Recently, Sam Ghali reminded us how important pediatric tube sizes, and how easy to calculate them. We think every medical students, interns and PGY1s should know this now. Here is his message on Twitter:
Here’s a great way to remember #Pediatric Tube Sizes based on a simple formula for endotracheal tube (ETT). This will get you to the right ballpark in an emergency:
ETT x 1= [Age ÷ 4] + 4
ETT x 2= NG/OG or Foley
ETT x 3= ETT Insertion Depth
ETT x 4= Chest Tube #FOAMed— Sam Ghali, M.D. (@EM_RESUS) July 9, 2019
PEDIATRIC TUBE SIZES
CALCULATE ENDOTRACHEAL TUBE (ETT) SIZE
[Age ÷ 4] + 4
There are many formulas to calculate the endotracheal tube size for kids. The given formula is one of the most common. Let’s think a six yo patient. Your ETT size is 6/4 = 1.5, and +4 = 5.5
NASOGASTRIC/OROGASTRIC TUBE OR FOLEY CATHETER SIZE
ETT x 2
NG/OG tubes and Foley catheters are measured as FRENCH. (Fr) If your ETT size is 5.5, then your NG/OG and Foley sizes will be 5.5 x 2 = 11 Fr.
HOW DEEP YOUR ETT SHOULD BE
ETT x 3
If your calculated tube size is 5.5, your depth should be 5.5 x 3 = 16.5 cm. So, 16.5 cm mark should be seen at the level of central incisors.
CHEST TUBE SIZE
ETT x 4
If the same six yo patient needs a chest tube, your chest tube size is 5.5 x 4 = 22 Fr. By the way, this is mainly for trauma. Moreover, do not forget, smaller size tubes can work as same as big ones.