Comparative Study Between Transcutaneous Ultrasonography and Direct Laryngoscopy for Assessment of Vocal Cord Mobility at the End of Thyroidectomy Operation

The aim of work of this study is to evaluate Transcutanous Ultrasonogrphy for assessment of vocal cord mobility in comparison to Direct laryngoscopy during extubation after thyroidectomyA. Preoperative settings: All patients will be assessed preoperatively by careful history taking, full physical examination, and laboratory evaluation and vocal cord mobility and voice quality be assessed by ENT and anesthesiologist by ultrasound.

B. Intraoperative settings:

On arrival of the patients to the operative room, electrocardiography, non-invasive blood pressure, and pulse oximetry will be applied. Baseline parameters such as heart rate (HR) , blood pressure (BP), and oxygen saturation (SpO2) will be also recorded.

Intravenous (IV) line will be inserted and IV lactated Ringer 500ml bolus then started as calculated by fluid chart. For both groups, General anesthesia will be performed After 3 minutes of pre- oxygenation, anaesthesia will be induced with IV 1 mcg/kg of fentanyl, 2 mg/kg of propofol and 0.5 mg/kg of atracurium to facilitate endotracheal intubation.

• Anesthesia will be maintained with 50% of oxygen in air, 1-2 % isoflurane and 0.1mg/kg atracurium every 20 minutes.

Both groups will receive rescue dose of fentanyl 0.5 mcg/kg for an increase in HR or MAP 20% above the baseline value. - All patients will be given IV 1 mg of granisetron and 40 mg of pantoprazole.

After end of surgery:

• Residual paralysis will be reversed with 0.05 mg/kg neostigmine and 0.02 mg/kg atropine. All patients underwent to two procedure mentioned above by two anesthesiologist.

Transcutanous ultrasonography by the investigator. Direct laryngeoscopy by the anesthesiologist. Transcutanous laryngeal ultrasonography: (TLUS) by using ultrasonogrphy sonosite 5- 10-MHz linear probe , patient 's position is supine with neck hyperextended in same position of surgery.Apply aseptic gel and sterile gloves to put probe on sutures .Probe is placed transversally on top of the thyroid cartilage to evaluate the vocal cords mobility.And move craniocaudal until two vocal cords are seen if difficult to find put probe on lateral side .True and false vocal cords will be seen, true will be hypoechoic below thyroid cartilage and false will be hyperechoic.When both true vocal cords move medially towards midline, this means NO nerve palsy.but when either one or both vocal cords not moved, this means there is nerve palsy. Direct Laryngeoscopy: Inserted in oral cavity and show both vocal cords mobility, if both mobile there is NO palsy , if one immobile and another mobile may be chance of stridor and if both immobile there is risk of airway obstruction. All results will be documented at the same time and comparison will be matched between the investigetor and the anesthesiologist and Statistical analysis will be done.

Postoperative settings: - All patients will continue to be monitored in the post- anesthesia care unit (PACU) for their HR normal range(60-100bpm), MAP normal(120/80)and SpO2> 95% on room air.

Analysis of voice change should be done by ability to speak and if there is any respiratory distress and by ENT consultation

Inclusion criteria

• Both sexes patients aged above 21 years
• BMI<40kg/m2
• American Society of Anesthesiologists(ASA) Physical Status Class- II and class- III
• Scheduled for elective thyroid surgery with intact vocal cords
• Approved to give informed consent and preoperative assessment by ENT specialist using Indirect laryngoscopy.

Exclusion criteria

• Patient refused to participate.
• Morbid obesity (BMI: >40kg/m^2)
• Age below 21 years.
• American Society of Anesthesiologists(ASA) Physical Status Class IV.
• Previous operation in thyroid gland.
• Any previous vocal cords paralysis.