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

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.

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  • Danielle Pigneri

    Hello! Thanks for reviewing our study! I would like to address a few of your comments.

    First, there is indeed a follow up study. We are conducting a multi center study which EAST has elected to sponsor. We will be presenting this and recruiting additional centers at the EAST conference next week.

    Second, I would like to highlight the benefits of having a more sensitive study. When used in the appropriate patient population (hypotensive blunt abdominal trauma), the ability to identify intraabdominal hemorrhage as the cause of their hypotension clearly provides the opportunity to intervene and stop the bleeding more quickly. However, this is not the only value to increased sensitivity. If the sensitivity of the examination is improved, then a negative study becomes more meaningful. This is especially useful when faced with a hypotensive patient with associated neurologic or pelvic trauma. A negative study with high sensitivity and specificity would allow for the surgeon to confidently rule out intraabdominal hemorrhage as the cause of hypotension and allow for expedited treatment of other injuries. Additionally, if a negative FASTeR carried an acceptable sensitivity, then a negative FASTeR study could be used to avoid ionizing radiation in the pediatric trauma patient population. We don’t yet know the actual sensitivity rate of the FASTeR study in trauma patients. This remains to be answered by the follow-up multi center trial.

    The purpose of this study is not to answer how much hemoperitoneum it takes to obtain a positive FAST/FASTeR or whether or not obesity leads to degraded images on ultrasound. Those items would be better answered through a different study design. Separately, those issues are not modifiable factors in the trauma bay. In trauma, you do the best with what you get. I can’t make a patient 50 pounds lighter in the trauma bay, but I can standardize my practice and roll all patients to the right. This practice costs nothing except perhaps a few extra seconds for a repeat look at the right upper quadrant.

    The study is small, but every positive study was a positive FASTeR at a volume of intraabdominal fluid at which the participant had already had a negative standard FAST. We had originally designed the study with plans to recruit a total of 30 volunteers, hoping to find 1-3 (3-10%) such outcomes. Given that six total participants had a positive FASTeR after negative FAST, this exceeded our threshold for deciding to move forward with the next phase of the study, the multi center trial. If you imagine that 30 total participants had been recruited, and that all of these additional patients had a positive FAST before a FASTeR, then the FASTeR population is still 6/30 (20%). This would still be a significant finding and justify moving forward. We elected to move forward with the multi center trial rather than delay to recruit additional peritoneal dialysis patients, which are few and far between.

    The purpose of this pilot study was to prove that the time and energy required for the multi center trial is justified. This it has. The multi center trial will determine if standardizing patient rolling to the right side and performing a FASTeR examination is worthwhile.

    • TheTraumaPro

      Thanks! I’m looking forward to seeing you at EAST! Michael