Assessing the Short-term Effects of Endotracheal Intubation on Voice Change and Acoustic Parameters: A Prospective Observational Study

Aims and objectives: (1) To examine vocal symptoms and acoustic changes perceived within 24 hours after endotracheal intubation and (2) to find the association between these changes and endotracheal tube (ET) parameters and determine which parameter affects voice the most. Materials and methods: A prospective analysis of 75 patients was done. They were examined preoperatively, and 2 and 24 hours postoperatively. The vocal symptoms of hoarseness, vocal fatigue, loss of voice, throat clearing (hawking), globus pharyngeus, throat pain, and the acoustic variables mainly average fundamental frequency, shimmer, harmonic noise ratio (HNR), and maximum phonation time (MPT) were assessed. The ET parameters considered were duration of anesthesia, number of attempts at intubation, size of the tube, ET cuff volume, and mean cuff pressure. Results: Approximately 60% of patients with cuff volume above 3 cm 3 and 80% of patients with more than two intubation attempts developed postoperative vocal fatigue, while 70% with mean cuff pressure above 20 cm of water developed postoperative hawking. Conclusion: The ET parameters, mean cuff pressure, and ET cuff volume are the most important variables that are associated with the increase in vocal symptoms. An increase in the value of these parameters is associated with more postoperative discomfort.