Remembering the classics: cuffed vs uncuffed endotracheal tubes in young children.

Myron Yaster, Robert Friesen

H H Khine, D H Corddry, R G Kettrick, T M Martin, J J McCloskey, J B Rose, M C Theroux, M Zagnoev. Comparison of cuffed and uncuffed endotracheal tubes in young children during general anesthesia. Anesthesiology 1997 Mar;86(3):627-31; PMID: 9066329

Ron Litman, of blessed memory, thought it would be a good idea to present a “classic” article once a week or so as the PAAD.  It doesn’t get any more classic than this! Thanks to Diane Gordon MD for asking for this one.

When we were “young pups”, cuffed endotracheal tubes (ETTs) were not used in children < 6-8 years of age because of a perceived risk of direct airway mucosal injury and impairment of submucosal blood flow at the cricoid ring, the narrowest part of the airway.  The resultant injury and edema were thought to result in post-intubation stridor and croup (see also the classic paper Koka BV, Jeon IS, Andre JM, MacKay I, Smith RM. Postintubation croup in children. Anesth Analg. 1977 Jul-Aug;56(4):501-5. PMID: 56013…and yes, the senior author is Robert Smith of the original pediatric anesthesia textbook and for whom the AAP award is named for!).  On the other hand, cuffed ETTs allow for fewer laryngoscopies for ill-fitting uncuffed tubes, were thought to reduce the risk of aspiration, allowed for lower fresh gas flows, and could be used to ventilate patients with stiff lungs more easily.   This classic paper by Khine et al. put this issue to rest on all counts. Perhaps most importantly, post-intubation croup and the need for racemic epinephrine was not any different in patients treated with cuffed or uncuffed tubes.

The formula for cuffed tubes used in the Khine et al paper:

                      Cuffed tube size (mm ID) = (age/4 + 3) rounding upward when needed.

A further argument in favor of cuffed tubes was the introduction of the microcuff tube. Its short, compliant cuff was a breakthrough for cuffed tubes in neonates and small infants. (Weiss M, Gerber AC, Dullenkopf A. Appropriate placement of intubation depth marks in a new cuffed paediatric tracheal tube. Br J Anaesth 2005;94:80-87. PMID 15486002)

A recent Cochrane review (Flavia A De Orange, Rebeca Gac Andrade, Andrea Lemos, Paulo Sgn Borges, José N Figueiroa, Pete G Kovatsis. Cuffed versus uncuffed endotracheal tubes for general anaesthesia in children aged eight years and under. Cochrane Database Syst Rev. 2017 Nov 17;11(11): PMID: 29149469) highlighted the “low quality of evidence” of the Khine et al.  and other papers on this subject.  Nevertheless, the “people have spoken” and the use of cuffed ETTs is now pretty much a done deal and standard of care in children, infants, and neonates. 

Myron Yaster MD and Robert Friesen MD