Fluids and electrolytes Flashcards
Total body water (TBW) is approximately__ of your
body weight.
60%
Two-third of your total TBW is comprised by
________
Intracellular fluid (ICF)
one-third is comprised of
_____
Extracellular fluid (ECF).
ECF: 1/4
plasma
ICF: 3/4
interstitial fluid
Contain mainly in skeletal muscle (highest)
INTRACELLULAR (⅔)
- 40% of body weight
- 60% of TBW
Intracellular Cations
K, Mg
Intracellular Anions
PO3, SO3, Proteins
Interstitial Fluid (fluid that is in between your cells
and blood vessels) + Plasma Volume (All the fluid
that contain inside your BV)
EXTRACELLULAR (⅓)
EXTRACELLULAR cation
Na
EXTRACELLULAR anion
Cl, HCO3
transports 3 Na molecules out vs.
2 K molecules in (K accumulates inside the cell;
Na accumulates outside the cell resulting in a
gradient)
Na/K ATPase
T or F
Most significant gains and losses of body fluid
comes from the ICF compartment. Due to
vomiting and diarrhea and blood loss.
F
*intracellular
- 15 % of body weight
* 25% of total body water
INTERSTITIAL FLUID
• 10% of total body water
• has high protein (organic anions) content
• 7% of body weight (in kg) = estimate of blood
volume
PLASMA
osmosis is determined by the ________ on
each side of the membrane
concentration of solutes
Fluid will move to move towards the container that has the
_______ concentration of solutes
higher
DETERMINANTS OF OSMOLALITY
- Sodium (Na)
- Blood Glucose
- Blood Urea Nitrogen (BUN)
are the watery fluid that you
can measured and see. This are your oral fluid and
amount of solid food you eat. We can also have
measured urine, intestinal fluid, sweat.
Sensible water losses
are the water that you lose
through metabolism. i.e oxidation. It is water that we
lose through respiration and through our skin.
Insensible water losses
Kidneys must excrete a minimum of_____ ml /
day of urine to clear products of metabolism
500 to 800
▪ Specialized sensors that detect small chances
fluid osmolality
OSMORECEPTORS
▪ Act through the kidneys
Dehydration: ↑ plasma osmolality →
o ↑ thirst & water consumption +
hypothalamus
o VASSOPRESSIN → ↑ water
reabsorption in the kidney
Baroreceptors are located in ______
aortic arch & carotid sinus
Modulate volume in response to changes in BP &
blood volume (If your blood pressure is low, they
have to calibrate it in order to increase your blood
pressure)
BARORECPTORS
Acute Volume Deficit =
CVS & Nervous system
signs
Chronic Volume Deficit =
Tissue signs (skin turgor, CVS & nervous system signs
ECF diagnostics
▪ ↑ BUN (if severe enough to ↓ glomerular filtration)
▪ Hemoconcentration (If you do CBC, you’ll see
that your hematocrit is higher than normal as your
blood is concentrated)
▪ ↑ Urine osmolality (very concentrated urine) >
Serum osmolality
▪ ↓ Urine NA < 20 meq/L
▪ ↑ both plasma + interstitial volumes
ECF VOLUME EXCESS
Causes of ECF volume excess
o Iatrogenic (excess IVF)
o 2° (secondary) to renal dysfunction,
congestive heart failure (CHF), liver
cirrhosis
T or F
Changes in Na are usually inversely proportional
to TBW
T
Normal Na =
130 - 150 mEq/L
▪ serum Na ≤ 130 mEq/L
▪ occurs when ECF > serum Na
HYPONATREMIA
Usually has very severe neurological symptoms:
Acute cerebral edema, seizures, coma
ACUTE HYPONATREMIA
▪ Well-tolerated up to levels of 110 meq/L well
below
▪ confusion, decreased mental status,
irritability, ↓ Deep tendon reflexes
CHRONIC HYPONATREMIA
o Form of paralysis that occurs because of
overcorrection of Na
o Sodium-Potassium pumps cannot handle
the load quickly enough
o Destroys CNS neurons- very sensitive to
electrolytes. Myelin sheath is destroyed
▪ CENTRAL PONTINE MYELINOLYSIS
▪ Solute excess / osmotic particles in ECF
▪ Na is not the only particle that determines your
serum osmolality. It also includes your BUN and
your blood glucose. These two components
crowd out the sodium and the sodium becomes
proportionately lower
▪ The kidneys try to compensate so you urinate
more (like in diabetes) so you lose more water
and sodium (collateral damage).
HYPEROSMOLAR HYPONATREMIA
Drug that is given to decrease CNS
swelling. It is a diuretic=removes Na. You
decrease blood volume in brain and pressure.
Mannitol
▪ Na ≥150 mEq/L
▪ From
o Loss of free water (↓ ECF
o Gain in Na > ECF
HYPERNATREMIA
Volume deficit with free water loss> Na loss - Insensible H2O loss from GIT/skin - Thyrotoxicosis - Hypertonic glucose solutions (peritoneal dialysis) -- Diabetes insipidus - Diuretics - High output urine output from polyuric phase of ATN
• NORMOVOLEMIC HYPERNATREMIA
• NORMOVOLEMIC HYPERNATREMIA: TREATMENT
Replace water with PNSS Free water deficit (L)= 𝑆𝑒𝑟𝑢𝑚 𝑁𝑎 − 140 140 × 𝑇𝐵𝑊 ½ deficit = replace in 1st 8 hours ½ deficit = replace in next 16 hours Once adequate volume achieved: replace water deficit with D5W or D5NSS or oral H2O Titrate to achieve ↓Na by: Acute HyperNa= 1 mEq/L & 12 mEq/day Chronic HyperNa = 0.7 mEq/hou
- Urine Na > 20 mEq/L
- Urine osmolality > 300
mOsm/L
–Mineralocorticoid
excess - Hyperaldosteronism
- Cushing’s Syndrome
- Congenital adrenal
hyperplasia
HYPERVOLEMIC HYPERNATREMIA
Serum Ca =
1% of total body Ca
o Ionized Ca (50%) = responsible for__________
neuromuscular stability
▪ When serum calcium is > 10.5 mEq/ L or increase in
ionized Ca > 4.8 mg/dL
HYPERCALCEMIA
It is Symptomatic HyperCa - if
> 12 mg/dL
Critical Level of HyperCa =
15 mg/dL
The most common cause of hypercalcemia in
admitted patients inside the hospital is actually
_________
Cancer.
The most common cause of hypercalcemia in outpatient setting (in the rest of the population) is \_\_\_\_\_\_\_\_\_\_
Primary Hyperparathyroidism.
HYPERCALCEMIA TREATMENT
▪ Aggressive Isotonic IVF Resuscitation - diuresis and
excretion of Ca from kidneys
▪ Furosemide – for diuresis,
▪ Meds to Stop Osteoclastic Activity
– It is a calcinamatic, it attaches to
parathyroid glands and signals to stop
releasing parathyroid harmone.
Calcitonin
Serum Ca < 8.5 mEq/L or Ionized Ca < 4.2 mEq/L
HYPOCALCEMIA
The most common cause of hypocalcemia is ________-
thyroid surgery (Thyroidectomy)
This occurs due to damage to parathyroid
gland, and most common cause of that is
thyroid surgery, because it accidentally
damages parathyroid. Hypoparathyroidism
(most common cause)
Transient Hypocalcemia or Postoperative
hypocalcemia for < 6 months (post thyroidectomy).
in hypoproteinemia
(low albumin) state.
Asymptomatic Hypocalcemia
Classic signs of Hypocalcemia
Peri-oral numbness
Cramps
Chvostek’s sign
Trosseau’s sign
HYPOCALCEMIA TREATMENT
▪ Asymptomatic - oral supplementation with 500 mg
Calcium Carbonate 2 tabs TID
▪ Symptomatic - monitored & treated
o IV calcium gluconate
▪ The 1o
intracellular divalent anion
▪ Increase in metabolically active cells
▪ Involved in energy production during glycolysis
▪ Controlled by renal excretion. .
▪ It is present in increased amounts in highly
metabolically active cells like your bone, GIT.
PHOSPHOROUS
PAROXYSMAL RHABDOMYOLISIS causes ________
hyperphosphatemia
MALIGNANT HYPERTHERMIA
causes________
hyperphosphatemia
HYPERPHOSPHATEMIA TREATMENT
▪ Oral: o PHOSPHATE BINDERS - Sucralfate / Aluminum-containing antacids o Ca Acetate Tabs - if associated with simultaneous hypocalcemia ▪ Dialysis
Hypophostanemia (intracellular shift acute cases)
Respiratory alkalosis
Insulin therapy
Refeeding syndrome
Hungry bone syndrome
HYPOPHOSPHATEMIA TREATMENT
▪ Oral o Neutra Phos packets - 2 packets Q6 per NGT ▪ IV o Potassium phosphate (KPHO4) o NaP04 IV
▪ 4th most common mineral in the body
▪ Mainly intracellular
o Present in every cell type, binds to ATP,
required for enzymes
MAGNESIUM
Magnesium total body content:
2000 mEq
HYPERMAGNESEMIA TREATMENT
▪ Ca Chloride (5-10 mL) - given IV to antagonize
cardiovascular events
o Hemodialysis
o Correct acidosis and volume deficits
▪ Common in critically ill hospitalized patients
▪ Can produce hypocalcemia and lead to persistent
hypokalemia
Hypomagnesemia
HYPOMAGNESEMIA TREATMENT
C. IV o Magnesium Sulfate Drip - recheck Mg level in 3 days D. Oral o Milk of magnesia per NGT
• 3 SYSTEMS THAT MAINTAIN pH RANGE
- Carbon Dioxide: excreted by lungs to maintain
normal CO2 - Strong Ions: completely dissociate in water (Na, Cl,
Ca, Mg, K) - Weak Acids: buffering systems of water (protein,
phosphates)
• pH < 7.35
ACIDOSIS
• pH will decrease when
o ↑ pCO2 concentration or ↓ HCO3 concentration
o ↑ concentration of strong anions
o ↑ concentration of weak acid
● From ↑ CO2 retention secondary to decreased alveolar
ventilation
RESPIRATORY ACIDOSIS
• RESPIRATORY ACIDOSIS TREATMENT
o ↑ Alveolar ventilation
o Reversing agents for drug overdose
o Intubation with mech ventilation to clear CO2
• From loss of HCO3, intake of acids, or ↑
generation of acids
METABOLIC ACIDOSIS