All posts by The Trauma Pro

Laboratory

Serial Hemoglobin / Hematocrit – Huh? Part 1

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The serial hemoglobin (Hgb) determination. We’ve all done them. Not only trauma professionals, but other in-hospital clinical services as well. But my considered opinion is that they are not of much use. They inflict pain. They wake patients up at inconvenient hours. And they are difficult to interpret. So why do them?

First, what’s the purpose? Are you looking for trends, or for absolute values? In trauma, the most common reason to order is “to monitor for bleeding from that spleen laceration” or some other organ or fracture complex. But is there some absolute number that should trigger an alarm? If so, what is it? The short answer is, there is no such number. Patients start out at a wide range of baseline values, so it’s impossible to know how much blood they’ve lost using an absolute value. And we don’t use a hemoglobin or hematocrit as a failure criterion for solid organ injury anymore, anyway.

What about trends, then? First, you have to understand the usual equilibration curve of Hgb/Hct after acute blood loss. It’s a hyperbolic curve that reaches equilibrium after about 3 days. So even if your patient bled significantly and stopped immediately, their Hgb will drop for the next 72 hours anyway. If you really want to confuse yourself, give a few liters of crystalloid on top of it all. The equilibration curve will become completely uninterpretable!

And how often should these labs be drawn? Every 6 hours (common)? Every 4 hours (still common)? Every 2 hours (extreme)? Draw them frequently enough, and you can guarantee eventual anemia.

Bottom line: Serial hemoglobin/hematocrit determinations are nearly worthless. They cost a lot of money, they disrupt needed rest, and no one really knows what they mean. For that reason, my center does not even make them a part of our solid organ injury protocol. If bleeding is ongoing and significant, we will finding it by looking at vital signs and good old physical exam first. But if you must, be sure to explicitly state what you will do differently at a certain value or trend line. If you can’t do this and stick to it, then you shouldn’t be ordering these tests in the first place!

In my next post, I’ll discuss a newly published paper that objectively shows the (lack of) utility of this testing method.

Abdomen, Technique, Video

Video: Minimally Invasive Repair Of Rectal Injuries

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Extraperitoneal rectal injury repair has evolved considerably over the past 40 years. Way back when, this injury automatically triggered exploration, diverting colostomy with washout of the distal colon, and presacral drain insertion (remember those?).

We eventually backed off on the presacral drains (pun intended), which didn’t make a lot of sense anyway. And we gave up on dissecting down deep into the pelvis to approach the injury. This only served to contaminate an otherwise pristine peritoneal cavity. Ditto for the distal rectal washout. So we have been performing a diverting colostomy as the primary method of treatment for years.

A Brief Report in the British Medical Journal Open shows us what may very well be the next stage in treating these injuries. Whereas they were previously left to heal on their own followed by colostomy closure after a few months, these authors from Sunnybrook Health Sciences Centre in Toronto are promoting a minimally invasive approach to definitive management.

They detail two cases, one an impalement by a steel rod through the rectum and bladder, and one stab to the buttock. The authors dealt with the non-rectal injuries using conventional techniques. The rectal injuries were repaired using trans-anal minimally invasive surgery (TAMIS). Both were discharged without complications.

Here is a link to the video of the technique used in the stab victim:

Click here for video

Bottom line: It’s about time! As long as there is not a destructive injury to the extraperitoneal rectum, this seems like a great technique to try. It may very well eliminate the need for a diverting colostomy.

But remember, this is only a case report. We don’t know about antibiotic duration, followup imaging, longer term complications, or anything really. A larger series of cases is warranted to provide these answers. This will take some time due to the low frequency of this injury. So if you try it, build your own series and publish it so we all can learn!

Reference: Minimally invasive approach to low-velocity penetrating  extraperitoneal rectal trauma. BMJ Open 5(1) epub 5/12/2020.

General, Imaging

What? Still Using MRI For Cervical Spine Clearance?

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Cervical spine clearance as evolved considerably over the years. First, there were five views of the spine using plain radiography. Then there were three. Then we moved to CT scan with clinical clearance. And currently, many institutions are relying only on CT.

But MRI has been used as an adjunct for quite some time. Initially, it was the tie breaker in patients who had equivocal CT findings, and for a while it was used for clearance in obtunded patients. And thanks to conflicting literature and disparate studies, the occasional usage became more frequent.

The group at Cedars-Sinai Medical Center in Los Angeles  noted that the percentage of patients undergoing MRI for cervical spine evaluation at their center slowly slowly crept up from 0.9% to 5.6% over a 10 year period. They designed a study to analyze the utility of this practice and inform their future practice.

Here are the factoids:

  • Over 9,000 patients had cervical spine CT during the 10-year study period; 513 (5.6%) were positive
  • Of the 513 CT-positive patients, 290 (56%) underwent an MRI. This showed:
    • Confirmation of the major injury in 250
    • Minor injury in 40
    • Clinically significant injury was seen in only 2 which was no surprise since they both had neurologic deficits
  • Of the 8,588 CT-negative patients, only 9 had clinically significant findings and 8 of them had neurologic deficits

Bottom line: So what have we learned here? First, MRI usage at Cedars-Sinai increased over time but was really not that useful. The main use was for imaging obtunded patients or those with an obvious neurologic deficit.

More than half of patients with positive CT scans also underwent MRI. If a major injury was seen on CT, MRI confirmed it. But if the CT findings were minor, none of the MRIs added any clinically significant findings in the absence of a neurologic deficit.

And what about MRI after negative CT? In the absence of a deficit, only one had a clinically significant finding (which only required a brace).

This study shows the wisdom of monitoring “how we do it.” There is sometimes some creepage away from what the literature shows is the best practice. The best way to remedy this is to do a good study, just like the authors did. They saw a slow change in practice, investigated it, and found that there was no good clinical reason for it. This gives the trauma program the ammunition to squelch the unwelcome behavior and return the clinicians to best practices.

Reference: Is MRI becoming the new CT for cervical spine clearance? Trends in MRI utilization at a Level I trauma center. J Tra publish ahead of print, DOI: 10.1097/TA.0000000000002752, 2020.

Tips, Video

Video: Keeping Up With Your Literature

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Every trauma professional at any level of training and expertise knows that it’s so important to keep up with new developments in your field. To that end, I created a video five years ago that described a super-efficient 5-step system for staying abreast.

Well, time passes and technology changes. So I’ve updated this classic with new recommendations and some refinements to the technique. I hope you enjoy! And please leave comments and recommendations on YouTube!

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Extremity

Novel Hip Reduction Technique: The Captain Morgan

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I’ve spent the week writing about posterior hip dislocation. In my last post, I shared a video showing the standard way to reduce it. Here’s something novel, though. Emergency physicians and orthopedic surgeons at UCSF-Fresno have published their experience with a reduction technique called the Captain Morgan.

Named after the pose of the trademark pirate for Captain Morgan rum, this technique simplifies the task of pulling the hip back into position. One of the disadvantages of the standard technique is that it takes a fair amount of strength (and patient sedation) to reduce the hip. If the physician is small or the patient is big, the technique may fail.

In the Captain Morgan technique, the patient is left in their usual supine position and the pelvis is fixed to the table using a strap (call your OR to find one). The dislocated hip and the knee are both flexed to 90 degrees. The physician places their foot on the table with their knee behind the patient’s knee. Gentle downward force is placed on the patient’s ankle to keep the knee in flexion, and the physician then pushes down with their own foot, raising their calf. Gentle rotation of the patient’s hip while applying this upward traction behind the patient’s knee usually results in reduction.

Some orthopedic surgeons use a similar technique, but apply downward force on the patient’s ankle, using the leverage across their own knee to develop the reduction force needed. The Captain Morgan technique use the upward lift from their own leg to develop the reduction force. This may be gentler on the patient’s knee.

The authors report a series of 13 reductions, and all but one were successful. The failure occurred due to an intra-articular fragment, and that hip had to be reduced in the operating room.

I’m interested in hearing comments from anyone who has used this technique (or the leverage one). And does anyone have any other techniques that have worked for them?

Reference: The Captain Morgan technique for the reduction of the dislocated hip. Ann Emerg Med 58(6):536-540, 2011.