chapter 13 injection techniques Flashcards
22 gauge catheters may tolerate flow rates up to
5 mL
20 gauge catheters may tolerate flow rates up to
3 mL
preferred vein when using a mechanical injector
antecubital
if using veins on the hand or the wrist limit flow rate to
2.0 mL or less
apply tourniquet about ___ proximal to choosen site
2 in.
CVAD
a venous catheters designed to deliver medications and fluids directly into SVC,IVC, and RA
PICC
a long catheters that is inserted through the large veins of the upper arm and advanced so the tip is located in the lower 3rd of the SVc
three phases of tissue enhancement
bolus, nonequlibrium, equlibrium
differences between tissue enhancement phases
1, rate of contrast
- time that elapses from the start of the injection
- when scanning is initiated
bolus phase
immediately follows after injection
30 or more HU
arterial structures are highlighted
Ct angiography images are taken while in the ___phase
bolus
nonequilibrium phase
follows the bolus phase
10 to 30 HU
contrast is still bright in the arteries than in the parenchyma but venous structures are opacified
Most routine body images are acquired while contrast is in the ____ phase
nonequilibrium
equilibrium
contrast is largely emptied from the arteries and greatly diluted in the veins and has soaked the organ parenchyma
less than 10 HU
worst phase for scanning the liver
eqilibrium
contrast typically reaches a near peak in the aorta ____ after the start on injection
15 to 22 sec
kidney scans are often acquired in the nephrographic phase which is____ after injection
80 to 120
For routine brain scanning a scan delay of ____or greater is typical to allow sufficient time for contrast to leak across a disrupted blood -brain barrier into abnormal tissue
4 min
drip infusion
IV line is initiated and contrast medium is allowed to drip in during a period of several min
drip infusion is not recommend for
scans of the neck, chest, abdomen or pelvis
extravasation
is the leakage of from a vein into the surrounding tissue
test bolus
method consist of administering 10 to 20 mL of contrast by IV and performing several trial scans to determine the length of time from injection to peak contrast enhancement in a target region
bolus triggering
uses a series of low radiation to monitor the progress of the contrast bolus , once adequate level of enhancement is achieved the table starts scanning
