Endotracheal Tube Selection and Intubation Guidelines for Children Under 1 Year of Age

Endotracheal Tube Size Selection

The American Heart Association recommends using a 3.0 mm ID cuffed endotracheal tube or a 3.5 mm ID uncuffed endotracheal tube for emergency intubation in infants under 1 year of age, with a depth of insertion based on the formula "weight in kg + 6 cm" at the lip, and a straight laryngoscope blade (size 1) for optimal visualization 1, 2, 3
Both cuffed and uncuffed endotracheal tubes are acceptable for intubating infants under 1 year of age (Class IIa, LOE C) 3, 4
For emergency intubation of an infant less than 1 year of age, if using a cuffed tube, select a 3.0 mm ID tube 1, 2
For emergency intubation of an infant less than 1 year of age, if using an uncuffed tube, select a 3.5 mm ID tube 1, 2

Cuffed tubes may be preferable in certain circumstances such as poor lung compliance, high airway resistance, or large glottic air leak (Class IIa, LOE B) 2, 3
Cuffed tubes may decrease the risk of aspiration 2
If using cuffed tubes, monitor cuff inflation pressure and limit according to manufacturer's instructions (usually less than 20-25 cm H2O) 2

Have tubes 0.5 mm smaller and 0.5 mm larger than the estimated size available during intubation 1, 2
Length-based resuscitation tapes are more accurate than age-based formulas for determining tube size in children up to 35 kg 1
If resistance is met during intubation, use a tube 0.5 mm smaller 1
If a large glottic air leak interferes with oxygenation or ventilation after intubation, consider replacing with a tube 0.5 mm larger or switching to a cuffed tube of the same size 1

Depth of insertion (cm at lip) = weight in kg + 6 cm 5
Alternatively, the depth can be estimated as 3 times the internal diameter of the tube 5

For infants under 1 year, a straight blade (typically Miller size 1) is generally preferred as it provides better visualization by lifting the epiglottis directly 5
The blade size should be appropriate for the infant's size, with size 1 being standard for most infants under 1 year 5

Verify proper tube placement using multiple methods (Class I, LOE B) 1, 2
Look for bilateral chest movement 1, 6
Listen for equal breath sounds over both lung fields, especially over the axillae 1
Listen for absence of gastric insufflation sounds over the stomach 1
Check for exhaled CO2 1
If perfusing rhythm is present, monitor oxyhemoglobin saturation with pulse oximetry 1
If uncertain about placement, perform direct laryngoscopy to visualize the tube between the vocal cords 1
In hospital settings, perform a chest x-ray to verify proper position in the midtrachea 1

Remember the "DOPE" mnemonic if a patient's condition deteriorates after intubation: Displacement, Obstruction, Pneumothorax, Equipment failure 1, 6
Maintain the patient's head in neutral position after securing the tube; neck flexion may push the tube further into the airway, while extension may pull it out 1
Tube replacement carries risks and should be performed in an appropriate setting by experienced personnel 1

The American Heart Association’s Neonatal Resuscitation Program recommends uncuffed endotracheal tubes sized by birth weight (or gestational age): 2.5 mm internal diameter for infants < 1000 g (or < 28 weeks), 3.0 mm for infants 1000–2000 g (or 28–34 weeks), and 3.5 mm for infants > 2000 g (or > 34 weeks) [7][8].

The American Heart Association mandates the use of multiple simultaneous confirmation methods during neonatal intubation, including exhaled carbon‑dioxide detection, heart‑rate response, bilateral chest rise, equal breath sounds, absence of gastric sounds, pulse‑oximetry (when perfusing rhythm present), and chest radiography for mid‑tracheal positioning 7.
Exhaled carbon‑dioxide detection is identified as the most reliable method for confirming tracheal placement in neonates who have adequate cardiac output 7.
A prompt increase in heart rate after tube insertion is considered the best clinical indicator of successful intubation in newborns [7][8].

In situations of poor or absent pulmonary blood flow (e.g., cardiac arrest), exhaled carbon‑dioxide may not be detected even when the tube is correctly placed, risking premature extubation; in such cases clinicians should rely on direct laryngoscopic visualization and overall clinical assessment 7.