hyponatremia

hyponatremia

Maximum rates of change

Acute hyponatremia no more than 4-6 mEq in 4-6 hours and daily no more than 8

Chronic hyponatremia no more than 10-12 mEq

Hypernatremia no more than 10-12

 hyponatremia weight * correction / time = flow rate

90 * 4 / 24 = 15 mEq

513 mEq in 1L, 159 of regular in 1L ns

3% 313 

rate 3 * 90, 90 kilograms change by 3 90 * 3 = 270 / 513 * 1000mL that's mililiters run over 24 hours.

over hours

543 mililiters = 22mL / hr

hypotonic to ctrl edema

use smaller change rate 4-6 go up by 3

take their weight multiply by 3, how much divide by 24

70 * 6 = 420 / 24 = 17.5 run at 17.5

70 * 6

3/31 Ahmad

desat listen for wheezing, nebs, steroids, suction them, spo2, abg, cxray

if chest xray clear - pulmonary embolism

sodium treatment goals - 4-6 mEq

Calculate 120 over 24 hours what his goal

124-126 how much fluid

the best way to approach to approach hyponatremia, they've already given a liter bolus of NS

Immediately repeat a BMP, go off of that number, that 1 liter will trigger the ADH pathway and they'll start pouring out urine

more hyponatremic. 

get sodium start diuresing on their which is inapporpriate. Chemical clamp. Depends on the urine output.  

normal urine output 50 - 100ccs an hour

if they are putting out more than 200 ccs an hour let them notify

get a BMP, get a urinalysis, want to know the specific gravity. get the serum osmos. The serum osms is more accurate than sodium

repeat labs q4hours. 

low to high pons will die

high to low brain will blow

labs every four hours, sodium goes backwards. 124 to 126 option 

if sodium goes backward

normal saline at liberal rate, absolute control

118 how much 3% saline

124 to 126 shooting for the lower number

6 

70*6 = 420 ml

420 / 24

17.5ml/hr

labs UA q4hr, if you get a large shift you can stop it.

what if sodium goes from 118 

original 120, to 130 is this hyponatremia is acute or chronic. 

first thing repeat the lab. 

acute can acutely correct it. within 48 hours takes too long for compartments to equilibrate. always treat as chronic if you don't know.

sodium 130 

DDAVP clamp 

Hyponatremia

Intracranial hemorrahge

sodium normonatremic 

135 in patient, neurosurgery says sodium goal 140 - 145. this situation is the same as hyponatremia. need to achieve this goal over 24 hours

3 percent saline 135 - 145 off by 10 points. 70 kg. 700ml will increase by 10. if they want over 12 hours 70 / 12 will be 60 ccs an hour.

two compartments 135 135 lower as well. 

head is 135

chest 135

legs 135

hyponatremia scenario. 

120 head

120 in body

120 in legs

if you give IV fluids in the arm then you will correct chest. 4 liters of normal saline. if you make central area 140 the head is still 120

body, whatever is more salty body will want to dilute. brain will try to move from brink 

shrink from the myelin sheaths from the axons. all the water is leaving this is where you get pontine myelonosis. 

slow correction if this goes to 124, slowly goes to 124. 

135 in head, 135 in chest now blood

give iv fluids, 145 in the body, do it quickly, brain will dilute the rest of the body. want the fluid to leave the brain, to shrink down, so the brain will have less fluid, less likely for herniation. if it is very severe, give mannitol. mannitol is nephrotoxic and is a sugar, they are going to pee, pee pee, mannitol never ever order mannitol until neurosurgery tells you to, serious drug don't order it yourself. once mannitol goes in, can't get it out. mannitol descending loop of henle. 

mannitol is a pure osmotic diuretic, 

we prefer 3% because it is more controlled. 

brain, salty patient. hypernatermic old nursing home. don't water their vegetables. come dehydrated, sodium of 160. chronic not watering.

hypernatremic, sodium correction 8-10, 10-12 is okay. same idea, shoot for lower goal. the reason 

body will give free water and brain will swell. then you will herniate. go slowly, over increments. to calcuate

hypernatremic calculate the free water deficit. 

md calc free water deficit - free water

d5w, dextrose molecule to make it stable, free water flushes, unclear how much free water is absorbed 75% depending on gut motility. d5w goes into serum 

don't include free water into our calculation. sodium should go to 140, problem make the brain explode. FWD 2.3 liter total. 

160 to 8-10 8 is 152

free water deficit 0.8L that's how much you can go over. 

d5w, with one liter, one liter D5w how much an hour.

1000 / 24 = 42 ml/hr 40 ccs an hour will get you to your goal. treat hyponatremia 

hypernatremia

hypernatremia in young person no cerebral atrophy 

elderly bad subdural vessels connecting to walls. brain shrink as you get older. 

hyponatremia lack of fluid.

drugs hypernatremia - 

iatrogenic - normal saline, abnormal saline sodium 154, switch to LR 130, 

hyper and hyponatremia could use it, 

iatrogenic, dehydration, medication lasix sodium goes high, overdiuresed, 

bicarbonate 

sodium is high and bicarbonate is high, loops are coming off the table, thirdspacing vessels, look like top things are leaking into the third space. 

thiazide diuretics, hyponatremia. 

contraction alkalosis, overdiuresed, third spaced, malnutrition, still want to diures, give albumin in the extracellular space, albumin suck it in, in the vascular space, gets diuresed out

bicarb if it is still give diamox. 

lasix, albumin, metolazone, diamox

120 - 130, ddavp, d5water,  free water deficit, hypernatremia now hypernatremia

sodium 130 , 126 600 bolus

hypernatremia and hyponatremia to treat properly.never rush

diabetes insipidus, hyponatremia peeing - ddavp, 

anoxia / cerebral trauma, is you messed up pituitary

cerebral salt wasting hyponatremic - salt tabs

Diabetes insipidus - tolvaptan

place foley in

clamping the foley theoretical neurohormonal 

bladder full, sends signal back to the brain, bladder is full, think it through. if bladder is full, SIADH

Bolt < ICP 15 EVD less than 20

GCS < 8 bolt, steroids

hyponatremia - 

legionella, hypothyroidism, adrenal insufficiency

SIADH, DI, 

each 1000 grams of diuresis give lasix. 

most accurate is serum osms. sodium overcorrected

the osm - serum osm. 

go by the lowest number

cannot above 125

123 not more than 127

create formula: Fluid rate (mL / hour) = [(1000) * (rate of sodium correction in mmol / L / hr)] / (change in serum sodium) Change in serum sodium = (preferred fluid selected sodium concentration - serum sodium concentration) / (total body water + 1) Total body water = (weight in kg) * (% body water), whereby % of body water is 0.6 in children and adult males, 0.5 in adult females and elderly males, and 0.45 in elderly females).

Here's the formula for calculating fluid rate to achieve a specific sodium correction rate:

Fluid Rate (mL/hour)

$\text{Fluid rate (mL/hour)} = \frac{1000 \times \text{desired rate of sodium correction (mmol/L/hour)}}{\text{change in serum sodium (mmol/L)}}$

Change in Serum Sodium

$\text{Change in serum sodium} = \frac{\text{[Sodium] of selected fluid - [Serum Sodium]}}{\text{Total Body Water + 1}}$

Total Body Water Calculation

$\text{Total Body Water (L)} = \text{weight (kg)} \times \% \text{Body Water}$

Where:

• % Body Water is:
  • 0.6 for children and adult males
  • 0.5 for adult females and elderly males
  • 0.45 for elderly females

You said:

plug in sample numbers and calculation for sample patient

ChatGPT said:

Let's work through a sample calculation:

Case:

• Patient: 70 kg adult male with serum sodium of 120 mmol/L.
• Goal: Increase serum sodium at a rate of 0.5 mmol/L per hour.
• Fluid: 3% saline, with sodium concentration of 513 mmol/L.

Step 1: Calculate Total Body Water

For an adult male:

$$\text{Total Body Water (TBW)} = 70 \text{ kg} \times 0.6 = 42 \text{ L}$$

Step 2: Calculate the Change in Serum Sodium

$$\text{Change in Serum Sodium} = \frac{\text{[Sodium] of fluid - [Serum Sodium]}}{\text{TBW} + 1}$$

Plugging in values:

$$\text{Change in Serum Sodium} = \frac{513 - 120}{42 + 1} = \frac{393}{43} = 9.14 \text{ mmol/L}$$

Step 3: Calculate the Fluid Rate

$$\text{Fluid Rate (mL/hour)} = \frac{1000 \times \text{desired rate of sodium correction}}{\text{Change in Serum Sodium}}$$

Substitute the desired sodium correction rate of 0.5 mmol/L per hour and the calculated change in serum sodium:

$$\text{Fluid Rate (mL/hour)} = \frac{1000 \times 0.5}{9.14} = \frac{500}{9.14} = 54.7 \text{ mL/hour}$$

Final Answer:

Administer 3% saline at a rate of approximately 55 mL/hour to achieve the desired sodium correction of 0.5 mmol/L per hour.

Hypertonic saline derivation

Given Information:

• 3% Saline Concentration: 513 mmol/L
• Patient Weight: Let's assume 60 kg.
• Goal: Calculate how much 3% saline is needed to increase serum sodium by 1 mmol/L using the idea that 1 mL/kg roughly achieves this increase.

Step-by-Step Dimensional Analysis

1. Calculate Sodium Increase per mL of 3% Saline:

   $$\text{513 mmol/L} = \text{0.513 mmol/mL}$$

2. Calculate Total Body Water (TBW): Using the approximation $\text{TBW} = 0.5 \times \text{body weight}$ (for an adult female), we have:

   $$\text{TBW} = 60 \, \text{kg} \times 0.5 = 30 \, \text{L}$$

3. Determine Sodium Change per mL/kg of 3% Saline: To raise serum sodium by 1 mmol/L in 30 L of body water, we need a total of 30 mmol of sodium:

   $$\text{Required Sodium} = 1 \, \text{mmol/L} \times 30 \, \text{L} = 30 \, \text{mmol}$$

4. Calculate Volume of 3% Saline Needed to Deliver 30 mmol of Sodium: Since 3% saline contains 0.513 mmol of sodium per mL:

   $$\text{Required Volume} = \frac{30 \, \text{mmol}}{0.513 \, \text{mmol/mL}} = 58.5 \, \text{mL} \approx 60 \, \text{mL}$$