Misc Equations Flashcards
Transudate
TP= <2.5
Modified Transudate
TP= 2.5-5.0
Exudate
TP= > 5.0
Shock Index
HR/Systolic BP
>0.9: moderate to severe shock
O2 Extraction Ratio
VO2/DO2
Arterial Oxygen Content
CaO2=
(Hb X 1.3 X SaO2) + (PaO2 X 0.003)
Albumin Deficit
10( desired Alb- Pt Alb) X Wt X 0.3
Vertebral Heart Size
Short Axis + Long Axis
Dog: <10.7
Cat: <8.0
Laplac’s Law
Wall Stress= (Pressure X Radius)/ 2(Wall Thickness)
Starling’s Forces
Describes fluid movement between blood and tissues. Movement is determined by difference in hydrostatic and osmotic pressures between plasma inside micro vessels and fluid outside of the them (interstitial).
A-a Gradient
FiO2 (Atmospheric Pressure-47) - (PaCO2/0.8)-PaO2
Venous Admixture (shunt) Calculation
Qs/Qt= (CcO2 - CaO2)/ (CcO2 - CvO2)
CcO2= capillary O2 content
CvO2=central venous oxygen saturation
Alveolar Ventilation
VA= (VT-VD) X RR
= Tidal Volume-
Anatomical Dead Space
X RR
Compliance
change in volume for the amount of pressure applied
C= 🔺V/🔺P
Osmolality
2(Na) + (Gluc/18) + (BUN/2.8)
Use when concerned for HHS/hyperosmolar condition
Normal= 300ish
Effective Osmolality
2(Na) + (Gluc/18)
BUN not effective osmole
Corrected Na
1.6 ( Measured BG- Normal BG/100) + Measured Na
Used in hyperglycemia
Hyperglycemia can cause pseudohyponatremia
Corrected Chloride
(Normal Na/Measured Na) X Measured Cl
Used in hypernatremia
Free Water Deficit
[(Measured Na/Normal Na) -1] X TBW
Na Deficit
(Target Na- Patient Na) X TBW
Strong Ion Difference
[Strong Cations] - [Strong Anions]
(Na + Mg + K + Ca) - (Cl + Lactate + Urate)
Simplified –> (Na) - (Cl)
Strong Ion Gap
Dog: (alb X 4.9) - Anion Gap
Cat: (alb X 7.4) - Anion Gap
Sodium Bicarbonate Supplementation
Base Excess X kg X 0.3
Total Body Water
(0.6)(Kg)
Base Deficit Calculation
Normal HCO3- Measured HCO3
Anion Gap
(Na + K) - (HCO3+ Cl)
Generally should be less than 20
High AG = Metabolic Acidosis
DKA
Uremia
Ethylene Glycol
Lactic Acidosis
(aspirin, ethanol and propylene glycol too)
Corrected Ca
0.8(Normal Alb- Pt Alb) + Measured Ca
Lactate Effect
Measured Lax X -1
Albumin effect
(Normal Alb- Measured Alb) X 4
Albumin Deficit
10 (Target Alb- Pt Alb) X kg X 0.3
Phosphate Effect
(Normal Phos- Measured Phos)/2
Rehydration Volume
kg X % Dehyd (decimal) X 1000
Coronary Perfusion Pressure
Diastolic Pressure - Pulm Capillary Wedge Pressure
Pulse Pressure
Systolic - Diastolic
Cardiac Output
SV X HR
Stroke Volume Index
Stroke Volume/ Body Surface Area
Fick’s Equation
CO= VO2/ (CaO2-CvO2)
Normal CVP
0-5 cm H2O
MAP
DP + (SP-DP/3)
Systemic Vascular ResistancE
(MAP- Right Atrium Pressure)/Cardiac Index
Cardiac Index
CO/Body Surface Area
Shock Index
HR/Systolic
Oxygen Delivery Equation
CaO2 X CO
O2 Extraction Ratio
VO2/DO2
Cerebral Perfusion Pressure
MAP-ICP
PaO2/FiO2
PaO2 should be 5X FiO2
Normal: >400
Severe Hypoxemia/Defect: <300
ARDS: <200
A-a Gradient
FiO2( Patm-47)-(PaCO2/0.8) - PaO2
Normal: 0-10, below 25
ARDS: 31 or greater
Arterial Oxygen Content
CaO2= (1.34 X Hb X SaO2) +
(PaO2 X 0.003)
Bicarbonate Supplementation
(HCO3 Goal- Measured HCO3) X 0.3 X kg
HCO3 Goal- Measured»_space; Base Excess
