I absolutely love when someone sends out a well crafted response to a podcast. I received an email from Bryan Winchell. He is the clinical coordinator flight nurse for Flight For Life in Tyler, Texas (great name ;). Bryan brings up some points regarding automatic blood pressure analysis that I think some people may not be completely aware of. I also included Eric Bauers response podcast he did a few days ago regarding the same topic. Check it out!
His email:
Good points on your transfusion podcast.
sBP vs MAP (or HR-modified MAP) rabbit hole
When using NiBP in critical illness, MAP is probably better all around than sBP/dBP. Most modern monitors calculate a MAP and extrapolate (less inaccurately) systolic/diastolic.
Good case for arterial lines!! See below picture: would you say the NiBP correlates with the arterial pressure or not? MAP says yes, SBP/DBP say no.
I think a lot of prehospital services are using the ABC Transfusion score. We added a "shock index >0.9 when beginning an RSI" as an additional bullet that can count for one of the points. I agree HR can be easily confounded. Definitely non-specific but an early sign; fair amount of people BBlocked that we've seen as well. ABC tries to index the non-specificity of HR by adding additional triggers to indicate transfusion.
We use the same triggers for transfusion as TXA. CRASH2 inclusion criteria was too broad. I agree with your sentiments here, not a wonder drug, probably useful, may cause harm in some cases... without a subgroup analysis we don't know yet.
We developed a GI Hemorrhage score internally that we use to guide transfusion in those cases. You'll probably see a good number of those in HEMS as well?
We do 100% transfusion review and grade utilization. I think the majority of services are carrying 2 PRBC and 2 plasma (lots of liquid plasma which is good). PAMPer seems to support use of plasma as well. Mixing plasma and PRBC has a logistical benefit of making the combined fluid less viscous, which transfuses faster.
Not sure the data is there yet for banked whole blood. My understanding is that when platelets are transfused as WB (not in concentrate) a large portion of them are screened out in the filter. There may not be a huge benefit to banked WB (as opposed to the military-based buddy system) over balanced (1:1 or 1:1:1) component therapy yet. Checking with our blood bank, but I believe there is an increased risk of transfusion reaction with WB due to higher titer levels.
While realizing citrate toxicity takes several units to develop, and that there is zero supporting literature for this, our medical director helped implement 1g Calcium for transfusion of 2+ units. Low risk, good inotrope, clotting cascade requires Ca++ at every turn. Our trauma department is supportive of this as well.
Thanks,
BW
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Bryan Winchell CCRN, FP-C, C-NPT
My Response:
Bryan,
I couldn't agree more about the methodology regarding automatic blood pressure analysis. The MAP as you mention will be more accurate than the systolic/diastolic values. I spoke with a rep from Zoll today who informed me that their monitor does configure heart rate into the MAP equation (gnarly!).
I tend to agree with you in regard to giving calcium early. Very easy decision when you look at the risk/benefit ratio. I would love to see your GI Hemorrhage screen you use (in the form of a FOAMfrat blog) ;)
Thanks for the excellent points. Stay safe brother!
-T
