Ultrasound-Guided PIV Placement Part 2 POD

jonas pologe · September 14, 2018 · Procedures, Ultrasound

The following is a powerful advanced technique that can be used to troubleshoot traditional short-axis US-PIV placement.

A familiar scenario: The elusive needle tip!

You’re placing an US-guided PIV and going ahead with your short axis technique
The vessel is directly under the center of the probe, right on that Bx-guide line
You know exactly how deep it is
The needle has entered the skin… the tip should be right over or very near the vessel…
But where is it??? You’re bouncing the needle a little and see tissue moving, you’re slowly sweeping the probe backward and forward where your needle tip should be, but it continues to elude you! Maybe it’s a little deep, maybe there’s some echogenic (bright) tissue hiding it, doesn’t matter, here’s what to do...

The answer: Long Axis — Hear me out!

Take your eyes off of the ultrasound screen
Pick up the probe and place it back down, marker toward you, exactly along the axis of the angiocath, DIRECTLY over it!
Without moving your hand, look back up at the screen. Unless you’re at a crazy steep angle, you will see your whole needle clearly!
If you see the vessel on the screen as well, you are now perfectly set up to continue placing your IV
Position the tip in the vessel lumen, then advance the angiocath over the needle as you normally would

Image result for long axis ultrasound guided IV

The other scenario: You’ve positioned the probe over the needle, you look up and see the needle but not the vessel any more, or maybe part of the vessel — here’s what you do

Slide/rotate the probe such that you have the vessel in view at its widest diameter on the screen
Then LOOK BACK AT THE ARM
If the probe is now to the right of the needle, you need to redirect to the right; if the probe is to the left, the needle needs to go left
Withdraw the needle a few mm and then redirect so that it is inline with the ultrasound
As you do this, look back up at the screen and you should see the needle coming into view

In a nutshell: If you’ve lost your needle tip

1. Use the probe to show you where the needle is

2. Use the probe to show you where the vessel is

3. With the probe over the vessel, position the needle so that it’s directly under the probe

4. Now all three are lined up and you’re ready to position the needle tip in the vessel lumen

A few last tips:

You can fine-tune your left-right control of needle tip in long axis by just moving the needle slightly one way or the other and seeing if it comes more into view or less into view — this will start happening automatically if you practice this technique a few times
I still recommend letting go of the probe and advancing the angiocath with non-dominant hand, however if an assistant takes the probe when you are ready to advance the angiocath, you can watch it go into the vessel and ensure that it is advancing smoothly into the lumen.
You can do this with one person as well but this requires advancing the angiocath and stabilizing the needle with one hand, which is more difficult and gives little tactile feedback as to whether it is advancing smoothly or meeting resistance
Once you’re comfortable with this long-axis technique, try doing the entire procedure in long axis. This tends to work very well for deeper, straighter veins.
There’s no reason you can’t switch back to short once you’ve found your needle tip and repositioned it; perhaps it’s a twisty vessel with multiple turns and you need to walk it in a little more - short axis is better for navigating in the left-right direction (as long as you’ve located your needle tip!)
Remember the concept of "angle of insonation": the steeper your needle angle, the more difficult it will be to see your needle because fewer ultrasound beams are bouncing back to the probe (more are being deflected in a different direction)

Jonas Pologe, PGY3, Emergency Medicine, Maimonides Medical Center

POD Aortic Dissection

jonas pologe · September 14, 2018 · Ultrasound, Cardiovascular

A patient came to the north side today with an acute aortic dissection. Here are images obtained by the ultrasound team when the patient first came in.

A suprasternal view showing an intimal flap:

A short axis view of the abdominal aorta showing an intimal flap

Diagnosis was made, BP meds started, cardiothoracic consulted, and CT expedited.

CT showed a severe type B thoracoabdominal aortic dissection:

Aortic Dissection

Pathophysiology:

Tear in the intima (inner most layer), bleeding into the media (middle layer)

Diagnosis of aortic dissection is very time sensitive:

mortality is directly proportional to time elapsed between symptom onset and diagnosis/treatment

How does it eventually kill you? (I think it’s important to ask this question about all disease processes)

acute aortic regurgitation —> cardiogenic shock

Cardiac tamponade —> obstructive shock

Major brach-vessel obstruction —> vasodilatory shock from dead organ or limb

Aortic rupture —> hemorrhagic shock

2 types that we care about: Stanford Type A and Stanford Type B

Type A

involves ascending aorta

— surgical — a/w aortic rupture, tamponade, aortic regurg, AMI, stroke — more common (68%)

Type B

does not involve ascending aorta — medical (BP control and monitoring) — a/w limb/organ ischemia — less common, (32%) — usually originates just distal to L subclavian artery

Classic history: old person,

very hypertensive

;

abrupt onset

tearing/ripping chest pain

radiating to bac

k; a/w neuro symptoms e.g.

weakness/numbness

(due to vessel branch occlusion); a/w syncope/diaphoresis/N/V

Other risk factors include Marfan’s, connective tissue disease, FHx aortic disease, known aortic valve disease, recent aortic manipulation (e.g. TAVR, surgery), known thoracic aortic aneurysm, tobacco; rarely 3rd trimester pregnancy, TB, syphilis, vasculitis, blunt trauma

Classic physical: Pulse deficit (present in <20% of cases), unequal BP in upper/lower extremities, neuro deficits, signs of tamponade

Diagnosis:

Labs: basics, coags, trop, consider d-dimer (actually high sensitivity/NPV for dissection due to blood often clotting I false lumen)

CT angio aorta: gold standard for diagnosis of aortic dissection

CXR: not sensitive, not specific — sometimes mediastinal or aortic knob widening, few other nonspecific signs

TEE: is an excellent modality that’s in the works but we don’t have it operational yet

TTE: next best thing, as usual with ultrasound it’s specific but not sensitive - see below

Ultrasound for aortic dissection — obtain the following views:

Subxiphoid: look for pericardial effusion

Parasternal long: look for effusion, look at the descending aorta, look for aortic regurg with color doppler and measure the aortic root (nl <4cm) if you want to be fancy

Suprasternal window:

look for dissection flap (image from University of Maryland department of cardiology)

Probe above the the patient’s sternum pointed inferoposteriorly with probe marker to patient’s left (assuming cardiology convention)

Abdominal aorta scan: look for dissection flap from diaphragm to iliacs, also measure diameter in short and long

Management (From the AAC/AHA aortic dissection guidelines):

ACC AHA AoD Treatment-Algorithm

Note: When blood pressure is intact, first bring heart rate with beta blockers, then control pain, then see if they need further BP control.

Superficial Cervical Plexus Block POD

jonas pologe · September 7, 2018 · Ultrasound, Procedures

That’s right. Time to talk about my favorite nerve block.

The SCPB

This block is

quick

and

easy

It makes

IJ central lines

painless procedures

It also provides excellent analgesia for

clavicle fractures

ear lobe lacerations

blind subclavian lines

, or

anything within this quadrilateral

How to do it

Find the

posterior aspect of the sternocleidomastoid (SCM) muscle

Position the probe half way down the SCM as you measure it from mastoid process to clavicle.

About at the level of the superior aspect of the thyroid cartilage, also about where the EJ crosses over the sternocleidomastoid.

The fascial plane under the posterior aspect of the sternocleidomastoid muscle is your target.

Like other

plane blocks

you are not targeting any one nerve in particular. By infiltrating this tissue plane, you get the superficial plexus as it peeks out from behind the SCM at this level:

Inject 5-10 cc of local anesthetic.

Ensure it is spreading in the plane like this.

Safety:

As with all ultrasound guided nerve blocks, visualize your needle tip always, especially prior to injection.
When you begin injecting, inject one mL only to ensure you see it spreading in the fascial plane. Then inject the rest.
Withdraw before you inject if there is even a slight possibility you are close to a vessel
Throw some color on your site to ensure you identify any vessels.
In general this is a very well tolerated and forgiving block.
The incidence of phrenic nerve involvement is extremely low with SCPB, far lower than with the interscalene block. Phrenic nerve involvement will be avoided if ensure you don’t go too deep - a few cm, or about half way down the deep edge of the SCM. Going deeper than this results in a deep cervical plexus block which will result in some motor and sensory blockade of the arm.
Horner’s syndrome is a rare and self-limiting complication.
The amount of local anesthetic used in this block is nowhere near close to toxic levels, so local anesthetic systemic toxicity will not occur as long as you manage to avoid the IJ and carotid.

Tips and troubleshooting

For a central line, you can set up, gown, drape, and set up your ultrasound like usual, then use the 5 cc lidocaine which come in the central line kit for your block. Place the block first, then flush your line/lay out your equipment, and your patient will likely be completely numb by the time you’re ready to start your line placement.
The other option is to place your block while you’re doing your pre-scan. This way you can use 5-10 cc, but you have to get it out of the Pyxis. Just clean the probe and the skin with a chlorhexidine swab and use sterile gel.
If it’s your first time doing a block, consider doing it as a 2 person block. Use some IV extender tubing and have another provider operate the syringe for you. I like slightly longer tubing than typical IV tubing, e.g. the one below. At Maimo, you can find it in the stock room between North and South sides, top shelf straight ahead when you first walk in.
Can't visualize your needle? Make sure your ultrasound probe is directly above it and in-line with it. Next, make sure it is as close to parallel to the surface of the probe/perpendicular to the ultrasound beams as possible. If you are approaching a 45 degree angle, your needle will be close to invisible. At close to a 0 degree angle, it will shine like a laser beam.
You can use the 27 gauge needles to make it more comfortable but they are a little harder to see.