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.
|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.
|Parameter||PL (n = 22)||UL (n = 24)||P value|
|# of Attempts||2||2||>.05|
|Procedure time (min)||19.5||15||>.05|
Patients with BMI >30
|Parameter||PL (n = 7)||UL (n = 5)||P value|
|# of Attempts||2.4||1.6||.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.