Category Archives: Resuscitation

How To Remember Those “Classes of Hemorrhage”

The Advanced Trauma Life Support course lists “classes of hemorrhage”, and various other sources list a similar classification for shock. I’ve not been able to pinpoint where these concepts came from, exactly. But I am sure of one thing: you will be tested on it at some point in your lifetime.

Here’s the table used by the ATLS course:

classes_of_shock

The question you will always be asked is:

What class of hemorrhage (or what % of blood volume loss) is the first to demonstrate systolic hypotension?

This is important because prehospital providers and those in the ED typically rely on systolic blood pressure to figure out if their patient is in trouble.

The answer is Class III, or 30-40%. But how do you remember the damn percentages?

multiscore-maxi1

It’s easy! The numbers are all tennis scores. Here’s how to remember them:

Class I up to 15% Love – 15
Class II 15-30% 15 – 30
Class III 30-40 30 – 40
Class IV >40% Game (almost) over!

Bottom line: Never miss that question again!

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Are Transfusing Too Much Blood During The MTP?

The activation of the massive transfusion protocol (MTP) for hypotension is commonplace. The MTP provides rapid access to large volumes of blood products with a simple order. Trauma centers each design their own protocol, which usually includes four to six units of PRBC per MTP “pack.”

This rapid delivery system, coupled with rapid infusion systems, allows the delivery of large volumes of blood and other blood products very quickly. But could it be that this system is too slick, and we are a bit too zealous, and could even possibly transfuse too much blood?

The trauma group at Cedars-Sinai in Los Angeles retrospectively reviewed their own experience via registry data with their MTP over a 2.5 year period for evidence of overtransfusion. All patients who received blood via the MTP were included. Patients who had a continuous MTP > 24 hours long, those who died within 24 hours, and those who had a missing post-resuscitation hemoglobin (Hgb) were excluded.

The authors arbitrarily defined overtransfusion as a Hgb > 11 at 24 hours. They also compared the Hgb at the end of the MTP and upon discharge with this threshold. They chose this Hgb value because it allows for some clinical uncertainty in interpreting the various endpoints to resuscitation.

Here are the factoids:

  • 240 patients underwent MTP during the study period, but 100 were excluded using the criteria above, leaving 140 study patients
  • Average injury severity was high (24) and 38% suffered penetrating injury
  • Median admission Hgb was 12.6
  • At the conclusion of the MTP, 71% were overtransfused using the study definition, 44% met criteria 24 hours after admission, and 30% did at time of discharge
  • Overtransfused patients were more likely to have a penetrating mechanism, lower initial base excess, and lower ISS (median 19)

The authors concluded that overtransfusion is more common than we think. This may lead to overutilization of blood products, which has become much more problematic during the COVID epidemic. They recommend that trauma centers track this metric and consider it as a quality of care measurement.

Bottom line: This is a nicely crafted and well-written study. It asks a simple question and answers it with a clear design and analysis. The authors critique their own work, offering a comprehensive list of limitations and a solid rationale for their assumptions and conclusions. They also offer a good explanation for their choice of Hgb threshold in defining overtransfusion.

I agree that overtranfusion truly does occur, and I have seen it many times first-hand. The most common reason is the lack of well-defined and reliable resuscitation endpoints. How do we know when to stop? What should we use? Blood pressure? Base excess? TEG or ROTEM values? There are many other possibilities, but none seem reliable enough to use in every patient. 

Patients with penetrating injury proceeding quickly to OR more commonly experience overtransfusion. This may be due to the reflexive administration of everything in each cooler and the sheer speed with which our rapid infuser technology can deliver products. The more product in the cooler, the more that is given, which may lead to the overtranfused condition. 

The authors suggest reviewing the makeup of the individual MTP packs, and this makes sense. Are there too many in it? This could be a contributing factor to overtransfusion. It might be an interesting exercise to do a quick registry review at your own center to obtain a count of the number of MTP patients with a final Hgb > 11. If you find that your numbers are high, consider reducing the number of red cell packs in the cooler to just four. But if you already only include four, don’t reduce it any further. And in any case, critically review the clinical indicators your  surgeons use to decide to end the MTP to see if, as a group, they can settle on one to use consistently. 

Reference: Overtransfusion of packed red blood cells during massive transfusion activation: a potential quality metric for trauma resuscitation. Trauma Surg Acute Care Open 7:e000896., July 26 2022.

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When To Stop The Massive Transfusion Protocol

Initiating the massive transfusion protocol (MTP) is generally easy. Some centers use the Assessment of Blood Consumption score (ABC). This consists of four easy parameters:

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

The presence of two or more indicators reliably predicts a 50% chance of needing lots of blood.

The shock index (SI) is also used. It’s more quantitative, just divide the heart rate by the systolic blood pressure. The normal value is < 0.7. As it approaches 0.9, the risk for massive transfusion doubles. This technique requires a little calculation, but is easily doable.

Or you can just let your trauma surgeons decide when to order it. Unfortunately, this sometimes gets forgotten in the mayhem.

However it got started, your MTP is now humming right along. How do you know when to stop? This is much trickier, and unfortunately can’t be as easily quantified. Here are the general principles:

  • All surgical bleeding must be controlled. Hopefully your patient didn’t get too cold or acidotic during the case, resulting in lots of difficult to control nonsurgical bleeding (oozing).
  • Hemodynamics are stabilizing. This doesn’t necessarily mean they are quite normal yet, just trying to approach it.
  • Vasopressors are off, or at least being weaned.
  • Volume status is normalizing. You may need an echo to help with this assessment.

If you have TEG, it probably wasn’t very useful. Until now. This is the ideal time to run a sample so you can top off any specific products your patient might need.

If you don’t have TEG, get a full coag panel including CBC, INR, PTT, lytes with ionized calcium.

Once the patient is in your ICU, continue monitoring and tweaking their overall hemodynamic and coagulation status until they are approaching normal. Then watch out for additional insults or any new and/or unsuspected bleeding. If this does occur, the threshold for return to the OR should be low. Unfortunately it is common for arteries in spasm to resume bleeding after warming and vasodilation.

When you are finally satisfied that there is no more need for the MTP, let your blood bank know so they can start restocking products and getting ready for the next go around!

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Blunt Traumatic Arrest In Kids: Are They Little Adults?

Over and over, we hear that children are not just little adults. They are a different size, a different shape. Their “normal” vital signs are weird. Drug doses are different; some drugs don’t work, some work all too well.

But in many ways, they recover more quickly and more completely after injury. What about after what is probably the biggest insult of all, cardiac arrest after blunt trauma? The NAEMSP and the ACS Committee on Trauma previously released a statement regarding blunt traumatic arrest (BTA):

 “Resuscitation efforts may be withheld in any blunt trauma patient who, based on out-of-hospital personnel’s thorough primary patient assessment, is found apneic, pulseless, and without organized ECG activity upon arrival of EMS at the scene.“

The groups specifically point out that the guidelines do not apply to the pediatric population due to the scarcity of data for this age group.

The Children’s Hospital of Los Angeles and USC conducted a study of the National Trauma Data Bank, trying to see if children had a better outcome after this catastrophic event. Patients were considered as children if they were up to and including age 18.

Here are the factoids:

  • Of 116,000 pediatric patients with blunt trauma, 7,766 had no signs of life (SOL) in the field (0.25%)
  • The typical male:female distribution for trauma was found (70:30)
  • 75% of those without SOL in the field never regained them. Only 1.5% of these survived to discharge from the hospital.
  • 25% regained SOL with resuscitation, and 14% of them were discharged alive.
  • 499 patients underwent ED thoracotomy, and only 1% survived to discharge. There was no correlation of thoracotomy with survival.
  • It appeared that there was a tendency toward survival for the very young (age 0-4) without SOL, but statistical analysis did not bear this out

Bottom line: Children are just like little adults when it comes to blunt cardiac arrest after trauma. Although it is a retrospective, registry-based study, this is about as big as we are likely to see. And don’t get suckered into saying “but 1.5% with no vital signs ever were discharged!” This study was not able to look at the quality of life of survivors, but there is usually significant and severe disability present in the few adult survivors after this event.

Feel free to try to re-establish signs of life in kids with BTA. This usually means lots of fluid and/or blood. If they don’t respond, then it’s game over. And, like adults, don’t even think about an emergency thoracotomy; it’s dangerous to you and doesn’t work!

Reference: Survival of pediatric blunt trauma patients presenting with no signs of life in the field. J Trauma 77(3):422-426, 2014.

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REBOA For Pelvic Fractures

Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) is one of the newer shiny toys that trauma professionals have adopted over the past 8 years or so. It is used to buy time for a patient who is near arrest in order to temporarily stop bleeding and get them to the operating room.

And as with all new toys, everyone wants one! I have always advised caution. Adopt a data-based approach to toy usage. Unfortunately information has been accumulating ever so slowly on this one. To help remedy this, the AAST created a registry in 2013 to consolidate the low REBOA experience numbers accruing across the US.

A group of seven surgeons representing higher-volume REBOA centers collaborated to review the AAST AORTA registry, which prospectively collects data on patients who undergo aortic occlusion. They retrospectively reviewed over six years of data on adult patients receiving REBOA for pelvic injury. They examined demographic, procedural, and outcome data in patients who underwent this procedure, both with and without other interventions like preperitoneal packing, angioembolization, or external fixation. For inclusion in the study, patients needed to have sustained blunt trauma and survived beyond the emergency department.

Here are the factoids:

  • Of the 207 patients with pelvic (Zone 3) REBOA in the registry, only 160 met inclusion criteria
  • Patients who only had REBOA suffered a mortality rate of 40% (5% in OR and 35% in the ICU)
  • Patients who had REBOA plus one of the other interventions had a 31% mortality rate (6% in OR and 25% in ICU)
  • Patients who had REBOA plus two other interventions also had a 31% mortality rate (12% in OR and 30% in the ICU)
  • Adding external fixation with or without another adjunct appeared to decrease mortality by half (from 50% to about 25%)
  • Complications were very common in all subsets, ranging from 35% to 86%
  • Patients receiving more interventions typically were more severely injured
  • No combination of REBOA and adjuncts was superior, but addition of an external fixator did appear to improve survival
  • Patients receiving angiographic embolization had a higher incidence of AKI, sometimes resulting in the need for dialysis
  • There were no significant outcome differences with REBOA use alone or with additional adjuncts

Bottom line: This was a primarily a descriptive study of how REBOA is integrated into pelvic fracture care at select US trauma centers. It was not really designed to compare the efficacy of REBOA vs preperitoneal packing vs angioembolization vs external fixation of the pelvis.

But it does show that survival remains dismal in these patients and the complication rates of REBOA + adjunct use are considerable. The authors correctly conclude that REBOA is being used in the treatment of pelvic fractures, frequently with the addition of other adjuncts. They state that the benefit of more interventions must be balanced against the potential for complications. And finally, they note that there is a need to fill in the evidence base if we are ever to adopt REBOA as a standard of care for select pelvic fractures.

What does this mean to all of you who are thinking of playing with this toy? Proceed with caution! The learning curve is steep. The complication rate is high. The opportunity for mayhem is great. This means that you must proceed deliberately. Get some advanced training with this technique. Use your performance improvement program to impartially critique its use with every deployment. And submit your experience to the national registry so we can all learn from your experience and figure out how to optimize use of this tool.

Reference: Patterns and outcomes of zone 3 REBOA use in the management of severe pelvic fractures: Results from the AAST Aortic Occlusion for Resuscitation in Trauma and Acute Care Surgery database. J Trauma 90(4):659-665, 2021.

 

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