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195 Cards in this Set

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What is the breakdown of % water in the human body?
neonates: 75%
infant: 65%
male: 60%
female: 50%
What happens with the water content in women?
older adults?
decreased d/t inc fat content
*decreases w/age
What are the two compartments that hold the water volume?
ICF: 40%
ECF: 20%
What is the breakdown of ECF and fluid?
Intravascular: 5%
Interstitial: 15%
What is osmosis?
movement of water across a semi-permeable membrane
How does osmosis occur?
moves from higher concentration to lower concentration
What is osmotic pressure?
pressure exerted by the side with more solute to prevent net movement of water across the membrane
what is an osmole?
molecular wt of a non-dissociable substance
what is osmolarity?
# of osmoles per Liter (volume) of solvent
what is osmolality?
# of osmoles per kg (wt) of solvent
what is tonicity?
the # of osmoles in a solution and its effect on cell volume
what happens w/an isotonic sol'n?
no effects on the cell
what happens w/hypotonic sol'n?
increases cell volume (water moves into the cell) d/t more water outside the cell than in
what happens w/hypertonic sol'n?
decreases cell volume (water moves out of a cell) d/t more water inside than outside
what regulates the ICF
Na/K pump
volume and composition regulated by the cell membrane
*exchange @ 3:2 ratio
What is the major ICF solute?
K
140meq/L
What is the major determinant of ICF osmotic pressure?
Potassium
what composes ECF
interstitial and intravascular compartments
What does ECF provide for?
a medium for cell nutrients, e'lytes, and waste products
What is the major ECF solute?
Na
conc: 145 meq/L
What regulates oncotic pressure?
plasma proteins (albumin)
Describe intravascular fluid?
aka: plasma
*high molecular wt
*does not diffues easily across cell membrane
Besides albumin, what are some other constituents in the extracellular compartment?
water
ions
nutrients,
gases
waste products
hormones,
enzymes
lactic acid
What comprises the interstitial fluid?
low protein concentration
small of amt of free fluid
neg pressure compartment
what is the pressure of the interstitial compartment?
-5mmHg
what is diffusion?
movement of molecules b/w compartments guided by the kinetic energy they exert
describe the diffusion process b/w ICF and interstitial?
through lipid bilayer (CO2, O2, H2O)
*protein channel (Na, K, Ca)
*reversible binding to a carrier
what is carried across the cell membrane by facilitated diffusion?
glucose
what is carried across the cell membrane by active transport?
Na, K, Ca
How is fluid exchange done across cell membranes?
osmosis
How is fluid exchange done across capillary endothelium?
osmosis
hydrostatic pressure
What is hydrostatic pressure?
the force of the weight of water molecules pressing against the confining walls of a space (in particular, capillaries)
what kind of pressure does blood have?
hydrostatic pressure
why does blood have hydrostatic pressure?
wt
volume
being pumped from the heart into arterial circulation
what happens during hydrostatic pressure?
gradient in capillary pressure b/w compartments force fluids out of the arterioles and into the interstitial compartment
what happens during hydrostatic pressure on the venous end of capillaries?
hydrostatic pressure gradient forces fluids out of the interstitial compartment and back into the intravascular compartment
what kind of pressure compartment is the interstitial space?
negative
what happens to fluid not reabsorbed into the intravascular space @ the capillary end?
sent to lymphatics
what is edema?
r/t changes in normal hydrostatic pressure
what happens when there is increased hydrostatic pressure @ the venous end of caps?
causes add'l fluid movement from the cap to the interstitial compartment
when does tissue edema appear?
seen when the interstitial compartment expands to accomodate increases in ECF
what does the interstitial compartment hold?
overflow from the intravascular compartment
How is ECF volume regulated?
thirst
ADH secretion
describe the thirst mechanism?
*primary mechanism
how is thirst triggered?
*increase in body fluid tonicity (serum osmolarity)
*decrease in ECF volume
what happens when ADH is secreted?
*response to changes in blood osmolarity
*released from post pituitary
*changes permeability to water @ the collecting ducts
How else is ADH secretion triggered?
carotid barorecptors
*dec 5-10% of blood volume
*hypotension
*pain
*nausea
*emotional stress
*HYPOXIA
why does hypoxia cause a stimulation of ADH secretion?
r/t low perfusion states
*done so we can conserve H2O
What is ANP?
Atrial Natriuretic Peptide
What is the significance of ANP?
*released from atria in response to inc atrial stretch
*vasodilation
*increases UOP d/t Na & H2O
What does aldosterone do?
*prevents hypovolemia/Na depletion
where is aldosterone secreted?
adrenal cortex
what triggers aldosterone secretion?
dec Na in ECF or inc Na in urn
what kind of pressure does Na exert?
osmotic
*water follows Na
Where are the barorecptors located that respond to aldosterone secretion?
*respond to a dec stretch
*aortic arch
*carotid body
*pulm vasculature
*atria
*great veins
what happens when the barorecptors respond to a dec stretch?
inc sympathetic tone
*dec blood flow to kidneys
how is the dec in renal blood flow when aldosterone is triggered?
blood flow dec via the afferent arteriole
What happens @ the kidney level w/aldosterone secretion?
*renin is released
what releases renin?
juxtaglomerular cells in the afferent arteriole
why is renin released?
*dec Na levels
*dec intravascular volume
how does renin act?
acts angiotension (plasma protein)
*converts to Ang I
What happens to Ang I?
*converted to Ang II by ACE
what does Ang II do?
acts on renal cortex to release aldosterone
where does aldosterone work?
*distal renal tubules
what is the net effect of aldosterone?
*inc Na reabsorption
*inc blood osmolarity
how is fluid status assessed during the physical exam?
*neuro status
*skin turgor
*mucous membranes
*peripheral pulses
*changes in BP (orthostatics)
*resting HR
*UOP
how is fluid status assessed by lab values?
*serial Hct
*ABG (pH, BE)
*BUN/Cr ratio
*serum Na
*urinalysis
what are some signs a pt is dry?
*inc Na level
*hypotension
*poor skin turgor
what are signs of >10% dehydration?
*obtunded/lethargic
*HR >100
*dec BP
*resp variation
*orthostatic changes
what are the orthostatic changes in HR and BP in dehydration?
inc >=15 bpm HR
dec BP >=10mmHg
what are some signs of hypervolemia?
*pitting edema
*tachycardia
*crackles (pulm edema)
*wheezing
*cyanosis
*pink frothy secretions
what are the late signs of hypervolemia?
*tachycardia
*crackles
*wheezing
*cyanosis
*pink frothy secretions (pulm edema)
What is the ultimate goal of fluid volume replacement?
tissue perfusion and oxygenation
What are some IV solutions?
*crystalloids
*colloids
what is a crystalloid solution?
with or w/o glucose
*low molecular wt
what is a colloid soln?
*high molecular wt
*contain proteins
*contain large glucose polymers
*isotonic soln
to maintain fluid =, what is the ideal osmolarity of body fluids?
300 mOsm/L
What are the two types of hypotonic soln?
*D5W
*1/2 NS
describe D5W?
*253 mOsm/L
*no electrolytes
*50g/L of glucose
how many grams/100cc does a sol'n of D5 have?
5g/100cc
describe 1/2 NS?
*154 mOsm/L
*Na = 77 meq/L
*Cl = 77 meq/L
What are the 4 types of isotonic soln?
*NS
*D5 1/4 NS
*LR
*Isolyte/Plasmalyte
describe NS?
*0.9% NaCl
*308 mOsm/L
*Na = 154 meq/L
*Cl = 154 meq/L
describe D5 1/4 NS?
*355 mOsm/L
*Na = 38.5 meq/L
*Cl = 38.5 meq/L
*glucose 50g/L (or 5g/100cc)
describe LR?
*273 mOsm/L
*Na = 130 meq/L
*Cl = 109 meq/L
*K = 4meq/L
*Ca
*Lactate (met by liver)
describe isolyte/plasmalyte?
*294 mOsm/L
*Na = 140 meq/L
*Cl = 98 meq/L
*K = 5 meq/L
*Mg
*Acetate
*gluconate
what types of solns are not used in renal patients? why?
*LR
*Isolyte/Plasmalyte
*d/t K added; renal pts cannot excrete (become hyperkalemic)
What are the 6 types of hypertonic soln?
*D51/2NS
*D5NS
*D5LR
*3% NS
*5% NS
*7.5% NaHCO3
describe D51/2NS?
*432 mOsm/L
*Na - 77meq/L
*Cl = 77 meq/L
*glucose 50g/L
what hypertonic soln is good for renal pts?
D51/2NS
*has glucose, but not much Na
describe D5NS?
586 mOsm/L
*Na = 154 meq/L
*Cl = 154 meq/L
*glucose 50g/L
describe D5LR?
525 mOsm/L
*Na = 130 meq/L
*Cl = 109 meq/L
*K = 4 meq/L
*Ca
*LACTATE
*glucose 50g/L
what is the usual fluid used for kids?
D5LR
what are the 2 types of colloids?
*human plasma proteins
*semisynthetic (glucose polymers)
How are most colloids dissolved?
in isotonic saline soln
what is the mol wt of colloids?
high
*maintain intravacularly
*maintain oncotic pressure
*higher 1/2 life than crystalloids
Describe the human plasma soln?
*albumin - 5% and 25%
*plasma protein fraction (PPF)
5%
how is human plasma colloid soln formed?
*from human blood
*heated to 60 C for 10 hrs
*dec risk of HIV or Hep B/C
what are the semisynthetic colloid solns?
*dextran
*hetastarch (hydroxyethyl starch)
describe dextran 70?
*higher mol wt
*used as volume expander
describe dextran 40?
*lower mol wt
*used to improve/maintain blood flow in microcirculation
what type of fluid is used for ENT cases?
dextran 40
r/t bloodflow to microcirculation
describe hetastarch?
*hespan 6% (in soln w/NS)
*hextend 6% (in soln w/electrolytes)
what is a good fluid for Jehovah's witness?
hespan
can there be hypersensitivity rxn to colloids?
yes
*hespan, dextran, PPF
*albumin is rare
does hespan affect platelets fxn?
yes
*affects aggregation
*dose >20ml/kg/day
what does Dextran 70 & 40 do to coags?
*over 1 liter/day
*40 has less plt effect than 70
what is the plasma 1/2 life of crystalloids?
30 min
what is the plasma 1/2 life of colloids?
3-6 hrs
which is more cost effective - crystalloids or colloids
crystalloids
what are the general indications for colloids?
*severe IV deficit
*rapid IV volume d/t hemorrhagic shock
*replace fluid w/large protein losses
describe pts who might experience large protein losses?
*burn pt
*hypoalbuminemia (lvr dz)
what is the goal of fluid replacement therapy?
*tailor to specific pt
*consider age, surg procedure,
med Hx
what is the replacement of GI losses in an NPO pt?
100-200ml/day
what is the replacement of insensible losses in the NPO pt?
500-1000ml/day
*cutaneous or respiratory
what is the replacement of urn losses in the NPO pt?
*1000 ml/day
what crystalloids are used most commonly?
*NS
*LR
*Isolyte/Plasmalyte
what do isotonic soln replace?
*insensible losses
*3rd space losses
what electrolytes determine principal choice of crystalloids?
*Na
*K
*Cl
what should fluid losses be replaced with?
solutions similar in composition to the loss
what is the ratio of crystalloids to colloid replacement?
3:1
what happens w/rapid infusion of crystalloids >5L
tissue edema
r/t hydrostatic pressure
what happens to the pt in the deresuscitation phase?
*Post-op day #3
*returns to IVC
what happens to a pt ~ postop day #3?
*hypervolemia
*pulmonary edema
what happens w/large infusions of saline soln?
*hyperchloremic metabolic acidosis
what happens w/large infusions of LR
*metabolic alkalosis r/t bicarb production
what kinds of pts can use dextrose soln?
*diabetic
*kids
what happens to a healthy pt during surgical stress?
hyperglycemia
what are the parameters for glucose control in critically ill pts?
80-110 mg/dl
intraop fluid replacement should be calculated using what?
*fluid deficit (NPO)
*normal losses (maint)
*wound losses (3rd space)
*blood loss
How do you calculate maintenance?
4/2/1 rule
4ml/kg/hr for 1st 10kg
2ml/kg/hr for 2nd 10kg
1ml/kg/hr for >20 kg
how do you calculate the fluid deficit of a surgical pt?
hours NPO x maintenance
what happens w/3rd spacing?
can result in severe depletion of intravascular volume
how does fluid evaporate from the pt?
*tissue trauma (op site)
*lungs (mech vent)
what is the breakdown of tissue trauma?
minimal: 2-4ml/kg/hr
moderate: 4-6ml/kg/hr (hernia)
severe: 6-8ml/kg/hr(lvr trp, bowel resx, whipple, etc)
what is the ratio of crystalloid to blood loss replacement?
3:1
what is the ratio of colloid to blood loss replacement?
1:1
what is the ratio of PRBC replacement to blood loss?
1:1
how is the deficit replacement given to pt? (NPO)
1/2 in 1st hr
1/4 in 2nd/3rd hr
maintenance should be given how often during surgery?
every hour
when do you start replacing 3rd space losses?
2nd hour of surgery til end of case
figure the total replacement for a 70kg pt undergoing an open chole for an est 3hrs?
Deficit: 500,275, 275
MIVF: 110, 110, 110
3rd space: n/a, 280, 280 (2-4)
EBL (50) n/a, 150
total: 660, 815, 665 (2140)
What is the blood volume for
full-term neonates?
premies?
infants?
men?
women?
85ml/kg
95ml/kg
80ml/kg
75ml/kg
65ml/kg
how do you calculate blood volume?
wt x volume factor for pt
(ie 70kg male is 70kg x 75ml = 5250ml EBV)
how do you calculate allowable blood loss? (ABL)
(start Hct - desired Hct) divided by average (start + des) Hct = Y
Y x EBV = ABL
what Hct level is the gold std?
30
Describe the ABO system?
*inherited from parents
*2 alleles on chromosome #9 express blood type
what are the 3 possible gene alleles for blood type
A,B,O
*2 A alleles = A
*1 A allele + 1 B allele = AB
*1 O allele + 1 A allele = A
(O is recessive)
describe the RH system?
*inherited
*3 chromosomes (6 alleles)
*D allele determines Rh +/-
what happens to Rh neg pt who is exposed to Rh + blood?
*develop Ab
describe the T&S?
*rapid (5 min)
*hemolytic rxn 1:10,000
*PRBC avail to > 1 pt
describe the T&C?
*5 min Rh/blood type
*45 min for Coombs test
what does the Coombs test do?
detects less common Ab in blood
what type of blood can be given in an emergency situation
O negative
what happens to pt after 2 units of whole blood is given in an emergency situation?
develops Ab to A & B
describe PRBC?
*Hct 70-80%
*volume 250-300ml
*use filter
*ALWAYS warm blood
what does warming blood do for the pt?
*prevents hypothermia
*promotes tissue oxygenation
(oxyhgb dissociation curve)
if a pt is given 1unit of blood, what happens to H/H?
Hgb inc 1g/dL
Hct inc 3g/dL
why doe we transfuse PRBC?
increase oxygen carrying capacity
what is FFP?
Fresh Frozen Plasma
describe FFP?
*fluid extracted for 1unit of blood
*frozen w/in 6 hrs of collect
*contains all coag factors EXCEPT platelets
*ABO compatibility required
what are the indications for FFP?
*reverse coumadin
*correct coags
*correct coags in ESLD
describe platelets (plt)?
*1 unit = 6 reg donor units
*transfused plt survive 1-7 days
*ABO compatibility desired
how much of an increase will you see if a pt is transfused w/one unit of plts?
5-10,000u/L
what happens to a pt w/a plt count of 10-20,000
spontaneous bleeding
what are the indications for transfusing plts?
*<50,000
*maintain levels during bldg
*thrombocytopenia (<150,000)
*dysfunctional plts
what blood products do not contain plts?
*PRBC
*FFP
what is cryoprecipitate?
*fraction of plasma that precipitates when FFP is thawed
what is contained in cryo?
*factor VIII
*factor XIII
*von Willebrand factor
*fibrinogen
how is cryo supplied?
large bags
*10-20 units
is ABO compatibility required for cryo?
no
*JMH does require
what is an autologous transfusion?
*pt's own blood
what is the criteria for autologous blood donation?
*4-5 wks prior to surgery
*req'd to maintain H/H 11 & 32
*5 to 7 days b/w donations
*up to 2-3 units (10ml/kg)
what is cell saver blood?
*sxnd w/heparin added to reservoir
how much of the surgical blood loss is returned to the pt?
*50% Hct
what are the contraindications for cell saver blood?
malignant tumors
*contaminated surgical site
what are some complications w/using cell saver blood?
*air emboli
*hemolysis
*coagulopathy (r/t heparin)
what is the volume of a cell saver bag of blood?
250ml
*never use a pressure bag to infuse cell saver blood
What are the ASA practice guidelines regarding transfusions?
RBC transfusion is rarely indicated when Hgb is >10 and is almost always indicated when Hgb <6
what is an acceptable Hgb level in a healthy pt?
7 g/dL
when should pts w/a documented medical hx be transfused?
when they are symptomatic
*tachycardic
*tachypneic
what do studies show in regards to PRBC transfusion?
H/H 10 & 30 support tissue oxygenation and have better outcomes for pt w/CAD
what are some transfusion considerations in Jehovah's witness pts?
*refuse bank/autologous blood
*take cell saver/CPB blood
*may accept/refuse colloids or blood products
what happens during a hemolytic reaction?
*destruction of RBC by Ab
what is an acute hemolytic rxn?
*ABO incompatibility d/t clerical errors
*immediate/severe
what are the s/s of an acute hemolytic rxn?
*tachycardia
*hyperthermia
*hypotension
*hemoglobinuria
*oozing in surgical field
(triggers DIC response)
what is the tx for an acute hemolytic rxn?
*stop transfusion
*support CV
*fluids, mannitol, lasix
*renal dopa
*recheck blood products to pt
*return blood to blood bank
what is a febrile rxn in a blood transfusion?
*common rxn to donors WBC, plt
*no hemolysis present
*inc temp > 1 C w/in 4 hrs
*dec incidence w/20-40mm filters
what happens w/hypothermia and blood transfusions?
*ventricular dysrhythmias
*fibrillation (if T < 32 C)
what is TRALI?
*Transfusion Related Acute Lung Injury
what are the manifestations of TRALI?
*rare
*transfusion of antileukocytic Ab
*WBC aggreg in pulm circ
*damage alv/cap membranes
*resolves in 12-48 hrs w/supportive therapy
*mimics ARDS
what are the risks of viral infxn w/blood transfusions?
1:1M for Hep C, HIV
1:350K for Hep B
what do you give to pts who have dilutional thrombocytopenia?
plts
what is citrate toxicity?
*significant hypocalcemia
*r/t blood transfusions and citrate preservative
why is pt @ risk for hyperkalemia when receiving PRBC?
*stored blood
*inc CO2 & K r/t hemolysis
*