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122 Cards in this Set
- Front
- Back
2 main fluid compartments and fluid distribution
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intracellular fluid (2/3 of volume)
about 30 L extracellular (1/3) ~13.5 L |
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2 major fluid subdivisions of ECF and fluid distribution
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▪ Plasma – fluid portion of the blood (25%)
▪ Interstitial fluid (IF) – fluid in spaces between cells (75%) |
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special cases of ECF (where it might be elsewhere than plasma/interstitial) (6)
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lymph, cerebrospinal fluid, eye humors,
synovial fluid, serous fluid, and gastrointestinal secretions |
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male vs. female water makeup
why the discrepancy? |
Healthy males are ~ 60% water
Healthy females are ~ 50% water women have higher body fat and smaller amount of skeletal muscle |
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how to calculate distribution of water into compartments in a person weighing x kg
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take weight and multiply by % of water (if M or F)
then take 3/4 of ECF and that goes in interstitial, 1/4 into IV |
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intracellular and extracellular- say where the intra/extraVASCULAR fluids are located in each compartment
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intracellular- extravascular fluid would be in tissues
intravascular would be fluid in erythrocytes extracellular- intravascular fluids = plasma extravascular = edema sort of fluids/interstitial fluids |
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3 electrolyte solutes in body
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▪ Inorganic salts
▪ Acids and bases ▪ Some proteins |
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3 non-electrolytes in body
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▪ Glucose
▪ Lipids ▪ Creatinine and urea |
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osmotic power of electrolytes vs. nonelectrolytes
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Electrolytes have greater osmotic power than nonelectrolytes
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fluid mvmt among compartments is regulated by what 2 types of pressures
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osmotic and hydrostatic pressures
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what happens to net leakage of fluid from blood?
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Net leakage of fluid from blood is picked up by lymphatic vessels and returned to bloodstream
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Exchanges between interstitial and intracellular fluids are...
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are complex due to the selective permeability of the cellular membranes
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two way water flow is...
how does water flow in this case? (in what direction) |
Two‐way water flow is substantial
Water flows in direction of highest osmolar concentration |
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To remain properly hydrated, what must be true?
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water intake must = water output
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Increased plasma osmolality triggers ... (2)
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thirst
and release of antidiuretic hormone (ADH) |
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7 compounds that go into calculating serum osmolality
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sodium
gluose BUN EtOH isopropanol methanol ethylene glycol |
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normal osmolality range of serum
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275‐290 mOsm/kg
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extracellular compartment primary electrolytes (2)
caveat |
Sodium = major cation
Chloride = major anion Caveat with high protein content of plasma?? (didn't mention this) |
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intracellular fluids major cation and anion
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Potassium = major cation
Phosphate = major anion |
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osmolality of extra and intracellular should be...
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equal
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4 routes of water output (which is biggest)
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mostly from urine
some are insensible (not sensed?) water losses from skin/lungs (respiration) poop sweat |
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3 routes of water input (which is biggest)
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metabolic water (from oxidation)
food (30%) most comes from beverages |
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hypothalamic thirst center is stimulated by (4)
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10-15% decrease in plasma volume
1-2% increase in plasma osmolality (i.e. hypernatremia) anything that decreases BP or senses BP decrease: baroreceptor input, angiotensin II |
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thirst is quenched when?
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as soon as we start to drink
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feedback signals that inhibit thirst center (2)
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Moistening of the mucosa of the mouth and throat
Activation of stomach and intestinal stretch receptors |
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thirst mechanism flow chart
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---skipped over
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Obligatory water losses (2)
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Insensible water losses from lungs and skin
Water that accompanies undigested food residues in feces |
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Obligatory water loss reflects the fact that (didn't go over this in class...) (2)
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Kidneys excrete 900‐1200 mOsm of solutes to
maintain blood homeostasis Urine solutes must be flushed out of the body in water |
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what receptors regulate ADH release
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hypothalamic osmoreceptors trigger or inhibit ADH release
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triggers for ADH release (7)
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▪ Prolonged fever
▪ Excessive sweating, vomiting, or diarrhea ▪ Severe blood loss ▪ Traumatic burns hypoglycemia pregnancy (total body volume doubles so thirst to achieve this) meds like SSRI, carbamazepine, NSAIDs via SIADH?? |
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Water reabsorption in collecting ducts is proportional to...
low vs. high lvls of said hormone and effect on urine |
to ADH release...so:
Low ADH levels = dilute urine and reduced volume of body fluids High ADH levels = concentrated urine and increased volume of body fluids |
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mechanisms and consequences of ADH release slide
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didn't go over
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dehydration definition in terms of water in body
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Water loss > water intake and the body is in negative fluid balance
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hypovolemia vs. dehydration
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hypovolemia = depletion of SODIUM and water
dehydration = depletion of water treated a little differently |
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causes of dehydration (6)
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Hemorrhage
Severe burns Prolonged vomiting or diarrhea Profuse sweating Water deprivation Diuretic abuse |
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4 sx, 1 lab indicating dehydration
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Dry mouth and thirst
BUN: SCr ratio > 20:1 Dry, flushed skin Oliguria Hypotension, tachycardia |
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prolonged dehydration may lead to...(5)
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Weight loss
Fever Mental confusion Loss of electrolytes Eventually hypovolemic shock |
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2 of body's reactions to dehydration (activate what 2 systems)
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SNS- vasoconstriction, increased HR
RAAS- kidneys reabsorb more Na and water |
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mechanism of dehydration (3)
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1) excessive loss of water from ECF
2) ECF osmotic pressure will now rise and suck water out of cells 3) cells shrink |
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etiology (2) of "hypotonic hydration" (overhydration/water intoxication)
sodium levels? |
Renal insufficiency or an extraordinary amount of water ingested quickly can lead to cellular overhydration (AKA “water intoxication”)
Sodium content is normal BUT diluted because excess water is present |
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pathophysiology of hypotonic hydration (2)
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Resulting hyponatremia (due to dilution) promotes net osmosis into tissue cells, causing swelling
These events must be quickly reversed to prevent severe metabolic disturbances, particularly in neurons |
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edema definition
pathophysiology (2 ways) |
Atypical accumulation of fluid in interstitial space*** (not extra fluid in vasculature) → tissue swelling
Increased flow of fluids out of bloodstream and/or hindered fluid return from bloodstream |
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diuretic for pedal edema- thing to keep in mind
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slowly pull fluid out of vasculature so fluid moves out of interstitial space into vessels...so it takes a while to fix
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Interstitial fluid accumulation causes what? (2)
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low blood pressure and severely
impaired circulation |
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factors that accelerate fluid loss causing edema (6)
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Hypertension, capillary permeability
Incompetent venous valves, localized blood vessel blockage (backed up fluids) Congestive heart failure, high blood volume |
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Hindered fluid return in edema usually reflects
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an imbalance in
colloid osmotic pressures |
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2 causes of hindered fluid return in edema and explain how they cause edema
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hypoproteinemia- forces fluids out of capillary beds at arterial ends, then fluids fail to return (oncotic pressure issue) at venous ends
blocked or surgically removed lymphatics- leaked proteins accumulate in interstitial fluid, and exert increasing colloid osmotic pressure, which draws fluid from blood and we don't have the lymphatics to return it to the blood stream |
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3 causes of hypoproteinemia
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▪ Protein malnutrition
▪ Liver disease ▪ Glomerulonephritis |
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adult avg fluid requirement (per kg, per day)
generally in a male that is how much per hour? exception to this rule |
Average fluid requirement = 30‐35 mL/kg/day
Generally in a guy, this is ~ 125 mL/h really heavy- 200kg+...adipose tissue doesn't have as much vasculature so equations don't apply |
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children total body water vs. adults
what do you use to calc fluid reqs in kids |
higher % of total body water than adult
so kids need weight based maintenance IVFs via 4/2/1 rule |
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4/2/1 rule for fluids
used for whom? |
4-2-1 rule: 4mL/kg/h for 1st 10 kg of weight
then 2mL/kg/h for 2nd 10kg for each kg above 20, it is 1 mL/kg/h can also be used for adults |
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daily water transfer to/from tract lumen- explain the input and output of water and how it balances out
sources of water to lumen (5) |
8000-8400 mL of water is reabsorbed out of intestine +400 from colon
ingest 2-3 L per day bile pancreatic juice saliva swallowed intestinal secretion total excreted to tract lumen ~ 9 L which balances out the 9 L absorbed |
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electrolyte composition of bodily fluid graph- take home msg: blood/interstitial fluids primarily made up of..(2)
intracellular is primarily (3) |
blood and interstitial fluid are primarily NaCl and bicarb
intracellular is K+, phosphate, protein |
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ions in stomach (2)
duodenum (2) ileum (3) colon (3) pancreas (4) bile (3) importance of this? |
fluids in stomach- Na+ and Cl
duodenum- Na+, Cl ileum- Na, Cl, bicarb colon- Na, K, Cl Pancreas- Na, K, Cl, TONS of bicarb bile- Na, Cl, some bicarb important when deciding what ions to replace |
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lactated ringers composition (5)
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sodium (130 mEq/L)
Cl (100) Lactate (28) potassium (4) calcium (3) |
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0.9% NaCl how much Na and Cl per liter?
drawback to NaCl |
sodium/Cl = 154 mEq/L
can cause hyperchloremic metabolic acidosis- use LR instead (less Cl) |
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LR- when to be careful with use (2)
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in CKD/AKI pt- due to having potassium
lactate is cleared by liver- so avoid large amounts in liver issues-->lactic acidosis- or watch carefully and switch when K+/lactic acid starts creeping up |
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gastric losses (e.g. NG suction)
losing what lytes? (2) fluid replacement choice? |
- will be losing acids (H+/Cl-) - replace with NS, 0.5 NS with or without K+
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pancreatic losses- lose what lytes? (2)
replace with what? |
Na, bicarb - LR with bicarb (idk why LR...)
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Biliary, small bowel- lose which lytes? (3)
replace with what? |
lose Na, Cl, bicarb but not as much bicarb so can get away with just LR
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diarrhea- lose which lytes (4)
use what to replace? |
lose a lot of everything- Na, K, Cl, bicarb- so use LR with or without bicarb
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fluids used for rescucitation (in emergencies) (4)
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Crystalloids
Colloids Hypertonic solutions- risk for hypernatremia, not a good option Oxygen‐carrying fluids |
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change in Mean arterial pressure by fluid- list order of fluids from best to worst (5)
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best option in changing MAP is blood, followed by dextran, albumin, lactate then glucose (dextrose)
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when picking fluids for rescucitation, what compartment do we want the fluids to be in?
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intravascular space (of ECF)
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what are crystalloids?
2 examples |
Solutions containing sodium as their major
osmotically active particle NS, lactated ringers |
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indications for crystalloids (4)
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Plasma volume expansion
Correct extracellular electrolyte and volume deficits Fluid challenge for oliguric patient (to see if they are dehydrated or not, or if it's kidney shit) Hemorrhagic shock |
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2‐liter rule for oliguric pt
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if you give them 2 L of crystalloid and look for increase in UoP to determine reason for oliguria
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3:1 rule for hemorrhagic shock- give reasoning
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3 mL of crystalloid should be given for every 1 mL of blood loss (due to third...space...loss)
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NS distribution in body and why we have the 3:1 rule
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3L of NS- all stays in ECF but distributes between interstitial space and IV space
so 75% goes into interstitial and 25% in IV...that's why 3:1 rule |
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distribution of D5W in body- how much in IV space?
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distribution of D5W- equally between ICF and ECF due to being metabolized to free water
so 3 L--> 2/3 of it goes into ICF, then of the 1/3 remaining fluids, 25% of THAT will be IV |
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3 ML of NS + D5W-->so 1.5 of each- how to work out distribution into IV space
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just...calculate each separately...add together
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for trauma...which fluid do you not want to give..
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D5W...it sucks for IV space
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D5W, 1/2 NS, NS and hypertonic NaCl (3%)- list their tonicities and how much free water they provide (free water goes into cells)
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D5W- hypotonic, 1L of free water
1/2 NS- hypotonic- 73% ECF, 27% ICF- 500mL free water NS- isotonic, 0 free water 3% NaCl- hypertonic, -2k free water (draws...water out?) |
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3 potential AE of crystalloids
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Peripheral and pulmonary edema
Electrolyte disturbances Hyperchloremic acidosis (too much NS- switch to LR |
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colloid definition
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Large molecular weight substances that do not pass readily across capillary walls
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3 colloids
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Hetastarch (Hespan) 6%
Albumin Dextrans |
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stop-gap measure for blood- what does this mean
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no O2 carrying capacity- so you can give this if they're bleeding but must be temporary
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hetastarch comes in what form
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6% solution in normal saline – 500 mL bag
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hetastarch- amt of plasma volume expansion
when to use administer with what? |
Plasma volume expansion ≥ infusion volume
Plasma volume expanding agent for use after cystalloids Does not carry O2 → administer with packed RBCs |
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hetastarch elimination (2)
renal dysfunction effect? issue with the elimination rate |
Broken down slowly by body
50% eliminated by 2 days 64% eliminated by 8 days even slower in renal dysfunction issue is coagulopathy if it builds up |
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hetastarch ADRs (4)
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Coagulopathy – usually in volumes greater than 1500 mL/day (20 mL/kg/day)
Volume overload (pulmonary edema) Anaphylaxis in 0.1% Hyperamylasemia |
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albumin- 2 formulations
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Available in 5% and 25% (both 12.5 g)
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5% vs. 25% albumin- what's the difference?
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500 mL of 5% increases IV space by 500 mL (due to staying in IV space)
use 25% if fluid expansion not desired |
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4 indications for albumin and which one (5 or 25%) to use
what NOT to use albumin for |
hemorrhagic shock after crystalloids and CI to hetastarch- use 5% to expand volume (have moved away from using albumin though)
paracentesis- 8g/L withdrawn -helps with cardiorenal perfusion (use 25%) hypotension due to fluid shifts during dialysis use (25%); but same effect as NS so... SBP- risk of renal failure due to intravascular volume depletion- give on days 1/3 (idk which %) NOT for hypoalbuminemia in chronic diseases (malnutrition, cirrhosis, etc)- because of short half life- temporary solution to long standing problem wastes albumin |
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in shock...what would you use
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you'd think albumin because it all goes into IV space but NS is just as good
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3 ADR for albumin
what 2 things do you not have to worry about |
Pulmonary edema, especially during sepsis/ARDS
Intestinal obstruction (moa unknown) Anaphylaxis in 0.5‐1.5% purified so don't have risk of hep and HIV |
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what is dextran?
2 forms |
Large glucose polymer
Dextran‐40 Dextran‐70 |
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2 uses of dextran
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Plasma volume expander
VTE prevention- wat- prevent clots? doesn't make much sense if you're trying to fix blood loss and yet prevent coagulation so not used much |
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dextran ADRs (4)
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Anaphylaxis in 1‐5%
Osmotic diuresis Bleeding diathesis Reticuloendothelial blockade |
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Blood usage (2)
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Volume expansion + oxygen‐carrying
capacity |
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blood disadvantages (4)
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Cost
Compatibility error Infection Citrate- causes hypocalcemia because it binds calcium in LR? wtf didn't talk about it |
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acid/bases on charts- how to read
x/x/x/x |
pH/ PCo2/PO2/HCO3-
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normal pH of bodily fluids (arterial blood, venous blood/interstitial fluid, intracellular fluid)
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Arterial blood: 7.4
Venous blood and interstitial fluid: 7.35 (more CO2) Intracellular fluid: 7.0 |
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Alkalosis/alkalemia – pH
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arterial pH > 7.45
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Acidosis/acidemia – pH
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arterial pH < 7.35
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respiratory acidosis/alkalosis results from...
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result from failure of the respiratory system
to balance pH |
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single most important indicator of
respiratory inadequacy |
PCO2
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normal PCO2 fluctuates between what?
values that signal respiratory acidosis and alkalosis |
Normal PCO2 fluctuates between 35‐45 mmHg
Values > 45 mmHg signal respiratory acidosis Values < 35 mmHg signal respiratory alkalosis |
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[H+] (acidity) equation for blood
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[H+] = 24x(pCO2/[HCO3-])
basically CO2 treated like acid |
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Most common acid‐base imbalance
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respiratory acidosis- hypercapnea (too much CO2)
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2 causes of respiratory acidosis
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shallow breathing- e.g. narcotics
hampered gas exchange |
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4 causes of hampered gas exchange that causes resp acidosis
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▪ COPD
▪ Pneumonia ▪ Cystic fibrosis ▪ PE |
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respiratory alkalosis causes
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Hyperventilation (“blowing off the CO2”)
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sx of respiratory acidosis (3) and mechanism
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headache
papilledema-optic disc swelling that is caused by increased intracranial pressure CO2 is vasodilator --> increases cerbral blood flow -->CNS changes (obtundation?) |
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metabolic acidosis/alkalosis definition
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All pH imbalances except those caused by abnormal PCO2 levels
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HCO3- levels- normal range
values that signal alkalosis and acidosis |
Normal HCO3‐ fluctuates between 22‐26 mEq/L
Values > 26 mmHg signal metabolic alkalosis Values < 22 mmHg signal metabolic acidosis |
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Second most common cause of acid‐base
imbalance |
metabolic acidosis
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sx of respiratory alkalosis (4)
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cardiac arrhythmias
decreased cerebral BF because decreased CO2 (vasoconstriction?)-->HA, syncope, seizures |
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when you see metabolic acidosis- 2 types you need to distinguish
how to calculate? |
Determine if anion gap or non‐anion gap
Anion gap = Na – (Cl‐ + HCO3 ‐) |
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anion gap vs. non-anion gap metabolic acidosis- AG ranges for both and etiology
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if AG < 12, it is non-anion gap and due to excessive loss of HCO3-
if AG >=12, it is an anion gap metabolic acidosis and due to accumulation of organic acids |
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4 sx of metabolic acidosis
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hyperventilate to blow off CO2 to compensate
CNS depression, though more common with resp acidosis GI symptoms peripheral vasodilation |
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non-gap metabolic acidosis etiologies (2 are drugs) (8)
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bicarb loss-->so diarrhea
pancreatic bicarb loss renal tubular acidosis post respiratory alkalosis potassium sparing diuretics (causing hypoaldosteronism) carbonic anhydrase inhibitors ureteral diversions into bowel (peeing out of your butt so diarrhea) acids (HCl, NH4Cl) |
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anion gap metabolic acidosis etiologies (10) all these things are adding acids
remember the mnemonic |
MUDPILES
Methanol Uremia Diabetic ketoacidosis Paraldehyde Isoniazid, ingestions (of toluene) Lactic acidosis from variety of causes (metformin, seizures, sepsis, shock, rhabdomyolysis) Ethanol, ethylene glycol Salicylates (ASA od) |
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metabolic alkalosis definition
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Rising blood pH and HCO3‐ levels
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typical causes of metabolic alkalosis (6)
losing acids |
Vomiting (excessive stomach acids lost)
Intake of excess base (i.e., antacids) Constipation (excessive HCO3‐ reabsorbed) Volume contraction (i.e., “contraction alkalosis”- from diuresing) Hypochloremia Excessive black licorice intake |
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respiratory and renal complications
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Acid‐base imbalance due to inadequacy of a
physiological buffer system is compensated for by the other system |
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treating metabolic acidosis (2)
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if PH < 7 can give bicarb, otherwise address underlying cause
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respiratory and renal compensations for acid/base disorders- explain what occurs generally, then specifically in each system what the limits are for compensation
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Acid‐base imbalance due to inadequacy of a physiological buffer system is compensated for by the other system
Respiratory system will attempt to correct metabolic acid‐base imbalances instantly but cannot fully compensate and can't over compensate Kidneys will work to correct imbalances caused by respiratory disease by altering bicarb absorption/secretion - can fully compensate but not over compensate but takes like 4 days to fix things |
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6 steps for interpreting ABG
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Determine if acidotic or alkalotic (pH)
Assess possible metabolic imbalance (look to see what is more screwy, bicarb or PCO2- off more is probably the issue) If other item isn't screwy, probably acute (no time for compensation) Assess possible respiratory imbalance Mixed metabolic‐respiratory imbalance Assess for compensatory process |
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IDK if have to know exact ranges...
venous blood values compared to arterial blood- pH, PO2, O2 sat, PaCO2, HCO3 |
pH lower because more CO2 (7.38)
PO2 lower because O2 has been delivered (35-40) SaO2 same as above (70-75) PaCO2 higher (41-51) HCO3 higher (24-28) |
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how to use goldberg graph
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- take ABG- plot PCO2 on bottom axis, HO3 on top, then look at pH and it'll tell you what it is...
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look at samples for ABG
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