Carotid VTI Passive Leg Raise for Volume Responsiveness. #FOAMED

 So you love the concept of the passive leg raise, but getting that darn LVOT VTI is really tough, right?

Well, what if you could just perform a carotid doppler instead?  Much easier window!  Our friends at the University of Arizona have been studying this, and there’s already been some stuff published on this.
So here it is:  How to and discussion.  Also a quick announcement about a trip to Sweden we’ll be taking soon.
This isn’t the end of carotid doppler for volume responsiveness, though.  There’s another technique being currently studied at Mass General, and we’ll bring that to you very soon.  Similar…..but different.  Coming soon.
Oh yeah, also, Introduction to Bedside Ultrasound Volume 1 and Volume 2 can be viewed on your computer now through iTunes!  With the newest Mac OS, Maverick, you can download ibooks to your computer.  So don’t forget to do that, and don’t forget to apply for our FOAMED scholarship.
Come learn with us:

7 Comments on “Carotid VTI Passive Leg Raise for Volume Responsiveness. #FOAMED”

  1. sakib

    Can I get away with not measuring the diameter of the carotid and just measure vti in carotid before and after PSL/fluid bolus?
    I remember mention of the other variables in the equation being relatively constant when measuring vti from cardiac 4 chamber view since the assumption was lvot vessel was stiff enough that the diameter wouldnt change before and after PSL thereby simplifying it to one step. Not sure if that same assumption can be made about common carotid.

    1. Mike

      Marik’s paper found a significant difference in carotid diameter before and after PLR, so technically you should measure it each time. Realilistically, I think it will only matter in those patients that only increase by right at 20%. If they increase by 50% or even 30 or 40%. I don’t think the carotid diameter will matter.

  2. Patton Thompson

    Hey guys awesome podcast as always. I am using a sonosite m turbo. When I go to calculate carotid flow in pulse wave doppler the only way is to click on an option called called volume flow (I have already saved the max diameter in systole in 2d mode 1 cm from the carotid bulb). My only option is to use a method called TAM (time average mean) i put the cursor on the pulse wave at the beginning of systole then another at the end of systole and a mean curve appears, but this usually appears slightly below the PWD Tracing. I then go to patient report and i am getting numbers for flow that make sense i.e. 500ml/min. My question is this: is TAM the same as VTI? In your tutorial the machine automatically took an average of the VTI from 3 beats. At least with the M turbo, VTI is not an option and neither was tracing the curve manually when using the linear probe on vascular setting. If TAM is ok or basically the same as VTI should I only be looking at systolic flow or should i also include the diastolic portion? Just curious if anyone else with a sonosite is having the same issue?


    Patton Thompson

    1. Bill

      I am using the sonosite edge and am having the same problem.I talked to the local rep here and she said VTI was not available with the vascular probe. It seems to me they should be able to do a software update enabling VTI with the vascular probe. I tried using the linear array probe on my carotid and was not able to get a good tracing. The volume flow numbers I obtained on myself using the vascular probe were low, in the 180-190 ml/min range.
      I would like to try this technique but feel that it will not be accurate using the volume flow number that the Edge calculates. Anybody have any solutions?
      Bill Clark

    2. DS

      I’ve been having the same difficulties with TAM (my machines only report TAP, time average mean vs time average peak). Any insights into the differences between TAP and TAM? However, by using the flow calculation, I’ve also been getting flow values that make sense.

      Furthermore, since we’re evaluating Pre and post “Intervention” values, it seems to me that the relative differences should still hold. More specifically, there should a number change (20%) that can be predictive of fluid responsiveness. has anyone tried this yet?


  3. Chiara

    Is there any limitation in using carotid VTI for volume responsiveness when i find atheromasic calcifications?

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