I frequently hear this statement that the special operations medical community is heading back to its roots in prolonged field care (PFC)… And I think it presents an excellent opportunity to review the concept of clinical ultrasound in SOF medicine. With the operational context of PFC shifting towards extended care in resource-constrained environments, it will be on you, the SOF Medics, to embrace a much broader spectrum of medicine, way past superb trauma care or sick call advice. In prolonged field care, as the hours or even days go by, the severely injured patient will need you to take a critical-care-type approach.

We all know that critical care medicine is challenging in the hospital environment, let alone in such austere settings. Now, ultrasound is an incredibly versatile diagnostic and monitoring tool. Let me tell you: once you get a hang of it, and it’s going to happen really fast, you will never want to practice medicine without ultrasound! Why would you do the minimum if you can always aim for the best?

How about a hypothetical SONO-guided PFC scenario to show you how it works?

TALE OF A RUSTY NAiL

Just a little technicality: The numbers in the text correspond with the PFC capabilities as listed the following table.

Your team is on a week-long mission in the middle of Noland. While searching through a building, one of your guys falls through a hole in the floor. You dash to check him out.

Your weapons guy has fallen all the way through the floor.  A large rusty nail pinned through his lateral calf. You complete the assessment, and proceed to get that nail out. Thankfully it didn’t injure any vital structures, and Carl’s leg is neurovascular intact. Wound care, antibiotics – his tetanus is up-to-date – you hope for the best.

Being a tough guy as he is, Carl insists that he is perfectly fine… But just to be safe, you decide to grab the ultrasound machine from a nearby TRUCK and perform an e-FAST exam (6). Thankfully, there is no pericardial, pleural nor peritoneal free fluid. Looking for a pneumothorax (PTX) is the last thing on your mental checklist. You are quite relieved to find none! Placing a chest tube is the easy part… Dealing with the aftermath would be quite cumbersome in your current position. 

The following morning Carl wakes up with a red and swollen leg. Your physical exam suggests cellulitis, but you know better than that! With extensive cellulitis you have about 50% chance of getting it right on just the clinical assessment. Rather than tossing a coin, you put the ultrasound probe on the leg, and sure enough you find an abscess (6). What’s more – you notice intense reverberation artifact coming from the center of the abscess cavity. Aha! There must be a foreign body hiding in there. 

As high-speed as you are, you know that regional anesthesia under ultrasound guidance takes less time, results in fewer complications and has a higher chance of success. You go for a sono-guided popliteal nerve block (5). You drain lots of purulent material and a rusty piece of nail. After the I&D you rescan the area to make sure you got it all (8).

Now, the problem is that Carl doesn’t look so well… You decide to start IV fluids, antibiotics and analgesia. After 3 failed attempts, you finally get the line started under ultrasound guidance (2,7). A quick IO would have been an option, but certainly less optimal! Especially if you think long-term management… In most cases the goal is to remove the IO needle within 3-4 hours. But if you insist on starting that way – ultrasound can save you a lot of trouble by confirming the intraosseous placement (2,7). No matter what they told you, those IOs happen to end up in a bunch of undesired places… (Check out the “Feedback to the Field” resources on the SOMA website to read about some awful IO fiascos).

You are finally ready for a telemedicine consult. Doc was able to review the images you sent. He surely agrees with your actions, and compliments your ultrasound skills (9). However, he cannot promise you a timely evac.

Carl seems to be resting, but when you start trending his vitals, you know things just aren’t getting any better. He is becoming more tachycardiac, and his BP is slowly going down. He is also febrile. You take the ultrasound machine to look at the heart, lungs and the IVC (1,2,3,6). You see a hyper-dynamic heart with clear lungs and relatively flat IVC… You integrate it with the clinical picture of febrile illness and soft-tissue infection… Crap… He is septic…

You make it back to the HOUSE. After yet another cell phone chat with your doc, you start pushing more IV fluids… You get another ultrasound-guided peripheral IV (2,7). They are working on that evac, but still no definitive time… Hours later, as you hit the 6th liter, Carl’s SBP barely holds 95 mmHg, and he is becoming tachypneic… His lungs sound very junky, so you decide to repeat your heart-lung-IVC scan (1,2,3,6). His IVC is full, his lungs are wet and his systolic function has decreased…  Septic cardiomyopathy?

With this picture you have no choice but to control his airway and put him on a vent. The junior medic is begging you to let him tube the patient, so you place the ultrasound probe on Carl’s neck in order to supervise your junior’s actions. First you identify the cricothyroid membrane, just in case you needed a surgical airway. Then you watch the screen to see the tube pass into the trachea (1,2,4,6) at first attempt! Your capnography is malfunctioning, and you know how reliable clinical exam is for ETT confirmation… You don’t have an x-ray, but you can clearly see bilateral lung sliding on ultrasound (3, 6). This way you know that junior didn’t go into the right main-stem. You place the probe over the stomach (7) just to see a large fluid-filled gastric bubble… “We are lucky he didn’t aspirate”… You quickly pass the OG tube and decompress the stomach. At once you realize Carl didn’t urinate in quite a few hours… Foley, Foley… Oh great – no bags… You can’t just put a Foley with no bag attached to it… You’ll have to do repetitive catheterizations… Ultrasound will help you assess his bladder volume (1,7) at regular intervals. That’s how you’re going to know when to empty Carl’s bladder, so you can follow his UOP.

You arrange for a video-conference with your doc, and you make the point of showing him Carl’s decreased systolic function on ultrasound in real-time (1,6,9). Given it’s a negative prognostic factor, it does the trick of speeding-up evacuation.

As they load him, someone bumps the ETT and it looks like it might have moved. You make sure the tube is still tied in place. It’s way too loud to auscultate for breath sounds, so you grab the probe instead, and document bilateral lung sliding as evidence of bilateral ventilation (1,3,4,10).

Carl makes a full recovery!

I hope you get the picture how multifunctional and versatile ultrasound is. It’s your force multiplier when it comes to prolonged field care!

Thanks to ultrasound you can build a life-saving bridge from the state of thinking that you recognize the problem, to knowing and being sure about the issue at hand. In the most critical circumstances it helps you maximize safety, efficiency and diagnostic accuracy, while decreasing mortality and morbidity of your patients.

While for now, an ultrasound machine is mostly out there in your TRUCK, or even at the HOUSE, soon enough in can be in your pocket. As the technology advances, and we move from portable to pocket-size devices, it has the potential to become a standard item in your RUCK arsenal.

Do you really want to practice sono-less PFC?

Questions? Comments? Concerns?