Equations Flashcards
Oxygen content
CaO2= (Hgb x SaO2 x 1.34) + (PaO2 x 0.003)
= 20mL/dL
Oxygen delivery
DO2 = CO x [(Hgb x SaO2 x 1.34) + (PaO2 x 0.003)] x 10
= 1,000 mL
Oxygen consumption
VO2 = CO x (CaO2 - CvO2) x 10
= 250mL/min or 3.5mL/kg/min
Static compliance
= tidal volume / (PP - PEEP)
Dynamic compliance
= tidal volume / (PIP - PEEP)
Alveolar gas equation
PAO2 = FiO2 x (Patm - Pvapor) - PaCO2/RQ
A-a gradient
= PAO2 - PaO2
= 5-15 mmHg
Ejection Fraction
= (EDV - ESV)/ EDV
MAP
= 1/3 SBP + 2/3 DBP
SVR
= [(MAP - CVP)/ CO] x 80
= 800-1500 dynes/sec/cm-5
PVR
= [(PAP - PAOP)/ CO] x 80
= 150-250 dynes/sec/cm-5
Coronary perfusion pressure
= AoDBP - LVEDP (or PaOP)
= 60-140 mmHg
Max allowable blood loss
= EBV x (starting hct - target hct)/ starting hct
Cerebral perfusion pressure
= MAP - ICP (or CVP)
= 50-150 mmHg
Anion gap
= [Na] - ([Cl] + [HCO3])
= 8-12 mEq/L
Gap = accumulation of acid
Non-gap= loss of bicarb or ECF dilution
Plasma osmolarity=
2Na + 0.055glucose + 0.36BUN
= 280-290 mOsm/L
Uncuffed ETT peds
= (age/4) + 4
Cuffed ETT peds
(Age/4) + 3.5
O2 remaining in cylinder
Step 1: (Tank capacity L/full tank pressure psi) = (contents remaining L/gauge pressure psi)
Step 2: contents remaining / flow rate L/min = min left
FiO2
= [(O2 flow rate x 100) + (air flow rate x 21)] / total flow rate
Parkland formula
4mL LR x % TBSA burned x kg
• 1/2 in first 8 hrs
• 1/2 in next 16 hrs
Modified Brooke formula
2 mL LR x % TBSA burned x kg
• 1/2 first 8 hrs
• 1/2 next 16 hrs
Celsius to Fahrenheit
F= (C x 1.8) + 32
Fahrenheit to Celsius
C = (F - 32) x 5/9
