Category Archives: Philosophy

Serial Lab Testing: Worthwhile or Worthless? Part 2

Yesterday, I posted a series of sodium levels that were drawn daily. There was no change in clinical status as the levels varied from 131 to 125 and back up.

Now let me give you a bit more information. The patient was actually getting serial checks every 6 hours (or more)! Here’s the updated chart:

Day/Time Na Treatment NaCl per day
Day 1 18:30 131
Day 1 22:54 132 0.9% NS @ 125/hr 3G
Day 2 05:59 133 continues 3G
Day 2 12:19 129 continues
Day 2 17:50 129 continues
Day 3 07:18 127 continues
Day 3 12:09 127 continues
Day 3 17:58 126 continues
Day 3 23:53 126 continues
Day 4 07:45 125 continues
Day 4 11:38 122 2% NS @ 25/hr 6G
Day 4 15:25 125 continues
Day 4 19:31 125 continues
Day 5 00:06 122 continues 6G
Day 5 04:04 126 continues
Day 5 08:01 122 continues
Day 5 11:50 132 stop
Day 5 16:14 126
Day 5 19:26 127
Day 6 00:20 129 9.2G
Day 6 04:42 127 2% NS @ 40/hr
Day 6 08:30 124 continues
Day 6 12:29 127 stop
Day 6 16:16 127 Salt tabs 2G tid
Day 6 20:28 132 continues
Day 7 05:22 134 Salt tabs 2G qid 8G
Day 7 12:33 135 continues
Day 8 07:02 131 stop None
Day 8 13:33 136

Confused? Me, too! This poor person had 30 blood draws in 8 days, with 6 per day for two of those days. Carefully look at the amount of salt given in each 24 hour period, and look at the sodium levels for that day.

See the variability, even when getting high doses of sodium chloride? What does this tell you? Was the salt administration helpful? Was seeing the lab value every 4-6 hours valuable?

Tell me what you think. Leave comments or tweet your opinions. Next, I’ll discuss the known variability of the serum sodium assay, and give you my opinion on the value of serial testing.

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Serial Lab Testing: Worthwhile or Worthless?

We’ve all done it at some point. Serial hemoglobin. Serial sodium. Serial serum porcelain levels. What does serial mean to you? And what does it tell us about or patient?

Today and tomorrow, I’d like to present an example from real life. For today, have a look at the daily sodium tests done for a patient with a head injury. The concern was for cerebral salt wasting, which is probably grounds for its own blog post.

So have a look at this series of sodium determinations. It represents serial values based on daily testing.

Day/time Na
Day 1 18:30 131
Day 2 05:59 133
Day 3 07:18 127
Day 4 07:45 125
Day 5 04:04 126
Day 6 04:42 127
Day 7 05:22 134

At what point, if any, would you be concerned with significant hyponatremia, and begin some type of supplementation?

Tomorrow, I’ll provide a little more info on levels and treatment

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The Tenth Law Of Trauma

Several years ago, I ran a series of posts on my Laws of Trauma. I assembled them into  newsletter that contained all nine that existed at the time. If you’d like to download it, just click this link.

I’ve  been struck by another pattern, and I think it’s about time to add the tenth law. Weirdly enough, it was inspired by Dancing With The Stars. You’ll see what I mean.

Here is the Tenth Law of Trauma:

“In trauma, it generally takes two to tango”

So what does this mean? When dealing with injury, there are a few broad quantitative categories.

  • Single person mechanism. This is one extreme. Common examples would be the elderly fall, a single vehicle car crash, or a self-inflicted stab or gunshot. There is a single “point of failure” that only the individual involved can manage, but for various reasons they do not or cannot. This law does not apply.
  • Multiple person mechanism. This is the other extreme, and thankfully is not seen very often at all. Examples are a tour bus crash, house explosion, or mass casualty event. Once again, those involved usually have little ability to recognize or avoid the imminent event, and the tenth law is null and void.
  • Two person mechanism. This one is very common, and is exemplified by the two car crash, pedestrian struck, or the various flavors of assault. And this is the one that the tenth law applies to.

When two people are involved in an event that leads to traumatic injury, there is usually (but certainly not always) a set of checks and balances that is present. And frequently there is at least one opportunity to avoid the event.

In the case of a two vehicle crash, one driver may have “gone off the reservation” and ignored the usual traffic laws for whatever reason. But the second driver usually has an opportunity to recognize this and change their behavior in order to avoid the situation. However, if they are distracted, impaired, or making assumptions about how other driver behave they can still get into trouble. Thus, it takes two.

What about the pedestrian struck? Likewise, the driver or the pedestrian may have done something nonstandard. Wear dark clothes at night. Glance at their phone while driving. Look at their passenger a bit too long while having a conversation. Once again, the other participant may have an opportunity to see the result of this unexpected behavior and jump or swerve out of the way.

Interpersonal violence it a bit more tricky. Sure, one of the potential participants may get wind that something is up and try to avoid or defuse the situation. But not always. And this situation is heavily charged with emotion and social pressures and is much more difficult to change or avoid.

Bottom line: Many, but certainly not all,  “two-person” mechanisms of injury are avoidable if both of the individuals involved are mentally present and attentive to their surroundings. Look at your own patient population and see how often this applies. You may be surprised!

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What Would You Do? The Elderly Patient With Subdural Hematoma – Final Answer?

I’ve spent the last several posts reviewing the sparse data that we have on the impact of subdural hematoma management in elderly patients. With this information, I had hoped to arrive at some answers as to what to do when certain common patient presentations are encountered.

Unfortunately, the data is not very good, and is structured to raise false hopes. Overall, it looks like about 30-40% of selected patients die in the postoperative period. And the percentage of patients who are discharged at their pre-injury level of independence is in the low single digits. In fairness, one paper did show an improvement from severely disabled to moderately disabled or recovered, although the authors obfuscated how many actually made it to the good recovery group.

The biggest problem with all of the literature we have is that the patients were selected for surgery based on the opinion of the neurosurgeon. This means that many patients who they felt would do poorly with operation were excluded. It is extremely likely that the inclusion of these patients would have dragged down the already poor numbers that were reported. But in fairness, we might have also found a few surprise saves among those patients; I guess we’ll never know.

So let me give you my take on the scenarios that I presented so many days ago. Remember, these are my opinions and are not meant to be gospel. Other trauma professionals will need to interpret the information themselves and make their own decisions.

Scenario 1 – An elderly female falls and sustains a modest subdural hematoma with no shift and a normal exam. Follow your established practice guidelines unless some of the factors in the following scenarios are present.

Scenario 2 – Same as above, but the patient presents 8 hours after the fall. The clock started ticking when the fall occurred. Since your practice guideline recommends monitoring for 6 hours and then a followup CT of the head, the initial CT is the followup scan. The patient could then be discharged if there are no alarming findings on initial CT and the neuro exam is normal.

Scenario 3 – Same as scenario 1 but the patient has advanced dementia. These patients were generally excluded from the studies, and they are not expected to do well. Frankly, they will likely be much worse after an operation and will require an even higher level of post-discharge care (if they make it that far) and more involvement of family. It is critically important that the trauma professionals have a frank talk with the family to make sure they understand the overwhelming likelihood that their loved one will never be as good as they were before the injury. Surviving an operation does not mean going back to their usual living situation. The family absolutely needs this information to make the best choice for their loved one.

Scenario 4 – Same as scenario 1 but the patient has a well documented “do not actively resuscitate” order in place. The patient and their family need the same talk as above so they can appreciate all of the risks and the few, if any, benefits of surgery. Only then can they make an informed if they want to consider temporarily rescinding their DNAR order to allow surgery.

Scenario 5 – Same as scenario 1 but the patient is 95 years old. The data showed that patients in their 80s tended to do even more poorly than younger patients. There were very few nonagenarians in the literature, but it can be expected they would do even worse than the octos. They and their families need the same depressing talk so they can make the right decision.

Bottom line: Communication is key. And good data is even more key, although we have too little of it. For now, all we can do is paint a somewhat depressing picture of generally poor outcomes in highly selected patients. Hopefully we’ll have better data some day and can slice and dice things a little better. This may eventually allow us to offer surgery to those patients who will actually benefit from it the most.

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What Would You Do? The Elderly Patient With Subdural Hematoma – Part 4

In my last post, I discussed a paper that examined the fate of very well-selected elderly patients with traumatic subdural hematoma. Today, I’ll focus on one that was just published that took all comers, kind of. Hopefully, this will give us a better idea of what outcomes to expect after emergency craniotomies.

This work was conducted at the University of New Mexico, and was yet another retrospective review. They took all comers with age > 65 and acute subdural hematoma. However, criteria for proceeding to surgery were based on neurosurgeon discretion. Only 62 patients were identified during a 5 year period, and the Glasgow Outcome Scale score was the primary outcome.

Here are the factoids:

  • 60% of patients were taking preoperative anticoagulant or antiplatelet drugs
  • Perioperative mortality was 39%, and this increased to 44% at three months
  • Of the remaining 38 survivors, 4 were in a vegetative state,  26 were severely disabled, 6 had moderate disability, and 2 had a good recovery
  • By 6 months, 20 of the patients in the severely disabled category improved to either moderate disability or good recovery

The authors conclude that, although mortality was high, a significant number of patients (31%) made a meaningful recovery by 6 months. These were patients who had achieved a GOS score of 4 or 5.

Bottom line: Once again, read closely. If you look at the numbers at discharge, 39% were dead and 3% were recovered. The rest ranged from a vegetative state to varying degrees of disability and independence. 

Over the first three months  postop, the severe disability number shrank, with 5 dying, 3 moving to moderate disability, and 12 making a recovery. This continued to improve somewhat over the next 3 months, but the authors don’t clearly state how many were actually in the recovered group.

So the final numbers that we can tease apart show a 44% mortality and at least 25% recovered. These sound pretty good, right?

Unfortunately, the retrospective design and small numbers are heavily influenced by the selection process. Remember, the patients who received an operation were more likely to survive if the neurosurgeon was skilled in selecting his or her patients vs declaring them as having a “nonsurvivable injury.” We still don’t know the answer to our questions for all comers, but it’s probably quite a bit worse than these numbers. I would imagine that every one of those not operated upon died, and including them would skew these numbers tremendously towards nonsurvival.

So what’s a trauma professional to do? In my next post, I’ll try to bring it all together in a way that we can apply to our own patients.

Reference: Mortality and functional outcome in surgically evacuated acute subdural hematoma in elderly patients. World Neurosurg 126:e1234-e1241, 2019.

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