Body Surface Area Is Not a Reliable Predictor of Tracheal Tube Size in Children

Abstract

ObjectivesThe age-based Cole formula has been employed for the estimation of endotracheal tube (ETT) size due to its ease of use, but may not appropriately consider growth rates among children. Child growth is assessed by calculating the body surface area (BSA). The association between the outer diameter of an appropriate uncuffed-endotrachealtube (ETT-OD) and the BSA values of patients at 24–96 months of age was our primary outcome.MethodsCole formula, BSA, age, height, weight and ultrasound measurement of subglottic-transverse-diameter were evaluated for correlations with correct uncuffed ETT-OD. The Cole formula, BSA, and ultrasound measurements were analyzed for estimation rates in all patients and age subgroups. The maximum allowed error for the estimation of ETT-OD was ≤0.3 mm. Patients’ tracheas were intubated with tubes chosen by Cole formula and correct ETT-OD values were determined using leak test. ETT exchange rates were recorded.ResultsOne-hundred twenty-seven patients were analyzed for the determination of estimation rates. Thirteen patients aged ≥72 months were intubated with cuffed ETT-OD of 8.4 mm and were accepted to need uncuffed ETT-OD >8.4 mm in order to be included in estimation rates, but excluded from correlations for size analysis. One-hundred fourteen patients were analyzed for correlations between correct ETT-OD (determined by the leak test) and outcome parameters. Cole formula, ultrasonography, and BSA had similar correct estimation rates. All three parameters had higher underestimation rates as age increased.Conclusion.The Cole formula, BSA, and ultrasonography had similar estimation rates in patients aged ≥24 to ≤96 months. BSA had a correct estimation rate of 40.2% and may not be reliable in clinical practice to predict uncuffedETT-size.

Prediction of endotracheal tube size in the pediatric age group by ultrasound: A systematic review and meta-analysis

“…We systematically studied and evaluated the use of US for the assessment of ETT size in the pediatric age group Table 3 . [ 4 5 6 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 ] We wanted to examine whether the US measurements give us a reasonable enough idea of the size of the ETT to be inserted, whether there is any co-relation of US with the traditional formulas. Additional information was also gathered regarding the impact of the US learning curve, ease of insertion of the ETT, depth of insertion of the ETT, utility of the US to detect correct placement, any effect of the US on the ETT exchange rates, whether the real-time US reduced the need for repeated laryngoscopy and thus avoided airway trauma.…”

“…The subglottic diameter is calculated using a high-resolution US computer linear probe mounted on the midline of the anterior neck with the head extended and neck flexed during mask ventilation. The subglottic tracheal diameter measured was used to pick an endotracheal tube of similar outer diameter in the studies done by Shibasaki M et al ,[ 4 ] Uzumcugil et al ,[ 11 ] Bhardwaj N et al ,[ 14 ] Gollu G et al ,[ 19 ] Kumar A et al . [ 33 ] The endotracheal tube with an outer diameter often less than the measured tracheal diameter was chosen to avoid damage to the airways.…”

Determinación del diámetro traqueal con ultrasonido y su relación con la fórmula de cálculo del tubo en niños de 1 a 12 años

“…Their increase correlated with age; different races cause the population to present phenotypic differences worldwide. The graphs of weight percentiles for the period and height-for-age are used to monitor growth; children in the <5 % weight and height-for-age range (with pathologically short stature) may have a smaller tracheal diameter relative to their age; this was stated by Daugherty et al [5] when determining that the predictions based on height were not accurate, the same as defined in another retrospective study in which 5175 records of patients with short stature were analyzed. It was concluded that the prediction of tube size based on height is as short stature as the estimate based on age, both in patients with pathological and nonpathological short length [14], thus showing that formulas such as Cole, Khine, and Motoyama can be misleading in this population.…”

“…Imaging methods, such as computed tomography and magnetic resonance imaging, are impractical apart from expensive. On the other hand, US is a method that allows easy, fast and precise visualization of the supraglottic, glottic and subglottic regions [5].…”

Comparison of the Effectiveness of Tracheal Ultrasonography and Conventional Techniques for the Determination of Endotracheal Tube Diameter in Pediatric Patients Undergoing Cardiac Surgeries

“…Pediatrik hasta grubunda uygun endotrakeal tüp (ETT) çapının belirlenmesinin nasıl yapılacağı halen tartışmalıdır. Bu durum; anatomik, yapısal ve ırksal farklılıklar nedeniyle çeşitli formüller geliştirilerek çözülmeye çalışılmaktadır (3)(4)(5) . Bu amaçla günümüzde seçilecek olan ETT'nin çapını yaş, boy ve kiloya göre hesaplamaya olanak sağlayan Cole formülü gibi değişik formüller kullanılmaktadır.…”