Fluids

intracellular fluid

fluid within cells (70%) most of the fluid in the body is in this

extracellular fluid

fluid outside cells, includes intravascular and interstitial fluids

congestive heart failure

most common condition where you see edema

RBC, WBC, platelets, plasma

components of blood

osmosis

water passes from an area of lesser solute concentration to greater concentration until equilibrium is established

diffusion

tendency of solutes to move freely throughout a solvent “downhill”

active transport

requires energy for movement of substances through the cell membrane from the lesser solute concentration to the higher solute concentration

capillary filtration

passage of fluid through a permeable membrane from the area of higher to lower pressure

hydrostatic pressure

force exerted by the fluid present within the blood capillaries against the capillary wall, helps push fluid out of the capillaries, helps to increase filtration, mostly occurs at the arterial end

oncontic pressure

exerted by proteins like albumin in the blood plasma, helps to push fluid into the blood capillaries, helps to prevent movement of fluid from the blood capillaries, mostly occurs at the venous end

RAAS

dehyreation decreases blood volume and BP, so the kidneys secrete renin, renin acitivates what that leads to aldeosterone release from the adrenal cortex, which increases sodium reabsorption and water retention

BNP

what lab is key for CHF, and is a hormone released by the ventricles when under pressure or volume overload, lowers the blood volume and pressure

osmotic regulation system

osmoreceptors detect increased blood osmolarity in the hypothalamus, thirst is triggered, hypothalamus signals the posterior pituitary gland which releases ADH into the bloodstream which acts on the collecting ducts of kidneys and allows for more water to be reabsorbed back into the blood.

insensibile water loss

not readily observable: expired breath, cutaneous transpiration (not from sweat glands)

isotonic fluids

has same osmolarity as blood plasma, used for dehydration, fluid loss, shock states, hypovolemia

0.9% sodium chloride

most commonly used isotonic fluid, used for dehydration, hypovolemia, blood transfusions

lactated ringers

contains sodium, potassium, calcium, chloride, used for burns, trauma, surgery, lactate is converted by the liver—> bicarbonate

D5W

starts off isotonic in the bag, but once the dextrose is metabolized, it becomes hyptonic in the body

D5NS

isotonic, used for initial fluid resuscitation, thicker, sugar is very rapidly absorbed

hypotonic fluid

osmolarity is less than body fluid (blood), meaning less concentration of solutes, used for increasing urine output, hypertonic dehydration, hypernatremia

0.45% sodium chloride

common hypotonic fluid that has lower salt than the blood, causing the water to shift from the blood into the cells

hypertonic fluids

osmolarity is more than body fluids, meaning more concentration of solutes. Causes water to shift out of body and into intravascular, used for decrease in cellular swelling, hyponatremia

3% sodium chloride

strong hypertonic solution, used for severe hyponatermia/cerebral edem

5% sodium chloride

even more concentrated, rarely used, same purpose but higher risk

colloids

large molecules that do not cross over membrane out of vessels, causes water to shift into the intravascular system to raise BP, used for hypotension, plasma expansion

dextran, albumin, hespan

3 common colloids

2600 ml

how many mL per day average intake?

1-2 L

near same as intake, should balance

hypovolemia

LOW blood volume, caused by decreased intake/ increased loss. BUN and creatinine will be elevated bc decreased perfusion to kidneys and cant pee it out. commonly treated with rehydration and isotonic fluids (expand volume without shifting water in or out of cells)how

hypervolemia

too much fluid in the bloodstream, causes include heart failure, kidney failure, cirrhosis, increase salt intake, excessive fluid intake, SS edema, distended jugular vein, hypertension, bounding pulses, tachycardia