Lecture 11 Flashcards
sterile liquid formulations (2/13)
vascular access devices
peripheral (needle, over-the-needle catheter) and central (peripherally-inserted central catheter - PICC, surgically implanted)
peripheral access - administration sets
basic set
add-a-line set
volume control set
basic set
piercing spike –> drop orifice –> drip chamber –> roller camp –> y site –> luer-lock adapter
add-a-line set
piercing spike –> drop orifice –> drip chamber –> backcheck valve –> luer-lock adapter –> y site –> roller clamp –> y site
volume control set
piercing spike –> roller clamp –> volume control chamber –> drop orifice –> drip chamber –> y-site –> needleless adapter
IV administration sets
macrodrip
microdrip
macrodrip
delivers large quantities
faster rates
10,15, or 20 drops per mL
microdrip
delivers smaller amounts
60 drop per mL
used in pediatrics
patients who need small or closely regulated amounts of IV solution
drop conversion factor
drop number
initial educated guess
seldom the exact converrsion factor for actual parenteral preparations
Poiseuille’s Law
rate = driving force/resistance
Q = delta(P)pi(r^4) / 8nl
components of resistance to flow
tubing (macrobore vs microbore)
in-line filter (may or may not be used)
viscosity of IV fluid
length of tubing
venous backpressure
acutal number of drops/mL depends on
viscosity of the CSP
surface tension
density
peripheral access
butterfly needle
over the needle catheter
central venous therapy
infusion of large volume of fluid
multiple infusions
long term infusion therapy
infusion or irritating medications like potassium
infusion of fluids of high osmolarity
parenteral nutrition (PN)
central lines
peripherally inserted central catheter - PICC
two common names - Hickman and Broviac
PICC line steps
- prep acess and introduce the thinwall percutaneous entry needle into the vessel
- using guidance, introduce the wire guide through the needle 15 to 20cm into the vessel
- leave the wire guide in place, but withdraw needle
- introduce the sheath-introducer assembly over the wire guide and twist to advance the assembly into the vessel
- determine the correct length by advancing the wire to desired location and mark the length with clamping forceps. withdraw wire guide and measure to determine correct catheter length
- leave sheath in place, remove the dilator
- introduce the catheter/obturator into the sheath and advance to position
- by grasping the two knows of the sheath, pulling outward and upward remove the sheath and remove obturator after catheter is in final position
- catheter can now be sutured to the skin and dressed
central venous access sites
through subclavian vein (chest) or through internal jugular vein (neck)
central vein catheter (CVC)
surgically implanted
hickman catheter
requires surgical insertion
dacron cuff prevents excess motion
inserts in subclavian vein
vascular access port (VAP)
requires non-coring needle (conventional, straight, right-angle)
the tube and the port are under the skin
advantages of central venous therapy
access to central veins
rapid infusion of large amounts of fluid
a way to draw blood and measure CV pressure
reduced need to repeated venipunctures
reduced risk of vein irritation from infusing irritating substances
risk of central venous therapy
sepsis
thrombus formation
perforation of vessel and adjacent organs
air embolism
disadvantages of central venous therapy
cost
requires more skill to insert then peripheral therapy
risks associated with infusion
complications from damage to the inner lining of the vein (intima)
intima types
stenosis (narrowing)
thrombus (clot)
venous occlusion
chemical inflammation (phlebitis) and pain
instrumented flow control
controllers (use gravity as driving force)
pumps (powered devices)
controllers
use gravity as driving force
drop counting sensor flows into the controller (automatic clamping device)
infusion pump caution
the use of excessive infusion pressure can be a hazard with respect to infiltration at the site of injection
infusion pumps
powered devices
provide pressure in the range of 2-12 psi (100 to 600 mmHg) – high end of this pressure range is used for intra-arterial infusions
features of infusion pumps
volumetric delivery, independent of vascular back pressure, position of patient, composition of infusion solution, or tubing resistance
pump does not turn the drip chamber into an ornamental item
safety features of infusion pumps
occlusion of line
infusion complete
air in line
empty container
flow rate error
IV infusion pumps
symbiq infusion system
omni-flow 4000 plus (complex therapy - program multiple drugs)
syringe pumps
use commercial syringes
smart machines
especially useful for giving intermittent IV medications
provide the best control for small volume infusions
useful for pediatric patients
other parenteral pumps
patient-controlled analgesia (PCA)
ambulatory pumps
implantable pumps
PCA
pain relief is generally obtained at a lower total dose of drug
patient-controlled analgesia pump
ambulatory pumps
refers to size and weight of the pump, as well as ability to operate without an external power source
attaches to hip
example - insulin pump
implantable pumps
usually with reservoirs of around 50mL
used for IV, intraspinal, and intra-arterial routes
can deliver as low as 1 mcg/hr
