Introduction and Indications
Central lines are intravenous catheters that are placed into the large veins of the body. They allow the infusion of various medications that cannot be given through a peripheral line (ie: a "normal" IV). They are commonly placed in patients who are in the intensive care unit (ICU).
Most intravenous vasopressors (medications that increase blood pressure) and vasodilators (medications that decrease blood pressure) should only be given through a central line. In addition, 3% sodium chloride infusions and certain chemotherapeutic medications should only be given through a central line because of the risk of damaging the smaller veins of the body. Finally, central lines can be used to measure the patient's central venous pressure; this data gives the clinician an idea about how much intravascular volume the patient has.
It is important to note that central lines are not necessarily the best way to give someone intravenous fluids such as normal saline or lactated Ringer's. 16 gauge peripheral IVs and Cordis® catheters (a different type of central line that is wider and shorter) allow much faster infusion rates than a standard central line.
Central lines are placed in one of the three readily accessible large veins of the body: the femoral, subclavian, or internal jugular veins. Suffice it to say that there are benefits and drawbacks to each location. Central lines come in single lumen, double lumen, and triple lumen varieties depending on the purpose of the line. A lumen is an access port that can be hooked up to intravenous tubing. The more lumens a line has the more "stuff" can be hooked up to it.
- Central line kit. Most kits contain the following items:
- Central line
- Introducer needle
- Guide wire
- Lidocaine vial
- Several smaller needles and syringes
- Dilating tool
- Sterile blue towels
- Sterile half (or full) drape
- Sterile gown(s)
- Sterile glove(s>
- Hair bonnet
- Sterile saline flushes
- Port tips ("dead heads")
- Ultrasound machine (if available)
- Sterile ultrasound probe cover
- Sterile ultrasound jelly
- Sterile dressing (usually a Tegaderm™)
- Chloraprep™ sticks (a mixture of chlorhexidine and alcohol)
These steps may not be done in this exact order, and quite frankly, some steps belw may be completely ignored, altered, or changed depending on the circumstance. This is meant to serve only as a guide to the placement of a central line.
- Get consent from the patient or next of kin.
- Hook the patient up to continuous heart rhythm monitoring (ie: telemetry).
- Check the patient's coagulation parameters (generally INR should be less than or equal to 1.3). Give fresh frozen plasma or vitamin K (usually 10mg IV if urgent correction is needed) as indicated.
- Check patient's platelets (goal should be greater than 100,000 in most circumstances).
- Use the ultrasound to survey the vein of interest to make sure it is open.
- Chloraprep™ widely around the vein of interest.
- Open up the central line kit in a sterile manner. At this point you should also introduce any sterile supplies you may need onto the kit so you have them when you need them. This usually includes sterile saline, port tips, and sterile drapes/towels.
- Put on your sterile gown, bonnet, gloves, and facemask.
- Use sterile drapes to section off the anatomy of interest. Remember that the guide wire is quite long and may accidentally hit non-sterile objects such as IV poles, etc. Move all these things out of the way and drape widely.
- Take the central line and flush each of the ports with sterile saline to ensure they are working properly.
- Put ultrasound probe in sterile sleeve. Ensure there is adequate ultrasound jelly on the non-sterile side of the sleeve.
- Find the vein of interest with the ultrasound. Pressing on the patient's skin with the probe should cause the vein to collapse; the artery, on the other hand, is difficult to compress because of its elasticity.
- Take the introducer needle and insert it towards the vein with your dominant hand. Your non-dominant hand should be holding the ultrasound probe.
- Use ultrasound guidance to make sure your needle is headed towards the vein.
- Aspirate with the syringe on the end of the introducer needle as you advance until you get a flash of blood. This indicates you are in the vein.
- Let go of the ultrasound probe and using your non-dominant hand stabilize the introducer needle so it doesn't get pulled out of the vein.
- Take the guide wire and advance it through the end of the introducer needle. There should be minimal resistance if the needle is still in the vein.
- Advance the guide wire about 15cm. Look for abnormal heart beats on the telemetry monitor. If present this indicates the guide wire is in the heart and should be withdrawn slightly.
- Thread the needle out of the vein and off the end of the guide wire. The guide wire should still be in the patient.
- Make a small skin nick at the entry point of the wire with a scalpel.
- Take the dilating tool and thread it over the wire. With a twisting motion dilate the nick in the skin. This will facilitate passage of the catheter. Note that you only need to insert the dilator a small amount.
- Remove the dilator over the wire.
- Take the previously flushed central line and thread it over the wire. Advance until the wire is coming out of the distal port. NEVER thread the catheter into the vein without having at least one hand on the guide wire. If you advanced the guide wire too far you may have to back it out of the patient so it has enough "slack" to come out the distal port before advancing the catheter into the patient.
- Thread the catheter over the guide wire and into the vein.
- Gently pull the guide wire out of the distal port.
- Attach a syringe with sterile saline to each of the ports (if there is more than one lumen). Then draw back to ensure there is blood return; this step will also remove any air bubbles in the system; then flush with sterile saline. Do this with each lumen/port of the catheter.
- Suture the port into place. Most central lines come with a click-on apparatus that will give you two additional holes for suturing it in place.
- Place a biopatch around the entrance of the line into the skin.
- Cover with a Tegaderm™ or other sterile dressing.
- For subclavian and internal jugular vein central lines a follow up chest X-ray must be ordered. The tip of the line should ideally be seen in the superior vena cava before it is ok to use.
Central lines are placed in patient's receiving intravenous medications that are caustic to smaller peripheral veins. They are placed in either the subclavian, femoral, or internal jugular veins. Infection is a big concern with central line placement so strict sterile technique should be used when placing one. There are different types of central lines; some have multiple ports on them. A chest X-ray should always be ordered if a subclavian or internal jugular vein is placed.
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