Evaluation of Preoperative Nasoendoscopy to Predict Difficult Intubation

Is Preoperative Awake Airway Nasoendoscopy A Good Tool To Predict The Expected Difficult Airway In Obese Patients?

Despite the availability of different methods for airway assessment, unexpectedly difficult intubations occur at a frequency of up to 15%. A variety of pre-intubation clinical screening tests have been advocated to predict difficult laryngoscopy and airway but their usefulness is limited in obese patients. Could awake invasive airway assessment be more predictive for difficult airways in obese patients? The use of nasendoscopy assessment for the airway could be a useful additional invasive tool to predict the difficult airway in obese

Predictors of difficult laryngoscopy and intubation may be less useful or irrelevant when there is a plan for video laryngoscopes (VL) intraoperative. VL improves laryngeal view in most patients, Their use achieves a high success rate for intubation of patients with predicted difficult intubation, and those who have failed direct laryngoscopy[6]. In a study of over 2000 (VL) video laryngoscopies intubations, Mallampati's score did not correlate with failed intubation. The strongest predictor of failure was neck pathology, including the presence of a surgical scar, radiation changes, or mass. In another study, risk factors for difficult VL intubation after direct laryngoscopy were Cormack-Lehane grade 3 or 4 views with direct laryngoscopy, short sternothyroid distance, and high upper lip bite test score. Obesity is a recognized risk factor for difficulty with airway management. An audit of major complications of airway management (NAP4) from over three million anesthetics in the United Kingdom found twice as many case reports of major complications in obese patients, especially in the morbidly obese. It is less clear whether obesity increases the risk of difficult laryngoscopy or intubation. Some studies suggest that obesity is a risk factor for both difficult mask ventilation and difficult laryngoscopy, while other studies suggest that with proper positioning and preparation, ventilation and laryngoscopy are not difficult [12,13]. Wilson's score is an important development in predictivity of airway difficulties, Wilson's in his study (1988) attempted to deductively identify patients for whom intubation will be difficult. This study aims to demonstrate the use of preoperative awake fibreoptic examination

Naso-endoscopy views from nose to larynx in obese patients using NOHL score during pre-operative assessment.

Findings will be recorded and scored according to NOHL (N=nose, O= oral, H= hypopharynx and L= Larynx ) every parameter takes a score from 1- 4 during pre-operative assessment.(the maximum values score = 16 and the minimum = 4)

This will be measured by centimeter between incisors during pre-operative assessment using a ruler and documented by Centimeter

This will be measured by centimeter from thyroid cartilage to patient's chin during pre-operative assessment using a rule

Degree of Difficulty in mask ventilation will be graded (1= easy, 2= difficult or 3=impossible) during induction of general anaesthesia

Cormak-Lehans Score will graded during endotracheal intubation and exposure of the larynx. (Grade 1= easy intubation while grade Grade 4= very difficult intubation)

Inclusion Criteria: Adult patients between 18-60 years of age either male or female with (ASA I, II or III ), scheduled for a bariatric procedure with a body mass index (BMI) greater than 35 K/M2, will be enrolled Exclusion Criteria: Patients on the tracheostomy tube Patients who are unable to give consent

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