Fluids and electrolytes Flashcards
Water is __% of body weight in males
60
Water is __% of body weight in females
50
Water is __% of body weight in newborns
80
Intracellular water: / of TBW
Extracellular water: / of TBW
- Extravscular water / of extracellular water
- Intravascular water / of extracellular water
2/3
1/3
3/4
1/4
What compartments of fluid can colloids, saline and glucose enter?
Colloids - plasma
Saline - plasma and interstitial compartment
Glucose - Plasma, interstitial compartment, intracellular compartment
Physical examination of a dehydrated patient reveals (hypovolemia):
Skin turgor, dehydration of mucous membranes, thready peripheral pulses, increased resting HR, decreased BP
Decreased urinary flow rate
Hemodynamic measurements used in practice:
CVP
PA pressure
Daily water intake/loss is approximately _____mL
2500
Evaporative loss accounts for ____ heat loss
20-25%
Normal maintenence requiremtns for fluid:
4mL/kg/hr for first 10kg of body mass
2ml/kg/hr for second 10kg of body mass
1mL/kg/hr for any Kg>20kg
Difference b/w crystalloids and colloids
- Crystalloids - acqious solutuions of ions (salts) w/ or w/o glucose
- Colloids - contain high-molecular weight substances such as proteins or large glucose polymers
- Colloid - intravascular
- Crystalloid - entire extracellular fluid space
Hypernatremia is sodium above ___mmol/L
145
Hypernatremia causes:
Elevated sodium -> hyperosmolality -> cellular dehydration
Restlessness, lethargy, hyperreflexia -> seizures, coma, death
Hypovolemic hypernatremia causes:
Body fluid loss
Diuretic use
GI loss
Heat injury
Osmotic diuresis
Euvolemic hypernatremia:
Central diabetes insipidus
Nephrogenic diabetes insipidus
Fever
Hyperventialtion
Mechanical ventilation
Hypodipsia
Medications (amphoterecin, aminoglycosides, Li, phenytoin)
Sickle cell disease
Suprasellar and infrasellar tumors
Hypervolemic hypernatremia:
Cushing syndrome
Hemodialysis
Hyperaldosteronism
Iatrogenic (salt, water, saline, enema, IV HCO3, enteral feedings)
Hypernatremia treatment: oral ______ fluids
Examples:
Hypotonic
IV solution of 5% dextrose in water or hypotonic saline
Diuretics
Reduce level gradually 10meq/24h
Rapid correction of hypernatremia can cause?
Cerebral edema
Hypernatremic patients w/ decreased total sodium should be given ______ to restore plasma volume to normal prior to treatment w/ a hypotonic solution
isotonic fluid
Hypernatremic patients w/ increased total body sodium should be treated w/ a _____ and 5% IV dextrose in water
Treatment for diabetes insipidus?
loop diuretic
desmopressin
Dangers of saline and chloride rich crystalloids?
Hyperchloremic metabolic acidosis
Acute kidney injury
Hyponatremia is <______mmol/L
135
Most common cause of hyponatremia?
SIADH
Hyponatremia and hypernatremia can cause cerebral edema, how?
Hyponatremia due to movement of water from the blood into cells
Hypernatremia - only occurs in rapid correction
Hypovolemic patients are sensitive to the vasodilating and negative inotropic effects of:
vapor anesthetics, propofol adn drug-induced histamine release
Hypovolemic patients are particularly sensitive to
sympathetic blockade from spinal or epidural anesthesia
Which drugs are indicated in general anesthesia prior to collection of hypovolemia?
Etomidate or ketamine
Hypokalemia can be induced by use of?
Diuretics
How do diuretics cause hypokalemia?
Diuretic-induced hypocholermia -> bicarbonate is absorbed and potassium is excreted
