropriate sized endotracheal tube and surgery will be allowed to proceed. At the end of the surgery, the patient will be extubated following reversal of neuromuscular blockade or shifted intubated to post operative ICU for as per indications.