US-guided Airway Nerve Block vs. Topical Lidocaine in Video Laryngoscopy for Difficult Bariatric Intubation.

Ultrasound-Guided Airway Nerve Blocks vs. Lidocaine Topical Anesthesia Using Video-Assisted Laryngoscopy in Suspected Difficult Intubation for Patients Undergoing Bariatric Surgery

The investigators will test the effects of ultrasound guided airway nerve block vs lidocaine topical anesthesia and it's direct effect in decreasing incidence of gag and cough reflex in suspected difficult intubation patients using video assisted laryngoscopey for those Undergoing bariatric surgery

A.Preoperative settings:

A thorough preoperative evaluation including a complete airway evaluation (mouth opening, mallampati grading, body weight, thyromental distance, and evaluation of dentition) will be performed. Standard fasting guidelines and anti-aspiration prophylaxis with tablet ranitidine 150 mg will be prescribed.

The patients will be explained about the awake C-MAC intubation during preoperative assessment.Injection of atropine 0.4 mg will be given half an hour before shifting the patient to the operating room (OR).

B.Intraoperative and postoperative settings:

Injection of atropine 0.4 mg will be given half an hour before shifting the patient to the operating room (OR). Inside the OR, standard monitoring, including electrocardiography (ECG), noninvasive blood pressure (BP), and pulse oximetry (SpO2) will be applied in all patients. An intravenous (IV) line will be secured and ringer lactate will be started. After recording the baseline heart rate (HR), BP and SpO2, Injection of Dexametomidate 0.7 mcg/kg/hr IV infusion and injection ketamine 0.5-2 mg/kg slow IV single dose until endotracheal tube secured.

For each group, local anesthetics will be given in first group (LA)guided by ultrasound and second group (T) with topical method until Adequate effect of local anesthesia confirmed by hoarseness of voice in Group LA patients and numbness of tongue in Group T patients. While giving supplemental oxygen through nasal prongs, C-MAC intubation will be performed. After the airway is secured, general anesthesia will be administered with propofol 2 mg/kg, and rocuronium 0.6 mg/kg.

Postoperatively, patient comfort will be assessed for sore throat, dysphagia, voice change, or any lip, gum, tongue, dental injuries, complete amnesia, partial recall, and unpleasant memories during awake C-MAC intubation.

Inclusion Criteria:

1. Age: 21-65 years old
2. Obese patients (BMI>35 kg/m2) undergoing bariatric surgery
3. Suspected difficult intubation: e.g:(Mallampati score ≥3 , Thyromental distance <6 cm, Limited neck mobility, History of difficult intubation)
4. ASA I-II

Exclusion Criteria:

1. Patients at increased risk for aspiration (e.g., full stomach or gastro-esophageal reflux disease) and pregnancy
2. Patients with expected difficult ventilation
3. Patients who have upper airway pathology or surgery
4. Patients with a mouth opening < 2 cm
5. ASA III-IV
6. Emergency surgery
7. Allergy to local anesthetics
8. Contraindication to nerve blocks e.g.:(Coagulopathy, Infection at site of injection)
9. Patient refusal
10. Neurological or cognitive impairment making the patient uncooperative
11. History of difficult airway complications e.g.: previous intubation failure or need for surgical airway
12. Cervical spine instability or fractures