Tag Archives: Massive transfusion

Abstracts

Best Of EAST #10: MTP With Whole Blood

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Here’s one last abstract to consider before the EAST meeting kicks off this afternoon. Every trauma center must have a massive transfusion protocol (MTP). But not every one has access to whole blood. And whole blood is all the rage now for transfusion in the trauma world.

Believe it or not, we must still ask the question “is using whole blood safe?” More than 50 years ago, all we had was whole blood. But we didn’t use it in trauma the way we do today. And we didn’t have the tools then to determine whether there were any adverse effects from its use. Now we do, and we are slowly rediscovering the nuances of using it. Some work has shown that small volumes of whole blood appear to be safe. But there is little information on the safety of using large volumes in MTP.

The group at Oregon Health Sciences University in Portland attempted to do this with a quick shot paper to be presented tomorrow morning. They reviewed their experience over a two year period. For the first 18 months, they used standard component therapy (PRBC + plasma + platelets) in their MTP. For the final six months, they used cold-stored uncrossmatched, low-titer group O blood. Any patient who had MTP activated and received even a single unit of blood was included in the study. 

Here are the factoids:

  • 83 patients received component therapy and 42 received whole blood; demographics were the same
  • The component therapy patients received an average of 6 PRBC, 5 plasma, and 0 platelets; the whole blood group received 6.5 units (4 PRBC, 4 plasma, and 1 platelets based on the usual composition of a unit)
  • Plasma:RBC ratio was 0.8:1 for the component group and 0.94:1 in the whole blood group (statistically significant, but not clinically significant, see below)
  • The authors described a component-equivalent unit of product which is not defined. It was 12 for component therapy and 27 for whole blood.
  • There were no differences in 24-hour or 30-day mortality, and no transfusion reactions

The authors concluded that MTP using whole blood is feasible, and that it appeared to be safe and effective. They also commented that it may lead to more balanced resuscitation.

My comment: Alright, this is the last time I’ll mention study power (for a while). If a study does not have the statistical power to show a difference between groups, then seeing no difference means nothing. The absence of a difference does not mean that the two groups are equivalent. And this study of 125 patients is small potatoes for showing any difference in a crude outcome like mortality.

Besides having a small number of subjects, the average number of units given was low for an MTP. For most trauma centers, this was just over one cooler of products. Although ISS was 29, the patients don’t sound like they had huge blood replacement requirements, so it’s no wonder that mortality was the same between the two groups.

And finally, the statement about more balanced resuscitation is open to debate. The difference between 0.8 units of plasma and 0.94 units is 35cc per unit of red cells given, a little over 1 tablespoon. It’s hard to believe that this would ever make a difference clinically.

To those who read only the title or the conclusion of an abstract (or paper for that matter), beware. The devil is in the details. This study is a good start toward addressing the question posed, but needs several hundred more subjects (and a lot more blood products given) to close in on an answer.

Reference: Massive transfusion with whole blood is safe compared to component therapy. EAST Annual Assembly Quick Shot #8, 2020.

Resuscitation

Massive Transfusion: What’s The Right Ratio?

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In my last post, I analyzed a survey that studied the massive transfusion protocol (MTP) practices of academic Level I trauma centers in the US. What centers do is one thing. But what does the literature actually support? A group from Monash University in Melbourne, Australia and the National Health Service in the UK teamed up to review the literature available through 2016 regarding optimal dose, timing, and ratio of products given during MTP.

One would think that this was easy. However, the search for high quality ran into the usual roadblock: the fact that there is not very much of it. The authors scanned MEDLINE for randomized, controlled studies on this topic, and found very few of them. Out of 131 articles that were eligible, only 16 were found to be suitable for inclusion, and 10 of them were still in progress. And only three specifically dealt with the ratio question. Even they  were difficult to compare in a strict apples to apples fashion.

Here are the factoids that could be gleaned from them:

  • There was no difference in 24-hour or 30-day mortality between a ratio of 1:1:1 (FFP:platelets:RBC) vs 1:1:2
  • However, a significantly higher number of patients  achieved hemostasis in the 1:1:1 group (86% vs 78%)
  • There was no difference in morbidity or transfusion reactions in the two groups
  • One study compared 1:1 component therapy with whole blood transfusion and found no difference in short-term or long-term mortality or morbidity

Bottom line: As usual, the quality of available data is poor if one limits the field to randomized, controlled studies. Ratios of 1:1:1 and 1:1:2 appear to be equally effective given the limited information available. A number of papers not included in this review (because of their less rigorous design) do seem to indicate that higher ratios of RBC (1:3-4) appear to be detrimental. And as time passes, more and hopefully better studies will be published.

What does this all mean for your MTP? Basically, we still don’t know the best ratio. However, it is recommended that your final ratios of FFP:RBC end up somewhere between 1:1 and 1:2. The only way to ensure this is to set up your MTP coolers so the the ratio of product they contain is better than 1:2. This means more plasma than 1 unit per 2 units of red cells. 

If you set it at the outside limit of 1:2, then that is the best ratio you can ever get assuming everything goes perfectly. However, if you have to thaw frozen plasma, use too much emergency release PRBC before activating MTP, or someone cherry-picks the coolers to transfuse what they think the patient needs, the ratios will quickly exceed this boundary.

So be sure to load your coolers with ratios that are closer to 1:1 to ensure that your final ratios once MTP is complete are what you want them to be. And monitor the final numbers of every one of your MTP activations through your trauma performance improvement program so you know what your patients are really receiving.

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

Guidelines

Massive Transfusion: What Ratios Are People Using?

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This is the first of a two-part series on massive transfusion protocol (MTP) ratios. Today, I’ll write about what ratios trauma centers around the country are using. Tomorrow I’ll review the literature we have to date on what the correct ratio should be. Are we all doing the right thing or not?

Back in the old days (which I remember fondly), we didn’t pay too much attention to the ratio of blood to plasma. We gave a bunch of bags of red cells, then at some point we remembered that we should give some plasma. And platelets? We were lucky to give any! And to top it all off, we gave LOTS of crystalloid. Turns out this was not exactly the best practice.

But things have changed. Some good research has shown us that a nice mix of blood component products is good and too much crystalloid is bad. But what exactly is the ideal mix of blood products? And what is everybody else doing? I’ll try to answer these questions in this series.

So first, what are all the other trauma centers doing? An interesting medley of anesthesia and pathology groups from the University of Chicago, a Dallas-based anesthesia group, and a blood center in my home base of St. Paul, conducted a survey of academic medical centers in 2016. They wanted to find out how many actually had a MTP and to scrutinize the details.

They constructed a SurveyMonkey survey and sent it to hospitals with accredited pathology residencies across the US. There were 32 questions in the survey, which asked for a lot of detail. As you can probably personally attest, the longer and more complicated the survey, the less likely you are to respond. That certainly happened here. Of 107 surveys sent out, it took a lot of nagging (initial email plus two nags) to get a total of 56 back.

Here are the factoids:

  • Most were larger hospitals, with 74% having 500 or more beds
  • All had massive transfusion protocols
  • Trauma center level: Level I (77%), Level II (4%), Level III (4%), Level IV (2%), no level (14%)
  • Nearly all (98%) used a fixed ratio MTP; very few used any lab-directed (e.g. TEG/ROTEM) resuscitation
  • Target RBC:plasma ratio: 1:1 (70%), 1.5:1 (9%), 2:1 (9%), other (9%)
  • Only 58% had the same RBC:plasma ratio in each MTP cooler
  • More than 86% had thawed plasma available (remember, these were generally large academic centers)
  • Half stored uncrossmatched type O PRBCs outside the blood bank, usually in the ED; only 1 stored thawed plasma in the ED
  • A total of 41% had more than one MTP (trauma, OB, GI, etc.)
  • 84% had some type of formal review process once the MTP was complete
  • About 68% had modified their MTP since the original implementation. Some increased or decreased ratios, expanded MTP to non-trauma services, decreased the number of units in each pack, changed to group A plasma from AB, or switched from ratio to TEG/ROTEM or back.

Bottom line: This is an intriguing snapshot of MTP practices around the country that is about four years old. Also remember, this is a somewhat skewed dataset. The survey was directed toward hospitals with academic pathology programs, not trauma centers. However, there is enough overlap that the results are probably generalizable. 

Most centers are (were) using MTP packs containing six units of PRBCs, and were attempting to achieve a fixed 1:1 ratio. Half of hospitals had the same number of units in each cooler, half varied them by cooler number. Nearly half had multiple flavors of MTP for different specialties. Very few used TEG/ROTEM during the initial phased of MTP. Most modified their MTP over time.

I’ve written quite a lot on most of these issues. See the links to my “MTP Week” series from earlier this year, below.

Tomorrow, I’ll review what we know and don’t know about the proper ratios to use in your MTP.

Reference: Massive Transfusion Protocols: A Survey of Academic
Medical Centers in the United States. Anesth & Analg 124(1):277-281, 2017.

MTP week series:

Prehospital, Resuscitation

Prehospital Use Of The ABC Score And MTP

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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.

Resuscitation

ABC: A Quick & Dirty Way to Predict Massive Transfusion

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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.

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.