The Effect of Thermal-Softened Endotracheal Tubes on Postoperative Sore Throat and Other Complications-A Systematic Review and Meta-Analysis

Abstract

Background: Endotracheal tube (ETT) intubation during general anesthesia (GA) is commonly associated with postoperative sore throat. This study aimed to evaluate whether thermal-softened ETTs reduce the postoperative sore throat incidence in patients undergoing elective surgery under GA. Methods: We conducted a comprehensive search of the literature across PubMed, Cochrane Library, and EMBASE to identify randomized controlled trials (RCTs) evaluating the effect of thermal-softened ETTs on postoperative sore throat in patients undergoing elective surgeries under GA. The primary outcome was postoperative sore throat incidence, while secondary outcomes included hoarseness, vocal cord lesions, and time to intubation. Data were extracted independently by two authors, and the risk of bias was assessed using the Revised Cochrane risk of bias tool (version 2.0). A meta-analysis was then performed using the random-effects model, with the results expressed as risk ratios (RRs) and mean difference (MDs). Results: Eight studies, with a total of 970 participants, were included. Thermal-softened ETTs significantly reduced postoperative sore throat incidence (RR: 0.60, 95% CI: 0.44 to 0.82, p = 0.001). Subgroup analysis showed no difference for single-lumen tubes (RR: 0.76, 95% CI: 0.45 to 1.26, p = 0.28), but remained significant for double-lumen tubes (RR: 0.5, 95% CI: 0.39 to 0.65, p < 0.00001). No significant difference was found in hoarseness (RR: 0.86, 95% CI: 0.64 to 1.17, p = 0.34), but a lower incidence of vocal cord lesions (RR: 0.52, 95% CI: 0.40 to 0.68, p < 0.00001) was observed. No difference was found in the time to intubation (MD: -6.51, 95% CI: -20.04 to 7.02, p = 0.35). Conclusions: Thermal-softened ETTs may reduce the incidence of postoperative sore throat and vocal cord lesions but have no significant effect on hoarseness or intubation time.

Keywords: equipment design; hoarseness; intratracheal; intubation; laryngeal diseases; pharyngitis; postoperative complications.

Figure 1

PRISMA flow diagram.

Figure 2

Risk of bias plot [15,16,17,18,19,20,21,22].

Figure 3

Forest plot of the incidence of postoperative sore throat on postoperative day 1 or 24 h postoperatively [15,16,17,18,19,20,21,22].

Figure 4

Funnel plot assessing publication bias for the incidence of postoperative sore throat. Studies are plotted by log risk ratio versus standard error. The vertical dotted line indicates the pooled effect estimate.

Figure 5

Forest plot of the incidence of postoperative hoarseness on postoperative day 1 or 24 h before sensitivity analysis [15,17,18,19,21,22].

Figure 6

Forest plot of the incidence of postoperative hoarseness on postoperative day 1 or 24 h after sensitivity analysis [15,17,18,19,21,22]. ✓ indicates studies included in the analysis, x indicates study excluded due to large weight.

Figure 7

Forest plot of the incidence of vocal cord lesions on postoperative day 1 or 24 h postoperatively [20,21,22].

Figure 8

Forest plot of the time to intubation before sensitivity analysis [15,16,19,20,21,22]. ✓ indicates studies included in the analysis.

Figure 9

Forest plot of the time to intubation after sensitivity analysis [15,16,17,20,21,22]. ✓ indicates studies included in the analysis, x indicates study excluded due to different intubation technique.