Monthly Archives: September 2015

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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 a few 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!

Related post:

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.

General

Admission To Nonsurgical Service = Longer LOS?

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Previous studies have shown that higher hospital costs are associated with longer length of stay (LOS). This makes sense, because the longer a patient stays in the hospital, the more that is “done” for them, and more daily charges are incurred. Obvious savings can occur if we look globally at services, medications, etc while the patient is in the hospital.

But does the admission service make a difference in LOS or cost? It shouldn’t if care is fairly uniform. A group of orthopedic surgeons at Vanderbilt in Nashville looked at a large group of isolated hip fracture patients (n=614) to see if LOS (used as a surrogate for cost) was significantly different. They also tried to control for a host of factors that could affect time in the hospital between the two groups.

Here are the factoids:

  • About half of the patients were admitted to the orthopedics service, and half to medicine
  • Median length of stay was way different! 4.5 days on Ortho vs 7 days on Medicine
  • Readmission rates were also significantly higher on Medicine, 30% vs 23%
  • After controlling for factors such as medical comorbidities, age, smoking and alcohol, ASA score, obesity, and others, a regression model showed that patients were still likely to stay about 50% longer if admitted to a medicine service.

Bottom line: Obviously, this is the experience of a single institution. But the difference in length of stay, and hence costs, was striking. As the US moves toward a bundled payment system, this will become a major problem. The initial LOS is more costly on the medicine service, and readmission for the same problem will not be reimbursed. Why the difference? Coordination of care between two services? Lack of familiarity with surgical nuances? This study did not look at that.

But it does point out the need to more closely integrate the care of the elderly in particular, and patients with a broad range of needs in general. An integrated team with orthopedic surgeons and skilled geriatricians is in order. And a set of protocols for standard preop evaluation and postop management is mandatory.

Related posts:

Reference: 

Does Admission to Medicine or Orthopaedics Impact a Geriatric Hip Patient’s Hospital Length of Stay? J Orthopedic Surg epub Sep 14, 2015.

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Treating Numbers: Pulse Oximetry

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How many times has this happened to you? You walk into a young, healthy trauma patient’s room and discover that they have nasal prongs and oxygen in place. Or better yet, these items appear overnight on a patient who never needed them previously. And the reason? The pulse oximeter reading had been low at some point.

This phenomenon of treating numbers without forethought has become one of my pet peeves. Somehow, it is assumed that an oximetry value less than the standard “normal” requires therapy. This is not the case.

In young, healthy people the peripheral oxygen saturation values (O2 sat) are typically 96-100% on room air. As we age, the normal values slowly decline. If we abuse ourselves (smoking, working in toxic environments, etc), lung damage occurs and the values can be significantly lower. Patients with obstructive sleep apnea will have much lower numbers intermittently through the night.

So when does a trauma inpatient actually need supplemental oxygen? Unfortunately, the literature provides little guidance on what “normal” really is in older or less healthy patients. Probably because there is no norm. The key is that the patient must need oxygen therapy. How can you tell? Examine them! Talk to them! If the only abnormal finding is patient annoyance due to the persistent beeping of the machine, they don’t need oxygen. If they feel anxious, short of breath, or have new onset tachycardia, they probably do. Saturations in the low 90s or even upper 80s can be normal for the elderly and smokers.

Bottom line: Don’t get into the habit of treating numbers without thinking about them. There are lots of reasons for the oximeter to read artificially low. There are also many reasons for patients to have a low O2 sat reading which is not physiologically significant. So listen, talk, touch and observe. If your patient is comfortable and has no idea that their O2 sat is low, turn off the oxygen and toss the oximeter out the window.

General

Hypotensive Patient? You’ve Got 90 Seconds!

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You’re running a trauma activation, and everything is going great! Primary survey – passed. Resuscitation – lines in, fluid going. You are well into the exam in the secondary survey.

Then it happens. The automated blood pressure cuff shows a pressure of 72/44. But the patient looks so good!

You recycle the cuff. A minute passes and another low pressure is noted, 80/52. You move the cuff to the other arm. Xray comes in to take some pictures. You roll the patient. 76/50. Well, you say, they were lying on the cuff. Recycle it again.

A minute later, the pressure is 56/40, and the patient looks gray and is very confused and diaphoretic. It’s real! But how long as it been real? An easy 5 minutes have passed since the first bad reading.

Bottom line: Sometimes it’s just hard to believe that your patient is hypotensive. They look so good! But don’t be fooled. If you get a single hypotensive reading, STOP! You have 90 seconds to figure out if it’s real, so don’t do anything else but. Check the pulse rate and character with your fingers. Do a MANUAL blood pressure check. It’s fast and accurate. If you have the slightest doubt, ASSUME IT’S REAL. Remember, your patient is bleeding to death until proven otherwise. And it’s your job to prove it. Fast!