Formulas Flashcards
How do you convert Celsius to Fahrenheit?
F = (C x 1.8) + 32
How do you convert Fahrenheit to Celsius?
Celsius = (F - 32) / 1.8
What is the formula for arterial oxygen content and the normal values?
Formula: CaO2 (mL/dL) = (Hb [g/dL] x 1.36 x SaO2 + (PaO2 [mmHg] x 0.003)
Values: 19-21mL/dL
CaO2 = (Hb x 1.36 x SaO2) + (PaO2 x 0.003)
What is the formula for cardiac output?
Formula: HR (beats/min) x SV (mL/beat)
CO = HR x SV
What is the formula for cardiac index?
Formula: CI (mL/kg/min) = CO (mL/min) / BW (kg)
Values: 100-200mL/kg/min (dog)
200mL/kg/min (cat)
What is the formula for oxygen delivery index?
Formula: DO2 (mL/kg/min) = Cl (mL/kg/min) x CaO2/100
Values: 20-35mL/kg/min
What is the formula for stroke volume and normal values?
Formula: SV (mL/beat/min) = CI (mL/kg/min) / HR
Values: 1.5-2.5 mL/beat/kg)
What is the formula for mean arterial blood pressure and normal values?
Formula: MAP (mmHg) = ([systolic - diastolic / 3) + diastolic
Values: 80-120 mmHg (dog)
100-150 mmHg (cat)
OR: diastolic x2 + systolic / 3
What is the formula for calculated plasma osmolality?
2 (Na + K) + BUN / 2.8 + Glu / 18
What is the formula for effective plasma osmolality?
2 (Na + K) + Glu / 18
What is the formula for blood pressure?
BP = SVR x CO
The delivery of oxygen to tissue is the product of cardiac output and arterial oxygen content and is expressed by what formula?
DO2 = CO x CaO2
What is the formula for correcting dehydration?
% dehydrated x body weight (kg) x 1000 = mL to replace
What are the two formulas for maintenance fluids?
For patients between 2-40kg
(Body weight [kg] x 30) + 70 = mL/day
For patients >40kg or <2kg
(Body weight [kg] to the 0.75 power) x 70 = mL/day
What is the formula for the big A in PAO2?
PAO2 = (Pb - PH2O) x FiO2 - PaCO2 / R
Pb is barometric pressure = 760
PH20 is pressure of water = 47
R is respiratory quotient = 0.8
This is the calculated alveolar oxygen pressure vs PaO2 which is measured arterial blood oxygen pressure.
What is the equation for A-a gradient?
A-a gradient = PAO2 - PaO2
This is done on ROOM AIR
What is the equation for P/F ratio?
P/F ratio = PaO2 / FiO2
This is done ON OXYGEN support via arterial
blood gas.
What is the Henderson-Hasselbalch equation?
pH = 6.1 + log (HCO3 - / PCO2 x 0.03)
6.1 is the logarithmic dissociation constant (pKa) of carbonic acid.
0.03 is the solubility constant of CO2 in plasma which converts PCO2 to CO2.
pH measures the tendency of carbonic acid to break down into bicarbonate and H+
What is the equation for anion gap (AG)?
(Na + K) - (HCO3 + Cl)
N: 12-24 mEq/L
*albumin is highest source of negative ions
*to better define a metabolic acidosis
*DUEL
What does DUEL stand for?
DKA
Uremia
Ethylene glycol
Lactic acidosis
Formula for patient albumin deficit
10 x (serum albumin goal) - current albumin x kg x 0.3 = patient albumin deficit
Free water deficit formula
([Current Na+ / 140] - 1) x 0.6 x kg
What is the carbonic acid equation?
Outlines the relationship of all elements of the buffering system as it operates in the body:
CO2 + H2O <-> H2CO3 <-> HCO3- + H+
Corrected chloride formula
[Normal Na+ / Measured Px Na+] x measured Px Cl-
Sodium bicarbonate formula
mEq of bicarb needed = 0.3 x kg x base excess
Formula for compliance (pertaining to lungs)
Compliance (C) = change in volume divided by amount of pressure applied
Alveolar ventilation formula
VA = (VT - VD) x RR
Alveolar ventilation = (tidal volume - anatomical dead space) x respiratory rate
