Blog

Scuba Injuries… in a Rush

I have to say that scuba injuries are not my strong suit. However, in doing this blog post, I have to say it’s not the worst thing to read about. For instance, you get a lot of random information like for some reason depth is measured in fathoms (which is just 2 yards, and seems completely unnecessary to have this). Also since a lot of these disorders were discovered in the 1800s, they have awesome nicknames like the bends, rapture of the deep, the chokes, and all the squeezes including face squeeze and ear squeeze.

For this blog post, I wanted to keep it simple and have it be a quick rundown of the things we need to know when looking at diving injuries as well as when our friends inevitably ask about if it’s okay for them to go diving. And as always, end on some fun history.

Pacemakers… In a RUSH

Goal of This Blog

Pacemakers are becoming increasingly common as our population ages, and are seen more and more in the emergency department. The goal of this post is to summarize common pacemaker settings, the 5-letter nomenclature of pacemakers, indications for pacemaker placement, pacemaker components, common pacemaker complications (majority of blog), and lastly the management of pacemakers in the ED (including applying a magnet).  …And as always, the blog ends with some medical history

Hyperglycemia

Here are some resources for hyperglycemia based on our session today. First here are RMC’s DKA protocols for adults and pediatric patients.

Then some videos (old and new) about DKA and HHS.

2013 DKA and HHS



These video review diabetic ketoacidosis and hyperglycemic hyperosmolar states. The second one has some formulas that you should know exist.

Pediatric DKA



The management of DKA in children has some important differences, namely worrying about cerebral edema.

Of note, the PECARN network released an article in NEJM June 14, 2018 comparing fast and slow IV administration of 0.45% and 0.9% NS to determine who gets neurologic deficits. There were no differences between the groups.

1: Kuppermann N, Ghetti S, Schunk JE, Stoner MJ, Rewers A, McManemy JK, Myers SR, Nigrovic LE, Garro A, Brown KM, Quayle KS, Trainor JL, Tzimenatos L, Bennett JE, DePiero AD, Kwok MY, Perry CS 3rd, Olsen CS, Casper TC, Dean JM, Glaser NS; PECARN DKA FLUID Study Group. Clinical Trial of Fluid Infusion Rates for Pediatric Diabetic Ketoacidosis. N Engl J Med. 2018 Jun 14;378(24):2275-2287. doi: 10.1056/NEJMoa1716816. PubMed PMID: 29897851.

Resuscitative Hysterectomy aka Peripartum C-Section

I hope I never ever have to do this, but these people at the Essentials of EM conference make it look easy. I think this is worth watching.

Some points I took away from the video:

  1. This is a resuscitative delivery. It is meant to save the mother. The fetus and uterus are diverting a lot of blood away from mom.
  2. Chest compressions are going on the entire time.
  3. The immediate next stop if you get ROSC is the OR, so call OB right away.
  4. Don’t forget to deliver the placenta and massage the uterus. Get that thing out and the uterus smaller. Both divert blood away from mom.

 

Idiot’s (Me) Guide to MRI

Whenever the Neurology team comes down and starts asking for special MRI scans with T2-this and gadolinium that, my eyes usually glaze over. So here’s a very brief guide to MRI’s. Very brief.

General Principles

The MRI works by applying a magnetic field to the body. This magnetic field aligns the protons in water nuclei. Next, external radio frequency energy is applied which displaces the protons from that alignment. When this RF energy is removed, the energy emitted is measured.

There are two different ways to apply this RF energy, each with different time constants. Each differ based on how often the pulses are applied (TR) or the time between the RF pulse and reading the emitted energy (TE).

  • T1: longitudinal, short TE and TR times, and
  • T2: transverse, longer TE and TR times.
  • T1 can be used using gadolinium (a non-toxic paramagnetic contrast agent) which changes the signal intensities in T1. This makes vascular structures very bright and is good for looking at the breakdown of the blood-brain barrier (tumors, abscesses, MS, among others).
  • FLAIR is a kind of T2 that uses longer times. T2 FLAIR is good for differentiating between CSF and other abnormalities.
  • Diffusion weighted imaging (DWI) detects the random movement of water protons in the space it has available to it. Normally, extra cellular water is able to move around freely. In ischemic tissue, diffusion becomes limited as the NA/K pump shuts down and water gets trapped in the smaller intracellular space.
Weighting Which tissue appears brighter
T1: T1-weighted MRI Tissue with short T1 relaxation time appears brighter (hyperintense). Grey matter is bright, CSF is dark.

This is good for looking at anatomy.

T2: T2-weighted MRI Tissue with long T2 relaxation time appears brighter (hyperintense). Edema lights up. Air will be black.
T1C: T1-weighted MRI after administration of contrast media Many tumors show signal enhancement after administration of contrast agent.

So contrast is good for looking at any structural abnormality.

FLAIR: fluid-attenuated inversion-recovery MRI Bright signal of the CSF (cerebrospinal fluid) is suppressed which allows a better detection of small hyperintense lesions.

This is good for looking at pathology in the white matter.

DWI: Diffusion weighted imaging Bright signal in ischemic tissue, good for looking for acute stroke.

And there you have it. I’ll find some good open source pictures to include, as well.

Posterior Reversible Encephalopathy Syndrome (PRES)

At last month’s mortality and morbidity conference, we discussed a case of Posterior Reversible Encephalopathy Syndrome (PRES). Our consultant, a neuro-intensivist, told us that PRES is not always posterior, not always reversible nor always presenting with encephalopathy. Thanks whoever named that syndrome.

The presentation is extremely variable. Typically presenting with:

  • headache,
  • altered mental status,
  • visual changes,
  • hypertension or
  • seizures.

And as our case demonstrated many (or all) of these can be initially absent. Most resolve (though can take weeks) though some do herniate and die. In the references, there is an article that lists three cases presenting with varying severity. Given this, PRES is likely more common than we think.

Risk factors for PRES include HTN, kidney disease, autoimmune disease, malignancy, transplant, cytotoxic meds, RAS, sepsis, pre-eclampsia, Takyasu, post-partum hemorrhage, Sheehan syndrome and MODS.

It is also associated with hemorrhage (20%), most are punctate though almost 10% of the bleeds can be pretty big.

Pathophysiology

Endothelial cell dysfunction leads to edema of the surrounding tissue. The posterior cerebrum is most vulnerable due to poor sympathetic innervation of its vasculature.

The symptoms seem to progress until it becomes obvious, hence many are missed on initial presentation. Even if diagnosed earlier, I don’t know what we can do other than remove the offending agent, lower the BP, and treat any seizures.

Imaging

MRI is the way to diagnose it. This will show increased T2 and T2 FLAIR signal intensity usually posterior, but remember PRES can present anywhere.

Treatment

Treatment is to lower the BP, treat seizure and remove any causative agent. Do not use NTG to lower BP as it can increase cerebral edema worsening things.

References

  1. Image taken from https://en.m.wikipedia.org/wiki/Posterior_reversible_encephalopathy_syndrome
  2. http://casemed.case.edu/clerkships/neurology/Web%20Neurorad/MRI%20Basics.htm
  3. Thompson, R. J., Sharp, B., Pothof, J., & Hamedani, A. (2015). Posterior reversible encephalopathy syndrome in the emergency department: case series and literature review. The Western Journal of Emergency Medicine, 16(1), 5–10. http://doi.org/10.5811/westjem.2014.12.24126

Bougie’s Galore

Here are some great videos on how to use bougies.

Intubation with bougies

Scott Weingart… yes, yes, but his video is good.

Shows a preloaded bougie, which is what we should probably be doing.

Has some great trouble shooting techniques

Bougie cric

Darren Braude’s video.

A different view of the whole thing.

I like this one because it shows the technique we’ll more likely be using.

Crazy bougie cric in real life

Ruben Strayer of EMUpdates posted a great video on how to do a cricothyrotomy. The only things that I would change are

  1. I would likely be soiling myself a lot more out of sheer panic
  2. I’d have everything ready (syringe and bougie)
  3. I’d pass the bougie in before removing the scalpel, just paranoid of losing that entrance
  4. I would have just cut the dude’s jaw wires instead of his neck

Great video of a procedure we do not do often. The more we see it, the less freaked out we’ll be by it.

He actually has another video of the same. How many cameras does this guy have in the resusc bay?