In this episode, we explore the evidence on whether smaller endotracheal tubes are... 1. Less likely to maintain a secure patent airway 2. Less reliable in facilitating positive pressure ventilation 3. Less able to seal the trachea and protect the lungs from aspiration We also discuss the potential harms associated with larger endotracheal tubes.  Our guests are Dr. Shamir Karmali and Dr. Peter Rose from the Department of Anesthesiology at Vancouver General Hospital. Thanks for listening! If you enjoy our content, consider supporting our mission at https://bit.ly/3n0sklh. — Follow us on Instagram @DepthofAnesthesia and on Twitter @DepthAnesthesia. Email us at [email protected]. Music by Stephen Campbell, MD. — References Coordes A, Rademacher G, Knopke S, Todt I, Ernst A, Estel B, Seidl RO. Selection and placement of oral ventilation tubes based on tracheal morphometry. Laryngoscope. 2011 Jun;121(6):1225-30. doi: 10.1002/lary.21752. Epub 2011 May 6. PMID: 21557233. Dominelli PB, Ripoll JG, Cross TJ, Baker SE, Wiggins CC, Welch BT, Joyner MJ. Sex differences in large conducting airway anatomy. J Appl Physiol (1985). 2018 Sep 1;125(3):960-965. doi: 10.1152/japplphysiol.00440.2018. Epub 2018 Jul 19. PMID: 30024341; PMCID: PMC6335094. El-Boghdadly K, Bailey CR, Wiles MD. Postoperative sore throat: a systematic review. Anaesthesia. 2016 Jun;71(6):706-17. doi: 10.1111/anae.13438. Epub 2016 Mar 28. PMID: 27158989. Ellis SF, Pollak AC, Hanson DG, Jiang JJ. Videolaryngoscopic evaluation of laryngeal intubation injury: incidence and predictive factors. Otolaryngol Head Neck Surg. 1996 Jun;114(6):729-31. doi: 10.1016/s0194-5998(96)70093-1. PMID: 8643294. Fiastro JF, Habib MP, Quan SF. Pressure support compensation for inspiratory work due to endotracheal tubes and demand continuous positive airway pressure. Chest. 1988 Mar;93(3):499-505. doi: 10.1378/chest.93.3.499. PMID: 3277803. Futagawa K, Takasugi Y, Kobayashi T, Morishita S, Okuda T. Role of tube size and intranasal compression of the nasotracheal tube in respiratory pressure loss during nasotracheal intubation: a laboratory study. BMC Anesthesiol. 2017 Oct 17;17(1):141. doi: 10.1186/s12871-017-0432-1. PMID: 29041911; PMCID: PMC5645985. Hu B, Bao R, Wang X, Liu S, Tao T, Xie Q, Yu X, Li J, Bo L, Deng X. The size of endotracheal tube and sore throat after surgery: a systematic review and meta-analysis. PLoS One. 2013 Oct 4;8(10):e74467. doi: 10.1371/journal.pone.0074467. PMID: 24124452; PMCID: PMC3790787. Hwang JY, Park SH, Han SH, Park SJ, Park SK, Kim JH. The effect of tracheal tube size on air leak around the cuffs. Korean J Anesthesiol. 2011 Jul;61(1):24-9. doi: 10.4097/kjae.2011.61.1.24. Epub 2011 Jul 21. PMID: 21860747; PMCID: PMC3155132. Karmali S, Rose P. Tracheal tube size in adults undergoing elective surgery - a narrative review. Anaesthesia. 2020 Nov;75(11):1529-1539. doi: 10.1111/anae.15041. Epub 2020 May 16. PMID: 32415788. Koh KF, Hare JD, Calder I. Small tubes revisited. Anaesthesia. 1998 Jan;53(1):46-50. doi: 10.1111/j.1365-2044.1998.00290.x. PMID: 9505742. Pavlin EG, VanNimwegan D, Hornbein TF. Failure of a high-compliance low-pressure cuff to prevent aspiration. Anesthesiology. 1975 Feb;42(2):216-9. doi: 10.1097/00000542-197502000-00019. PMID: 1115375. Randestad A, Lindholm CE, Fabian P. Dimensions of the cricoid cartilage and the trachea. Laryngoscope. 2000 Nov;110(11):1957-61. doi: 10.1097/00005537-200011000-00036. PMID: 11081618. Shah C, Kollef MH. Endotracheal tube intraluminal volume loss among mechanically ventilated patients. Crit Care Med. 2004 Jan;32(1):120-5. doi: 10.1097/01.CCM.0000104205.96219.D6. PMID: 14707569. Stenqvist O, Sonander H, Nilsson K. Small endotracheal tubes: ventilator and intratracheal pressures during controlled ventilation. Br J Anaesth. 1979 Apr;51(4):375-81. doi: 10.1093/bja/51.4.375. PMID: