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Comparison of Formulae for Orotracheal Intubation Depth in the Paediatric Population
Jen Heng Pek1, Elizabeth Mj Tan, Ying Hao
1Acute Care Clinic, Sengkang Health, Singapore Children's Emergency, KK Women's and Children's Hospital, Singapore.
Insights
The endotracheal tube (ETT) size multiplied by 3 formula is the most accurate for determining paediatric orotracheal intubation depth. However, confirmation of proper ETT placement remains essential.
Area of Science:
- Emergency Medicine
- Paediatric Critical Care
- Airway Management
Background:
- Accurate orotracheal depth calculation is crucial for paediatric intubation.
- Limited validation data exists for common paediatric intubation formulae in emergency settings.
- The Broselow tape, ETT size x 3, and age-based formulae are frequently used.
Purpose of the Study:
- To compare the accuracy of three common formulae for determining orotracheal intubation depth in children.
- To evaluate the reliability of these formulae in an emergency department setting.
Main Methods:
- Retrospective observational study of paediatric intubations in a Children's Emergency Department (2009-2013).
- Calculated formula-based depths and compared them to actual endotracheal tube (ETT) placement.
- Radiological accuracy assessed by ETT position between T2-T4 vertebral bodies.
Main Results:
- The ETT size x 3 formula demonstrated the highest accuracy (76.5%).
- The age-based formula (67.9%) and Broselow tape (63.5%) were less accurate.
- Broselow tape frequently underestimated depth compared to other methods.
- ETT size x 3 accuracy was highest in patients >25 kg; Broselow tape accuracy varied by age.
Conclusions:
- The ETT size x 3 formula is superior for estimating orotracheal intubation depth in children.
- Clinical confirmation of ETT placement via auscultation and chest radiography is still mandatory.
- Further research may refine paediatric airway management guidelines.
Introduction:
Multiple formulae have been proposed for calculating orotracheal depth for paediatric intubation. However, literature on the validation of these formulae in the emergency department setting is limited. Three methods described in the local Advanced Paediatric Life Support curriculum include the Broselow tape, endotracheal tube (ETT) size x 3, and the age-based formula of age divided by 2, add 12. We aimed to determine their accuracy.
Materials And Methods:
Patients with intubation performed in the Children's Emergency from 1 January 2009 to 31 December 2013 were included in this retrospective observational study. The depths of ETT placement based on the formulae were calculated from the actual depth of ETT. ETT position between T2 to T4 vertebral bodies of the chest radiograph was taken as the reference position for radiological accuracy.
Results:
ETT size x 3 has the highest accuracy of 76.5%, as compared to 67.9% for age-based formula and 63.5% for Broselow tape. When the formulae were inaccurate, Broselow tape often predicted a depth that was too shallow as compared to ETT size x 3 (P = 0.006) and age-based formula (P = 0.011). The accuracy of Broselow tape was not uniform across the age groups, with highest accuracy in patients 1 to 8 years old. ETT size x 3 had the highest accuracy in patients weighing more than 25 kg.
Conclusion:
ETT size x 3 was superior for determining orotracheal intubation depth but cannot preclude the confirmation of appropriate placement of ETT by auscultation and chest radiograph.
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