The Utility of Oro-Helical Length for Estimation of The Optimal Endotracheal Tube Insertion Depth in Neonates

Document Type : Original Article


1 Pediatrics Department, Faculty of Medicine, Ain Shams University, Cairo, Egypt

2 Ministry of Health, Cairo, Egypt



Background: Although endotracheal intubation is an emergency procedure that is frequently performed in neonatal care, there is still uncertainty about the best method for the estimation of the optimal depth of the endotracheal tube (ETT) in neonates. We aimed to compare two different methods of estimation of ETT insertion depth in neonates.
Methods: This study was conducted on 120 neonates needing intubation. The ETT insertion depth was estimated in 60 neonates according to the oro-helical length (OHL) method and it was estimated in the other 60 neonates according to the Tochen’s formula method. Both groups were compared in correct estimation of the proper ETT position in chest radiography.
Results: The incidence of ETT malposition did not differ significantly between the OHL group (31.7 %) and the Tochen’s formula group (45 %) (P > 0.05). There was also no significant difference in chest expansion in both groups in chest X ray.  Two neonates in the OHL group developed air leaks (3.3 %) versus 3 neonates in Tochen’s formula group (5 %) with no significant difference (P > 0.05). Furthermore, there was no significant difference between both methods regarding the incidence of accidental extubation, There was a positive correlation between the estimated ETT insertion depth by OHL measurement and weight and gestational age (p < 0.001).
Conclusion: The OHL measurement can be used as an alternative to Tochen’s formula for estimation of the optimal ETT insertion depth especially in emergency situations when the weight of the baby is not known.


  1. Sharma D, Tabatabaii SA, Farahbakhsh N. Role of ultrasound in confirmation of endotracheal tube in neonates: a review. J Matern Fetal Neonatal Med. 2019;32(8):1359-1367.
  2. Sawyer T, Foglia E, Hatch LD, Moussa A, Ades A, Johnston L, Nishisaki A. Improving neonatal intubation safety: A journey of a thousand miles. J Neonatal Perinatal Med. 2017;10(2):125-131.
  3. Almeida CC, Pissarra da Silva SMS, Flor de Lima Caldas de Oliveira FSD, Guimarães Pereira Areias MHF. Nosocomial sepsis: evaluation of the efficacy of preventive measures in a level-III neonatal intensive care unit. J Matern Fetal Neonatal Med. 2017;30(17):2036-2041.
  4. Liu HK, Yang YN, Tey SL, Wu PL, Yang SN, Wu CY. Weight is more accurate than gestational age when estimating the optimal endotracheal tube depth in neonates. Children (Basel). 2021;8(5):324.
  5. Bellini C, Turolla G, De Angelis LC, Calevo MG, Ramenghi LA. Development of a novel reference nomogram for endotracheal intubation in neonatal emergency transport setting. Acta Paediatr. 2019;108(1):83-87. 
  6. Andersen LW, Raymond TT, Berg RA, Nadkarni VM, Grossestreuer AV, Kurth T, et al. American Heart Association’s Get with The Guidelines–Resuscitation Investigators. Association. Between Tracheal Intubation During Pediatric In-Hospital Cardiac Arrest and Survival. JAMA. 2016;316(17):1786-1797.
  7. Weiner GM, Zaichkin J, Kattwinkel J, eds. Textbook of Neonatal Resuscitation. 8th ed. Elk Grove Village, IL: American Academy of Pediatrics and American Heart Association; 2021
  8. Uygur Ö, Öncel MY, Şimşek GK, Okur N, Çelik K, Bozkurt Ö, et al. Is Nasal Septum-Tragus Length Measurement Appropriate for Endotracheal Tube Intubation Depth in Neonates? A Randomized Controlled Study. Am J Perinatol. 2021;38(7):728-733.
  9. Tochen ML. Orotracheal intubation in the newborn infant: a method for determining depth of tube insertion. J Pediatr. 1979;95(6):1050-1.
  10. Gill I, Stafford A, Murphy MC, Geoghegan AR, Crealey M, Laffan E, et al. Randomised trial of estimating oral endotracheal tube insertion depth in newborns using weight or vocal cord guide. Arch Dis Child Fetal Neonatal Ed. 2018;103(4):F312-F316.
  11. Shin HJ, Chang JS, Ahn S, Kim TO, Park CK, Lim JH, et al. Clinical factors associated with weaning failure
    in patients requiring prolonged mechanical ventilation. J Thorac Dis. 2017;9(1):143-150.
  12. Lee D, Mele PC, Hou W, Decristofaro JD, Maduekwe ET. The oro-helical length accurately predicts endotracheal tube insertion depth in neonates. J Pediatr. 2018;200:265-269.e2.
  13. van Sambeeck SJ, Martens SJ, Hundscheid T, Janssen EJ, Vos GD. Dutch paediatrician's opinions about acute care for critically ill children in general hospitals. Eur J Pediatr. 2015;174(5):607-13. 
  14. Flinn AM, Travers CP, Laffan EE, O'Donnell CP. Estimating the endotracheal tube insertion depth in newborns using weight or gestation: a randomised trial. Neonatology. 2015;107(3):167-172.
  15. Puttawong D, Manopunya S, Visrutaratna P, Kosarat S, Khuwuthyakorn V, Tantiprabha W. Accuracy of various recent recommendations to estimate the optimal depth of orotracheal tube in Thai neonates. J Matern Fetal Neonatal Med. 2022;35(17):3343-3347.
  16. Gray MM, Delaney H, Umoren R, Strandjord TP, Sawyer T. Accuracy of the nasal-tragus length measurement for correct endotracheal tube placement in a cohort of neonatal resuscitation simulators. J Perinatol. 2017;37(8):975-978.
  17. Wang TC, Kuo LL, Lee CY. Utilizing nasal-tragus length to estimate optimal endotracheal tube depth for neonates in Taiwan. Indian J Pediatr. 2011;78(3):296-300.
  18. Peterson J, Johnson N, Deakins K, Wilson-Costello D, Jelovsek JE, Chatburn R. Accuracy of the 7-8-9 rule for endotracheal tube placement in the neonate. J Perinatol. 2006;26(6):333-336. 
  19. Schmölzer GM, O'Reilly M, Davis PG, Cheung PY, Roehr CC. Confirmation of correct tracheal tube placement in newborn infants. Resuscitation. 2013;84(6):731-737.
  20. Niwas R, Nadroo AM, Sutija VG, Gudavalli M, Narula P. Malposition of endotracheal tube: association with pneumothorax in ventilated neonates. Arch Dis Child Fetal Neonatal Ed. 2007;92(3): F233-234.
  21. Ingimarsson J, Björklund LJ, Curstedt T, Gudmundsson S, Larsson A, Robertson B, et al. Incomplete protection by prophylactic surfactant against the adverse effects of large lung inflations at birth in immature lambs. Intensive Care Med. 2004;30(7):1446-1453.
  22. Tatwavedi D, Nesargi SV, Shankar N, Mathias P, Rao Pn S. Efficacy of modified Tochen's formula for optimum endotracheal tube placement in low birth weight neonates: an RCT. J Perinatol. 2018; 38(5):512-516.
  23. Aziz MF, Dillman D, Fu R, Brambrink AM. Comparative effectiveness of the C-MAC video laryngoscope versus direct laryngoscopy in the setting of the predicted difficult airway. Anesthesiology. 2012;116(3):629-636.