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
synthetic colloid solutions: hydroxyethyl starch (6%) 2 types effectiveness excretion administration considerations oncotic pressure max dose population that may benefit
hespan (in .95% NaCl solution)
hextend (in a balanced electrolyte solution similar to LR)
not as effective as albumin for volume expansion, but less expensive than albumin
primarily excreted via kidneys
coagulopathy due to dilution thrombocytopenia
max dose limited to <20mL/kg/day
oncotic pressure 30
dose dependent coagulopathy
not used a ton in OR but jehovahs witnesses may accept this
Pedema association
more so with colloids only because of faster fluid shift
colloids need to knows
less tissue edema association, less volume infused, volume of choice for hypoproteinemia
fluid choice of crystalloids indications and things to consider
how do large volumes effect plasma oncotic pressure
most effective for initial management of ECF losses (hemorrhagic shock, major surgery, or trauma)
large volumes lead to hemodilution (albumin, RBC’s, thrombocytopenia), and decreased plasma colloidal oncotic pressure, edema and transudates
thrombocytopenia and decreased clotting with dilution FVO and alot of IVF. maybe consider trendelenburg before you infuse mucho
fluid choice of colloids indications and things to consider
continued fluid resuscitation should include colloids, attempting to minimize interstitial edema of vital organs: heart, lung, brain
colloids are effective plasma expanders
infusion of 500mL albumin or hetastarch
6% expand plasma volume by 500mL
colloids draw about 20mL into plasma volume per gram of colloid given
preoperative goals
meet basal fluid requirements replace losses restore/maintain hemodynamic stability enhance microvascular blood flow so that oxygen is delivered to tissues maintain aerobic cellular metabolism
sources of intraop fluid requirements
maintenance fluid deficit blood loss evaporative losses (3rd space loss)
average normothermic 70kg patient with normal metabolic rate may lose ______mL water/day
2500ml
maintenance fluid requirement (MIVF)
4-2-1 rule
4cc/kg/h + 2cc/kg/h + 1cc/kg/h
trick: add 40cc to weight. does not work for <20kg pt
fluid deficit etiology and equation
maintenance requirement multiplied by number of hours patient has been NPO. also consider other losses like preop bleeding, vomiting, diuresis, diarrhea, bowel prep, occult losses, fluid sequestration (edema), ascites, increased insensible losses, hyperventilation, fever, sweating
ex) 8hrs NPO x 80kg pt = 120x8=960cc deficit
fluid deficit replacement strategy (based on 80kg patient)
1/2 of deficit replaced in first hour of surgery plus MIVF
1/4 of deficit replaced in 2nd hour of surgery plus MIVF
remiaining 1/4 replaced in 3rd hour of surgery plus MIVF
hr 1: 590cc
hr 2: 370cc
hr 3: 370cc
evaporative loss and 3rd space loss etiology
evaporative loss related directly to surface area of surgical wound and duration of exposure ex) open belly case
3rd space loss is due to fluid shifts and intravascular volume deficit caused by redistribution of fluids ex) trauma, infection (sepsis), burns, ascites
calculating 3rd space loss need to know and replacement measurement
type of procedure, degree of exposure, amount of surgical manipulation
based on whether tissue trauma is minimal, moderate, or severe
guidelines only, variation from patient to patient
replacement measured in ml/kg/hr
not until incision is made then add evaporative loss to maintenance and replacement
minimal surgery examples and additional fluid requirements
(dont even usually see replacement)
eye cases, lap whole, hernia, knee scope
0-2ml/kg/h
moderate surgery examples and additional fluid requirements
open chole, appendectomy
3-5ml/kg/h
severe surgery examples and additional fluid requirements
bowel surgery, THR
6-9ml/kg/h
emergency surgery examples and additional fluid requirements
gun shot, MVA
10-15ml/kg/h
estimating blood loss 1gm= where to look gauze 4x4 ray tech lap pads wet sponges
scale: 1gm=1cc
visual estimation: remember floor, surgical drapes, bed sheets, suction containers
soaked gauze 4x4=10cc
ray tech 10-20cc
soaked lap pads 100-150cc
wet sponges 20-30% of dry value
(pay attention to if they moistened the lap pad or if it goes in dry)
most adults can tolerate how much EBV loss/what HGB
10%, or a HGB of 6-7g/dL (Hct 18-21%)
measure Hgb after how much loss in EBV
15-20%
who requires higher hgb, whats the hgb cutoff
elderly patients, patients with significant CV, pulmonary, neurologic disease
hgb <5 significant morbidity/mortality
blood loss replacement: crystalloid, colloid, blood
crystalloid: 3ml crystalloid for 1ml blood loss
colloid: replace 1:1
replace 1ml PRBC for every 2mL blood loss
neonates (premature and full term) blood volume
95ml/kg
85ml/kg
infants blood volume
80ml/kg
children blood volume
75ml/kg
adults blood volume (male and female)
75ml/kg
65ml/kg
elderly blood volume (male and female)
65ml/kg
60ml/kg
allowable blood loss and equation
determines how much blood you can lose to reach a particular HCT
based on IBW
ABL=EBV x (pts starting HCT - allowable HCT) / pts starting HCT
multiply allowable HGB x 3 for allowable HCT
ex) healthy 75kg male with HCT 40% will allow HCT to drop to 25%.
EBL 75x75 = 5625
abv=(5625 x .15) / .4
=2110cc
universal donor
O-
universal recipient
AB+
massive transfusion
replacement of patients total blood volume (5L) in less than 24h
acute administration of >1/2 patients EBV in 3 hours or less
transfusion of 10 units of RBC’s in 24h
blood product administration risks/complications (10)
which factors will be low in PRBC unit
infections (hep c, b, HIV, bacterial sepsis)
allergic reactions/febrile reactions
TRALI (lung injury, noncardiogenic p edema)
hemolytic reactions
acute hypotensive transfusion reaction
metabolic complications (decreased pH, increased K esp with increased storage time)
coagulopathy ( usually after massive transfusion)
dilutional thrombocytopenia (responds well to plt transfusion)
low factors V and VII (stored factors may be 15-20% of normal)
DIC (activation of clotting system -> microvascular fibrin deposition -> activation of fibrinolysis)
citrate toxicity
citrate preservative may bind to and chelate calcium
empiric administration of calcium is not warranted unless ical levels are low
clinically significant hypocalcemia resulting in cardiac depression does not occur in most normal patients unless the transfusion rate exceeds 1 unit every 5 minutes
PRBC's need to know type test HCT in one unit of PRBC's NS in 1U of prbc's how long can 1U of PRBC's be stored before use
type specific ABO and Rh factor alone is sufficient in 98.9% of patients (incompatibility seen in 1 in 1000)
further testing if antibodies present or patients has had numerous blood products
HCT of one unit of PRBC’s is 70%
reconstituted with 100cc ish of NS
1U good for 35-42d
1 unit PRBC’s will increase HGB _____ and HCT ______
HGB 1g/dL
Hct 2-3%
transfusion alternatives (3)
autologous blood
cell saver
acute normovolemic hemodilution
autologous blood
unit of packed rbc’s
complications include anemia, preop MI from anemia, administration of wrong unit, need for more frequent blood transfusion, febrile and allergic reaction
cell saver
salvage of blood from surgical site
blood processed is washed and separated
rbc’s are transfused back
contraindications to cell salvage: surgery with wounds contaminated with bacteria, amniotic fluid, malignant cells or patients with sepsis, chemical contaminations.
usually always in cards cases (but dont do it alot)
acute normovolemic hemodilution
remove blood from patient (after induction)
replace blood volume lost with crystalloid or colloid
after surgical blood loss has slowed or stopped, patients blood transfused back to patient
not often done (makes sense)
platelets how are they obtained uses usual volume how much does 1U increase plt count single donor name six pack of platelets outcome 2 risks and how often they happen
one unit obtained by centrifuging single unit
uses include thrombocytopenia, dysfunctional platelets, active bleeding, platelet count less than 50k
volume usually 200-400cc
one unit increases plt count 7,000-10,000 one hour after transfusion
incidence of platelet related sepsis 1 in 12k
bacterial contamination risk 1:2k
aphaeresis means single donor
30-60k raise in 60kg pt from on “six pack of platelets”
FFP what it contains usual volume must be \_\_\_\_ compativle uses each unit increases clotting factor level by: each unit increases coags by: contraindication
contains clotting factors and plasma proteins (no platelets)
volume 200-250cc
must be ABO compatible
used for urgent reversal of warfarin, known coagulation factor deficiencies, correction of microvascular bleeding in the presence of increased PT or PTT, correction of microvascular bleeding in the patient transfused with more than one blood volume when PT and PTT cannot be obtained in a timely fashion
each unit increases each clotting factor level by 2-3%
FFP is contraindicated for augmentation of plasma volume or albumin concentration
increase coags by 20-30%
cryopecipitate derived from contains: uses compatibility administration considerations
derived from precipitate remaining after FFP is thawed
contains: factor VIII (hemophilia A), fibrinogen, vWF, XIII
used in treatment of von wildebrands disease, fibrinogen deficiencies (ex massive transfusions)
ABO compatile
administer through a filter rapidly (200ml/h) and complete within 6 hours
