Misc Equations

Question 1

Transudate

Answer 1

TP= <2.5

Question 2

Modified Transudate

Answer 2

TP= 2.5-5.0

Question 3

Exudate

Answer 3

TP= > 5.0

Question 4

Shock Index

Answer 4

HR/Systolic BP
>0.9: moderate to severe shock

Question 5

O2 Extraction Ratio

Answer 5

VO2/DO2

Question 6

Arterial Oxygen Content

Answer 6

CaO2=
(Hb X 1.3 X SaO2) + (PaO2 X 0.003)

Question 7

Albumin Deficit

Answer 7

10( desired Alb- Pt Alb) X Wt X 0.3

Question 8

Vertebral Heart Size

Answer 8

Short Axis + Long Axis
Dog: <10.7
Cat: <8.0

Question 9

Laplac’s Law

Answer 9

Wall Stress= (Pressure X Radius)/ 2(Wall Thickness)

Question 10

Starling’s Forces

Answer 10

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).

Question 11

A-a Gradient

Answer 11

FiO2 (Atmospheric Pressure-47) - (PaCO2/0.8)-PaO2

Question 12

Venous Admixture (shunt) Calculation

Answer 12

Qs/Qt= (CcO2 - CaO2)/ (CcO2 - CvO2)

CcO2= capillary O2 content
CvO2=central venous oxygen saturation

Question 13

Alveolar Ventilation

Answer 13

VA= (VT-VD) X RR

= Tidal Volume-
Anatomical Dead Space
X RR

Question 14

Compliance

Answer 14

change in volume for the amount of pressure applied

C= 🔺V/🔺P

Question 15

Osmolality

Answer 15

2(Na) + (Gluc/18) + (BUN/2.8)

Use when concerned for HHS/hyperosmolar condition

Normal= 300ish

Question 16

Effective Osmolality

Answer 16

2(Na) + (Gluc/18)

BUN not effective osmole

Question 17

Corrected Na

Answer 17

1.6 ( Measured BG- Normal BG/100) + Measured Na

Used in hyperglycemia
Hyperglycemia can cause pseudohyponatremia

Question 18

Corrected Chloride

Answer 18

(Normal Na/Measured Na) X Measured Cl

Used in hypernatremia

Question 19

Free Water Deficit

Answer 19

[(Measured Na/Normal Na) -1] X TBW

Question 20

Na Deficit

Answer 20

(Target Na- Patient Na) X TBW

Question 21

Strong Ion Difference

Answer 21

[Strong Cations] - [Strong Anions]

(Na + Mg + K + Ca) - (Cl + Lactate + Urate)

Simplified –> (Na) - (Cl)

Question 22

Strong Ion Gap

Answer 22

Dog: (alb X 4.9) - Anion Gap
Cat: (alb X 7.4) - Anion Gap

Question 23

Sodium Bicarbonate Supplementation

Answer 23

Base Excess X kg X 0.3

Question 24

Total Body Water

Answer 24

(0.6)(Kg)

Question 25

Base Deficit Calculation

Answer 25

Normal HCO3- Measured HCO3

Question 26

Anion Gap

Answer 26

(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)

Question 27

Corrected Ca

Answer 27

0.8(Normal Alb- Pt Alb) + Measured Ca

Question 28

Lactate Effect

Answer 28

Measured Lax X -1

Question 29

Albumin effect

Answer 29

(Normal Alb- Measured Alb) X 4

Question 30

Albumin Deficit

Answer 30

10 (Target Alb- Pt Alb) X kg X 0.3

Question 31

Phosphate Effect

Answer 31

(Normal Phos- Measured Phos)/2

Question 32

Rehydration Volume

Answer 32

kg X % Dehyd (decimal) X 1000

Question 33

Coronary Perfusion Pressure

Answer 33

Diastolic Pressure - Pulm Capillary Wedge Pressure

Question 34

Pulse Pressure

Answer 34

Systolic - Diastolic

Question 35

Cardiac Output

Answer 35

SV X HR

Question 36

Stroke Volume Index

Answer 36

Stroke Volume/ Body Surface Area

Question 37

Fick's Equation

Answer 37

CO= VO2/ (CaO2-CvO2)

Question 38

Normal CVP

Answer 38

0-5 cm H2O

Question 39

MAP

Answer 39

DP + (SP-DP/3)

Question 40

Systemic Vascular ResistancE

Answer 40

(MAP- Right Atrium Pressure)/Cardiac Index

Question 41

Cardiac Index

Answer 41

CO/Body Surface Area

Question 42

Shock Index

Answer 42

HR/Systolic

Question 43

Oxygen Delivery Equation

Answer 43

CaO2 X CO

Question 44

O2 Extraction Ratio

Answer 44

VO2/DO2

Question 45

Cerebral Perfusion Pressure

Answer 45

MAP-ICP

Question 46

PaO2/FiO2

Answer 46

PaO2 should be 5X FiO2 Normal: >400 Severe Hypoxemia/Defect: <300 ARDS: <200

Question 47

A-a Gradient

Answer 47

FiO2( Patm-47)-(PaCO2/0.8) - PaO2 Normal: 0-10, below 25 ARDS: 31 or greater

Question 48

Arterial Oxygen Content

Answer 48

CaO2= (1.34 X Hb X SaO2) + (PaO2 X 0.003)

Question 49

Bicarbonate Supplementation

Answer 49

(HCO3 Goal- Measured HCO3) X 0.3 X kg HCO3 Goal- Measured >> Base Excess