Equations Flashcards
Free water deficit
Free water deficit = (current Na/normal Na – 1) x 0.6 x BW
Sodium deficit
Sodium Deficit = (target Na – patient Na) x 0.6 x BW
Sodium Bicarb Dose
0.3 x BW x base excess (give 50-80% of dose)
Anion Gap
(Na + K) – (HCO3 + Cl)
Acid-base: Free water effects
Dog: 0.25 (Na – 145)
Cat: 0.22 (Na – 155)
Acid base: chloride effects
Dogs: 110- [Cl x (145/Na)]
Cats: 120- [Cl x (155/Na)]
Acid base: TP
Dogs: 3 x (6.5 - TP)
Cats: 3 x (7 - TP)
Acid base: Albumin
3.7 x (3.1 - Alb)
Acid-base: PO4
0.58 x (4.3 - PO4)
Plasma Volume
Plasma volume = (1 – HCT) x BW x blood volume
Pseudohyponatremia correction (3 formulas)
Corrected Na = measured Na + 0.016 x (BG – 100)
For every 100 mg/dL glucose Na decreases by 1.6 mEq/L
Corrected Na = measured Na + 1.6 [(BG-100)/100]
Free water clearance (Diabetes insipidus)
CFW = Vu x (1 – (Nau + Ku / Nap)
Cerebral perfusion pressure
CPP = MAP – ICP
Sensitivity
true positive / (true positive + false negative)
Specificity
true negative / (true negative + false positive)
Parkland Formula
4 mL x TBSA (%) x BW
(IVF for burn tx - give 1/2 within first 8 hrs; give rest over next 16 hours)
Whole Blood administration (3)
2 x PCV rise desired (%) x BW
2 mL WB/kg raises PCV by 1%
~20 mL/kg
pRBC administration
= 1.5 x PCV rise desired (%) x BW
= [(desired PCV – actual PCV)/donor unit PCV] x blood volume x BW
Pulse Pressure Variation
Pulse pressure variation = 100 X (PPmax- PPmin)/{(PPmax+PPmin)/2}
Fractional shortening
(LVIDd – LVIDs)/LVIDd
Ejection Fraction
(EDV-ESV) (Х) 100/EDV
Fick Equation
(VO2) = CO [CaO2 – CvO2]
Pulmonary vascular resistance
= [(Mean PAP – PAOP)/CI]
Cardiac index (CI)
CO/BSA
Plasma Osmolality
2(Na + K) + (gluc/18) + (BUN/2.8)
Albumin deficit
10 x (desired albumin-pt albumin) x weight (kg) x 0.3
