Trauma in Pregnancy

Resuscitation of the Pregnant Trauma patient

 

General principles

·      Trauma is the most common cause of non-obstetrical maternal death in the United States

·      Best fetal resuscitation is good maternal resuscitation.

·      Stabilization of the pregnant women is the first priority; then, if the fetus is viable (≥ 23 weeks), fetal heart rate auscultation and fetal monitoring can be initiated and an obstetrical consultation obtained as soon as feasible

·      In Rh-negative pregnant trauma patients, quantification of maternal–fetal hemorrhage by tests such as Kleihauer-Betke should be done to determine the need for additional doses of anti-D immunoglobulin.

·      Tetanus vaccination is safe in pregnancy and should be given when indicated.

 

 

Airway

·      Greater risk for difficult intubation than non-pregnant patient

·      Pregnancy related changes à decreased functional residual capacity, reduced respiratory system compliance, increased airway resistance, and increased oxygen requirements

·      Gastric emptying is delayed in pregnancy à greater risk for aspiration

·      Respiratory tract mucosal edema à A smaller size of endotracheal tube is recommended

·      Choice of RSI medications NOT affected by pregnancy status

 

Breathing

·      Place chest tube one to 2 intercostal spaces higher than usual to account for displacement of the diaphragm during pregnancy

·      Marked increases in basal oxygen consumption à lower threshold for supplemental oxygen

 

Circulation

·      Fluid and Colloid resuscitation like standard trauma protocol

·      Uteroplacental vasculature is highly responsive to vasopressors, and their administration may decrease placental perfusion à vasopressors should be avoided unless refractory

·      Avoid supine hypotension: Compression of IVC by the uterus can cause up to 30% reduction in cardiac output à Place in left lateral position or by manual displacement of the uterus while the injured patient is secured in the supine position

·      O-negative blood should be transfused in order to avoid Rh sensitization in Rh-negative women

·      Vital signs: heart rate increases by 15% during pregnancy. Tachycardia and hypotension, typical of hypovolemic shock, may appear late in the pregnant trauma patient because of her increased blood volume.

·      Maternal vital signs and perfusion may be preserved at the expense of uteroplacental perfusion, delaying the occurrence of signs of hypovolemic shock

·      Attempt to obtain supra-diaphragmatic intravenous or intraosseous access for volume resuscitation and medication administration.

 

 

FAST

·      The FAST is less sensitive for free fluid in the pregnant patient than in non-pregnant patients.  Sensitivity decreases with increasing gestational age, likely due to altered fluid flow within the abdomen.

·      Management of suspected placental abruption should not be delayed pending confirmation by ultrasonography as ultrasound is not a sensitive tool for its diagnosis.

 

 

Secondary survey

·      In cases of vaginal bleeding at or after 23 weeks, speculum or digital vaginal examination should be deferred until placenta previa is excluded by a prior or current ultrasound scan.

 

Imaging

·      Radiographic studies indicated for maternal evaluation including abdominal computed tomography should not be deferred or delayed due to concerns regarding fetal exposure to radiation.

·      Ionizing radiation has the highest teratogenic potential during the period of organogenesis (5–10 weeks), with an increased risk of miscarriage before this period.

·      With abdominal CT during the third trimester the fetal exposure is around 3.5 rads, which is still under the threshold for fetal damage

·      Contrast agents should be used if indicated.

 

 

Resuscitative Hysterotomy in Cardiac Arrest

·      Should begin within 4 minutes and completed within 5 minutes of cardiac arrest

·      Both maternal and fetal survival decrease significantly after 5 minutes

·      Do NOT delay the procedure for the arrival of an obstetrician or neonatologist.

·      Do NOT evaluate for fetal cardiac activity or tocometry.

·      Do NOT prepare a sterile field (but be as clean as possible).

·      Do NOT transport to an alternative location.

·      Performing RH increases maternal cardiac output by 30%.

 

RH Algorithm.png


 

References:

 

Tamingthesru.com

EmDocs

Jain, Venu, et al. "Guidelines for the management of a pregnant trauma patient." Journal of Obstetrics and Gynaecology Canada 37.6 (2015): 553-571.

Smith, Kurt A., and Suzanne Bryce. "Trauma in the pregnant patient: an evidence-based approach to management." Emergency medicine practice 15.4 (2013): 1-18.

 

 · 

Resuscitative TEE

Important: Please complete the Sexual Harassment Online Module ASAP!




Resuscitative Transesophageal echocardiography (TEE)

  • TEE allows the emergency physician to maintain the standard of an ultrasound-informed resuscitation in the scenario of cardiac arrest, where TTE is significantly limited.

  • Focused or resuscitative TEE (4 views) differ from comprehensive TEE (>20 views) that cardiology performs in that it is employed to identify specific questions.

  • TEE allows for potentially shorter chest compression pauses

  • TEE allows for evaluation for the quality of chest compressions

  • TEE allows for visualization of fine V-fib not seen on the monitor

 

Indications: Cardiac arrest (ACEP)

Contraindications: Esophageal injury or stricture and lack of a definitive airway

How to manipulate a TEE Probe:

5 different ways you can physically manipulate the TEE probe

1. Withdraw or Advance up or down patient’s esophagus

2. Turn probe to right or left

3. Turn tip of flip in anterior- ante-flexing or in the posterior direction called retro-flexing --> large wheel

4. Turn tip to Left or right -->  small wheel (not typically used for our purposes)

5. In addition, you can rotate the transducer housed within the probe itself (AKA omniplane or multiplane)-->  adjusts the beam angle anywhere between 0° and 180° -->  two smaller buttons ( crystal rotation)

TEE manipulation.jpg

 

TEE-controls- wheels.png

 

 

The views are obtained in the following order: : 

The midesophageal 4-chamber view (ME 4C) is obtained by advancing the TEE probe to the thoracic esophagus and orienting the multiplane at 0-20° in neutral flexion. You may need to retroflex slightly to see all four chambers.

-   The midesophageal long-axis view (ME LAX) is obtained by leaving the probe in the same location as the midesophageal 4-chamber, but increasing the multiplane to between 110° and 160° while in neutral flexion. 

-   The transgastric short axis view (TG- SAX) is obtained by first moving the multiplane to 0°, then advancing the probe into the stomach and ante-flexing the probe

-   The bicaval view (ME bicaval) is obtained by turning the entire probe to the patient’s right towards the superior vena cava (SVC) and inferior vena cava (IVC) while in the mid-esophagus, keeping the multiplane at 90-100° with neutral flexion

 ( The first 3 views are recommended by ACEP. Bicaval not recommended by ACEP) 







TEE views and their analogous TTE views



TTE-and-TEE.gif

Midesophageal four chamber view (ME 4C)

-  Apical four chamber view

-  Great visualization of all chambers as well as the tricuspid and mitral valves in one plane.

-   Evaluation of right and left ventricular systolic function and size

-   Preferred view to evaluate for the presence or absence of a perfusing rhythm during a pulse check.

ME4C.png

 

Midesophageal Aortic Long Axis view (ME LAX)

-  Midesophageal analogous to the parasternal long axis view in TTE

-   View includes the mitral and aortic valves, as well as the left atrium, left ventricle, and left ventricular outflow tract of the right ventricle.

-   Evaluate left ventricular systolic function, and provides feedback on compression adequacy and location. High-quality compressions cause maximal compression of the left ventricle and visualization of the aortic valve opening and closing indicating forward flow of blood.  Poor quality compressions are seen over the aortic root and there is no valvular indication of forward flow. 

ME- LAX.png

 

Transgastric Short Axis view (TG- SAX)

- Analogous to the parasternal short axis TTE view

- Evaluate left ventricular systolic function, including any regional wall motion abnormalities

- Can evaluate for acute MI and the presence of septal flattening in this view

TGSAX.png

Mid Esophageal Bicaval View (ME bicaval)

-   Analogous to the inferior vena cava view of TTE

-   Transducer plane cuts through the left atrium (LA), right atrium (RA), IVC and SVC.

This view allows the operator to evaluate for hypovolemia, atrial size, and interatrial septum bowing.

-   Aids in the placement of central venous catheters, transvenous pacemakers, or extracorporeal life support (ECMO) vascular cannulas by observing the initial wire placement in the vasculature

- Can aid inevaluation of fluid status to guide fluid resuscitation (looking at respiratory variation in SVC)

bicaval.png

 

Pitfalls

-  Compressions do not need to be stopped for TEE insertion. Additionally, the TEE can be left in the esophagus during defibrillation. The probe should be inserted or withdrawn while the tip is in neutral position, and not while the tip is flexed to avoid esophageal injury. 

-  Images should be optimized to avoid foreshortening of the ventricles and to include the appropriate structures for each view.

-  Pericardial effusions must be taken into clinical context, as small effusions can cause tamponade if accumulated rapidly, while large effusions can be well tolerated if they accumulate slowly.

-   Clotted hemopericardium may be isoechoic with the myocardium, making it difficult to identify.

-  Right ventricular failure is not specific to pulmonary embolism, and can be due to pulmonary hypertension or other etiologies such as right sided myocardial infarction, or even cardiac arrest itself.

-  Pleural effusions can be mistaken for pericardial effusions. Multiple views should be used to corroborate findings.

-  Fat pads can be mistaken for pericardial effusions, but these are hypoechoic rather than anechoic and limited to the anterior and apical regions of the heart, not circumferential.

 

 Resource: 

Check out this 3D module that you can practice on 

https://pie.med.utoronto.ca/TEE/TEE_content/TEE_standardViews_intro.html

References:

Drs Lawrence Haines, Judy Lin and Alyssa Phuoc-Ngyuyen

Images: Adapted from Arntfield R, Pace J, McLeod S, et al. Focused transesophageal echocardiography for emergency physicians-description and results from simulation training of a structured four-view examination. Crit Ultrasound J. 2015;7(1):27.

Teran, Felipe, et al. "Evaluation of out-of-hospital cardiac arrest using transesophageal echocardiography in the emergency department." Resuscitation 137 (2019): 140-147.

EmDocs

ACEP policy statement

https://www.acep.org/patient-care/policy-statements/guidelines-for-the-use-of-transesophageal-echocardiography-tee-in-the-ed-for-cardiac-arrest/

 · 

POTD: Superficial Thrombophlebitis (feat. Dr. Doge Pologe)

Today's POTD is inspired by resident extraordinaire Dr. Doge Pologe. As usual, TL;DR is below the main text. 

Thrombophlebitis is essentially a composite of two diagnoses: phlebitis, which is a clinical diagnosis in the setting of an erythema and pain overlying a vein and an identified thrombus. In the lower extremities, this is most likely to occur in varicose veins. 

1-Figure1-1.png

In general, risk factors for thrombophlebitis are the same as for DVT (think Virchow's Triad of hypercoagulability, hemodynamic changes (stasis/turbulence), and endothelial injury/dysfunction). These include pregnancy, history of vein excision/ablation, history of prior thrombosis, malignancy, and prior IV catheter placement. 

Special cases:

  • "Mondor": thrombophlebitis of a breast vein, anterior chest vein, or of the dorsal penile vein. The two former should prompt a search for breast cancer and the later is usually due to repetitive trauma

  • "Trousseau's sign of malignancy": migratory thromboembolism, has a strong association with adenocarcinoma of the pancreas and lung


Diagnosis
:
Diagnosis of phlebitis is clinical. Ultrasound should be used to identify a thrombus to distinguish between phlebitis and thrombophlebitis. Patients should also have duplex ultrasound to identify a DVT especially if the area of concern is above the knee. This is important because the rate of concurrent DVT in all cases is 25% and the rate of concurrent PE is 5%. 

Thrombophlebitis on ultrasound will demonstrate heterogeneous internal echoes within a superficial vein. Unlike an abscess or a lymph node, this will not be discrete and you should be able to trace it out. in the words of the Doge:

"it looks like a weird continuous twisty spaghetti
abscess thing; 
but it's not to be feared, 
mostly superfluous, so get frisky and ultrasound that biddy, 
color doppler, diagnosis, ka-ching". 

There may be flow present (which can help distinguish an abscess from thrombophlebitis; abscess = no flow). Some examples (by the Doge Pologe and myself):

thrombophlebitis.png
Screen Shot 2019-04-15 at 6.57.02 PM.png

Treatment:
As with treatment of below the knee VTE, the treatment of superficial thrombophlebitis is controversial. Patients can be considered low risk (for VTE) if they meet these criteria:

  • Affected vein segment < 5cm

  • Remote from the saphenofemoral/saphenopopliteal junction

  • Low risk for VTE

**Repeat duplex should be obtained in 7-10 days or for worsening symptoms to check for propagation!

NB: thrombophlebitis post-ablation are always low risk and do not require treatment

For these uncomplicated cases, treatment is aimed at alleviating symptoms and prevention of propagation. This includes the following:

  • NSAIDs

  • Warm/cool compresses

  • Elevation of the extremity

  • Compression stockings

Patients that do not qualify as low risk or if they have recurrent thromboembolism should be considered for anticoagulation. Although studies looking at anticoagulation for SVT are small and flawed, NSAIDsLMWH, and fondaparinux have all been shown to decrease incidence of DVT. Patients can also be discharged on Xarelto (this is the only NOAC to be studied for this indication). 

In addition, thromboembolism can become suppurative. Signs and symptoms include high fever (as opposed to the low-grade fever that accompany simple thrombophlebitis) and purulent drainage (duh). In these cases, consider antibiotics


TL;DR

  • Thrombophlebitis = phlebitis (redness/pain along vein) + thrombus

  • Find the thrombus on ultrasound! Look for internal echoes.

  • Low risk patients = below the knee, affected vein < 5cm, distance remove from saphenofemoral/saphenopopliteal junction can be managed with NSAIDs, compression stockings, warm/cool compresses, elevation

  • Low risk patients should get repeat study in 7-10 days to check for propagation

  • High risk patients: consider anticoagulation with LWMH, fondaparinux, or Xarelto

  • Antibiotics for suppurative thrombophlebitis

Special thanks to Dr. Jonas Pologe, Dr. Lawrence Haines, and Dr. Leily Naraghi Bagher Pour. 

Sources:
http://www.emdocs.net/core-em-superficial-venous-thrombosis-svt/
https://www.bmj.com/rapid-response/2011/10/31/superficial-thrombophlebitis-not-straightforward-we-may-think
https://emedicine.medscape.com/article/463256-overview
https://www.uptodate.com/contents/phlebitis-and-thrombosis-of-the-superficial-lower-extremity-veins
https://radiopaedia.org/cases/superficial-thrombophlebitis-1?lang=us

 · 

Ultrasound-Guided PIV Placement Part 2 POD

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

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:

suprasternal.jpg

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

abdominal.jpg

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

CT showed a severe type B thoracoabdominal aortic dissection:

CT-aorta.jpg

Aortic Dissection

Pathophysiology:

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

Pathophysiology_Theaorticdissectionsoriginatewithanintimaltearin_Ascendingaorta65Aorticarch10.jpg

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

types.jpg

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

Image result for subxiphoid 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

para-long.jpg

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)

SSNV.jpg

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

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

:

boundries.jpg

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.

land-marks-jpeg.jpg
with-probe-jpeg.png

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

just-sono-arrow.jpg

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:

PastedGraphic-2.tiff

Inject 5-10 cc of local anesthetic.

Ensure it is spreading in the plane like this.

1.jpg
2.jpg
3.jpg

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.

Further reading and references:

http://highlandultrasound.com/superficial-cervical-plexus-block/

 - Highland crushes nerve block education with their website and their SCPB page is no exception

https://www.ultrasoundpodcast.com/2015/03/superficial-cervical-plexus-block-with-bedsidesono-trust-us-this-is-really-awesome-foamed/

 - Mike and Matt of ultrasound podcast also did an amazing episode on this where many of the images in this tutorial are from

https://www.nysora.com/cervical-plexus-block

 -

Another good resource

 · 

Visualize the Vessel: Jonas Pologe's Guide to US-Guided PIV Placement

Ultrasound-Guided PIV: Tricks of the Trade

That’s right, time to talk about one of my favorite topics ever: the ultrasound-guided PIV!

These are tricks of the trade that I have picked up from our amazing ultrasound faculty at Maimonides as well as concepts I have learned based on trial and error. I hope this guide provides some short-cuts to ultrasound-guided PIV expertise to newer trainees!

Procedure:

Scan the area with a tourniquet up to identify your best candidate vein. Look for the largest, most superficial, and most distal. It should ideally be greater than 3mm in diameter.

Visualize the trajectory of your vessel in both short axis and long axis.

short-axis-2.jpg
long-axis-sm.jpg

Probe marker should be to YOUR left (the same side as the “Z” indicator at the top of the screen). That way when you move your needle left or right, it will go the same direction on the screen.

As you scan, note nerves and arteries which must be avoided.

short-axis-1.jpg
short-axis.jpg

The patient/extremity should be positioned such that the vessel is straight, and the probe as upright as possible on the patient’s arm.

Prep with chlorhexidine, prep the probe as well or cover the probe with a tegaderm, use sterile gel (“surgilube”).

Get your angiocath ready. Your go-to is a long 20 gauge. If it’s superficial and big and you are already confident in your PIV skills, you may consider placing a short 18, especially if needed for a CT angio. We don’t stock long 18s at this time but may stock them again in the future; these were an excellent option for larger but deeper vessels.

Find the vessel again in short axis at the point you have chosen to cannulate.

Press the Bx button to drop a guide line down the center of your screen. Position the vessel right in the center of that line.

keyboard-sm.jpg
short-with-bx.jpg

This center line corresponds to the center of the probe:

notched-probe.jpg

The “0” on the probe with no notch on it is the center of the probe.

unnotched-probe.jpg

Note how deep the vessel is by looking at the hash marks at the R side of the screen. My vessel above is  about 0.75 cm down.

Now keep the probe still and look back at the patient’s arm.

Y

ou know exactly where the vessel is. Right under the center of your probe. You know its trajectory as well. VISUALIZE IT COURSING UNDER THE SKIN. That’s where your angiocath will go.

Now you are ready to enter the skin with your angiocath. Glance up at the screen one more time to make sure your vessel is still perfectly centered on your guide line. Look down at the arm and visualize the vessel again. Enter the skin a little ways back from your probe at a 30-45 degree angle. You know how long your angiocath since you’re looking at it and exactly where the vessel is since you are visualizing it. Using this information,

advance the needle with the aim of positioning your needle tip just over the vessel

, right at the vessel wall. As you do this,

look back up at the screen and you should see your needle tip coming into view

.

Confirm that you’re really seeing the needle tip

: Move the probe back (away from the direction of your needle) and watch the needle tip disappear; move it back toward the needle and watch it come into view again. Do this whenever you have any doubt that you’re actually looking at the tip.

Adjust left/right as needed so that your needle tip is perfectly above the vessel.

Enter the vessel by advancing downward a millimeter.

Sometimes a tiny “jab” will help get through the vessel wall.

Confirm that you’re looking at needle tip again.

You may have flash at this point but don’t look for it; it does not matter.

Drop the angle of your needle at this poin

t. The patient should be positioned so you can effectively drop the angle (arm should be straight if using AC fossa).

drop-angle.jpg

Then

advance the probe and needle sequentially millimeter by millimeter

: Advance the probe (needle disappears on the screen), advance the needle (needle tip reappears on the screen), advance the probe again (needle disappears on the screen), advance the needle again (needle tip reappears on the screen), etc.

The needle tip should be centered in the vessel prior to each advancement.

This is demonstrated beautifully by Dr. Cameron Kyle-Sidell in this 4-minute video.

https://emin5.com/2016/04/24/ultrasound-guided-iv-placement/

Once you have “walked” the needle tip into the vessel 5mm or more, keep the needle perfectly still, take the probe off the patient and put it down. Now with your non-dominant hand free, reach over and gently advance the angiocath over the needle while keeping the needle still with your dominant hand. It should advance smoothly.

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A few last teaching points:

  • Practice this skill on a model whenever you have a chance.

  • Use the trick of dropping the Bx line, noting depth, and visualizing the vessel under the skin before starting a central line; if you are good at it with PIVs, you will find this part of central line placement extremely easy.

  • Needle tip visualization is more difficult with deeper vessels and at steeper needle angles.

  • If you are more than 1cm deep and have lost your needle tip, you may find it by switching to long axis

  • Practice the microskill of “twisting” on a vessel in order to convert your short axis to a long axis view; practice this on your own radial artery as often as possible until it becomes second nature.

  • You can do the entire procedure in long axis. This is a very powerful technique, especially for deeper vessels, but is technically more challenging and requires more practice.

  • Use regular 22-gauge angiocaths with the “hockey stick” probe for babies and toddlers. If you are comfortable with this by the time you rotate on PICU, they will love you forever.

  • An US-guided a-line is essentially the same procedure as an US-guided PIV.

Jonas Pologe, PGY3, Emergency Medicine, Maimonides Medical Center

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