Exam 1 FINAL: fluids + renal Flashcards
IBW
50 + 2.3*inches over 60”
45.5 for female
Nutrition body weight
IBW + 0.25(wt-IBW)
hypotonic
-fluid moves into cell
-ECF more concentrated than ICF
-<275
Isotonic
275-290
Total osmolarity
osmolarity of IV solution + osmolarity of added electrolytes
-multiply electrolytes by mEq but do NOT multiply for more than 1L of solution
maintenance fluid requirement
30-40mL/kg/DAY
-divide by 24 for hourly rate
-use actual BW unless over 130% of IBW, then use IBW
Types of fluids
-crystalloids
-colloids
Crystalloid fluids
-any tonicity
-NS, D5W, LR, salt solutions
-provide water/sodium
Normal saline use
-RESUSITATION
Lactated ringers use
-resuscitation
-replace blood loss
-slay use this one over NS
1/2 NS use
-maintenance fluids
D5W
-free water replacement
-NOT resuscitative
-NOT MIVF by itself
Balanced salt solutions
-closer to physiologic levels
-LRs
-Normosol-R
-Plasma-lyte
NS composition
-154mEq of Na and Cl
-0 free water
1/2NS composition
-77mEq Na and Cl
-500mL free water
Colloid Solutions use
-inc plasma oncotic pressure
-inc molecular weight = longer halflife
-volume expansion
-hemorrhagic shock
-hypovolemic shock
Albumin
-colloid solution
-shock/burns
-blood product
-supportive/sx tx unless hypoproteinemia
Synthetic colloids
-heta and tetrastarch
-no good, dont use
pack RBCs use
-acute blood loss
-poor resuscitation from fluids alone
-low hemoglobin (1 unit RBCs inc by 1g/dL)
most common MIVF
-D5W + 1/2NS + 20mEq/L KCl
-inc plama pressure
signs of dehydration
-dry skin and membranes
-delayed capillary refill
-tachycardia and hypotension
-weak pulse
-dec urine output
-BUN/SCr > 20
Sodium normal levels
135-145
Serum Osmolality Calculation
(2*Na) + (BUN/2.8) + (glucose/18)
-high osmolality indicates smth else in blood
-Na is top left value on fishbone, BUN top right, glucose tail
Pseudohyponatremia
-isotonic
-elevated lipids and proteins in plasma
-sodium appears low but still there
-measured serum osmolality not affected
Corrected Serum Sodium
-serum Na + 1.6([BG-100)/100]
Hypotonic hyponatremia
-most cases of hyponatremia
-hypovolemic if TBW and Na are dec
-isovolemic: TBW up Na normal
-HYPERvolemic: TBW and Na up
-mostly asx (Na>125)
HYPOvolemic HYPOtonic HYPOnatremia
-TBW and Na down
-renal causes or from blood/GI loss
-dehydration
ISOvolemic HYPOtonic HYPOnatremia
-TBW up and Na normal or up
-caused by adrenal, hypothyroid, SIADH
-psychosis, seizures, coma
SIADH
-inappropriate ADH release
-most common cause of ISOvolemic HYPOtonic HYPOnatremia
-caused by antipsychotics, carbamazepine, SSRIs, NSAIDs
-tx: remove drugs. free water restriction, vaptans prn
HYPERvolemic HYPOtonic HYPOnatremia
-TBW and Na up
-edema
-seen in cirrhosis, HF
Acute hyponatremia sx
-nausea
-weakness
-HA
-coma
-seizures
-respiratory arrest
Hyponatremia tx goal
-avoid rise in Na > 0.5 mEq/L/h or no more than 8-12 mEq/L/day
HYPOvolemic hyponatremia tx
-3% NS (hypertonic) for sx
-NS (isotonic) for asx
Isovolemic hyponatremia tx
-furosemide and 3% NS for sx
-NS for asx and water restriction
Hypervolemic hyponatremia tx
-furosemide and judicious 3% NS for sx
-furosemide for asx
Chronic hyponatremia
->48 hours
-minimal brain swelling
-mild neurologic sx
-brain herniation/death rarer than acute
Acute sx hyponatremia
-cerebral edema
-neurologic probs (seixures)
-brain herniation and death
Acute sx hyponatremia tx
-inc serum Na by 1-2mEQ/L/hr until sx resolve
-serum Na goal = 120
-DO NOT CORRECT TO QUICKLY
-total inc of 4-6 is usually good
-max inc of 8-12 in first 24 hours
Demyelination risk
-overcorrecting of Na too quickly
Na defecit calculation
TBW = 0.6(wt) (0.5 in females)
defecit= TBW * (goalNa - currentNa)
-goal 122?
Na replacement
-half amount calculated by defecit over first 8 hours
-then half the initial rate
-example: 330mEq defecit
-20.6mEq/h * 8hr, then 10.3 over 16 hr
20.6mEq/h*1000mL/154mEq = 124mL/hr 8h, then 67mL/hr16h of NS
Hypernatremia
-always HYPERtonic
-HYPOvolemic: dec TBW and Na
-ISO: dec TBW and Na
-HYPER: inc TBW and Na
HYPOvolemic HYPERnatremia tx
-restore volume first w NS
-replace free water deficit
Free H2O deficit calc
NL TBW * [(Na/140)-1]