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