It’s 3 o’clock in the morning and you’re dispatched to a vehicle vs. pedestrian. Your helicopter lands on scene and you and your partner make your way to the back of the ambulance. You open up the side door and the first thing you see is a big eyed paramedic looking at you squeezing a BVM with two hands telling you that it’s very difficult to bag this patient but they see no signs of pneumothorax such as JVD or trachea deviation because that’s what we are taught. You look at your partner and they inform you from feet to head the patient is really pale looking and upon assessing their vitals you notate that the BP is 70’s/30’s, the heart rate is in the 150’s, Spo2 is in the 80’s and the EtCo2 is in the 20’s. As you sit there trying to think of a treatment plan, imagine if you had a tool that could aid you in your treatment and exam.
I have that tool for you and it’s in this blog. I am going to discuss the use Point of Care Ultrasound (POCUS) in the prehospital setting and how it can benefit not only our patients but how it can benefit you. So, let’s take a small journey back in time. In 1994 the first Emergency Medicine ultrasound curriculum was published by Mateer et al. This has helped pave the way for POCUS on becoming a useful diagnostic tool. Because of its success, it has become an integral part of the care provided in the ED. Over the last two decades it has evolved and now aids physicians in improving their diagnostic accuracy and allows them to provide overall better patient care. Because of this, we started to see POCUS being used in the prehospital setting in the late 1990’s early 2000’s. In 2011, POCUS was defined as one of the top five research priorities for physicians in physician-provided prehospital critical care. As we know today prehospital point of care ultrasound can potentially improve patient outcomes.
So, when it came to allowing pre-hospital providers to utilize the ultrasound there was a study performed. The aim of the study was founded on answering three previously defined research questions:
1. Which ultrasound examinations can be reliably transferred to the prehospital setting?
2. How does prehospital ultrasound affect patient management and the patient pathway?
3. How should providers achieve and maintain specific ultrasound skills?
When it comes to prehospital use of POCUS, we have learned that it can be utilized for several things. Some of the treatment and assessments we can utilize POCUS for are FAST exams, pneumothorax, IV’s, and cardiac activity, etc.
Focused Assessment with Sonography in Trauma
POCUS and trauma belong together like Ying and Yang. The way POCUS aids in our assessments and treatment is by allowing us to do a FAST exam. What is a FAST exam? A FAST exam is where we are looking for blood/fluid in the abdominal cavity that is not supposed to be there. Identifying a positive FAST exam can aid us in the use of hanging whole blood in quicker the field along with relating this valuable information to trauma surgeons. This could help them set up the appropriate resources and potentially expedite the patient to the OR.
Have you ever attempted to listen to lung sounds in a moving ambulance with lights and sirens on? Or listened to lung sounds in a helicopter en-route to the hospital? How did that go? Did you hear anything? Yeah, I didn’t think so. This is where POCUS comes in handy. We can use the ultrasound to determine if our patients are suffering from a pneumothorax, or if there is nothing to be concerned about. When locating your landmarks remember, in a patient who is sitting upright start at the apical lateral lung. If your patient is a supine patient start on the anterior chest between the 2nd and 3rd intercostal space along the mid clavicular line. What you’re looking for is called “stratosphere” or “Bar code” sign. To do this, place your ultrasound machine into “M” mode. M mode detects the difference in motion between the two pleural lines. A normal lung will show you a “seashore sign” with transition of lines differentiating movement at the pleural lines, whereas pneumothorax prevents detection of the motion creating a single “bar code” pattern. I strongly like this because in the aircraft or in the back of the ambulance regardless of how much noise there is, POCUS could give us a good indication if we’re dealing with a pneumothorax and if we should intervene. This could ultimately aid us in the decision to perform a finger thoracostomy or placing a chest tube. Or this can aid us in making an educated decision to monitor the patient closely. When it comes to the diagnosis of pneumothorax with POCUS it has been shown to have a moderate diagnostic accuracy and experts agree with it.
Now we know that obtaining intravenous (IV) access is a necessity when working in the prehospital or hospital setting. But what happens when you need intravenous access but have that patient we all are familiar with – fistula in one arm, poor vasculature in the other or maybe that patient with a serious history of IV narcotic abuse? Placing an IO in a stable or conscious patient is not ideal. What could be your next option? For those with access to POCUS, Ultrasound guided IV access is an excellent option. Ultrasound guided peripheral IVs are quickly becoming the standard of care for patients with difficult IV access. Especially in Emergency Departments across the country.
Differentiating between separate types of vasculature can be difficult when you first start out. Let’s start with these 3 structures:
- Artery: When pressure is applied to the arm with the probe, an artery will pulsate. These structures are harder to collapse and would take a greater amount of pressure.
- Veins: When pressure is applied to the arm with the probe, the vein will collapse. These structures are fairly easy to collapse. Note – when within close proximity to the artery, a vein might have a pulsating look to it. Avoid these initially while you build up experience.
- Nerves: Nerves present with a “honeycomb” look to them. These structures do not collapse when pressure is applied, nor do they pulsate.
When performing this skill make sure you have all of your equipment ready. Place your machine in a position near the patient’s head to allow yourself for best positioning. Ensure you, the monitor, and the patient are in ideal position. This will be the key to your success. Also, USE A TOURNIQUET.
You will want to choose a longer IV catheter for this. Usually these catheters come in lengths of 1.75in or 1.88in long. In some cases, this might not even be long enough so a midline/PICC would be a better option depending on your hospital’s resources.
Locating a Vessel
The next step is to locate and confirm a venous structure. Do this by utilizing a short axis view and working from the lower forearm to the upper arm. The basilic vein should be avoided initially. This is the vessel of choice for the PICC teams. A short axis view (probe is horizontal, with indicator pointing towards patient’s left), is the best way to search for these vessels. Once you have located a vessel, utilize your midline market on the screen to follow your vein. This is the same logic as a normal IV when you are looking to make sure that your vein is going straight. Once you have found an appropriate vessel, orient yourself and the probe to follow the vessel proximally.
When instructing this technique, I teach them to hold the angio with your thumb on the top of the device, and your pointer on the bottom. This allows greater y-axis manipulation versus other ways of handling it, in my opinion. Next, you want to puncture your site a few centimeters distal to your probe. As you make your way through the tissue, give your catheter a gentle up and down motion to find your catheters tip on the machine.
Tracking Your Tip
As you advance your catheter, you need to advance your probe along the vein as well. Do not lose the tip of your needle! If you do lose your tip, look for tissue movement as you continue your gentle wiggles with the catheter. There will be many cases where prior to the needle puncturing into the vein, you will see the vein tissue start to collapse around the top part of the vessel. This will help you know where your tip is as well.
Access into The Vessel
Once you have felt a “pop” and are able to see your tip within the lumen of the vein, continue to slowly advance the needle and the catheter through the middle of vessel. Remember, bring the probe with you on every movement you make with the angio. Once you feel you are appropriately seeded inside the vessel, advance the rest of the catheter into the vein without the needle. This should feel smooth, like you are feeding it through butter. If it does not, you are not in. Reevaluate with a long axis view or with saline turbulence. You can now secure your IV. I hope this helps you the next time you utilize ultrasound for IV access.
When it comes to cardiac activity POCUS has been used greatly in a cardiac arrest setting to see how well the heart is performing. It has been used to determine cardiac motion during pulse checks in cardiac arrest, which the results could be used as an aid in patient management. In some cases, POCUS has been used with patients in a prolonged downtime along with patients in pulseless traumatic arrest and the evaluation of cardiac motion has assisted in determining if resuscitation efforts needed to be ceased due to zero chance of survival.
It has been shown that prehospital POCUS can make positive changes in our patient care and treatment. One thing we can start doing is collecting data from our patient outcomes with the use of POCUS. Did performing a FAST exam allow us to hang whole blood faster? Did performing a FAST exam allow us to activate the appropriate resources faster and increase our door to OR time? Have we confirmed pneumothorax with the use of POCUS and if it was alleviated by placement of a chest tube or finger thoracostomy what was the patient’s overall outcome? The evidence is out there and supports the use of prehospital POCUS, it’s and it’s this medic’s opinion that it’s time we bring the data to support it and give it a place in standard Emergency pre-hospital care!
Justin Krantz is a Critical Care Paramedic (CCEMT-P) and 911 paramedic based in Brevard County, FL. Originally from Central Florida, he has been involved with emergency services since he began as a Lifeguard in 2007. He is currently working for a local government agency in an EMS role along with their training division, as well moonlights as a fixed wing flight paramedic for a private air medical company along with working in the ED clinical setting. Justin is an avid student of Free Open Access Medical Education (FOAMed) and Evidence Based Medicine (EBM).
The role of point of care ultrasound in prehospital critical care: a systematic review, Published June 26, 2018 https://pubmed.ncbi.nlm.nih.gov/29940990-the-role-of-point-of-care-ultrasound-in-prehospital-critical-care-a-systematic-review/
The role of point of care ultrasound in prehospital critical care: a systematic review, Published June 26, 2018 https://sjtrem.biomedcentral.com/articles/10.1186/s13049-018-0518-x
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