Radiology

If you build it, will they come (back)?

This is a review of 2.5 years worth of lower back pain.  Basically, every single patient with an ICD-9 code had their chart reviewed to ask the question, “If you got an MRI in the ED, are you less likely to return?”

They specifically did not look at yield, rather, just whether or not patients initially thought to have plain, old back pain came back.
The answer, contrary to those of us who think more is more, is no.   Repeat visits for those that had an MRI was 4.3%, repeat visits for those without an MRI at initial visit- 4.6%
However, it does give you some insight into who returns – they were more likely male (5.9% vs 2.8%) – further demonstrating that males are in fact the weaker sex.  They were more likely English speaking (4.9% vs 2.1%) and, speaking of which, non-English speakers were less likely to have an MRI (12.2% vs 7.4%), and self-pay patients were also less likely to have an MRI (9.8% vs 5.1%).   Its unclear if this further demonstrates a touch of bias on the provider side, if English-speaking patients speak up more about wanting diagnostics, or if non-English speakers just go to another hospital since this was a single center study.
As a secondary measure, they also looked at disposition for these patients.  Only 16% were discharged after MRI (vs 82% of those without MRI), 74% of those MRI’ed were placed in observation status (vs 11% of those not), 9% of those MRI’ed were admitted vs 3%, and 4% of those not MRI’ed left prior to completing treatment. Now, for some fancy math.
of the 797 patients who received an MRI over this time period, if only 11% were placed in obs status (rather than 74%), that is only 88 patients rather than 591 patients placed in obs status. that’s 503 patients with an unnecessarily padded bill. At $35.8013 per RVU, were talking tens of thousands of dollars billed that’s wasted.
Or, to put it another way, if you are in an area with a good payor mix, why not just obs & MRI them all?
Standard
Mythbusting, Improving Outcomes, Radiology, Radiology

Spinal Abscess: The Baystate Review

This is a review of all spinal abscesses at Baystate (total 162), from 2005 – 2015.  They compare 88 randomly selected controls whom had similar ICD-codes less the spinal abscess plus an MRI that was negative for acute infectious process. 

Interesting take home points, much of which is consistent with prior (albeit scant) literature:

-73% of patients are over age 50.

-more likely to have their second visit (50.6% vs 29.6% of controls) – though this 50.6% of patients with a second visit is surprisingly low for me – no word on how many were sent home from the ED, and had an MRI as an outpatient that were not included in this calculation.; or maybe we’re getting better at finding the needle in the haystack?  Or maybe we’re MRI’ing everyone?

-Many received antibiotics within the month: (35.2% vs 6.8% of controls) – this signifies a huge red flag for me.  If a patient revisits the ED and recently had pyelo (or anything infectious really), and now presents with back pain, probe a bit more for the possibility of vertebral osteo or discitis. 

-percentage of patients with history of IVDA: 20.4% vs 4.6% … this number seems low, but also is somewhat in line with prior studies – thus making me wonder how many I’ve missed…

– percentage of patients with alcoholism with a spinal abscess: 19% vs 8% – the more I get interested in ID, the more I realize that alcoholism is basically a form of immunosuppression.

-percentage of spinal abscess patients with obesity 21.6% vs 2.3%; I’m surprised only 2.3% of controls were obese.  Not sure what role this plays as being a diabetic in and of itself was not associated with a higher increased risk in this study.

-fever was present 62.4% in those with a spinal abscess vs 13.6% of those without; this includes self reported fever, which I have to wonder how often we sweep this aside when the patient is afebrile in the ED.

-16% had no identifiable risk factors; a third of the patients  presented with back pain, fever, neurologic deficits vs 6%

-Other symptoms and signs related to potential spinal cord impingement were seen with similar frequencies and of similar durations among cases and controls- meaning, focal deficits seen in both groups.

-noncontiguous co-infection: 53.7% of time (pneumonia, distant osteo, endocarditis… of those with a co-infection, 20% had more than one).

-blood cultures were positive 63.4% of the time, and >75% of the time it was staph Aureus. 

-Majority of lesions were found in the L-spine at 56.2%  – which means almost half are elsewhere!

-while “admits” for spinal abscess were up from 2.5 to 8 in 10,000 admissions from 2005 to 2015, I have to believe that number is somewhat inflated as admits like chest pain, pneumonia and renal colic probably decreased, while MRI became more readily available. 

All in all, this paper is pretty much in line with others on this topic, and strengthens the signal a bit for certain key points: a good number of spinal abscesses are not in the L-spine; many patients are older than you think, and, among other things: its more than just IVDA. 

Standard
Cardiology, Cardiology, Critical Care, Improving Outcomes, Improving Throughput, Mythbusting, Pulmonary, Radiology, Radiology

Probing the dyspneic patient.

For undifferentiated dyspnea, how would you like to have an accurate diagnosis in 24 minutes?

I love this study.

Basically, for all dyspneic patients (not trauma related, and over age 18), 10 EP’s were given an H&P, vital signs, and an EKG, as well as access to a Chest X-Ray, Chest CT, cardiologist performed echo, and labs including an ABG.

These same 2,683 patients, in tandem, had point of care ultrasound testing (lung, IVC, echo). Here’s the catch – the ultrasonographers were only provided the H&P, vital signs, and EKG then asked to make a diagnosis. The treating provider was blinded to POCUS diagnosis.

These numbers for diagnostic accuracy of POCUS are astounding.

+LR for acute HF? 22 (-LR 0.12)

+LR for ACS? 105 !!!

+LR for pneumonia? 10.5 (-LR 0.13)

+LR for pleural effusion? 95 (-LR 0.23)

+LR for pericardial effusion? 325!!! (-LR 0.14)

+LR for COPD/asthma? 22 (-LR 0.14)

+LR for PE? 345!!!

+LR for pneumothorax? 4635!!! (-LR 0.12)

+LR for ARDS? 90

Yes, for certain things like pneumonia, the difference in p-values between tradition means and POCUS diagnosis was not significantly different, but what about volume status? I cant imagine blindly giving 30 cc/kg would benefit the patient with a plethoric IVC and pleural effusion. There is some elegance a play here.

Additionally, sure, ED diagnosis for ACS had a higher LR, but they also had a cardiologist performing and interpreting echos in the ED (a rather rare siting in a US ED I would imagine) – without much improvement in their -LR (0.53 vs 0.48). For PE, the -LR of POCUS was predictably mediocre if not outright bad (0.6), while the -LR for ED diagnosis of PE, with the benefit of chest CT, was -0.10.

Now look, I get that these EP’s were quite sono-savvy. They all had 2+ years of experience, over 80 hours of ultrasound lessons & training, with at least 150 lung and 150 ED echo’s under their belt. The diagnosis was made in 24 minutes with POCUS in comparison to 186 minutes for traditional means. And while most of us can not do a year+ ultrasound fellowship, and neither can we all be as savvy with the probe as these authors (or Matt, Mike, Jacob, Resa, Laleh, etc) – it does not mean we shouldnt try. You can still greatly increase your yield just by practicing. To boot, the cognitive offload you experience by saving yourself a few hours by (correctly!) knowing which direction you are heading with a patient is an immense boon to both your mental heath & your patients well being.

Standard
Improving Throughput, Mythbusting, Radiology, Radiology

Whaddaya Mean You Can’t Learn POCUS?

After taking a few one day ultrasound courses, a common theme amongst classmates is something to the effect of, “well, I get it now, but what about next week when the instructor isn’t there to guide me?”

Admittedly, I have wondered about the same thing; and wondered about the retention of knowledge and ability to apply what you have learned at these 1-2 day crash courses.

So you think you cant learn ultrasound? Or that you can not retain it after a weekend course? Well, those damn whippersnappers from Oregon are putting the non-believers to shame.

Medicine interns at Oregon Health & Science University were taught point of care ultrasound 3 months into their first year, as one day of a 5 day medical “boot-camp.” The day-long program consisted of 15-20 minutes of didactic training, and was followed by a 40 minute hands on session. Learners were placed in groups of 2-3 individuals and taught one-hour modules consisting of: the basics (knobology, physics, etc), CLUE protocol, FAST exam, hydronephrosis eval, and aorta & neck anatomy.  The 40 minute hands on portion was divided into 20 minutes for completing modules demonstrating pathology on SonoSim machines and 20 min for facilitator-led hands-on practice with volunteer models. (example- 20 didactic minutes learning FAST, 20 minutes on simulation, then 20 minutes on a real-live person!).  This was followed by two optional 1 hour courses done within 6 months.

A 30 question multiple choice test was administered prior to the course to all 33 interns, testing image interpretation, image acquisition/optimization, and clinical applications of ultrasound. The test was re-administered 6 months later; there was a significant drop out rate (27%), and it was untracked as to whom took the optional one hour courses.

Survey says?

Mean pretest scores – 61%

Mean post-test scores- 85%

Mean 6 month post-test scores – 79%

Great news – We probably intuitively know & retain much more than we think, but just have to continue to pick up the probe to hone our craft.  Bad news, I’m not certain that an ability to retain enough knowledge to improve a multiple choice test score is the same as making a correct clinical decision off of limited ultrasound skills.  Admittedly, POCUS in the wrong hands can be a problem, and making clinical decisions based off limited ultrasound skills and knowledge is a difficult leap to take, but its one we invariably have to make in order to grow as a clinician.

So, yeah, don’t tell me you can’t learn ultrasound.

Standard
Improving Throughput, Mythbusting, Radiology, Radiology

Sono-guided Right IJ? Skip the chest film.

1,322 sono guided IJ central lines. Guess how many pneumothoraces.

One. Exactly one.

Overall success rate – 96.9%.

One percent of the time the catheter required repositioning. So, basically a failed rate of 2%.

Zero arterial placements.

Sure, 1,322 over a one year period is insanity (Henry Ford in Detroit, if you’re curious), and you can easily argue that a hospital that places that many central lines probably has it down cold.

Bottom line, if you are competent enough to place an ultrasound guided right sided IJ central line, you can skip the xray, especially if it is going to delay care. You do not image your femoral lines before usage, do you?

Standard
Improving Outcomes, Improving Throughput, Mythbusting, Neurology, Neurology, Radiology, Radiology

Community EM rejoice- CT within 6 hours safe for SAH rule out.

There is yet another paper to further elucidate who should get the CT / LP work up for subarachnoids. The authors looked at six EDs over 5 years, and encompassed 2,248 patients – of which 1898 had suitable LPs for analysis (insufficient sample, exposed to light [?], blood contamination, incorrect storage or transport [?], or they just plain lost the sample). CT reads were done by on-call radiologists in training (I imagine that means residents), or by board-certified radiologists. Images were then reviewed by a board-certified neuro-radiologist OR by a board-certified general radiologist for a final report. There was no “time limit” from onset of headache for exclusion (ie, patients did not need to be scanned within six hours).

92 patients of the 1898 patients were positive for blood via spectrophotometry – 4.8%. Nine of these positives ended up having a subarachnoid hemorrhage (9.8% of their LPs, or 0.47% of patients). What do these nine patients generally have in common? Six of them had a headache for a week or longer. One had a previously coiled embolism. One had a negative CT performed within 3 hours of onset.  All of these nine patients got coiled or clipped.

So, what do we make of these? If you present within 6 hours with a negative CT (or, dare I say, less than a week!), you have a 0.053% of having a subarachnoid. If you still do the LP in those <6hours from onset (or, <1 week from onset), the baseline risk of a false positive is 10% vs 1.1% chance of true SAH.

Time for some well-informed shared decision making, and perhaps a higher threshold for those that present with a prolonged headache.  Further good news to take away from this study- it does not seem as neuro-radiologists need to make the call and that the <6 hour proposal can be safely extended to the community setting at this point.

 

(First link is to free text of article.  Pubmed did not have a working link to the paper at time of post.  If the first link does not work, try here)

Standard
Improving Throughput, Mythbusting, Radiology, Radiology

Who is really distracted by distracting injuries?

Those that (still) recommend the pan-scan in trauma, it would seem.  Over a once year period, this 803 patient prospective study (451 of which with distracting injuries) evaluated all awake, alert, blunt trauma patients with a GCS of 14-15 to determine the validity of an abdominal exam.  Endpoints were injuries which required the OR and those which required a transfusion.

Screen Shot 2015-06-20 at 5.48.46 PM

A ten percent failure rate of the abdominal exam for an intra-abdominal injury seems rather high, but this is ten percent of all who actually had an injury. When you consider “all-comers,” it’s more like 1.1% of those with a distracting injury and 0.57% for those without a distracting injury.  With that, you would need to scan over a hundred patients to find one intra-abdominal injury that you would have otherwise missed.  Throw in the fact that all five missed injuries in the distracted cohort had solid organ injuries, and that none of them required surgical intervention or blood transfusion, and you can see how the authors come to their conclusion:

These data suggest that clinical examination of the abdomen is valid in awake and alert blunt trauma patients, regardless of the presence of other injuries.”

Standard