EUS: Comprehensive LE DVT studies & LP Guidance

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Brown Ultrasound Tape Review – 9:17:15

 

ARTICLE #1  –  If “2-Point Compression” is Good, Would “5-Point Compression” Be More Good?

Srikar et al.  Isolated Deep Venous Thrombosis: Implications for 2-Point Compression Ultrasonography of the Lower Extremity. Annals of Emergency Medicine 2015; 66: 262-267

For the evaluation of DVT, the American Institute of Ultrasound in Medicine recommends compressibility and spectral Doppler waveforms of the Common Femoral, proximal Deep Femoral, Femoral, Popliteal, and proximal Great Saphenous veins.  But ever since Bernardi et al found equivalence with “2-Point Compression” plus D-Dimer, many ER physicians have been employing this faster technique at the bedside, which uses compressibility and direct visualization of the Common Femoral and Popliteal veins only.  This study questioned whether we should consider assessing more veins by investigating the prevalence of thrombi elsewhere in symptomatic patients.  This was a 6 year retrospective study of 2451 symptomatic patients who received “comprehensive” studies of the Common Femoral, Deep Femoral, Femoral, Popliteal, and Calf veins, which were interpreted by vascular surgeons.

LE veins www.ultrasoundpaedia.com/normal-dvt-leg/

Location of Thrombus (Thrombi) # (n = 362 positive tests) (%)
Common Femoral only 5 (1.4)
Deep Femoral only 3 (0.8)
Femoral only 20 (5.5)
Popliteal only 53 (14.6)
Calf veins only 58 (16)
Common + Femoral 15 (4.1)
Common + Femoral + Deep 7 (1.9)
Common + Femoral + Popliteal 28 (7.7)
Common + Deep + Popliteal 7 (1.9)
Common + Popliteal 3 (0.83)
Common + Femoral + Deep + Popliteal 35 (9.6)
Femoral + Deep 1 (0.27)
Femoral + Popliteal 56 (15.4)
Calf + proximal veins 71 (19.6)

The Bottom Line:  Expanded assessment of more veins takes more time and some extra training, but may decrease D-Dimer testing and subsequent follow up comprehensive studies.  Isolated assessment of femoral and popliteal would have missed many thrombi in this study, but it is currently unknown exactly what embolic risk these other clots pose, and whether knowing of their existence adds any value in considering further hematological workup.

 

ARTICLE #2  –  Breaking News Bulletin: Some Lumbar Punctures Are Harder Than Others!

Nomura et al, A Randomized Controlled Trial of Ultrasound-Assisted Lumbar Puncture. J Ultrasound Med 2007; 26: 1341-1348

In this randomized, prospective, double-blind study, Nomura et al sought to answer whether ultrasound imaging during lumbar puncture (LP) can increase success and ease of LP, and whether there are select populations that may benefit more.  In 46 patients, they compared the Palpation Landmarks method (PL) to the Ultrasound Landmarks method (UL), and stratified by BMI; the ED sonographers took a 5-minute training course and performed two practice scans to qualify.  With patients either sitting or in the lateral decubitus position, the linear array probe was held midline in the sagittal view to view the dorsal spinous processes, the optimal site was marked with ink, and the LP was performed without real-time guidance.  Operators’ “ease” and patients’ “comfort” were both evaluated with the Visual Analog Scale, from 0-10, with 0 representing “very easy” and “minimal discomfort,” respectively.

All Patients

Parameter PL (n = 22) UL (n = 24) P value
Age 39 35 >.05
BMI 27 26.1 .06
# of Attempts 2 2 >.05
Ease 5.2 3 >.05
Patient comfort 2.6 1.7 >.05
Procedure time (min) 19.5 15 >.05

 

Patients with BMI >30

Parameter PL (n = 7) UL (n = 5) P value
Avg Age 42 31 .03
BMI 34 34 .83
# of Attempts 2.4 1.6 .22
Ease 6.9 2.7 .01
Patient comfort 5.5 2.8 .22
Procedure time (min) 25.3 20.3 .57

The Bottom Line:  While this study suffered from lack of statistical significance, there were trends towards less attempts, more operator ease, more patient comfort, and less time required when ultrasound was employed, and the differences were greater when the patients’ BMI was >30.  Further study is required here, but there seems to be little downside and some potential upside to checking your landmarks with Ultrasound, particularly when your palpated landmarks are obscured deep under soft tissues.

One thought on “EUS: Comprehensive LE DVT studies & LP Guidance

  1. Awesome summaries. Re DVT US; the other day I had a patient with a normal bedside (2 point compression), but abnormal comprehensive (5 point compression). Reinforcing to me that the bedside US for DVT is a somewhat specific test. If you see the thrombus or don’t have compressibility, you’ve got your diagnosis, but if your test is normal, they could still have a DVT.

    I’m not sure if the time it would take to train EM physicians to perform a 5 point compression (and the extra time it would take per patient to perform the test) would be worth it. It sounds like the vast majority of clinically significant clot burdens would be picked up on the 2 point compression (although I have no evidence to back this claim up).

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