IR Flashcards
Which needle is smaller: 8G it 18G?
18G (smaller the gauge, bigger the needle)
Which catheter is bigger: 6F or 8F?
8F (bigger the French, bigger the catheter)
What does the gauge of a needle refer to?
The outer diameter of the needle
What does the French of a catheter refer to?
The outer diameter
What does the French of a dilator refer to?
The outer diameter
What does the french of a sheath refer to?
The inner lumen diameter (an 8F catheter is the largest that will fit in an 8F sheath)
What is the standard size of a guide wire used in IR?
0.035 inch
Note: Microwires are usually 0.018 or 0.014 inch.
What is a glide wire?
A hydrophilic wire that is used to pass through occlusions, stenoses, or small/tortuous vessels
1 mm = ? Inch
1 mm = 0.039 inch
1 mm = ? French
3F
Note: To get the diameter in mm, divide the French by 3.
How can you convert from French to mm?
Divide by 3
What is the minimum size catheter needed to fit a standard 0.035 inch wire?
4F
Note: A 4F catheter has an outer diameter of 4F (you just need to memorize that this will have the minimum inner diameter to fit a 0.035 mm wire). Don’t try to convert.
How large will the puncture site be if you use an 8F catheter?
8F (catheters are sized by outer diameter)
How big will the puncture site be if you use an 8F sheath?
10F (sheaths are sized by inner lumen diameter)
Note: You can get the outer lumen diameter by adding 2F.
1 French = ? Mm
0.33 mm
What unit is usually used for wire length?
Cm
Note; Inches are usually used for wire diameter.
How many mm will the puncture site of a 6F sheath be?
8F/3 = 2.7 mm
Note: The outer diameter of a sheath is 2F larger than the inner diameter.
What is the minimum mm that a puncture site be if you use a 6F sheath that is coaxially placed into a short access sheath?
10F/3 = 3.3 mm
Note: A 6F sheath has an outer diameter of 8F, so the minimum 8F short access sheath would have an outer diameter of 10F.
A 3F catheter is about as wide as a ___ Gauge needle
20G
Note: Both of these are approximately 1 mm.
What is the standard sized puncture needle used in IR (without a micro puncture)?
19G (to allow passage of a 0.035 inch wire)
Note: 19G is the outer diameter (just memorize this).
What is the micro puncture technique?
Using a smaller initial puncture and micro wire to gain access, then dilating up:
- Initial puncture with a 21G needle (rather than the larger standard 19G)
- Place 0.018 inch microwire and withdraw needle
- Use dilator(s) to increase size to 4F or 5F (which will allow a standard 0.035 inch wire)
What are non-steerable wires used for?
Support for exchanging catheters (NOT for navigating vessels)
What is a standard wire length?
180 cm
Note: A long wire is usually ~260 cm.