All posts by TheTraumaPro

Deer Hunting and Tree Stand Injuries

Deer hunting season is upon us again in Minnesota and Wisconsin, so it’s time to plan to do it safely. Although many people think that hunting injuries are mostly accidental gunshot wounds, that is not the case. The most common hunting injury in deer season is a fall from a tree stand.

Tree stands typically allow a hunter to perch 10 to 30 feet above the ground and wait for game to wander by. They are more frequently used in the South and Midwest, usually for deer hunting. A recent study by the Ohio State University Medical Center looked at hunting related injury patterns at two trauma centers.

Half of the patients with hunting-related injuries fell, and 92% of these were tree stand falls. Only 29% were gunshots. And unfortunately, alcohol increases the fall risk, so drink responsibly!

Most newer commercial tree stands are equipped with a safety harness. The problem is that many hunters do not use it. And don’t look for comparative statistics anytime soon. There are no national reporting standards. No matter how experienced you are, always clip in to avoid a nasty fall!

The image on top is a commercial tree stand. The image below is a do-it-yourself tree stand (not recommended). Remember: gravity always wins!

Serial Lab Testing: Worthwhile or Worthless?: Final Answer

In my last two posts, I detailed the serum sodium measurements in a hypothetical patient two ways. The first was a listing of daily values, and the second provided values obtained every six hours or so. It also showed the sodium supplementation that was ordered based on those values. (I’ve included the table at the bottom of this post)

What did you think? Did the extra determinations help you decide what, if any, treatment was needed? Did the therapies ordered help?

Here are my thoughts:

  • Overall, there was not a huge or rapid decline in sodium values. Given the initial values, I would not have started a saline infusion on day 1, just watched a few daily values and the patients physical exam. The infusion only provided 3gm of salt per day, and the serum Na remained fairly stable for the first 3 days.
  • There was a significant amount of intra-day variation seen on the six hour table. You need to know the normal “within-person ” variation for any lab test you order. If two assays on specimens drawn at the same time can vary by 5%, you must factor this in to your decision making. If the value is 3% lower than the previous draw, the difference could represent normal variation. Obtaining more frequent assays exacerbates the amount of variation you see and my be confusing.
  • From day 5 to 6, the sodium appeared to be rising without any salt supplementation! But then a higher dose was given, and one of the intra-day values dropped to 124. What’s up with that? More variation?!
  • Is the morbidity of frequent blood draws worth it if there is no clinical change in the patient’s exam? What morbidity, you ask? Sleep disturbances, with all the cascading problems like delirium, sundowning, administration of additional meds to compensate, and on and on. Unnecessary medication or interventions. Plus it does not promote patient or family satisfaction at all.

Bottom line: Unless your patient has a clinical problem that may deteriorate rapidly, serial lab determinations are probably not of much value. The example patient was many days out from a TBI with some extra-axial blood. So yes, he could develop hyponatremia, but it would have probably surfaced earlier. Know your within-person  variability, which for sodium is roughly +2 meq. Is your new value within that limit? Then it is statistically the same as the first value unless you see a trend over several measurements. And as always, if you note a marked change in just one value, repeat it immediately before beginning any more drastic interventions.

Reference: Biological variation of laboratory analytes based on the 1999-2002 national health and nutrition examination survey. Natl Health Statistic Reports 21:March 1, 2010.

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

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.

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