Tag Archives: Massive transfusion

Prehospital Use Of The ABC Score And MTP

Early and appropriate resuscitation is critical in any severely injured trauma patient. Typically, the trauma team assesses the patient upon arrival and makes a determination as to what type of resuscitation fluids are most appropriate. If blood is judged to be necessary, individual units can be given, or the massive transfusion protocol (MTP) can be activated.

I’ve previously written about two objective methods to assist in the decision to activate your MTP, shock index (SI) and assessment for blood comsumption (ABC). These have traditionally been applied once the patient arrived. What would happen if you used prehospital information to calculate the ABC score and were able to activate your MTP sooner rather than later?

The group at the University of Colorado in Aurora studied this concept. The charge nurse captured information to calculate the ABC score from the initial prehospital information received by phone while the patient was enroute. He or she would then activate the MTP in order to have blood products delivered as close to patient arrival as possible.

They reviewed their experience over a 29-month period. The first 15 months used their original system, calculating ABC on arrival and then deciding whether to activate MTP. During the final 14 months, it was calculated prior to patient arrival and the MTP was “pre”-activated when the score was 2 or more. The primary outcome studied was mortality, and secondary variables were appropriate activation of MTP, and adherence to balanced resuscitation ratios.

Here are the factoids:

  • A total of 119 patients with hypotension and/or MTP activation were studied; 24 occurred pre-implementation and 95 post
  • Pre-implementation, 63% of 24 hypotensive patients had MTP activation and only 6 (40%) received blood. Only 2 patients (33%) had RBC:FFP ratios between 1:1 and 2:1.
  • Post-implementation, 98% of hypotensive patients had MTP activation, a 6-fold increase
  • Also post-implementation, 42% of the activations received the blood, and balanced product ratios increased to 77%
  • Overall mortality decreased from 42% to 19% after implementation, all of which occurred in the penetrating injury group
  • Hospital and ICU lengths of stay were unchanged and there were no readmissions

Bottom line: The authors actually rolled two studies into one here. The main focus of the paper was to look at use of ABC score using prehospital information, but they also changed their MTP setup at the same time. During the initial part of the study, they did not have thawed plasma available, so the first cooler contained only red cells. Plasma was delivered when available, usually about 45 minutes after the first cooler had arrived. Post-implementation, thawed plasma was included in the first cooler.

So is the reduction in mortality (only in penetrating injury) due to early availability of the entire cooler, or because the desired product ratios were much more consistently met? Unfortunately, we can’t know.

This is a relatively small study, but the results with respect to blood actually being given, attainment of ratios, and mortality are impressive. Is the takeaway message to activate MTP early based on prehospital info or to make sure all coolers stock plasma? My take is that it’s probably best to do both!

Related posts:

Reference: Effect of pre-hospital use of the assessment of blood consumption score and pre-thawed fresh frozen plasma on resuscitation and trauma mortality. JACS 228:141-147, 2019.

ABC: A Quick & Dirty Way to Predict Massive Transfusion

It’s nice to have blood available early when major trauma patients need it. Unfortunately, it’s not very practical to have several units of O neg pulled for every trauma activation, let alone activate a full-blown massive transfusion protocol (MTP). Is there any way to predict which trauma patient might be in need of enough blood to trigger your MTP?

The Mayo Clinic presented a paper at the EAST Annual Meeting several years ago that looked at several prediction systems and how they fared in predicting the need for massive transfusion. Two of the three systems (TASH – Trauma Associated Severe Hemorrhage, McLaughlin score) are too complicated for practical use. The Assessment of Blood Consumption tool is simple, and it turns out to be quite predictive.

Here’s how it works. Assess 1 point for each of the following:

  • Heart rate > 120
  • Systolic blood pressure < 90
  • FAST positive
  • Penetrating mechanism

A score >=2 is predictive of massive transfusion. In this small series, the sensitivity of ABC was 89% and the specificity was 85%. The overtriage rate was only 13%.

The investigators were satisfied enough with this tool that it is now being used to activate the massive transfusion protocol at the Mayo Clinic. Although the abstract is no longer available online, it appears to be remarkably similar to a paper published in 2009 from Vanderbilt that looks at the exact same scoring systems. Perhaps this is why it never saw print? But the results were the same with a sensitivity of 75% and a specificity of 86%.

Here’s a summary of the number of parameters vs the likelihood the MTP would be activated:

ABC Score         % requiring massive transfusion
0                                1%
1                               10%
2                               41%
3                               48%
4                             100%

Bottom line: ABC is a simple, easy to use and accurate system for activating your massive transfusion protocol, with a low under- and over-triage rate. It doesn’t need any laboratory tests or fancy equations to calculate it. If two or more of the parameters are positive, be prepared to activate your MTP, or at least call for blood!

In my next post, I’ll look at the impact of using ABC based on prehospital information.

Related post:

References: 

  • Comparison of massive blood transfusion predictive models: ABC, easy as 1,2,3. Presented at the EAST 24th Annual Scientific Assembly, January 26, 2011, Session I Paper 4. (No longer available online)
  • Early prediction of massive transfusion in trauma: simple as ABC (assessment of blood consumption)?J Trauma 66(2):346-52, 2009.

The January 2019 Trauma MedEd Newsletter Is Available!

Welcome to the current newsletter. This is part 2 of my discussion of the massive transfusion protocol (MTP). Here are the topics I cover:

  • What Is The Ideal Blood Product Ratio?
  • TEG And Your MTP
  • MTP and TXA
  • The History Of Fractionated Blood Components
  • Use Of Whole Blood For Massive Transfusion

The next issue covers fat embolism syndrome and will be released to subscribers at the end of the month. Non-subscribers will have to wait another week for the public release.

To download the current issue, just click here! Or copy this link into your browser: http://bit.ly/TME201901.

Liquid Plasma vs FFP: Definitions

I’ll spend the next few days discussing plasma. This is an important component of any trauma center’s massive transfusion protocol (MTP). Coagulopathy is the enemy of any seriously injured patient, and this product is used to attempt to fix that problem.

And now there are two flavors available: liquid plasma and fresh frozen plasma. But there is often confusion when discussing these products, especially when there are really three flavors! Let’s review what they are exactly, how they are similar, and how they differ.

Fresh frozen plasma (FFP)
This is plasma that is separated from donated whole blood. It is generally frozen within 8 hours, and is called FFP. However, in some cases it may not be frozen for a few more hours (not to exceed 24 hours total) and in that case, is called FP24 or FP. It is functionally identical to FFP. But note that the first “F” is missing. Since it has gone beyond the 8 hour mark, it is no longer considered “fresh.” To be useful in your MTP, it must be thawed, and this takes 20-40 minutes, depending on technique.

Thawed plasma
Take a frozen unit of FFP or FP, thaw, and keep it in the refrigerator. Readily available, right? However, the clock begins ticking until this unit expires after 5 days. Many hospital blood banks keep this product available for the massive transfusion protocol, especially if other hospital services are busy enough to use it if it is getting close to expiration. Waste is bad, and expensive!

Liquid plasma (never frozen)
This is prepared by taking the plasma that was separated from the donated blood and putting it in the refrigerator, not the freezer. It’s shelf life is that of the unit of whole blood it was taken from (21 days), plus another 5, for a total of 26 days. This product used to be a rarity, but is becoming more common because of its longer shelf life compared to thawed plasma.

Finally, a word on plasma compatibility. ABO compatibility is still a concern, but Rh is not. There are no red cells in the plasma to carry any of the antigens. However, plasma is loaded with A and/or B antibodies based on the donor’s blood type. So the compatibility chart is reversed compared to what you are accustomed to when giving red cells.

Remember, you are delivering antibodies with plasma and not antigens. So a Type A donor will have only Type B antibodies floating around in their plasma. This makes it incompatible with people with blood types B or AB.

Type O red cells are the universal donor type because the cells have no antigens on the surface. Since Type AB donors have both antigens on their red cells, they have no antibodies in their plasma. This makes AB plasma is the universal donor type. Weird, huh? Here’s a compatibility chart for plasma.

Next time, I’ll discuss the virtues of the various types of plasma when used for massive transfusion in trauma.

EAST 2018 #8: 4-Factor PCC Plus Plasma. What?

Many trauma centers have moved toward reversing warfarin with prothrombin complex concentrate (PCC) in place of plasma due to the speed and low volume of infusate with the former. In the US, 3-factor PCC was approved by the FDA first, but it has a lower Factor VII content. This usually required infusion of plasma anyway to make up the Factor VII, so what was the point (although there was some debate on this)?

Then 4-factor PCC was approved, and it alone could be used for warfarin reversal. But so far, PCC has not been routinely used for reversal of coagulopathy from trauma. We still rely on plasma infusion for this. The abstract I am discussing today compares reversal with 4-factor PCC alone to reversal with 4-factor PCC and plasma in coagulopathic patients.

This study retrospectively reviewed adult patients who received one of the above treatments over a 3 year period. Patient who were on oral anticoagulants were excluded. The goal INR was 1.5, and time to correction and number of PRBC transfused were measured.

Here are the factoids:

  • There were 516 patients who met criteria, but only 80 FFP patients and 40 PCC+FFP patients were analyzed
  • Patients were an average of 58 years old, had an ISS of 29, and 87% had sustained blunt injury
  • PCC+FFP resulted in faster correction of INR (373 min vs 955 min)
  • PCC+FFP received fewer units of PRBC (7 vs 9 units) and FFP (5 vs 7 units)
  • Mortality rate was lower in the PCC+FFP group (25% vs 33%)
  • There was no difference in thrombotic complications

Bottom line: Well, this is an interesting start. I think this abstract suggests that we should incorporate giving 4-factor PCC into the massive transfusion protocol to try to reduce the INR faster. However, the patient numbers are low and several of the results are only weakly significant (units transfused, mortality, p=0.04). Some additional confirmative studies will be needed before this is ready for prime time!

Here are some questions for the authors to consider before their presentation:

  • Why did your study group drop from 516 to 120? What impact might this have had on you analyses?
  • Did you look at the correction times stratified by initial INR? Severely coagulopathic patients could skew the numbers, especially if they were predominantly in only one of the study groups.
  • It did not look like the patients received much PRBC or plasma (<10 units of each). How injured / coagulopathic were they?
  • The mortality rates are rather high for an average ISS of 29. Did you analyze to see what impact ISS had on mortality? Could this have influenced your analysis?
  • Big picture question: Should we consider routinely giving PCC as part of the massive transfusion protocol in patients who are known to be coagulopathic? Based on the graph, it looks like patients will need more than a single dose. Reversal time was still very long for PCC+FFP.

Thanks for an intriguing abstract!

Reference: EAST 2018 Podium paper #12.