Category Archives: General

More On CT Usage In Unstable Patients

Yes, it is practically dogma that CT should not be used in unstable trauma patients. Either they go directly to the OR, or an attempt to stabilize them is briefly undertaken in the trauma bay. And as you know, I’m not a big believer in dogma. But this one has withstood the test of time. You can see my comments about a previous paper below in the related posts.

But now some authors in Colombia have published a paper that seems to call this idea into question. Could it be true? Read carefully!

This was a small, retrospective review of patients from a large Level I government designated trauma center. They reviewed their experience over a two year period, identifying all hemodynamically unstable patients in the registry. They excluded dead patients, those with isolated head injury, and any who had surgery at an outside hospital prior to transfer.

Here are the factoids:

  • 171 patients were reviewed, and of course they tended to be young males
  • 91 went straight to the OR, and 80 were taken to CT first
  • “Unstable” patients were defined as having SBP < 100 and/or HR > 100
  • Mechanism of injury for the OR group was 95% penetrating, but for the CT group was about 50:50 penetrating/blunt
  • The mean SBP and HR for the “unstable” patients taken to CT were 92 and 110, respectively
  • Mortality was the same for both groups (18% OR vs `13% CT)

Bottom line: The authors concluded that it is permissible to take unstable patients to CT if you don’t spend too much time there based on similar mortality rates. But the problem was that I don’t consider their patients to have been unstable! Mean SBP in their “unstable” group was over 90 torr and the heart rate was only 110! The lowest SBP was only 79. And mortality is too crude of an outcome to rely on. Furthermore, the patients they took to CT tended to have blunt mechanisms, and may not have had ample efforts at resuscitation in the trauma bay first, or may have met criteria to go to CT anyway (see related posts below).

Reference: Computed tomography in hemodynamically unstable severely injured blunt and penetrating trauma patients. J Trauma 80(4):597-603, 2016.

Print Friendly, PDF & Email

What The Heck? Head CT – The Answer

It appears that no one was able to figure this one out! To recap, a young person (female in this case) sustained blunt trauma to the head. When her head was scanned, the following was found on the scout scan:

What is all this odd stuff? They look like some kind of metallic clips placed all over the head. The answer? Hair extensions! Here’s what they look like up close.

Unfortunately, they cannot be left in place during the CT. The amount of scatter is significant enough to degrade the quality of the study. By definition, if you have taken your patient to CT, they are stable and you have a little time. So carefully remove all of the extensions and place them in a bag and save them for the patient (they can be expensive!). 

Make sure the CT tech obtains another topogram to confirm removal of all of the extensions. Then proceed with your CT as usual!

Print Friendly, PDF & Email

Why Do They Call It: Extra-axial Blood?

You’ve seen it on head CT reports. “The patient has a collection of extra-axial blood…” Then it goes on to describe the location and size of a subdural hematoma. But why is it called “extra-axial?”

The answer lies in the embryology of the central nervous system. Yes, it’s been a long time since any of us have read anything about that. Early animals had a straight neural tube, which slowly evolved into a brain and spinal cord. This is known as the axis of the nervous system.

The brains of early vertebrates developed at the end of the neural tube, and were oriented in the same longitudinal axis as the rest of it. As brains got bigger, a 90 degree bend occurred at the cephalic flexure.

So in humans, there is a difference between the body axis and the brain axis. But the brain axis is what really counts. This means that any blood outside of the brain axis is defined as extra-axial.

Bottom line: Extra-axial blood is defined as any bleeding outside of the brain parenchyma. This includes subdural and epidural hematomas, and subarachnoid hemorrhage. It does not include any intraparenchymal bleeding like contusions, strokes, or hematomas.

Print Friendly, PDF & Email

What’s The Best Test For Blunt Cerebrovascular Injury?

Blunt injury to the carotids or vertebrals (BCVI) is a little more common than originally thought, affecting about 1% of blunt trauma patients. We have many tools available to help us diagnose the problem: duplex ultrasound, CT angiography (CTA), MR angiography (MRA), and even good old conventional 4 vessel angiography

But which one is “best?” This is a tough question, because there is always some interplay between clinical accuracy and cost. The surgical group at the Medical College of Wisconsin – Milwaukee did a nice job teasing some answers from existing literature on the topic. The authors tried to take a comprehensive look at costs, including money spent to prevent stroke, the cost of complications of therapy, and the overall cost to society if the patient suffers a stroke.

Here are the factoids:

  • For patients at risk for BCVI, the stroke rate is 11% without screening, 6% with duplex ultrasound screening, 4% with MRA, and 1% with either CTA or conventional angiography
  • From a societal standpoint (includes the lifetime costs of stroke for the patient), CTA is the most cost effective at $3,727 per patient
  • From the hospital standpoint (does not include lifetime cost), no screening is the most cost effective, but has the highest stroke rate (11%)
  • CTA prevents the most strokes, and costs about $10,000 per patient while decreasing societal costs by about $32,000 per patient screened

Bottom line: The “best” test for patients at risk for blunt cerebrovascular injury is the CT angiogram. It minimzes the stroke rate, and provides information on all four vessels supplying the brain, which is probably why the duplex ultrasound has a higher miss rate (can’t see the vertebrals or into the skull). But how do you decide who is at risk for this problem. Tune in tomorrow!

Reference: Screening for Blunt Cerebrovascular Injuries is Cost-Effective. J Trauma 70(5):1051-1057, 2011.

Print Friendly, PDF & Email