Tag Archives: MTP

What’s The Best Trigger For Your Massive Transfusion Protocol?

Every trauma center verified by the American College of Surgeons Committee on Trauma (ACS-COT) must have a massive transfusion protocol (MTP). The details and logistics of the protocol are up to the individual center. The difficult question is: how is a trauma professional to know that the MTP should be activated?

Sometimes it’s extremely obvious. The patient is very hypotensive. Blood is spurting all over the room. But sometimes it’s more subtle and the need just seems to creep up on you. And frequently, this delays activation and the actual arrival of the blood that is so desperately needed.

I’ve previously written about common triggers for the MTP, including psychic powers, shock index, and ABC index. See the links below to read my MTP week posts. But is one better than the other? The group at Vancouver General Hospital in British Columbia, Canada performed a systematic review of the literature to try to answer this question.

A total of 45 pertinent articles were identified in the literature up to 2017. Fifteen different scoring systems were evaluated involving combinations of clinical assessment, laboratory tests, and ultrasound evaluation.

Here are the factoids:

  • The best validated score using clinical assessment plus ultrasound was the Assessment of Blood Consumption score (click here for my post). This was the easiest to score compared to other systems using ultrasound.
  • Shock index (SI) was the only validated system using just the clinical exam
  • Some other studies were promising, with excellent areas under the receiver operating characteristic curve (AUROC), but had not been validated. The best of the bunch was one from Mina et al, but it is complicated enough to require a smartphone tool for calculation.
  • Other promising studies required laboratory evaluations which preclude their use at the time of patient arrival
  • Scoring systems that used more variables generally showed better correlation with actual need for MTP, but were more less likely to provide suficiently early predictions
  • Most validation studies involved single centers
  • No studies were designed to or able to show improved outcomes

Bottom line: There are many, many systems out there for predicting need for activation of the MTP (at least 15 to date)! This review concludes that the system used should be tailored to the center implementing it.

Simpler is better. I still recommend either Shock Index (SI) or ABC. Shock index is quickly calculated based on physical exam as heart rate divided by systolic blood pressure. The normal range is 0.5 to 0.7. The likelihood of MTP escalates 2x with SI > 0.9, 4x if SI > 1.1, and 7x with SI > 1.3. The ratio can easily be calculated based on numbers available from EMS providers prior to arrival. Basically, pick your threshold.

The Assessment of Blood Consumption (ABC) uses four parameters, three of which could be reported prior to patient arrival:

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

If two or more criteria are met, the patient has a 41% likelihood of needing MTP.

So basically, use a system that works for you. From my experience, centers that use a system tend to use ABC. But definitely pick a system, don’t leave it up to chance with the trauma surgeon. And use your trauma PI program to assess utilization to see if it’s the best tool for your center.

Related posts:

Reference: Systematic Reviews of Scores and Predictors to Trigger Activation of Massive Transfusion Protocols. Accepted ahead of print, J Trauma, 2019.

Massive Transfusion And Tranexamic Acid (TXA)

Tranexamic acid has been in use for decades, just not for trauma. The CRASH-2 trial was a massive multi-country study showed that there was a slight mortality reduction from 16% to 14.5% in trauma patients who had or were at risk for “significant hemorrhage.” Moreover, there was no difference in vascular occlusive events, blood product transfusions, or need for surgery. Sounds great, right?

The MATTERs trial was initiated by the US military and tried to address some of the perceived shortcomings of CRASH-2 and found an absolute mortality reduction of 6.7%. But it also showed DVT rates that were 12x higher and PE rates 9x higher when this drug was given.

Since those two studies, a significant number of critiques have been published, as well as some additional research. Unfortunately, this has only served to cloud the picture. TXA is very inexpensive and readily available, so there has been a significant move to adopt both in the trauma center, as well as during prehospital care prior to arrival.

The trauma group at Denver Heath published a study of 232 patients with a 20% mortality rate from their injuries. They identified three subsets of patients based on their fibrinolytic response upon presentation to the hospital: physiologic fibrinolysis (49% of patients), hyperfibrinolysis (28%), and fibrinolytic shutdown (23%).

They found that mortality significantly increased in those receiving TXA who were physiologic or hyperfibrinolytic, but unchanged in those in shutdown. They cautioned that giving this drug before the patient’s fibrinolytic status was known could contribute to mortality.

Bottom line: So confusing! And many centers already include TXA in their massive transfusion protocol. Most have not seen unexpected mortality after giving the drug, so the jury is not in yet. Each trauma center should weigh the currently known pros and cons, and decide whether they are “believers” or not. Carefully review all mortalities and thrombotic complications after administration to see if there was any relation to the use of TXA.

References:

  1. Massive transfusion protocols and the use of tranexamic acid. Current Opinion Hematol 25(6):482-485, 2018.
  2. Tranexamic Acid is Associated with Increased Mortality in Patients with Physiologic Fibrinolysis. J Surg Res 220:438-443, 2017.
  3. CRASH-2 Study of Tranexamic Acid to Treat Bleeding in Trauma Patients: A Controversy Fueled by Science and Social Media. J Blood Transfus Article 874920, 2015.

TEG And Your Massive Transfusion Protocol

Thromboelastography (TEG) and its fraternal twin rotational thromboelastometry (ROTEM) are relatively new toys in the trauma community. They allow for (somewhat) rapid assessment of clotting function, and allow the trauma professional to surmise what products might push abnormal clotting characteristics back toward normal.

Many trauma centers already own this technology due to its use by non-trauma services. But there have been a growing number of research presentations on the topic over the last five years, and many centers are clamoring to buy these units for use in their MTP.

But remember, new technology is usually expensive, and isn’t always all it’s cracked up to be. TEG and ROTEM require a (often-times) new machine and a never-ending supply of disposable cartridges for use, like your ink jet printer. Some hospitals are reluctant to provide the funds unless there is a compelling clinical need.

Surgeons at the University of Cincinnati compared the use of TEG with good, old-fashioned point-of-care (POC) INR testing in a series of major trauma patients seen at their Level I center.

Here are the factoids:

  • This was a retrospective review of 628 major trauma patients who received both TEG and POC INR testing using an iSTAT device over a 1.5 year period
  • Median ISS was 13, and there were many sick patients (20% in shock, 21% received blood, 11% died)
  • INR correlated with all TEG values, with better correlation in patients in shock
  • Both INR and TEG correlated well with treatment with blood, plasma, and cryoprecipitate
  • Processing time was 2 minutes for POC INR vs about 30 minutes for TEG
  • Charges for POC INR were $22,000 vs $397,000 for TEG(!!)

Bottom line: Point of care INR testing and TEG both correlated well with the need for blood products in major trauma patients. But POC INR is much cheaper and faster. Granted, the TEG gurus will say that you can tailor the products administered to meet the exact needs of the patient. But in all my travels, I’ve see very few centers that have fully, effectively, and contemporaneously incorporated TEG or ROTEM into their massive transfusion protocol from start to finish.

The area where TEG and ROTEM are most helpful are in the “mop up” phase at the tail end of the MTP. These tools allow trauma professionals to determine exactly which products are needed to normalize parameters, and they frequently diverge from the 1:1:1 to 1:1:2 ratios at that point to achieve this.

If you don’t have one of these toys yet, make sure that you have a very good clinical reason to do so. If you do, think very carefully about how you can meaningfully incorporate it in the massive transfusion process and write it into your protocol.

Reference: All the bang without the bucks: defining essential point-of-care testing for traumatic coagulopathy. J Trauma 79(1):117-124, 2015.

What Is The Ideal Blood Product Ratio?

Back in the day when I was a resident when a massively bleeding patient came in, we gave crystalloid. And frequently, a lot of it. The books in those days said slam in two liters of saline or lactated Ringer’s solution. It was believed that there was little downside to crystalloid. Consequently, quite a bit of it was given before we ever thought about blood products.

And there were no systems in place to standardize how blood was requested, what was sent, or how much was used. We generally started off with a bunch of packed red cells. Yes, every now and then we might remember to ask for some plasma, and even less commonly some platelets or cryoprecipitate. Ratios? We didn’t really pay attention. In reality, there were probably four red cell packs to one unit of plasma, on average. And the ratio to platelets was so low it was hard to even measure!

By now, we have plenty of data showing that this crystalloid-heavy resuscitation contributed to coagulopathy and poor outcomes. We’ve adopted a more balanced concept of resuscitation, which of course we call “balanced resuscitation.” What does this term mean? Basically, it’s a combination of restricted crystalloid use, more optimized ratios of blood products, and some degree of permissive hypotension in select patients.

Before we dive more deeply into ratios, let’s agree on the nomenclature. You may hear people talking about a 1:1 ratio, or 2:1:1, or even 1:1:2. Which product is which? Always read the paper or text carefully, as there is no real standard here. Typically, if only two numbers are specified, RBCs are first and plasma second. But when three are given, you must determine whether the red cells are first or last. Here are the most common configurations:

  •               RBC : plasma : platelets
  •               Plasma : platelets: RBC

Many papers have been written examining the ratio puzzle. Mortality, complications, renal or lung injury, deep venous thrombosis and pulmonary embolism, lengths of stay, transfusion reactions (of all types), and much more have all been investigated.

The most helpful literature covering transfusion ratios are systematic reviews. The main focus seems to be finding the magic ratio of red cells to everything else. The old-time higher ratios (1:?:4) were generally considered to be inferior, so most research has focused on comparing 1:1:1 to 1:1:2. Here are the main factoids, and all keep to the plasma:platelets:RBC format:

  • There was no discernible difference in 24-hour or 30-day mortality between groups with ratios of 1:1:1 or 1:1:2
  • Patients with a 1:1:1 ratio received significantly more platelets and plasma that the 1:1:2 patients
  • Giving cryoprecipitate or fibrinogen concentrate early had no effect on mortality

Although systematic reviews try to make up for shortcomings of individual studies, they introduce their own problems. However, they overall seem to indicate that the “magic” ratio lies between 1:1:1 and 1:1:2. Most centers strive for the former, but due to many reasons (e.g. no thawed plasma, delivery issues) more realistically try to stay under the latter.

Bottom line: Think about the logistics in your own trauma center, and design your massive transfusion protocol so that you can maintain a ratio somewhere between 1:1:1 and 1:1:2. Every MTP activation should be analyzed by your trauma performance improvement process and must review your final ratios. One thing I’m sure of is that we will continue to refine this over the coming years, so stay tuned!

Reference: Optimal Dose, Timing and Ratio of Blood Products in Massive Transfusion: Results from a Systematic Review. Transfus Med Rev 32(1):6-15, 2018.

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.

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