fluid balance

how much urin is produced in an hour

1ml/kg/hr

kg to pounds

times by 2.2

what is the boys percentage on water

60%

where does water stay in the body

40% is in intracellular

20% is in fluid compartment

16% is interstitial

4% in plasma

how is fluid regulated in the body stimulated by baroreceptors

baroreceptors detect pressure → send info to vasomotor center in the medulla (brainstem) → initiates thirst and releases noraepinehrin (vasodilation, broncho dilation, pulmonary dilation)

how is fluid regulated in the body stimulated by the adrenal gland

adrenal medulla → releases epinephrine and norepinephrine (vasodilation)

adrenal cortex→ releases aldosterone which stimulates the kidneys to release angiotensin 1 that gets turned into angiotensin 2 by renin → vasodilation

how is fluid regulated in the body stimulated by the hypothalamus

hypothalamus senses pressure → stimulates pituitary glad to release ADH → signals kidneys to reabsorb water into the blood stream

hypothalamus tells kidneys what to do with fluid volume

what’s the recommended amount of fluid to drink in a day

2-3 L

what are some signs and symptoms if fluid output exceeds input

• dry mucous membranes

• skin turger → longer

• colour fades

• decreased cap refill

• decreased LOC

• hypotension

what is osmolarity

tells us how concentrated a fluid is

high osmolarity= high concentration

what are the three main substances that affect osmolarity

sodium: a major contributor to blood osmolarity and water balance

glucose: sugar in the blood stream that can increase osmolarity (pulls water towards it)

Urea: waste product from protine breakdown that contributes to measured osmolarity

what is normal osmolarity

275-295 mOsm/kgH2O (number of dissolved particles per kilogram of water

above 295: blood is more concentrated

below 275: more diluted

how does osmolarity effect water movement

water moves through osmosis to areas with higher concentration of solutes

hypertonic,(shrink) hypotonic (swell)

what is aquaporins

special protine channels in cell membranes that allow water to move through quickly

what does dehydration and overhyrdation do to osmolarity

dehydration: increases

over hydration: decreases

what are electrolytes

minerals that carry an electrical charge when resolved in water

cations: positive

anions: negative

where are electrolytes found in the body

ECF: includes blood plasma and interstitial fluid: mostly contains sodium, chloride and calcium

ICF: mostly contains potassium, phosphate, and magnesium

why is electrolyte balance so important

concentrations are important because cells use differences in electrical charges to communicate → action potentials

what are the steps of an action potential

resting: cell is negatively charged inside (-70mv)

depolarization: sodium enters cell making the inside more positive

Repolarization : potassium leaves the cell making it more negative again

hyperpolerization: potassium gets pumped out: makes cell temporarily more negative then it should be

what does the sodium and potassium pump do?

maintains the concentration gradient needed for an action potential

uses ATP to move 3 NA out and 2 K in

what is blood made out of

plasma: 55% → water, electrolytes, proteins, nutrient and waste

blood cells: 45% → RBC, WBC, platelets

what electrolytes are tested and for why

sodium: water balance

potasium: heart rhythm and muscle func

chloride: fluid and acid balance

bicarbonate: helps regulate blood PH (should be neutral)

where does urea come from

you eat protine → breaks down into amino acids in blood stream → excess amino acids are broken down into carbon and nitrogen → nitrogen is removed → producing ammonium→ the liver converts toxic ammonium into urea → kidneys remove through urin

what is IV fluid administration

• aims to maintain homeostasis and correct fluid imbalances (primarily via osmosis)

• the correct IV fluids will achieve the desired effect

what is tonicity

how a fluid effects the size of your cells based on its concentration compared with blood plasma

determine weather water will move into cells causing them to swell(hypotonic)

move out of cell causing them to shrink (hypertonic)

or stay the same: isotonic

what are IV fluids main solutes

sodium: remains mostly out of cells helping determine how water distributes between the extracellular and intracellular spaces

dextrose: adds particles to the IV solution

what are the 2 categories of IV fluids

colloids

crystalloids

what do colloids do?

• protine based normally (cant easily cross capillary walls)

• stay in circulation (plasma exspanders) → cause high renal work load

• helps increase blood volume by holding water inside blood vessels

• contains molecules (protine) that create oncotic pressure which helps retain water in the blood stream

• ex: albumin

• used in cases of shock or large volume fluid replacement

• risks: fluid overloud, over work of kiddneys

what are crystalloids

fluids that distribute through the body

• contain water and small resolved substances (h20+ electrolytes + other solutes (normally glucose for energy)

• easily move between ECF and ICF

• tonicity directs fluid movement

what’s the difference of protine containing IV in the bag verses the body

they are isotonic in bag but hypertonic in the body due to the protine content

eg: 5% albumin

what happens to osmolarity in dextrose containing IVs

if dextrose is the dominate solute → once in the body it is quickly used up by cells → the remainder fluid will become isotonic or even hypotonic

• its slightly hypertonic in the bag due to dextrose eg: D5 ½ NS

what is fluid maintnce?

meeting body requirements

• oral intake (eating/feeding tube)

• IV infusion

• SC infusion

what is fluid resuscitation

replacing deficits

• PO if minor

• iv if concerning

• goal = educate perfusion → rescue intravascular volume

what is fluid restriction

restricting fluid intake

how do you calculate adult fluid circulation

35ml/Kg/day of water

how do you calculate paediatric IV fluids

4/2/1 rule

first 10kg: 10×4 → 40ml/hour

next 10 kg: 10×2 → 20ml/hour

remaining kgs = 1ml/kg/hr

why do we add dextrose to IVs and how much

if someone is NPO→ not eating → glucose stores are running low → body increasingly breaks down fat for energy → ketones are produced → dextrose helps reduce that

50-100g a day helps avoid starvation ketosis

each 1L of iv is 5% (50 g of glucose) dextrose → 170 cals

what are common isotonic crystalloid fluids

• normal saline (NS) 0.9%

• lactated ringers (LR or RL)

• plasma-Lyte 148

• D5W

• D5.2NS

what are common isotonic colloids fluids

(they are hypertonic in the body)

• 5% albumin

• dextran 40

• dextran 70

• hydroxyethyl starch (e.g hetastarch)

what is normal saline (0.9%NS)

it contains

• 0.9% sodium chloride → per 100ml of fluid

• 154 mEq/L of sodium

• 154 mEq/L of chloride

-isotonic: free to move

• resuscitation fluid # 1

• adults: give patients 500ml bolus → then reassess

• child: give 15ml/kg bolus → then reassess or switch to D5 ½ NS

side effects of prolonged use

• hyperchloremia (to much chloride in bloodstream) → to much chloride → bicarbonate concentration can decrease → metabolic acidosis

• low other electrolytes

• because there’s no dextrose → no energy/calories, nutrition

Lactated ringers (LR, LQ)

contents per L

• Na →130 mEq/L

• potasium → 4 mEq/L

• calcium → 2.7 mEq/L

• chloride → 109 mEq/L

• sodium lactate → 28 mEq/L (metabolized into bicarbonate)

tonicity: isotonic

side effects: hyperkalemia, no dextrose

contraindication for paediatric kids: high electrolytes

plasma -Lyte 148

contents per L

• Na→ 140 mEq/L

• potassium→ 5 mEq/L

• magnesium → 3 mEq/L

• chloride → 98 mEq/L(normo-chloremic: normal concentration of chloride in blood)

• alkalizing agents(converted into bicarbonate) → acetate: 27 mEq/L, gluconate: 23 mEq/L → not a good treatment for metabolic acidosis bc there isn’t enough bicarbonate

-21 calories ( not very nutritious)

-common choice for post OR fluids

cautions: can have hypersensitivity reactions: high volumes is not ideal

dextran 40

• large polysaccharide (molecule made of sugar)

• colloid: stays in circulation (volume expander)

• contains some 0.9%NS

• reduces platelet agression

• reduces RBC aggregation: less likely to clump together

• decreases blood viscosity → makes blood less thick alowing it to flow better

• risk: increase bleeding risk: bc it interferes with normal clot formation

• can be good for fluid resuscitation → risk of fluid overloud

what are common hypertonic fluids (move out of cells)

(high glucose or high sodium)

• D5NS(normal sailing but combined with dextrose)

• D5LR

• D5 plasma -lyte

• D10W

• D5 0.45%NS (D5, ½ of the electrolyte Nacl)

-hypertonic in the IV bag but become isotonic quickly in the body when the dextrose gets used up

• 3% NaCl → good treatment for head injury to decrease ICP

• 25% albumin (colloid) → good treatment for resuscitation fluid (watch fluid shift)

D5.45 NS

contents per L

• 50g dextrose

• Na→77 mEq/L

• Cl ^→ 77 mEq/L

tonicity: hypertonic

• first choice for paediatric maintenance fluid (+ consider adding KCL)

• good choice if dextrose is requested (D5NS → also a good choice short term)

• side effects: hyponatremia

25% albumin

contents per L

albumin 250 g

Na 130-160 mEq/L

• tonicity: hypertonic

• categorie: colloid

• drug type: biological ( heat treated to eliminate pathogens) made from donated plasma

cautions: plasma volume expander → can draw 3.5 times its infused volume of additional fluid into circulation

3% NaCl

• tonicity: hypertonic

• catagory: crystalloid

• very potent: only used in extreme cases and in small volumes

• dangerous cuz It can cause a big increase in Na

• used: cerebral edema, extrema sweat loss

what are common hypotonic fluids (fluids into cells)

(low NaCl or dextrose)

• 0.45% NS ( ½ NS)

• 3.3% dextrose 0.3% sodium ( 2/3 1/2)

• give If….

• hypernatremia: too much sodium relative to water in blood

• dehydration: the body doesn’t have enough water → high blood sodium causes water to to leave cells → cells become dehydrated and shrink

what can cause upper GI bleeds

• peptic ulcers

• esophageal varices

• esophagitis

• mallory- weiss tears

what can cause Lower Gi bleeds

• inflammatory bowel disease

• diverticular disease

• tumors

• colon polyps

• hemorrhoids

• anal fissures

• proctitis

how can you help decrease GI bleeds

stop any contributing drugs

• NSAIDs

• drugs that decrease clotting: antiplatlets, anticoagulants,thrombolytics

what is the treatment for GI bleeds

• IV fluids → resescitation and or maitnence

• blood products

• antibiotics if caused by a pathogen

-adjunct treatment: PPIs → decrease stomach acid

what do you need to asses for GI bleeds

• VS (MAP)

• periferal pulses

• endoscopy or colonoscopy

• BW

• pathogen specific

what are the blood tests you would do for someone with a GI bleed

• RBC count: number of red blood cells

• differential: when you suspect a pathogen → types of WBC and %

• C-reactive protine: increase when there is inflammation in in the body

• pathogen specific tests: (culture + sensitivity): help identify the bacteria or virus

what is hemoglobin? and the reference range?

amount of oxogen carrying proteins in the blood

• 12.0-15.5

what is hematocrit?and the reference range?

percentage of blood volume made up of red blood cells

• 34.9-44.5

what is erythropoietin? and the reference range?

hormone made by the kidneys that stimulates RBC production.

4.0 -21.0

what is the reference range for platelets?

3.4-10.6

what is hemoglobin made up of

• found inside red blood cells

• contains iron that helps bind oxogen

• low hemoglobin can indicate anemia or blood loss

-4 globin protine chains: 2 alpha and 2 beta

-4 heme groups: one attaches to each protine chain

-4 iron: one attaches to each heme group

(each group binds 1 oxogen - 4 oxogen per hemoglobin)

• each RBC→ 270 million hemoglobin molecules

why cant we give isotonic IV fluids to a hemoroging patient

Bc isotonic fluids replace fluid volume but they do not replace the RBC that carry oxogen

→ giving Isotonic fluids can cause remaining blood to be diluted (diluting RBC and clotting platelets)

what are the different types of blood products

1. packed RBC: purpose→ increase oxogen delivery (good for significant blood loss)

2. whole blood: purpose→ replace multiple blood components at once → (RBC, plasma, clotting factors, platelets)

3. platlets: purpose→ helps stop bleeding by forming platelet plugs (give when platelets are low or not functioning)

4. fresh frozen plasma: purpose→ replacing clotting factors

5. cryoprecipitate→ replace fibrinogen → is converted into fibrin to strengthen blood clots

how do we match blood types

red blood cells have antigens on there surface → plasma contain antibodies that can attack RBC with different antigens (hemolysis)

blood types

• A→ a antigens on RBC and anti -B antibodies in plasma

• B→ b antigens on RBC and anti- A antibodies in plasma

• AB→ a and b antigens on RBC and no antibodies

• O→ neither a or b antigens on RBC but both a and b antibodies in plasma

what does Rh + vs - mean

positive: has the RH antigen

negative: do not have the RH antigen

people who are positive can receive both negative and positive but negative can only receive negative

what’s the universal donor and recipient

donor → O-

recipient → AB+

what is LTOWB?

low-titer group O whole blood

• it contains low levels of anti A and anti B antibodies

• its group O blood

• and it contains RBC, platelets, plasma and clotting factors (whole blood)

• very good for emergency situations where you dont know somones’s blood because it contains very little anti a and b antibodies

• more available then O- blood and more effective then PRBCs

what is a transfusion reaction?

happens when a paitent has an unwanted response to receiving blood

reactions

• acute hemolytic→ incompatible RBC are destroyed

• febrile non-hemolytic → fever and chills occur

• allergic→ itching, hives, rash

• anaphylactic→ severe allergic reaction → possible airway compromise

• TACO→.circulatory overload causes breathing difficulty

• TRALI→ acute lung injury following transition

what do you do if someone has a transfusion reaction

stop the blood transfusion immediately

assess ABCs + vitals

do normal Iv solution with new tubing

what is hyponatremia?

too much sodium loss (less then 135 mEq/L)

• most common imbalance

• loss of sodium through → GI, diaphoresis, excessive diuretic drugs, renal disease

• s/s: weekness, hypotension, LOC changes

• treatment: D5NS

what is hypernatremia

too much sodium (more then 145 mEq/L)

s/s: hypertension and edema

tx→ restrict salt intake + diuretic medications to remove Na+

what is hypokalemia

not enough potassium (less then 3.5 mEq/L)

when potassium is low muscle and heart cells cannot function electrically as well as they should

loss of K+→ GI, potassium waisting diuretic drugs

s/s: weakness, hypotension, arrhythmias

tx: KCL(Iv) K-dur (PO)

what is hyperkalemia

too much potassium (more then 5 mEq/L)

causes: kidney failure, potassium sparing diuretics

check if true by a hemolyzed blood sample

• s/s: abdominal cramps, cardiac arrest

• tx: kayexalate (PO, NG) → binds K+ in GI for excretion

what is hyperchloremia

high chloride levels (more then 108 mEq/L)

• causes → renal disease, over resucitation

• s/s: headache, altered LOC, cardiac arrest

• risk: metabolic acidosis

• causes renal vasoconstriction → low GFR → risk of renal failure

• tx; treat metabolic acidosis if present, diuretics, hydrate with low Cl

what is hypocalcemia

• low calcium (less then 8.5mg/dl)

• causes → long term patients, critical illness, Vit D deficiency, renal disease

• s/s: paresthesias(abnormal skin sensation), muscle cramps, irritability, seizures

• tx: calcium gluconate (IV) and check Mg levels ( if paitent doesn’t have enough magnesium calcium cant be absorbed

what do you do if someone is NPO for 3 days

discuss a plan for providing nutrition

what do you do if somone is NPO for 5 days

need more additional nutrition beyond IV support (GI tube feeds, TPN, TPN and liquids)