Endotracheal Tube Sizes During Surgical Procedures in Adult Patients. A Systematic Review With Meta-Analyses and Trial Sequential Analyses

BACKGROUND: Despite the long-standing practice of endotracheal intubation, limited attention has been given to perioperative complications and benefits of choosing different sizes of endotracheal tubes. This review examines the existing literature to evaluate the potential benefits and harms of selecting different tube sizes for adult surgical patients undergoing general anesthesia for elective procedures.

METHODS: This review followed the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines. The primary outcome is the proportion of participants with postoperative sore throat after intubation. Secondary outcomes are the proportions of participants with postoperative hoarseness after intubation, re-intubations, airway injury caused by intubation or use of instruments related to intubation, adverse events, and serious adverse events. A comprehensive search was conducted in CENTRAL, OVID, and EMBASE. The last search was performed on February 10, 2025, and included only randomized clinical trials. Meta-analysis, Trial Sequential Analyses (TSA), and Grading of Recommendations were performed.

RESULTS: The search identified 20 860 articles, which resulted in 45 full-text screenings. After further exclusions, six trials met the inclusion criteria, including 917 patients. The performed meta-analyses for smaller versus larger tube sizes found a significant reduction in favor of small tube sizes for sore throat after 1 and 24 h postoperatively and for hoarseness 1 and 24 h postoperatively. No significant difference was found between smaller and larger tube sizes for adverse events and airway injury. No trial sequential analysis obtained the required information size, but the Z-curve crossed the upper boundary, indicating a reliable significance. All included trials had a high risk of bias and very low to moderate quality of evidence.

CONCLUSION: The findings suggest that selecting a smaller tube size for endotracheal intubation may potentially enhance patient comfort and recovery. Because of the high risk of bias and very low to moderate certainty of evidence, there is a need for more robust, high-quality research in this area.