fluids Flashcards
ii. The normal osmolarity of serum is about
290
iii. At any temperature above absolute zero, electrolytes will
diffuse throughout a solution to achieve uniform osmolarity.
iv. In biological systems, fluid compartments
(e.g., the extracellular and intracellular compartments) are separated from each other by semi-permeable membranes
If you have two solutions of different concentrations that are separated by a semi-permeable membrane, the tendency of those solutions to equalize their concentration by moving water across the membrane is called the _________
osmotic pressure gradient.
vi. The movement of water is called
osmosis
vii. The effect osmolarity has on this process is called
tonicity
_________are fluids that are close to the normal serum osmolarity of 290 mOsm/L.
a. Isotonic fluids are
_______fluids are fluids that have a lower osmolarity than serum.
b. Hypotonic fluids
_______are fluids that have a higher osmolarity than serum.
Hypertonic fluids are fluids that have a higher osmolarity than serum.
small solutes; can move a little freely with this type of fluid
crystalloid
big solutes; like blood wit this type of fluid
colloid
protein
plasma
nml Na
a. Normal value: between 135-145 mEq/L.
Critical for fluid balance, nerve function, muscle function.
c. The #1 extracellular electrolyte.
Na
hypotonic crystalloid
D5W
of 1/2 NS (.45%)
Because sodium is so closely linked to serum osmolarity, sodium derangement leads to changes of the body’s osmotic pressure gradient.
This causes cells to ______ in hyponatremia
or ______ in hypernatermia
this phenomena is worse here
cells to swell (in hyponatremia), or to shrink (in hypernatremia).
g. While this phenomenon affects all cells, it has an outsized effect on brain cells.
hyponatremia is defined as
this is usually due to
Hyponatremia (Na <135)
May not see clinical signs until Na+ is <125.
sxs of hyponatermia
Symptoms include lethargy disorientation, muscle cramps, anorexia, hiccups, nausea/vomiting, seizures.
Patient may have weakness, agitation, stupor, hyperreflexia, orthostatic hypotension, delirium, coma, death
Extrarenal losses
losing fluids faster than they can replenish it
Treatment of hyponatermia is to
correct the water overload (or deficit) and/or raise the sodium. (hypertonic sollution 3%)
vii. Find the underlying cause.
viii. Fluid restriction and monitoring.
ix. May give hypertonic saline for severe symptoms
Careful of rapid correction of hyponatremia because
Careful of rapid correction—can cause central pontine myelinolysis (i.e., brain damage).
list the colloids
blood albumin dextran FFP PRBCs
dextran
glucose polysaccharide
hypernatremia is defined as and caused by
i. Hypernatremia (Na >145)
(1) inadequate fluid intake;
(2) excess water loss;
(3) iatrogenic (in the hospitalized patient).
FFP needed for
pts that would be bleeding a lot
coagulants
PRBC
trauma -usually whole blood but not always
how to make decisions about fluids
do you need to make a decision right away
unstable pt start with
2 L NS
responder or non responder
10% of body weight loss in an adult is what stage of dehydration
severe
mild and moderate dehydration looks like
6%
8%
replenishing fluids in a pt with CHF or renal failure
really need to be slow with fluids
maintenance fluids
what’s normal
unlike resuscitation you’re not trying to make up for significant loss
usually NPO
100-150mL an hour
small lil lady 90
70Kg adult looses
2500-3000 mL/day
4-2-1 for children
4mL up to 10Kg
2Ml for next 10Kg
1mL per Kg after that
or broselow tape with weight and height
27 yo women in 1st trimester has been vomiting for 3 days
BP 90/60 HR 120 skin turgur decreased
what do we start with
need to know stable of unstable
this woman is severely dehydrated but unstable
10-15 mL/kg bolus
around 1 L
given antiemetics
after a second L of NS–> peeing
too much NS can lead to acidosis
Parkland Formula
burn formula
exposed tissue come with incredible amounts of bluid loss
4ml x % body surface area burned x weight for the first 8 hrs
give 1/2 fluid at 8 hrs and then 1/2 that at 16
non focal LOC
infection-meningitis, encephalitis
trauma
seizure
CVA
overdose
metabolic- hypoglycemia or hyponatremia
alcohol
when you have someone with hyponatremia you need to
this is the neuro electrolyte
will shrink or swell brain cells
check a glucose
ADH effects of osmolarity
CONSERVES WATER
hormonal control of Na
too much ADH can lead to water intoxication
aldosterone effects on osmolarity
conserves SODIUM and too much leads to K loss and Na retention
pseudohyponatremia is due to
high concentrations of glucose lipids or proteins in the plasma
makes the water want to leave the cells and rush into extracellular space making it look lik ehyponatremia
water is drawn out and into plasma
each 100 mg/dL glucose elevation decreases the Na by
1.6- 1.8 mEq/L
treatment of pseudohyponatremia
manage the underlying cause
consider volume status and serum osmoles
sxs of hypervolemic hyponatremia
confusion HA vomiting seizures coma and death
hypervolemic hyponatremia Rx
if stable need to restrict water and weight
is seizing or coma would consider using hypertonic saline
hypovolemic and hyponatermia tx
seen with decreased extracellular fluid
rx volume replacement with NS
central pontine myelinolysis
what is the general rule to help avoid this
looks like pig on CT
too rapid correction of hypovolemic hyponatremia
Na that causes shrinkage fo the brain cells and leads to damage
in general better to correct no faster than it occured
(in chronic pts no more than .5 mEq/hour)
older woman LOC
Na=164
BUN=55
Cr=2.5
dehydration and hypernatremia
too little water or no ADH can lead to this as does sweating hyperventilation
hypernatremia sxs
when >155 -160 OR osm>350
Irritability restlessness
seizures
coma
permanent neuro damage
tx with NS or D5 1/2 NS
44 yo man that missed 2 dialysis treatments
NEED EKG first
seen with peaked T waves
the kidneys aren’t filtering so the body is retaining potassium
5.5 mEq/L: EKG changes
Peaked T-waves (repolarization abnormalities).
> 6.5 mEq/L ekg changes
: P wave flattens, PR prolongation (paralysis of atria).
> 7.0 mEq/L EKG
QRS prolongation, ventricular arrhythmias.
> 9.0 mEq/L EKG
Cardiac arrest due to asystole, ventricular fibrillation, or PEA.
three goals of treating hyperkalemia
➤ Protect the cardiac conduction system;
➤ Shift potassium from the extracellular fluid compartment back into the cells;
➤ Remove excess potassium from the body.
what type of Ca do you give
calcium Chloride for Coding
needs to be given through a central line
need to avoid unless you’re in a situation that really calls for it
very caustic to the tissues
calcium Gluconate for any other time
why do you give insulin
to move K into the cell
if their sugars are high
if they are normal given glucose and insulin
other than insulin what else moves Ca into the cell
ALBUTEROL
Intravenous calcium is given in hyperkalemia in order to
Intravenous calcium to antagonize the membrane actions of hyperkalemia (see ‘Calcium’ below)
hypokalemia looks like what on a EKG (4)
i. Flattened T waves
ii. Prolonged QT interval
iii. U waves
iv. Ventricular arrhythmias
muscle WEAKNESS
Tx of hypokalemia
Not an emergency unless cardiac manifestations are present.
Replete potassium (50 mEq will raise serum K+ by 1.0)
Can give orally, which is safer but slower.
When giving IV, need to use a large vein (potassium is is very irritating)
v. Give up to 20 mEq/hr.
what causes hypokalemia
i. Diuretics
ii. Vomiting
iii. Diarrhea
also
alkalosis
insulin
albuterol and beta adrenergic
hypokalemia defined as
Defined as potassium less than 3.5 mEq/L
other than excessive excretion what else can cause hypokalemia
b. Can be caused by potassium being shifted into the cells
i. Alkalosis
1. Insulin and glucose use
- Use of beta-2 agonists (e.g., albuterol).
27yo woman presents to the ED with tingling around her mouth for two days. She also has some facial twitching.
ii. PMH: had thyroid surgery two weeks ago.
PE: Normal vitals.
LABS you want
Chem 7
TSH
CBC
But her calcium is 6.4 (normal is 8.5-10.5).
normal Ca levels
8.5-10.5 CC looks like an 8
Hypocalcemia Ca++ defined as
<8.5
what’s more common hypo or hyper Ca
hypo more common than hypercalcemia.
causes of hypo Ca
Most commonly results from a chronic disease, with chronic kidney disease being the most frequent cause.
- Hypoparathyroidism
- Acute pancreatitis
- -> fatty sludge chelates to the Ca - Alkalosis
- Massive blood transfusions
EKG with hypoCa
prolonged QT interval that may progress to Torsades de Pointe.
sxs of hypoCa
- Dry skin and brittle nails
- Muscle cramping
- Pruritus
- Shortness of breath
- Numbness and tingling
- Syncope, angina, heart failure
- Hyperreflexia, tetany, clonus
Chvostek’s sign
Tap the patient’s face just in front of the ear. A positive Chvostek’s sign is when the patient’s lip twitches on the same side where you’re tapping.
Trousseau’s sign
hyperca evaluation
Apply a blood pressure cuff, inflate it above the patient’s systolic blood pressure, and leave it on for 3-5 minutes.
A positive Trousseau’s sign is when the patient’s hand and forearm muscles go into spasm.
TX of hypoCa
- ABCs
- Treat severe hypocalcemia with IV calcium gluconate or calcium chloride.
- Mild hypocalcemia can be treated outpatient with oral calcium replacement and Vitamin D supplements.
Ca plays essential role in
Important in transmission of nerve impulses, muscle contraction, cardiac electrical conduction, and other things
There are multiple complex interrelated mechanisms that contribute to serum calcium homeostasis. These involve
Vitamin D levels the small intestine renal tubules parathyroid hormone (PTH) and bone.
The most direct of these mechanisms, is PTH. If PTH is high, then calcium is high and phosphorus is low. If PTH is low, then calcium is low and phosphorus is high.
causes of hyperCa
- Elevated PTH
- Cancer with bony metastases
- Elevated Vitamin D
- Thiazides
- Sarcoidosis
- Many other possible causes….
sxs of hyperCa
Stones, Bones, Groans, Moans, Thrones, and Psychiatric Overtones.”
- Nephrolithiasis
- Bone pain
- Lethargy and fatigue
- Abdominal pain
- Polyuria and polydipsia
- Confusion, depression, irritability, anxiety, hallucinations…
tx of hyper Ca
- IV fluids
a. Large amounts of isotonic crystalloid to restore volume. - Increase calcium excretion with a loop diuretic (NOT a thiazide).
- Drugs that decrease the release of calcium from bone
a.Calcitonin, mithramycin, corticosteroids,
bisphosphonates
not typically on a chem panel but need to order these if you suspect any electrolyte abnormalities
magnesium and phosphorus
hypo phophorus sxs
muscle dysfunction
weakness
decreased cardiac output
confusion delirium
sxs usually occur with levels less than 2mg/dL
treat hypophos
underlyinG
DKA/diarrhea anatacid
vit d
TX with oral repletion until level <1mg/dL then give IV
hyperphosphorus
usually asymptomatic
secondary to laxatives/enemas renal failure
prolonged exercise
diet/phosphate binders if indicated
what is a blous
however big the IV is will determine how fast the pt gets it when the line is wide open
ALWAYS think about this
the bolus is as fast as it will go in
you can say this but if you want to go slower you have to specify 150cc an hour is crazy slow (7 hours per liter)
