Fluid Management and Blood Therapy Flashcards
why are surgical patients usually hypovolemic
NPO status, bowel preps, surgical trauma (open belly), evaporative losses and dry anesthetic gases
goals of fluid therapy
avoid or correct hypovolemic state
restore intravascular volume
maintain oxygen carrying capacity
maintain adequate tissue perfusion (inadequate tissue perfusion is associated with poor surgical outcomes)
TBW %, ICV %, ECV %
TBW 60% (42L) ICV 40% (2/3 TBW) ECV 20% (1/3 TBW) plasma ECV 4% interstitial ECV 16%
as adipose tissue increases, water content ____________
goes down
average TBW with 70kg male/female
term infants
premature infants
elderly
male: 60% TBW
female: 55% TBW
term infants 75% TBW
premature infants 80-90% TBW
elderly 50-55% TBW
(as you age, less TBW)
Sodium composition, plasma and ECF
142mEq/L
140mEq/L
Potassium composition ICF and ECF
150mEq/L
4.5mEq/L
why do we not use osmolarity for people
its temperature dependent, as temperature increases, volume gets larger so thats why its not accurate for human bodies
Osmolality
refers to number of osmotically active particles per kg of H2O
=(Serum Na+ x 2) + BG + blood urea (mmol/kg)
increase by blood urea, hyperglycemia, hypernatremia
osmolarity
number of osmotically active particles per liter of solution, another way to express concentration
tonicity
measurement of particles capable of exerting osmotic force
hypotonic: solution with lower osmolarity than plasma
hypertonic: solution with higher osmolarity than plasma
Plasma oncotic pressure created via (3)
albumin (most important ECV constituent)
proteins
gamma globulins
endothelial glycocalyx
gel layer in capillary epithelium that creates a physiologically active barrier within vascular space. helps keep fluid in intravascular space, promotes laminar flow
- binds to circulating plasma albumin, preserving oncotic pressure and decreasing capillary permeability to water
- also contains inflammatory mediators, free radical scavenging, activation of anticoagulation forces
NDF=
(capillary hydrostatic pressure-tissue hydrostatic pressure)-(capillary plasma oncotic pressure-tissue fluid oncotic pressure)
things to help assess for fluid volume status (10)
preop eval skin turgor mucous membranes edema lung sounds vital signs UOP HCT (most looked at in OR for FV status) urine specific gravity BUN/creatinine
how many liters of crystalloid are required to expand the IV compartment 1L
3-4L of crystalloid
regular plasma concentrations sodium potassium chloride phosphate magnesium calcium pH osmolality
Na 142 K 4 Cl 103 Phosphate 1.4 Mag 2 Calcium 5 pH 7.4 Osmolality 291
Composition of LR Na K Cl Ca Lactate pH osmolality
Na 130 K 4 Cl 110 Ca 3 Lactate 28 pH 6.2 Osmolality 275
Composition of NS Na Cl pH osmolality
Na 154
Cl 154
pH 5.6
Osmolality 310
Lactated Ringer Solution (7 points to know)
saline with electrolytes and lactate buffer
slightly hypotonic, thats why you dont give to neuro patients
provides 100cc free water per liter of solution
lactate converted to bicarbonate
more physiologic solution than .9% NS
avoid in ESRD r/t K
avoid mixing with PRBC, Calcium binds to citrate
Normal Saline Solution (7 points to remember)
isotonic solution in large volumes, produces high chloride content which leads to dilution hyperchloremic metabolic acidosis preferred solution for diluting PRBC's can use for kidney patients least physiologic fluid available cautious in large volumes
Normosol- R solution and electrolytes Na K Cl Mag Acetate Gluconate pH
most physiologic but expensive. can mix PRBC's with it. good for head trauma or regular trauma situation Na 140 K 5 Cl 98 Mag 3 Acetate 27 gluconate 23 pH 7.4
D5W solution tonicity electrolyte consideration uses (2 populations) consider PK calories (8 considerations total)
hypotonic (260)
causes free water intoxication and hyponatremia
provides 170-200 calories/1000cc for energy
can cause hyperglycemia (except DM receiving insulin or neonate)
dextrose metabolized
would take hella volume of this to replace
great for decreased BG in DM. hang 250 in OR and use as piggyback
pedes have immature livers so may need this solution
3% or 5% NaCl solutions
uses
risks
3% has Na/Cl 513mEq
5% has Na/Cl 856mEq
used for low volume resuscitation, burns, closed head trauma
principle role is tx of hyponatremia
risk of hyperchloremia, hypernatremia, cellular dehydration
not used in OR so much
colloid solutions (general) properties (2) administration consideration half life drug that can be given with it
osmotically active substances
high molecular weight
administered in volume equivalent to volume of fluid/blood lost from intravascular volume
half life in circulation is 16h but can be 2-3h in pathophysiologic space
active with glycocalyx to keep volume in intravascular space
ERAS protocol related (?)
albumin solution where its derived from and makeup of it (3) solutions (2) administration considerations (3) t1/2
blood derived colloid solution obtained from fractionated human plasma does not contain coagulation factors or blood group antibodies available as 5% or 25% solution 5% solution common in OR, 5% oncotic pressure 20 expands IV volume up to 5x volume given drawing fluid in from ISF plasma t1/2 about 16h can cause anaphylaxis
synthetic colloid solution: dextran makeup 2 types and their uses SE uses administration considerations
not given anymore related to anaphylaxis
water soluble glucose polymers
enzymatically degraded to glucose
dextran 70 used for volume expansion
dextran 40 used for improved blood flow in microcirculation and prevention of thrombosis
side effects include: highly antigenic, platelet inhibition, non cardiac pulmonary edema, interfere with crossmatching
used to be used in OR for vascular patients or vascular anastomosis, prevents clots
would usually have to give as test dose and wait
