Here’s a brief video from one of the device manufacturers that illustrates the technique of duplex ultrasound in the lower extremity.
[embedyt] http://www.youtube.com/watch?v=FHerMNhCR54[/embedyt]
Admit it. You’re curious. You order this test for your trauma patients all the time but you’ve never seen it done. It’s simple and noninvasive, but it does require access to all areas to be evaluated. This means that extremities that are casted or splinted, or that have extensive dressings in place may be incompletely evaluated.
The study is called “duplex” because it makes use of two modalities: traditional ultrasound and Doppler ultrasound. Traditional ultrasound is used to view the compressibility of the veins of interest at a number of locations. Doppler measures the speed of blood flow under the probe, and can show areas of sluggish flow.
The following diagram shows the traditional ultrasound technique being used to compress the vein of interest (femoral, popliteal, etc.). Part A shows the probe gently resting over the vessels. Part B shows a fully compressible vein (normal), and Part C shoes partial compression due to the presence of thrombus.
The following diagram shows what the actual ultrasound study looks like. The right side is normal, but the left side shows a venous thrombosis.
The FAST exam is an integral part of trauma evaluation. Even after experience and credentialing of providers, there tends to be some variability in performance. This is especially true when the abnormal findings (or amount of fluid present) is relatively small.
Can we improve this by doing something as simple as using gravity to help? When the patient is supine, fluid tends to pool in the pelvis, where interpretation is a little more complicated. The surgery program at Guthrie/Packer Hospital created a small pilot study to see if they might improve the sensitivity of FAST by rolling patients to their right briefly, before returning to the supine position and performing the exam.
They enrolled seven participants who were already undergoing peritoneal dialysis (PD), so there was easy access to the peritoneal cavity for administration of known amounts of free fluid. First, each patient was drained of any residual dialysate via their PD catheter. They then underwent a baseline FAST exam. Next, they were placed in the right lateral decubitus position for 30 seconds, then placed supine again and the FAST was repeated. Each patient then had 50cc of dialysate infused, and the process was repeated until a positive FAST was obtained.
Here are the factoids:
Bottom line: The authors conclude that this may be a valuable technique to help detect smaller quantities of fluid than we normally do. I’m not so sure. First, it’s a tiny study in a patient group that is very different from trauma. And it’s impossible to quantify how much dialysate was left after initial drainage of the PD catheter. Finally, we know that FAST can’t “see” small quantities of fluid, but we have constructed our management algorithms around this fact. So we have a good idea of when we should do further imaging or run off to the operating room. Making this test more sensitive may skew these practice guidelines toward doing more (and potentially unneeded) imaging and surgery.
Questions and comments for the authors/presenters:
Click here to go the the EAST 2017 page to see comments on other abstracts.
Related posts:
Reference: Can we be faster? FAST examination after rolling to the right dramatically increases sensitivity. Quick Shot #7, EAST 2017.
Neurosurgical involvement in the management of simple traumatic brain injury (TBI) has been slowly dwindling over the past several years. This is the result of the general consensus that very few of these patients progress to need neurosurgical procedures.
A group at Wright State University in Dayton sought to define the progression of one specific finding in TBI, the subarachnoid hemorrhage (SAH). Secondarily, the wanted to determine if a neurosurgery consultation was warranted in these patients.
They performed a five year retrospective review of their registry data, identifying patients with both mild TBI (GCS 13-15) and SAH. They excluded patients with any other brain lesion on CT.
Here are the factoids:
Bottom line: The authors conclude that initial neurosurgical consultation is not needed, since only 9% of patients have worrisome findings on repeat CT. They do, however, recommend that the practice of repeat scanning be continued because of this same number.
Our trauma service looked at this issue a year ago, and determined that most of these lesions either do not progress, or never require any intervention if they do, with a few notable exceptions. For that reason, we abandoned both neurosurgical consultation and repeat CT scans for patients with non-aneurysmal SAH, a single parenchymal hemorrhage, or linear skull fractures. We continue to do both for patients with epidural and/or subdural hemorrhage. You can download a copy of this protocol here.
Questions and comments for the authors/presenters:
Click here to go the the EAST 2017 page to see comments on other abstracts.
Related posts:
Reference: Management of subarachnoid hemorrhage (SAH) by the trauma service: are repeat CT scanning & routine neurosurgical consultation necessary? Poster #16, EAST 2017.
The general rule for penetrating trauma, especially gunshots to the abdomen, is that you don’t need to obtain a CT scan to help you decide to go to the OR. (Of course, there are a few exceptions.) And the corollary has always been that you don’t need to get a CT scan after you operate for penetrating trauma.
But the group at UCSF is questioning this. They retrospectively looked at 5 years of data on patients who underwent trauma laparotomy without preoperative imaging. They focused on new findings on CT that were not reported during the initial operation.
Here are the factoids:
Bottom line: This is a very interesting and potentially practice changing study. However, there is some opportunity for bias since only select patients underwent postop scanning. Nevertheless, one in five patients who did get a postop scan had an injury that required some sort of intervention. This study begs to be reworked to further support it, and to develop specific criteria for postop scanning.
Questions/comments for the authors/presenters:
Click here to go the the EAST 2017 page to see comments on other abstracts.
Related posts:
Reference: Routine tomography after recent operative exploration for penetrating trauma: what injuries do we miss? Poster #14, EAST 2017.