Stroboscopy and acoustic analysis of voice following endotracheal intubation in otological surgeries

Stroboscopy is an endoscopy that is performed with intermittent light at a frequency that approximates the frequency of a moving object so that it appears in slow motion or motionless. It is used to analyze the structure and motion of the vocal fold. To compare the stroboscopic findings of various vocal parameters such as symmetry, amplitude, periodicity, mucosal wave of vocal folds, and glottis closure before and after elective endotracheal intubation and to compare acoustic analysis of voice using fundamental frequency, intensity, maximum phonation time, and dysphonia severity index in patients before and after elective intubation, who were undergoing otological surgeries. It also assesses the correlation between changes in these vocal and acoustic parameters and the size of the endotracheal tube, duration of intubation, and number of attempts made during intubation. This study creates awareness and provides insights to avoid intubation-related vocal fold injury. This was a prospective cohort study involving 31 patients done in a Tertiary Care Centre. All patients who underwent otological surgeries by elective endotracheal intubation were included. All of them underwent stroboscopic and acoustic evaluation preoperatively, 24 h, and 7 days postoperatively. Statistically significant changes in mucosal wave pattern score were observed in the 1st postoperative day that reverted to normal by the end of 7th postoperative day and in GRBAS which was significant at the end of both 1st and 7th POD. Other parameters like fundamental frequency, intensity, DSI, MPT, amplitude, symmetry, periodicity, and glottis closure remain unaltered. There was a moderate positive correlation between the duration of intubation (minutes) and mucosal wave 1st POD (P-value: 0.003). The majority of the patients (61%) had normal laryngeal structures. A total of 39% had evidence of injury, the most common being right vocal fold hemorrhage improved by the end of 7th postoperative day and became normal.