Comparison of King Vision and Truview Laryngoscope for Postextubation Visualization of Vocal Cord Mobility in Patients Undergoing Thyroid and Major Neck Surgeries: A Randomized Clinical Trial.

BACKGROUND: Visualization of vocal cords following extubation after thyroid and major neck surgeries is highly desirable for the surgeon as well as the anaesthesiologist to rule out vocal cord palsy or oedema. As the patient is emerging from general anaesthesia, it may be challenging for the anaesthesiologist to optimally visualise and grade vocal cord movement following extubation.

SETTING: Randomized clinical trial at a tertiary care centre.

METHODOLOGY: After obtaining institutional ethics committee approval, 60 patients posted for thyroid and major neck surgeries under American Society of Anesthesiologists (ASA) grade I and II were recruited for the study. Written informed consent was obtained. Pre-operatively indirect laryngoscopy was performed in all the patients to assess baseline vocal cord function. All patients were premedicated and induced and maintained as per standardized anaesthesia protocol. Patients were randomized using a sealed envelope technique to either Group K where intubation was performed using Kings vision laryngoscope or Group T where intubation was performed using True view laryngoscope. Glottis visualization was graded in all patients and intubated. Ten minutes prior to extubation injection. dexmedetomidine 1 μg/kg was administered. Once patients satisfied extubation criteria, laryngoscopy was performed using respective video-laryngoscope in each group, patient extubated under vision and assessed for vocal cord visualization and mobility grade (VMG) and patient reactivity score (PRS). Heart rate, systolic blood pressure, diastolic blood pressure and mean arterial pressure was also noted. Total intraoperative morphine consumption was recorded. Vocal cord function was assessed again before the day of discharge by indirect laryngoscopy.

RESULTS: Age ( P = 0.27), sex ( P = 0.08), body mass index ( P = 0.70), ASA ( P = 0.39), mallampati class ( P = 0.72) and morphine used ( P = 0.39) were comparable in both groups. There was no statistically significant difference among the two groups with respect to VMG ( P = 0.18). There was no statistical difference in the PRS ( P = 0.06) in both groups. Increase in heart rate or mean arterial pressure from baseline was not significant statistically in both groups. Time taken for laryngoscopy during extubation was significantly less with group T as compared to group K ( P = 0.000).

CONCLUSION: Both Kings Vision and Truview Video-laryngoscopes provide comparable laryngoscopic view with similar patient comfort, although clinically Truview may be a better choice due to less time consumed for visualisation and rating vocal cord movement during extubation.