8/ And #POCUS? ๐ข๐ฝ๐๐ถ๐ฐ ๐ก๐ฒ๐ฟ๐๐ฒ ๐ฆ๐ต๐ฒ๐ฎ๐๐ต ๐๐ถ๐ฎ๐บ๐ฒ๐๐ฒ๐ฟ (ONSD) is a surrogate for disc edema
Here is orbital anatomy on ultrasound
9/ To measure ONSD:
โฎLOTS of gel
โฎMeasure 3 mm behind globe, transverse & longitudinal
โฎ๐๐ท๐ฆ๐ณ๐ข๐จ๐ฆ ~2+ ๐ฎ๐ฆ๐ข๐ด๐ถ๐ณ๐ฆ๐ฎ๐ฆ๐ฏ๐ต๐ด @AnnaEMin5
11/ ...the ๐ข๐ก๐ฆ๐ measurement is interpreted in a spectrum of possibilities. An absolute cutoff is not practical, #POCUS likely not accurate enough
Per Wilson et al. in novices
โฎONSD < 3.6 mm ~rules out
โฎONSD > 5.3 mm ~rules in
โฎ3.6-5.3 - ??? doi.org/10.1002/emp2.1โฆ
โข The ๐ฝ๐ฟ๐ผ๐ฏ๐ฒ ๐บ๐ฎ๐ฟ๐ธ๐ฒ๐ฟ ๐ถ๐ ๐ผ๐ป ๐๐ต๐ฒ ๐ฅ๐๐๐๐ง, or oriented toward the LA/LV relative to RA/RVx
โข The top of the screen (๐๐ฝ๐ฒ๐ ) ๐ถ๐ ๐ฐ๐น๐ผ๐๐ฒ๐๐ to the probe and
โข Atria are furthest
3/ With those constraints one can determine general ๐๐ฐ๐ probe location
โข Probe marker ~3 oโclock (๐ถ๐ด๐ถ๐ข๐ญ๐ญ๐บ 2:30)
โข ~5rd IC space
โข ~Midclavicular line (๐ข๐ญ๐ต๐ฉ๐ฐ๐ถ๐จ๐ฉ ๐๐๐ ๐ข๐ฏ๐ฅ ๐ข๐ฑ๐ฆ๐น ๐ข๐ณ๐ฆ๐ฏ'๐ต ๐ข๐ญ๐ธ๐ข๐บ๐ด 1:1)
โข Probe tilted to head