Formulas Flashcards
Cardiac Output
Stroke volume x Heart rate
(SV x HR = CO)
CaO2
Arterial O2 Content
(Hb x 1.36 x SaO2) + (PaO2 x 0.003)
DO2
Oxygen Delivery
(CO x CaO2)
O2ER
Oxygen Extraction Ratio
(VO2/DO2)
Canine shock bolus
90mL/kg (total blood volume)
Feline shock bolus
70mL/kg (total blood volume)
Isotonic fluid challenge formula
3-5mL/kg over 5 mins
Synthetic colloid bolus and total shock dose
2-5mL/kg over 30 min (total shock dose 10-20mL/kg in dogs and 5-10mL/kg in cats)
Hypertonic Bolus
3-5mL/kg of 7-7.5% NaCl over 10-20min
pRBC or FFP typical dose
10-20mL/kg over 2-4hrs
Fresh Whole Blood
20-30mL/kg over 2-4hrs
Plasma Osmolality
2(Na + K) + [(BUN/2.8) + (glucose/18)]
Normal = 290-310
Effective Osmolality
2(Na+) + (glucose/18)
Arterial BP
HR x SV
MAP
(SBP + 2DBP)/3
Pulse pressure
SBP-DBP
Shock Index
HR/SBP
BP
SVR x CO
Laplace’s Law
Wall stress = (pressure x radius)/(wall thickness)
Minute ventilation
TV x RR
Insensible losses (normal)
20mL/kg/d
A-a gradient
PAO2 = (FiO2 x (Patmos -PH20)) - (PaCO2/Rq)
Fraction of inspired O2- 0.21 in rm air
Atmospheric pressure- 760mmHg
Partial pressure of water- 47mmHg at sea level
Respiratory quotient- 0.8
Volume to be transfused (pRBC)
[BW(kg) x (90 in dog or 70 in cat)] x [(desired PCV - pt PCV) / (donor PCV)]
OR
Desired PCV % increase x 1.5 x BW (kg)
RER
2-45kg: [BW(kg) x 30] + 70
<2kg or >45kg: [BW(kg) x 70]^0.75
RER for water
1mL = 1kCal of RER
Corrected Na
(PtNa+) + [(Pt BG - 100 (normal BG))/100) x 1.6]
**if glucose >400 x 2.4 instead
Losses
Sensible: urination 20mL/kg/d, defecation 10mL/kg/d
Insensible (skin/resp): 20mL/kg/d
Normal = 50mL/kg/d
Fluid deficit
10mL/kg per every 1% dehydration
OR
% dehydration x BW (kg) x 1000 x 0.8
(1kg H2O = 1000mL)
Free water deficit
[(current Na) / (normal Na) -1] x [0.6 x BW(kg)]
Maintenance fluids
Dog: (kg)^0.75 x 132
Cat: (kg)^0.75 x 80
Na deficit calculation
(target Na - pt Na) x (0.6 x lean BW(kg))
