Tag Archives: Serial hemoglobin

Solid organ

The End Of Serial Hemoglobin/Hematocrit In Solid Organ Injury

Leave a comment

Here’s the final post on my series covering serial hemoglobin testing in the management of solid organ injury.

We developed our first iteration of a solid organ injury practice guideline at Regions Hospital way back in 2002. It was borne out of the enormous degree of clinical variability I saw among my partners. We based it on what little was publicly available, including an EAST practice guideline.

Recognizing that the EAST guideline couldn’t dictate bedside care, we gathered together to meld it with our own clinical experience. We fashioned our first practice guideline later that year and tested it.  It included instructions for bedrest (only overnight), vital signs monitoring, and lab testing (on admission and once the next day).

That last bit about serial lab tests is an important one. We had seen anecdotal evidence in our patients that it wasn’t very helpful. For example, I had one patient in the ICU whose serial Hgb had just returned normal. However, a minute later they experienced a hard hypotensive episode, and I took him immediately to the OR and took out a ruptured and bleeding spleen.

I’ve written several posts on how quickly Hgb changes after hemorrhage. Unfortunately, this lab test just lags too long to be a reliable indicator of anything. A very recent study has been published by Texas Health Presbyterian in Dallas. The retrospectively reviewed patients with liver or spleen injury over five years. They examined how often serial hemoglobin determinations influenced management during the study period. Possible interventions were none, operation, angioembolization, or blood transfusion.

Here are the factoids:

  • There were 143 patients enrolled, and half had no interventions, a third had interventions within 4 hours, and the remainder (16%) had an intervention after 4 hours
  • In the early intervention group, one-third underwent laparotomy, 42% angiography, and 9% had both; 17% received transfusions based on clinical parameters alone and not lab results
  • Of the 16% that did have a later intervention (23 patients), 12 received a blood transfusion only based on a Hemoglobin value, and all but one had no further interventions. That patient had a laparotomy based on the lab test.
  • All other patients in the late intervention group went to OR or angioembolization based on hemodynamics or a change in physical exam.
  • The number of blood draws was phenomenal, with an average of 19 in the early intervention group, 17 in the delayed intervention group, and 7 in the no-intervention group

The authors concluded that serial hemoglobin measurements were not well-supported by the literature and that the decision for intervention was nearly always driven by hemodynamics or physical exam.

Bottom line: Although this study is small, the results are very clear. As we were taught in our surgical training, hemodynamics and physical exam are vital in managing solid organ injury. Unfortunately, hemoglobin is a lagging indicator, and the repeated discomfort and unnecessary cost overshadow its clinical value. This is most significant when treating pediatric patients.

Try to recall the last time you and your trauma colleagues had a patient whose need for intervention was based on a lab draw. Now take your practice guideline back to the drawing board and eliminate the serial exams!

Click here for an example of a serial Hgb-free solid organ injury practice guideline

Reference: Role of Serial Phlebotomy in the Management of Blunt
Solid Organ Injury in Adults. J Trauma Nurs 30(3), 135–141, 2023.

 

General

Serial Hemoglobin To Monitor Chest Tube Output? Huh?

Leave a comment

I’ve already written about the (f)utility of serially monitor hemoglobin (Hgb) or hematocrit (Hct) levels when managing solid organ injury nonoperatively. What about if you are concerned with bloody output from a chest tube drainage system? Could it be of any use there?

Seems like a reasonable idea, right? Wrong. As always, think it through and do the math! Here are the questions you need to ask yourself:

  • What is the Hgb or Hct of the fluid coming out of the chest tube? At worst, it will be the same as the patient, assuming that pure, whole blood is coming out. But this is seldom the case. The fluid is usually described as “serosanguinous”, which is not very exact, but tells you that it is thinner than blood. And if it looks more like Kool-Aid, the concentration is very low indeed.
  • What is the volume in the container? Most collection systems will collect a maximum of 1 to 1.5 L of juice.
  • How fast is it coming out? These things almost never fill right in front of your eyes. It’s a slow process, with less than a few hundred ccs per shift.

Here’s a few hundred ccs of thin drainage in a collection system. Probably decrease in Hgb value – < 0.1, which is far less than the range of lab error.

Bottom line: So now do the math. Let’s say the fluid has half the hematocrit / hemoglobin of whole blood. Losing one unit (500cc) of whole blood will generally drop your Hgb by about 1 gm, or your Hct by about 3%. If the blood is half-strength like I am proposing (and the usual drainage is typically much thinner), it will take twice as much (one liter) loss to drop the lab values by that much. This will probably come close to filling up the average collection system. If it takes a day or two or more to fill up, you are not going to see much change in their lab values. And most of the time, the blood in the system is thin like Kool-Aid, so your patient is really losing very little actual blood.

So measuring serial hemoglobin / hematocrit as you watch a hemothorax drain doesn’t make sense. Unless the output is pure blood and the system is filling up in front of your eyes, of course. In that case, a trip to the OR to fix the problem might be a better idea than doing a blood draw and sitting around waiting for the result to come back.

Related post:

General

Serial Hemoglobin / Hematocrit – Huh?

Leave a comment

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!

Related post:

Reference: Serial hemoglobin levels play no significant role in the decision-making process of nonoperative management of blunt splenic trauma. Am Surg 74(9):876-878, 2008.