EVD Tips

[Guest]

Incoming intern here, anyone have any tips for EVDs that really helped them?

[Focus]

Draw trajectory lines from nasion/medial canthus and 1cm anterior to tragus all the way to your incision every time.

[Guest]

Be picky about measurements. It's a landmark-guided procedure with success that relies on burrhole location. Poorly placed drains often have holes drilled too medially/laterally/anterior/posterior. Quality check your hole location on the post-placement CT for learning. If your hole is well-placed, and your insertion trajectory is perpendicular to the skull surface, you'll nail even very small ventricles most of the time.

[Guest]

Side: Usually right frontal, but think of any future surgeries that might be needed. If for example there is a possibility you might do a right sided craniectomy for subdural, or a right craniotomy for AComm or MCA aneurysm clipping, then place it on the left side for those patients to avoid moving it post-op.

Kocher's point: So many different ways of measuring, find a way that gives you consistent results in your hands and stick to it. For me, it is 10.5 cm from glabella (right above the nasion), and mid-pupillary line. I double check that this mid-pupillary line is at least 2.5 or 3 cm from midline, otherwise I might have skived off the true mid-pupillary line towards the midline (very dangerous, close to SSS). I always shave past the midline, and always mark the midline with a dotted line (I do that in craniectomies as well when I want to be as wide as possible, but still away from SSS).

Drilling: Use the widest drill bit in the cranial access kit. This way, even if you hole is off a little bit, you can still manipulate the trajectory of the catheter. Use the safe stopper at a relatively safe distance: not too close so you don't have to stop what you are doing and adjust it when it touched the patient and you aren't through the skull yet, and not too far away so you don't plunge into the brain. It is the speed of your hand rotation, not the pressure you exert on the skull that drills the bone away, helps avoiding plunging as well.

Dura: Do not forget to pierce through the dura. I use the sharp tunneler in the ventricular catheter kit to do so. I have seen an epidural once from a non-punctured dura and the catheter indenting into the dura, thus creating a large epidural space before eventually piercing the dura.

Trajectory: Strictly perpendicular to the skull. Notice that the skull is convex/curved at this entry point, so the perpendicular line is facing outwards, and sometimes slightly facing anterior as well. Placing the back of an empty syringe flushed on the scalp at this point can help give you an idea what the perpendicular should look like. Head should be positioned in the neutral position, with the patient facing the ceiling. You might need a coresident, medical student or a nurse to hold the head during drilling to avoid moving your trajectory by mistake.

Depth: If you have to place a frontal EVD deeper than 6 cm from scalp, reassess what you are doing. We tend to place it deeper because we fear that we are barely touching the ventricles, or it might be pulled out while tunneling, only to find out in the post-procedure CT that it is too close to the third ventricule, or even the brainstem/basilar. At least my first EVDs tended to be deeper. You will usually feel a tactile feedback when you are at the ependyma and pierce it to get into the ventricles if you are paying attending to that while introducing the catheter.

CSF: Do not lose CSF during the procedure. Pinch the catheter, or connect the tunneler immediately, etc. Think if you need to send CSF for any reason: suspecting infection, germ cell tumor, etc.

Secure catheter: make sure you secure it well so it doesn't get pulled out by patient, nurse, or during transport. I use a pressure loop with lots of staples. Pay attention not to staple through the catheter itself otherwise it will leak CSF.

Level: Do not forget to place it at the correct level from the EAM, and inform the bedside nurse, and even place orders in EMR for that. I have seen an ICH once from over drainage due to poor communication, in an otherwise perfectly placed EVD.

CT: As mentioned by a previous poster, use the post-procedure CT to learn and constantly improve your EVD until you master it.

Good luck with intern year!

[Guest]

stop being bad

[Guest]

How many EVDs do most interns do by the end of their 1st year?

[Guest]

(06-20-2022, 08:40 PM)Guest Wrote: How many EVDs do most interns do by the end of their 1st year?

Depends on where you train, 0-50

[Guest]

(06-20-2022, 08:57 PM)Guest Wrote:

(06-20-2022, 08:40 PM)Guest Wrote: How many EVDs do most interns do by the end of their 1st year?

Depends on where you train, 0-50

I'm starting PGY2 year at a top program and I have done just 3 EVDs (all supervised). What can I do to increase my exposure?

[Guest]

(06-21-2022, 10:56 AM)Guest Wrote:

(06-20-2022, 08:57 PM)Guest Wrote:

(06-20-2022, 08:40 PM)Guest Wrote: How many EVDs do most interns do by the end of their 1st year?

Depends on where you train, 0-50

I'm starting PGY2 year at a top program and I have done just 3 EVDs (all supervised). What can I do to increase my exposure?

Nothing, what can you do? Lot of places out there recommend pentobarb comas and at max ICP bolts, some are EVD shy.

[Focus]

It will come with time and call responsibilities. I didn't do many EVDs as intern either because I started on the consult service in July when the PGY2 was still getting acclimated/trained.

Also, shunts.