Effect of Endotracheal Tube Size on Vocal Outcomes After Thyroidectomy: A Randomized Clinical Trial

The optimum size of endotracheal tube (ETT) for general anesthesia remains unresolved. Choice of ETT size may be of particular relevance to thyroid surgery because of the increased risk of laryngeal trauma and concerns regarding postoperative vocal outcomes.

To test our hypothesis that intubation with a smaller ETT would lead to reduced postoperative vocal impairment and associated reduced laryngoscopic evidence of laryngeal trauma compared with intubation with a standard-size ETT.

This double-blind randomized clinical trial studied patients 18 years and older undergoing elective thyroidectomy at an academic teaching hospital from October 15, 2012, through June 13, 2013.

Patients were randomized to group 1 (standard-size ETT, 8.0 mm for men and 7.5 mm for women; n = 24) or group 2 (small ETT, 7.0 mm for men and 6.5 mm for women; n = 25). Patients were assessed preoperatively and at 24 hours and 3 weeks postoperatively.

Fiberoptic videolaryngoscopy with modified scoring system, voice assessment using the GRBAS (grade, roughness, breathiness, asthenia, strain) rating scale, vocal self-assessment using the 30-item Voice Handicap Index, and subjective pain score.

At 24 hours, no significant differences were found between patients in groups 1 and 2 in change in GRBAS scores, change in laryngoscopic score (1.71 vs 1.76, P = .90), or postoperative pain score (3.3 vs 3.2, P = .91). At 3 weeks, no significant differences were found in changes in the 30-item Voice Handicap Index score (-2.2 vs -1.3, P = .74), GRBAS scores, or laryngoscopic score (0.25 vs 0.16, P = .67).

We did not find evidence that smaller ETT size for thyroidectomy has any significant effect on postoperative vocal outcomes, incidence of laryngeal trauma as assessed by laryngoscopy, or pain scores. However, because of the small sample size, our study may have been underpowered to detect small differences.

clinicaltrials.gov Identifier: NCT02136459.