Category Archives: Imaging

EAST 2017 #6: FAST Exam After Rolling to the Right

January 4, 2017 The Trauma Pro 2 Comments

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:

Of the seven patients recruited, one was excluded because the initial FAST was equivocal due to body habitus and polycystic kidney disease
A maximum of 3 aliquots were given (150cc max)
Two patients became positive after right side down before any additional fluid was infused
None of the four remaining patients had a positive FAST after infusion of any aliquot in the supine position
All four became positive after the right side down maneuver, two after 50cc, one after 100cc, and one after 150cc

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:

Did you record the volumes and administration times of dialysate given prior to the study? This may correlate with the initial positives and volumes needed to give a positive result.
Similarly, did you look at BMI and body habitus to see if there might be a correlation?
Are you planning any type of followup study, as you suggested in the abstract?

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.

Head, Imaging

EAST 2017 #5: Subarachnoid Hemorrhage, Neurosurgical Consults, and Repeat Head CT

January 3, 2017 The Trauma Pro 5 Comments

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:

301 patients were enrolled during the 5 year period
All had a neurosurgical consultation
Time between the initial CT and a followup scan was about 11 hours
91% showed stable or resolving SAH on the followup scan
9% showed a worsening SAH or additional lesions on the repeat scan

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:

Did you look at platelet count or INR in the study. Were patients excluded based on abnormal values?
Did every patient get a repeat scan?
Break down the lesions in the 9% of patients who had some sort of progression or new finding. Did you see any common themes (age, chronic alcohol use, etc.)?
Did you encounter any patients with “non-central SAH”, that might indicate an aneurysm? How were they dealt with?
How has or will your trauma service change its practice based on your findings.

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.

General, Imaging

EAST 2017 #2: CT Scan After Recent Operative Exploration for Penetrating Trauma

December 29, 2016 The Trauma Pro Leave a comment

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:

230 of 328 patients undergoing a trauma lap did not have preop imaging
85 of the 230 patients (37%) underwent immediate postop CT scan. These patients tended to have a gunshot mechanism and higher injury severity score.
Unreported injuries were found in 45% (!) and tended to be GU and orthopedic in nature
47% of those with unreported injuries found required some sort of intervention

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:

Be sure to break down your results by gunshot vs stab. This will help formulate those criteria I mentioned above.
Specifically list the occult injuries and interventions required. In some studies, those “required interventions” are pretty weak (urology consult vs an actual procedure).
How exactly did the operating surgeons determine who to send to CT? Was it surgeon-specific (i.e. one surgeon always did, another never did)? Was it due to operative findings (hole near the kidney)? This is also needed when developing specific criteria for postop imaging.
Nice poster!

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.

Imaging

EAST 2017 #1: Accuracy of CT Scans Done Outside The Trauma Center

December 28, 2016 The Trauma Pro Leave a comment

Imaging prior to transfer to a trauma center has been the subject of debate for years. The focus has primarily been on the necessity of these scans, and the sheer numbers that are done. For the most part, the discussion has been driven by the potential for radiation exposure.

This paper, from the University of Oklahoma, takes a different approach. The authors looked at the accuracy and adequacy of imaging performed prior to transfer to their Level I trauma center.

Patients were enrolled prospectively over an 8 month period in 2012. Outside images were interpreted by a single radiologist who was blinded to the outside interpretation. If images were repeated, they were compared to the first scan, and the reason for the redo was noted.

Here are the factoids:

235 consecutive transfer patients were enrolled, and 203 who had at least one CT scan were included in the final dataset
76% of these patients had additional imaging performed once they arrived at the trauma center
Reasons for additional images were insufficient workup (76%) and technical inadequacy (31%)
Missed injuries were detected on outside CT scans 49% of the time, and the majority of them (90%) were deemed clinically significant
Missed injuries on a repeated scan were present in 54% of patients, and 76% were clinically significant
Overall, 73% of images (either outside or repeat) contained additional injuries

Bottom line: This is a new approach to assessing the value of outside imaging prior to transfer to a trauma center. I have always recommended that trauma centers work with their referral partners to assure them we don’t need them to do the workup for us. I encourage them to obtain only what they need to decide if they can keep the patient. But once they find anything that they cannot treat, stop all workup and prepare to transfer.

Questions/comments for the authors/presenters:

Why did you use such an old dataset?
Is this a prospective enrollment/retrospective analysis study designed to use an existing, old dataset?
How did you decide that outside imaging represented an inadequate workup? Do you have a diagnostic imaging guideline that you follow?
What are the credentials for your trauma radiologist?
How did you determine that a missed injury was clinically significant? Be sure to provide a list and explanation during your presentation.
Be sure to separate out missed injuries seen on the original CT from new missed injuries seen on the repeat scan.
Congratulations on looking at an old problem in a new way!

Click here to go the the EAST 2017 page to see comments on other abstracts.

Related posts:

Reference: Adequacy and accuracy of non-tertiary trauma center computed tomography: what are we missing? Paper #7, EAST 2017.

Imaging

Pan Scanning for Elderly Falls?

October 21, 2016 The Trauma Pro Leave a comment

The last abstract for the Clinical Congress of the American College of Surgeons that I will review deals with doing a so-called “pan-scan” for ground level falls. Apparently, patients at this center have been pan-scanned for years, and they wanted to determine if it was appropriate.

This was a retrospective trauma registry review of 9 years worth of ground level falls. Patients were divided into young (18-54 years) and old (55+ years) groups. They were included in the study if they received a pan-scan.

Here are the factoids:

Hospital admission rates (95%) and ICU admission rates (48%) were the same for young and old
ISS was a little higher in the older group (9 vs 12)
Here are the incidence and type of injuries detected:

	Young (n=328)	Old (n=257)
TBI	35%	40%
C-spine	2%	2%
Blunt Cereb-vasc inj *	20%	31%
Pneumothorax	14%	15%
Abdominal injury	4%	2%
Mortality *	3%	11%

* = statistically significant

Bottom line: There is an ongoing argument, still, regarding pan-scan vs selective scanning. The pan-scanners argue that the increased risk (much of which is delayed or intangible) is worth the extra information. This study shows that the authors did not find much difference in injury diagnosis in young vs elderly patients, with the exception of blunt cerebrovascular injury.

Most elderly patients who fall sustain injuries to the head, spine (all of it), extremities and hips. The torso is largely spared, with the exception of ribs. In my opinion, chest CT is only for identification of aortic injury, which just can’t happen from falling over. Or even down stairs. And solid organ injury is also rare in this group.

Although the future risk from radiation in an elderly patient is probably low, the risk from the IV contrast needed to see the aorta or solid organs is significant in this group. And keep in mind the dangers of screening for a low probability diagnosis. You may find something that prompts invasive and potentially more dangerous investigations of something that may never have caused a problem!

I recommend selective scanning of the head and cervical spine (if not clinically clearable), and selective conventional imaging of any other suspicious areas. If additional detail of the thoracic and/or lumbar spine are needed, specific spine CT imaging should be used without contrast.

Related posts:

Reference: Pan-scanning for ground level falls in the elderly: really? ACS Surgical Forum, trauma abstracts, 2016.

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