Catheter Size

Nursing Considerations (Ambu Bag Selection)

Patient’s age and size

Nursing Considerations (Ambu Bag Selection)

Respiratory needs

Nursing Considerations (Ambu Bag Selection)

Emergency vs

controlled setting

Nursing Considerations (Ambu Bag Selection)

Infection control policies

Sterile Suction Catheter

A medical device used to clear secretions from a patient’s airway, especially during tracheostomy or ET tube suctioning

Catheter Size – Neonates

ET size (mm ID) 2.5–3.5

Catheter Size – Neonates

Catheter (CH/Fr) 5–8 CH

Catheter Size – Neonates

Diameter (approx.) 1.7–2.7 mm

Catheter Size – Infants (1 mo–1 yr)

ET size (mm ID) 3.5–4.0

Catheter Size – Infants (1 mo–1 yr)

Catheter (CH/Fr) 8–10 CH

Catheter Size – Infants (1 mo–1 yr)

Diameter (approx.) 2.7–3.3 mm

Catheter Size – Children (1–8 yr)

ET size (mm ID) 4.0–6.0

Catheter Size – Children (1–8 yr)

Catheter (CH/Fr) 10–12 CH

Catheter Size – Children (1–8 yr)

Diameter (approx.) 3.3–4.0 mm

Catheter Size – Adolescents/Adults

ET size (mm ID) 7.0–9.0

Catheter Size – Adolescents/Adults

Catheter (CH/Fr) 12–14 CH

Catheter Size – Adolescents/Adults

Diameter (approx.) 4.0–4.6 mm

Catheter Size Notes

Catheter size should be about half the internal diameter of the ET or tracheostomy tube

Catheter Size Notes

Too large → airway trauma or excessive suctioning

Catheter Size Notes

Too small → may not clear secretions effectively

Catheter-to-Airway Ratio

Compares the internal diameter of the ET/trach tube (large circle) to the suction catheter diameter (small circle)

Catheter-to-Airway Ratio

Letter A is recommended – catheter occupies less than 50% of the airway diameter, leaving adequate space for air to pass

Catheter-to-Airway Ratio

Oxygen can continue to reach the lungs during suctioning

Catheter-to-Airway Ratio

Low chance of hypoxia, atelectasis, collapsed alveoli, and airway trauma