All posts by The Trauma Pro

Massive Transfusion And Tranexamic Acid (TXA)

May 3, 2019 The Trauma Pro Leave a comment

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:

Massive transfusion protocols and the use of tranexamic acid. Current Opinion Hematol 25(6):482-485, 2018.
Tranexamic Acid is Associated with Increased Mortality in Patients with Physiologic Fibrinolysis. J Surg Res 220:438-443, 2017.
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.

protocols

TEG And Your Massive Transfusion Protocol

May 2, 2019 The Trauma Pro Leave a comment

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.

protocols

What Is The Ideal Blood Product Ratio?

May 1, 2019 The Trauma Pro Leave a comment

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.

CNS

Redefining Mild TBI: Who Needs To Be Transferred?

April 29, 2019 The Trauma Pro Leave a comment

One of the more common reasons for transfer to a higher level trauma center these days is the “mild or minimal TBI.” Technically, this consists of any patient with a Glasgow Coma Scale score of 14 or 15. A transfer is typically requested for observation or neurosurgical consultation, or because the clinicians at the initial hospital are not comfortable looking after the patient.

Is this really necessary? With the number of ground level falls approaching epidemic proportions, transferring all these patients could begin to overwhelm the resources of high level trauma centers. The surgical group at Carolinas Medical Center examined their experience with a simple scoring system they designed to predict high risk minor TBI patients, and thus suitability for transfer. Here is their checklist:

Category A	Traumatic SAH Tentorial or falcine SDH < 4mm thickn Convexity SDH < 4mm thick Solitary IPH < 1cm Isolated intraventricular hemorrhage < 4mm
Category B	Any Category A lesion greater than the allowed size Midline shift Skull fracture Compression of basal cisterns Diffuse SAH or SAH involving basal cisterns Subacute or chronic SDH
	SAH = subarachnoid hemorrhage, SDH = subdural hemorrhage, IPH = intraparenchymal hemorrhage

Patients were considered to be low risk if they had only one or two category A lesions. If they had more than two, or any Category B lesions, they were higher risk and transfer was considered justified.

The authors retrospectively reviewed their experience with these patients over a three year period. They followed patients to see if they needed neurosurgical intervention, and evaluated the cost savings of avoiding selective transfers based on their criteria.

Here are the factoids:

A total of 2120 patients were studied, with 68% low risk and 32% high risk
Two of the low risk patients (0.14%) ultimately required neurosurgical intervention, compared to 21% of high risk patients
Mean age (56), and patients taking anticoagulants or antiplatelet agents were the same in the two groups, about 2-3% for each
System saving by avoiding EMS transfer costs would have been $734K had the low risk patients been kept at the initial hospital

Bottom line: This study was presented as a Quick Shot paper at this year’s Eastern Association for the Surgery of Trauma meeting, so there are some key details missing. Was there an association between anticoagulation or antiplatelet agent and two failures in the low risk group? What were they, and what intervention did they require?

If this data holds up to publication, then it may provide a useful tool for deciding to keep minimal TBI patients at the local hospital. This is usually far more convenient for the patient and their family, but would require additional education of the clinicians at that hospital to help them become comfortable managing these patients.

We use a similar tool within our Level I trauma center to decide which patients require a neurosurgical consultation. Since the low risk patients almost never require intervention, our trauma service provides comprehensive management while in hospital, and arranges for TBI clinic followup post-discharge. You can view and download a copy using the link below.

Link: Regions Hospital SAH/IPH/Skull fracture practice guideline

Reference: Redefining minimal traumatic brain injury (MTBI): a novel CT criteria to predict intervention. Quick Shot Paper #48, EAST 2019.

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