All posts by TheTraumaPro

Best Practice: Use of CT Scan In Trauma Activations – Part 1

Computed tomography is an essential part of the diagnostic workup for many trauma patients. However, it’s a limited resource in most hospitals. Only so many scanners are affordable and available.  Typically, trauma centers have a scanner located in or very near the trauma bay, which makes physical access easy. Others may be located farther away, which can pose logistical and safety issues for critically injured patients.

Even if the CT is close to the ED, availability can be an issue. This availability applies not only to trauma scans, but to others as well. There is an expectation that CT be immediately available when needed for trauma activation patients. However, chances are that the same scanner is also used for high priority scans for services other than trauma, such as stroke evaluation.

Who gets the scanner first? Obviously, many trauma patients need rapid diagnosis for treatment of their serious injuries. But a fresh stroke patient also has a neurologic recovery countdown clock running if they might be eligible for lytic administration.

And don’t forget that trauma and stroke aren’t the only services vying for that scanner. The hospital undoubtedly has a stream of elective scans queued up for other in-house patients. Every urgent or emergent scan needed for trauma sets the elective schedule back another 30 minutes or more.

How does your trauma center manage CT scan usage for trauma? The vast majority essentially lock it down at some fixed point. This is typically either upon trauma activation, or at patient arrival. The former is very common, but also very wasteful because there can be a significant wait for the patient to actually arrive. Then add on the time it takes to complete the trauma bay evaluation. Up to an hour may pass, with no throughput in the CT scanner. This can be a major work flow headache for your radiology department.

Is there another way? My center was one of those that stopped the scanner after the current patient was finished at the time the trauma activation was called. We have two scanners just 30 feet from the trauma bays, so one could continue working while the other was held. However, this cut their throughput by 50% for roughly half an hour. We recognized that this was a creating a problem for the whole hospital, so we worked with the radiology department to come up with a better way.

Tomorrow I’ll detail the new system we implemented, and provide data showing the real impact of this new system on CT scan productivity.

What The Heck? CT Imaging Problem: The Answer

I received some good guesses about this image yesterday, but no one got the right answer.

The patient had sustained blunt trauma and was undergoing CT imaging. The scout for the abdominal CT showed some kind of weird debris that interfered with the image, but when we uncovered and looked at the patient, nothing was visible:

What the heck? If you look carefully at the left side of the image, you can see that the “debris field” is on the surface of the patient. We can’t see in 3-D on images, but the difference in appearance on the left and right sides looks like it this stuff is wrapping around the patient.

She was brought in by EMS with a warming blanket in place. On closer inspection, this was a thin, disposable blanket that heats up when removed from an airtight plastic pouch. These blankets contain thin pockets of a mineral mixture that looks like gravel. When exposed to air it heats up.

But on CT it looks like bone density material! When we looked at the patient, we were just lifting off the blanket that contained the offending material. Hence, we couldn’t find it.

Here’s a picture of one of these products. Note the six mineral pouches embedded in it., Don’t let this happen to you!

 

What The Heck? CT Imaging Problem

Here’s one for you. A patient is brought to you after a motor vehicle crash. You’ve completed your evaluation in the trauma resuscitation room, and you move off to CT for some imaging.

As the techs are preparing to do the abdominal CT, they perform the scout image to set up the study. This is what you see:

The arm was left down due to a fracture (note the splint along the forearm). But what is all that debris on the image? Other than a few abrasions here and there, nothing is visible on the skin in those areas.

What the heck? What do you think these are? Will they interfere with imaging? And what can you do about it?

Tweet or comment with your answers. I will explain all tomorrow.

Zebra Alert: Blunt Injury To The Thoracic Duct

Today I’m going to review a very uncommon clinical problem in trauma: injury to the thoracic duct. To review, the lymphatic system coalesces into channels along the spine. These vessels travel upwards to drain into the venous system as the left and right lymphatic ducts. The exact drainage points vary, but are near the junctions of the internal jugular and subclavian veins bilaterally. Technically the larger of the two, the left lymphatic duct, is termed the thoracic duct. However, injuries can occur on either side.

Injuries to the lymphatic ducts are very rare due to their small size and their protection by surrounding structures and tissues. For this reason, the literature on this topic consists almost exclusively of case reports. Injury can occur from direct penetration by gunshots or stabs, or may be associated with high energy blunt trauma. It has also been reported to occur in cases of multiple posterior rib fractures and vertebral fractures.

In the rare event that these ducts are damaged, they pose a major management problem because lymph does not clot. These vessels are not self-sealing like most others in the body. They will only close through healing (scarring) or by ligation. The typical disruption occurs near the junction of the duct with the venous system, so lymph (chyle) typically accumulates in the thorax on the affected side. This results in a hydrothorax until the patient begins eating, when it turns chylous and makes the diagnosis easy. Here a various shades of chyle that you might see in the chest tube drainage.

If in doubt, triglyceride levels can be measured, and a value greater than 110 mg/dL is considered positive.

Initial management is usually dietary, via reduction in fat intake to render the drainage clear. This may be accomplished by a low fat diet or by TPN. I don’t really buy the effectiveness of this, since the fat content is not what causes the leak to persist. It merely makes it unusual to look at. I suspect that the 1-2 week period that most recommend for dietary treatment just provides an opportunity for normal healing/scarring to occur. Octreotide should be given as well because it may decrease overall lymphatic output. Lower output accelerates closure because the amount of scarring needed to close the smaller hole is less.

Interventional radiologists have attempted embolization and needle maceration of the ducts, but the few of these described have been unsuccessful. This is not recommended.

If closure is not achieved in two weeks, then consideration should be given to surgical ligation of the leaking duct. This structure is small and thin-walled, and not the easiest to see. Fats should be administered via NG (olive oil and cream have been described) at the start of the operation to stimulate chyle production. This allows easier identification of the leak site intraoperatively. Suture ligation, clipping, or both can be used to stop the leak.

References:

  1. A case of a traumatic chyle leak following an acute thoracic spine injury: successful resolution with strict dietary manipulation. World J Emerg Surg 6:10, 2011.
  2. Blunt rupture of the thoracic duct after severe thoracic trauma. J Trauma Open 3:e000183. doi:10.1136/tsaco-2018-000183m 2018.
  3. Bilateral Chylhotorax after Falling from Height. Case Reports in Surg  article 618708, 2014.

Little-Known Whole Blood Transfusion Program: Part 2

In my last post, I described a long-standing whole blood transfusion program that was implemented by Royal Caribbean Cruise Lines (RCCL)about 10 years ago. Today, I’ll dig into the specifics of their protocol and review their results.

Here is an image of the protocol. You can click it to download a full-size pdf copy.

Here are the key points in the protocol:

  • It is only implemented if it will take more than 4 hours to get the patient ashore for more advanced care
  • If the patient is hemodynamically stable, permissive hypotension to MAP 75 is encouraged and TXA infusion / Vitamin K administration are considered when appropriate. The patient disembarks at the next port of call with advanced hospital capabilities.
  • If hemodynamically unstable, two large bore IVs are maintained, TXA and Vitamin K are given when appropriate, and whole blood collection and administration are initiated. Helicopter / coast guard transport is deemed acceptable to closest advanced hospital.

And here are the guidelines for donor selection:

  • The donor hierarchy is:
    • sexual partner of the patient
    • male passenger with blood donor card
    • male passenger without blood donor card
    • female passenger with blood donor card (beware of TRALI)
    • medical staff members
    • crew
  • Only one unit is taken from each donor, and they must not be anemic

Here are the factoids describing RCCL’s seven year experience with the program:

  • 73 patients received transfusions, including 67 passengers and 6 crew
  • Mean hemoglobin on presentation was 6
  • A total of 1-6 units were given
  • Six patients ultimately died; no details were given
  • There were no ABO seroconversions, and only two adverse reactions occurred, both allergic
  • The majority of the medical staff felt that this was a valuable program

Bottom line: This is the first whole blood transfusion program I have seen outside of hospitals and the military. Royal Caribbean has incorporated lessons learned from both in developing their protocol. It includes all the principles of balanced resuscitation, including limiting crystalloids, permissive hyportension, and 1:1:1 transfusion ratios. There are many other opportunities to implement similar protocols in areas where medical capabilities are austere, and this protocol should be used as a model to develop them.