Central venous catheters
##Contraindications
- In elective placement: ?INR 2.5, Plt 40 -> consider products. (Consider other reasons for platelet dysfunction, e/o for transfusion in liver patients). However, in the ICU: risk/benefit matters more.
###Equipment
- consent
- chlorhexadine wipe x3
- central line kit (sterile drape, 25 guage needle, 5 ml syringe, saline flush, 22 gauge finder needle, introducer needle, guidewire, dilator, No 11 blade, Suture (3-0 or 4-0, nylon or silk))
- ultrasound machine and sterile probe covor
- local anesthetic (often NOT in kit)
- 4x4 pads
- chuck to place under the patient
- Dressing
- Sterile glove and gown
CVC choice
- perc sheath to introduce PM, PA cath, or high rate infusion, multi-port for infusions, blood sampling, CVP monitoring
- 13cm for R IJ, 16cm for L IJ, 20/24 for femoral. (?subclav?)
Particularly for dialysis lines: important to have long enough to reach RA:
- https://pubmed.ncbi.nlm.nih.gov/22497790/ RCT n=100, longer line targeting RA improved duration, daily dialysis dose, reduced clots, no excess adverse effects
- less UE DVT - https://europepmc.org/article/MED/11526263
Malpositioning is probably not all that important: https://pubmed.ncbi.nlm.nih.gov/18326129/
US Guidance principles
- use linear array high frequency transducers
- orientation = probe marker oriented to the operator's left when machine is positioned beyond the site of insertion. This should result in the marker on the US screen corresponding to the side of the marker.
- can use short axis (transverse to vessel) and out of plane (meaning, needle is a point) OR long axis (in line with vessel) and in-plane (can see the whole needle)
Seldinger Technique
Prior to sterile:
- take a nonsterile look at the vein you're planning to canalize, mark with pen indent or cap. Confirm patency (if it is fully compressible, there is not a clot right there. also, doppler wave form) of vein if possible
- open kit, ultrasound probe cover, and chlorhexadine into sterile area over kit
- wash hands, cap/mask/gown/glvoes
Once sterile
- place drape over the patient following the arrows, tent over the patient's face, opening over the access site.
- put gel in the ultrasound sheath and put on the sheath, tape or clamp to drape.
- clean skin x2 w circular motion starting from access point
- check kit - take caps off the catheter and put wire through.
- visualize the jugular vein with the US - turn 90 degrees (long way) to appreciate direction of travel.
- anesthetize skin w 25g needle. Only needs to be placed under superficial skin but do over a larger area
Needle Access
- use large bore finder needle on 5 ml syringe, short "jabs" to get through skin
- keep eyes on US screen, vein should be in center of screen
- follow tip of and aspirate blood. Common to go deep - withdraw while aspirating.
- once blood returns, confirm needle is in the vessel with US, then let go of ultrasound probe, keep one hand holding needle while resting on patient
Insert Guidewire
- disconnect syringe and occlude the needle hub (or, if kit has a needle threading port, leave in place)
- insert guidewire through needle. If you get resistance, remove guidewire, put on syringe, and see if blood still returns
- remove needle over guidewire
- confirm placement of guidewire with ultrasound (visualize in vein, vein confirmed by compressibility. ideally, both long and short axis views.). Keep 1 hand holding the guidewire.
Insert Catheter
- use no. 11 blade to enlarge puncture site via stab incision
- hold guidewire while threading dilator over the guidewire, then insert and remove the dilator (may need to use multiple dilators if large bore).
- hold guidewire and thread catheter over the guidewire (if triple, shortest and brown port is where the guidewire will come out). Do not insert catheter in to skin until wire has come out the port.
- insert catheter to desired depth (introducer sheath completly in - can always pull back but cannot push forward after), then remove the guidewire (if resistance, stop and remove both ?shear)
- aspirate blood to syringe from catheter port, flush all ports with saline
Dress and Confirm
- suture in place with at least 2-3 of the spots
- dab of antibacterial ointment (or antibiotic on dressing) and apply dressing
- Confirm placement (generally with XR, check for PTX with US)
- place caps on lines
- find needles and dispose.
###Right Internal Jugular
Place in 15-20 degree trendelenburg if possible to enlarge vein / decrease risk of air embolus
Landmarks
- IJ widest below level of cricoid cartilage
- R IJ preferred due to higher pleural dome on L side (and straight shot into R atrium).
- triangle between SCM heads and clavicle
- insert at 30-40 degrees, Angle on line from angle of jaw to ipsilateral nipple, expect 1.5-3cm
- on US: should have no pulsatile flow, should be compressible, if patient awake have them valsalva to ensure enlarges
- artery should be just lateral.
####Confirmation XRay: catheter tip at or slightly above level of carina (minimize atrial arrhythmias / myocardial wall erosion)
###Subclavian
Note: less water column (height( of fluid that negative intrathoracic pressure has to pull in - thus with large negative intrathoracic pressure (e.g. large breathing efforts) could be possible to entrain air)
Landmarks
- fibrous connective tissue to clavicle and 1st rib prevents collapse in low flow
- cannulation takes place at medial third of the clavicle.
###Femoral
Landmarks
- artery = mid point from pubic symphysis to anterior superior iliac spine
- vein = 1 cm medial to arterial pulse.
- puncture skin 2-4cm, vessel 1-2 cm below inguinal ligament to avoid bowel perf or external iliac puncture (which can cause retroperitoneal bleeding)
Femoral line avoidance is based on old data - probably safe a underused nowadays https://acphospitalist.org/archives/2018/08/perspectives-avoiding-the-femoral-vein-in-central-venous-cannulation-an-outdated-practice.htm