Category Archives: Resuscitation

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.

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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.
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MTP Week Part 4: How To Build Your Massive Transfusion Protocol

Massive Transfusion Protocol (MTP) week continues! I’m releasing the next Trauma MedEd newsletter to subscribers at the end of the week, which deals with advanced MTP topics. So leading up to that, I am reviewing the basics for the next several days. I’ll continue today with MTP activation triggers.

What criteria should trigger your massive transfusion protocol? Sometimes, it’s obvious. The EMS report indicates that your incoming patient is in shock. Or there was notable blood loss at the scene. Or they have a mangled extremity and will need blood products in the OR, if not sooner.

But sometimes the need for ongoing and large quantities of blood sneaks up on you. The patient is doing well but has an unexplained pressure dip. And it happens again. You give one of your  uncrossmatched units of blood. It happens again. At some point, you come to the realization that you’ve given six units of blood and no plasma or other products! Ouch!

Many trauma centers have adopted MTP criteria like:

  • More than 4 units given over 4 hours
  • More that 10 units to be given over 24 hours
  • Loss of half a blood volume over 24 hours

I call these the “psychic power” criteria, because one must surely be prescient to know this information just shortly after the patient arrives. Don’t include criteria like these at your center!

Instead use some sort of objective criteria. A simple one is the use of any of your blood refrigerator products or emergency release blood, or a calculated score such as the ABC score or shock index (SI).

ABC score is the Assessment of Blood Consumption score and gives one point each for a heart rate > 120, SBP < 90, positive FAST, penetrating mechanism.  ACS score > 2 was predictive of requiring MTP with sensitivity and specificity of about 85%. Overtriage was about 15%.

Shock index (SI) is defined as the heart rate divided by the SBP. Normal values are in the range of 0.5 to 0.7. Need for MTP was found to increase to 2x for SI of 0.9, 4x with an SI of 1.1, and 7x with SI 1.3.

A recent paper compared these two systems retrospectively on 645 trauma activations over a 5-year period. They found that they both worked well with the following results:

  • Shock index > 1 – 68% sensitive 81% specific
  • ABC > 2 – 47% sensitive, 90% specific

The study suggests that shock index is more sensitive, and takes less technical skill to calculate. Bottom line: just pick the some objective criterion you are most comfortable with and use it!

Reference: Accuracy of shock index versus ABC score to predict need for massive transfusion in trauma patients. Injury 49(1): 15-19, 2018

Well folks, that’s it for MTP week! Hope you enjoyed it.

And don’t forget to subscribe to TraumaMed if you want to get a full newsletter discussing advanced MTP topics tomorrow. Otherwise, you’ll be reading a post on CT scans and rib fractures in the elderly! Subscribe and download back issues by clicking here.

Links: (note – future links will not be live until 9am the day they are published)

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MTP Week Part 3: How To Build Your Massive Transfusion Protocol

Massive Transfusion Protocol (MTP) week continues! I’m releasing the next Trauma MedEd newsletter to subscribers at the end of the week, which deals with advanced MTP topics. So leading up to that, I am reviewing the basics for the next several days. I’ll continue today with information on deactivating and analyzing your MTP.

Deactivation. There are two components to this: recognizing that high volume blood products are no longer needed, and communicating this with the blood bank. As bleeding comes under surgical control, and CBC and clotting parameters (and maybe TEG/ROTEM) normalize, the pace of transfusion slows, and ultimately stops. Until this happens, the MTP must stay active. Even a low level of product need should be met with coolers stocked with the appropriate ratios of products.

There are two ways to stop the MTP: the surgeon or their surrogate calls the blood bank (when no more blood products are to be used), or the blood bank calls the surgeon after the next cooler has been waiting for pickup for a finite period of time. This is typically about 30 minutes. It is extremely helpful if the exact deactivation time is recorded in the electronic medical record. However, this information can be obtained from the blood bank.

Analysis. It’s all over, and now the real fun begins. For most trauma centers, the blood bank maintains extensive data about every aspect of each MTP event. They record what units were released and when, when they were returned, which ones were used, were they at a safe temperature on return or were they wasted, and much, much more! Typically, one of the blood bank supervisors or a pathologist then compiles and reviews this data. What happens next varies by hospital.

Ideally, the information from every MTP activation gets passed on to the trauma program. Presentation at your transfusion committee is fine, but this data is most suitable for presentation at the trauma operations committee. And if significant variances are present (e.g. product ratios are way off) then it should also be discussed at your multidisciplinary trauma PI committee as well.

There are relatively few standard tools out there that allow the display of MTP data in an easily digestible form. Here are some of the key points that must be reviewed by the trauma PI program:

  • Demographics
  • Components used (for ratio analysis)
  • Lab values (INR, TEG, Hgb, etc)
  • Logistics
  • Waste

I am aware of two tools, the Broxton form and an MTP audit tool from the Australian National Blood Authority. The Broxton tool covers all the basics and includes some additional data points that cover activation criteria, TXA administration, and administration of uncrossmatched blood. Click here to check it out. The Australian tool is much more robust with more data points that make a lot of sense. You can download a copy by clicking here.

Tomorrow, I’ll continue with activation criteria for the MTP.

And don’t forget to subscribe to TraumaMed if you want to get a full newsletter discussing advanced MTP topics this Friday. Otherwise, you’ll be reading a post on CT scans and rib fractures in the elderly! Subscribe and download back issues by clicking here.

Links: (note – future links will not be live until 9am the day they are published)

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MTP Week Part 2: How To Build Your Massive Transfusion Protocol

Massive Transfusion Protocol (MTP) week continues! I’m releasing the next Trauma MedEd newsletter to subscribers at the end of the week, which deals with advanced MTP topics. So leading up to that, I am reviewing the basics for the next several days. I’ll continue today with some tips on the logistics of your MTP.

MTP logistics include details such as who will be delivering the blood, what actually goes in each cooler, what ratios should be used, limitations imposed by the use of frozen plasma, and documentation. I’ll discuss details about ratios and FFP in the next Trauma MedEd newsletter.

The runners who travel between blood bank and the patient need to be selected carefully. Blood bank tech? Not ideal because they’ve got more important work to do. ED or OR tech? Maybe, as long as you’ve got a reliable pool. Student or resident? Probably not, because they may not know their way to the blood bank, which are typically placed in the farthest corner of the basement as possible. One of the most creative solutions I’ve seen is the use of a hospital security officer. Think about it. They know the hospital layout cold, including that obscure corner where the blood bank is located. And there are plenty around all the time!

Documentation is critically important, both in the trauma bay and the blood bank. Trauma activations, especially ones requiring MTP, are very fast moving and complex. Two sets of documentation are crucial: accurate records of blood product administration (on the trauma flow sheet), and documentation of just about everything else (in the blood bank). A specific timestamp on the trauma flow sheet that records the exact time of activation of MTP is a big plus.

What about coolers? I’ve seen everything used from uninsulated plastic buckets, picnic coolers, and pneumatic tube containers to large, self-contained rolling refrigeration units. The choice of container really boils down to cost vs waste. The cheaper it is, the less insulated it is, the more likely that blood products will be discarded due to high temperature if not transfused promptly. The best blend of cost vs utility seems to be the good, old-fashioned picnic cooler. It’s very portable, reasonably cheap, and can be tested for temperature maintenance. Just be sure to secure a pouch to the outside to keep platelets at room temperature to maintain full functionality.

Here’s a sample MTP cooler that’s ready for use. The platelets are in the pouch on the left. Note the reminder to prompt the team to give TXA if not contraindicated. This is often forgotten in the heat of the trauma activation.

Who actually runs your MTP? In some ways, it should run itself. Coolers get delivered, products get transfused. However, some decision making is needed to decide how long to continue and whether any tweaking of product ratios needs to happen. In the emergency department, the surgeon or emergency physician can do this. But once a trauma patient arrives in the OR, that is no longer the case. The emergency physician was left behind in the ED and the surgeon is up to her elbows in trouble. What about the anesthesiologist? Nope, they are busy keeping the patient safely asleep, regulating rapid infusions, and actually administering the blood.

Most of the time, however, these two physicians actually end up running the MTP while multi-tasking at their other job. Unfortunately, this can lead to errors and delays. One best practice to consider: a highly trained trauma resuscitation nurse or advanced practice provider (APP) can run the MTP from the sidelines. They travel with the patient from ED to OR, managing the MTP the entire time. This offloads responsibility from busier people.

Tomorrow, I’ll continue with MTP deactivation and analysis.

And don’t forget to subscribe to TraumaMed if you want to get a full newsletter discussing advanced MTP topics this Friday. Otherwise, you’ll be reading a post on CT scans and rib fractures in the elderly! Subscribe and download back issues by clicking here.

Links: (note – future links will not be live until 9am the day they are published)

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