So we've discussed hyponatremia a ton on the blog site. That's because hyponatremia has become a little bit sexy. Not so with sodium that is too high. But I've seen a bunch of less than ideal management of hypernatremia, so I figured it is time to put out a podcast about it. This is mostly so I have a place to go to look all of this up.
Join us at the EMCrit Conference Jan 11 2017
Articles
Read this Book
- Joel Topf is of PBF is 2nd author of an excellent fluids and electrolyte text. He has released it for free on the Precious Body Fluids Blog
How do you become Hypernatremic
Loss of free water and/or
Loss of hypotonic fluid and/or
Increased Solute and
thirst or access to water must be thwarted
Hypernatremia Results in…
- Impaired glucose metabolism
- Rhabdo
- AMS
- Seizures
Avoid Iatrogenic Complications
Cerebral Shrinkage is Bad
Extrarenal water loss
Salt gain
| Nephrogenic DI
| Central DI
| Renal losses
|
This table stolen directly from Deranged Physiology (primarily b/c I hate making html tables)
Chart of Figuring Out What the Hell is Going On
Treatment
Stop or Correct the Underlying Cause
Correct Quickly if Na got high superrapid-style (Idiots drinking a quart of soy sauce)
Correct < 10 meq/day (< 0.5 mmol/L/hr) if the Na went up gradually (2-3 mmol/L/hr if rapid rise in sodium)
Oral/Gastric Tube is the safest way to correct
Administer Hypotonic Fluids (D5W, 1/4 NS, 1/2 NS, sterile water (central line))
Do not administer NS unless pt is HYPOVOLEMIC (NS doesn't work!!!; see Androgue-Madias for mathematical demonstration of this)
Calculating Required Volume
remember to account for daily losses
Probably the best way to go is to calculate with the AM-formula, resend a sodium every 2 hours for the first few hours and then recalculate with each new sodium level.
Diabetes Insipidus
The triphasic response of central DI after CNS insult (I put this here only b/c it keeps showing up on the damn crit care boards
Vasopressin Dosing
Dosage is highly variable; titrated based on serum and urine sodium and osmolality in addition to fluid balance and urine output
Continuous I.V. infusion: 0.0005 unit/kg/hour; double dosage as needed every 30 minutes to a maximum of 0.01 unit/kg/hour
Hypertonic Sodium Gain
free water + furosemide (why not a thiazide)
ICU Hypernatremia
See the PulmCrit Post
Update
My bud, Graham Walker, has updated his amazing mdcalc site to include the effects of various fluids on the sodium in hyper(and hypo)natermia:
Now on to the Podcast…
Podcast: Play in new window | Download (19.5MB) | Embed
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Scott Weingart
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Hi, my name is Scott Weingart.
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4 Comments on "Podcast 187 – Hypernatremia (Uggggh!)"
[…] Elektrolyter/hypernatremi: trevlig podcast och vidareläsning från emcrit […]
Scott, you may not think hypernatremia is a sexy topic but I do and I am glad you talked about it. The treatment of it is done so very, very wrong so often that I really, really appreciate you brought it up. I loved it! Thank you.
[…] EmCrit: Podcast 187 – Hypernatremia (Uggggh!) […]
Comment on remark at ~3 min:
It is my understanding that while HYPERnatremia can cause osmolar loss of intracellular free water and shrinkage/demyelinisation, a too rapid normalization of hypernatremia (if “chronic”) causes a rapid influx of water into the neurons and thus cerebral edema. – similar to the pathophys of HYPOnatremia.