Endotracheal tube size and sore throat following surgery: a randomized controlled study

Background

Sore throat following endotracheal intubation is a common problem following surgery and one of the factors that affects quality of recovery. This study was done with the primary aim of assessing whether the size of the endotracheal tube (ETT) affects the risk of sore throat in women following anaesthesia.

Methods

One hundred healthy adult women undergoing elective surgery were randomly allocated to oral intubation with either ETT (Mallinckrodt Hi-ContourTM) size 6.0 or 7.0. Pre- and postoperatively sore throat was assessed on a four-graded scale,  (0-3) 0= no sore throat, 1= mild sore throat (less severe than with a cold), 2= moderate sore throat (similar to that noted with a cold) and 3= severe sore throat (more severe than with a cold). Hoarseness was assessed on a binary scale (yes or no). The women also rated their discomfort from these symptoms. Postoperatively the assessments were made after 1-2 hours, 24 hours and if they had symptoms at 24 hours, a follow-up call was made at 72 and 96 hours.

Results

Demographic characteristics were comparable between the groups (Table 1). After 1-2 hours postoperatively there were a higher proportion of patients with sore throat in ETT 7.0 versus ETT 6.0 (51.1% vs. 27.1%), p= 0.006 (Fig.1).
When comparing changes between the pre- and postoperative values, this difference between the groups was also evident, p=0.002 (Table 2).  The severity of discomfort from sore throat was also higher in ETT 7.0 (38.8%) compared to ETT 6.0 (18.8%), p=0.02. No differences were found in the incidence of hoarseness between the groups. Remaining symptoms lasts up to 96 hours postoperatively in 11%, irrespectively of tube size.

Conclusion

To use a smaller size of the endotracheal tube can alleviate women’s suffering from sore throat and discomfort at the PACU.