Formula's Flashcards

1
Q

Dalton’s law

A

Ptotal = P1 + P2

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2
Q

Boyle’s law

A

P1V1 = P2V2

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3
Q

Henry’s law

A

Concentration = P (soluble)

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4
Q

Fick’s law of diffusion

A

Vgas = Area/Thickness * diffusion constant * (P1 - P2)

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5
Q

Diffusion constant

A

D = soluble/molecular weight

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6
Q

Starling-Landis equation

A

Jv = Lp * A * [(Pmv - Pint) - sigma(d) (pi(p) - pi(int))]

Jv = microvascular filtration rate
Lp = hydraulic conductivity (measure water permeability)
A = surface area
P mv = hydrostatic pressure microvessels
P int = hydrostatic pressure interstitium
sigma (d) = osmotic reflection coefficient
pi (p) = colloid osmotic pressure plasma
pi (int) = colloid osmotic pressure interstitium

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7
Q

Ohm’s law

A

Ql = (Pint + Ppump - Psv)/Rl

Ql = lymph flow
Pint = hydrostatic pressure interstitium
P pump = effective driving pressure generated by cyclic intrinsic contraction and extrinsic compression of lymphatic vessels
Psv = systemic venous pressure
Rl = resistance to lymph flow

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8
Q

Oxygen delivery index (DO2) (2)

A

1) CO * CaO2

CO = cardiac output
CaO2 = arterial oxygen content

2) CI (ml/kg/min) * CaO2/100

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9
Q

Arterial oxygen content (CaO2)

A

CaO2 = [1.34 * SaO2 * Hb] + [PaO2 * 0,003]

SaO2 = saturation
Hb = hemoglobin (g/dL)

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10
Q

P (A) O2 (alveolar oxygen pressure) - shortened

A

P (A) O2 = 150 - PaCO2

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11
Q

Oxygenation index (OI)

A

OI = MAP * FiO2 * 100/PaO2

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12
Q

Oxygen saturation index (OSI)

A

OSI = MAP * FiO2 * 100/SpO2

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13
Q

P (A) O2 (alveolar oxygen pressure) - full version

A

P (A) O2 = (Pbar - Ph2o) * FiO2 - (PaCO2/RQ)

Pbar = atmospheric pressure
Ph2o = partial pressure of water
RQ = respiratory quotient (0.8)

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14
Q

Venous admixture expressed as percent of cardiac output (Qs/Qt)

A

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

Qs = shunt fraction
Qt = cardiac output
CcO2 = oxygen content of end-capillary blood
CaO2 = oxygen content of arterial blood
CvO2 = oxygen content of mixed venous blood

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15
Q

Minute ventilation (Ve)

A

Ve = Vt * RR

Vt = Tidal volume
RR = respiratory rate

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16
Q

Tidal volume (Vt)

A

Vt = Vd + Va

Vd = dead space ventilation
Va = alveolar ventilation

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17
Q

Alveolar ventilation (Va)

A

Va = Ve - Vd

Ve = minute ventilation
Vd = dead space ventilation

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18
Q

Bohr’s equation (4)

A

1) Vt * Fe = Va * Fa

Vt = tidal volume
Fe = CO2 in exhaled gas
Va = alveolar volume
Fa = CO2 in alveolus

2) Vd/Vt = (Fa - Fe)/Fa

Vd = dead volume

3) Vd/Vt = (P(A)CO2 - PeCO2)/P(A)CO2

P(A)CO2 = partial pressure of CO2 in alveolus
PeCO2 = Partial pressure of CO2 in expired air

4) Vd/Vt = (PaCO2 - PeCO2)/PaCo2
PaCO2 = arterial partial pressure of CO2

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19
Q

Alveolar ventilation equation

A

P (A) CO2 = directly proportional to ( vCO2 /V(A)) * k

vCO2 = amount of CO2 produced by metabolism
V(A) = alveolar ventilation
k = 0,863

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20
Q

Pressure gradient between RA and RV in systole

A

pressure gradient = 4 velocity [m/s]2

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21
Q

Flow rate in high flow

A

Flow rate = Patient’s minute volume = respiratory rate * tidal volume

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22
Q

Equation of Motion

A

Pvent + Pmuscles = Elastance * volume + resistance * flow

Pvent = pressure generated by ventilator
Pmuscles = pressure generated by inspiratory muscles

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23
Q

Serum osmolality

A

Osmolality = 2 [Na] + (BUN/2.8) + (glucose/18)

BUN in mg/dL
Glucose in mg/dL

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24
Q

Free water deficit

A

Free water deficit (L) = (current [Na]/ normal [Na] - 1) * 0.6 * body weight

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25
Q

Sodium deficit

A

Sodium deficit = (target [Na] - patient [Na]) * 0.6 * body weight

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26
Q

Henderson-Hasselbalch equation

A

pH = 6.1 + log [HCO3] / (0,03 * pCO2)

6.1 is the pKa in body fluids
0.03 is the solubility coefficient for carbon dioxide in
plasma

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27
Q

Anion gap

A

Anion gap = [Na] + [K] - ([HCO3] + [Cl])

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28
Q

Strong ion difference

A

Strong ion difference = (sodium + potassium) - (chloride)

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29
Q

Albumin effect in SID approach

A

(measured albumin * 10 * [(0.123 * pH) -
0.631])

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30
Q

Phosphorus effect in SID approach

A

(measured phosphorus * 0.323 * [0.309 *
pH - 0.469])

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31
Q

Total weak acid concentration (Atot)

A

Atot = albumin effect + phosphorus effect

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32
Q

Strong ion gap

A

[SID - (bicarbonate + Atot)]

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33
Q

Simplified SIG dogs

A

SIG simplified = [albumin] * 4.9 – AG

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34
Q

Simplified SIG cats

A

SIG simplified = [albumin] * 7.4 - AG

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35
Q

AG phosphorus adjusted

A

AG + (2.52 – 5.58 * measured phosphorus)

36
Q

Free water effect dogs

A

0.25([Na] - mid-normal [Na])

37
Q

Free water effect cats

A

0.22([Na] - mid-normal [Na])

38
Q

Corrected chloride

A

measured [Cl] * (mid-normal [Na]/
measured [Na])

39
Q

Chloride effect

A

mid-normal [Cl] - corrected [Cl]

40
Q

Phosphorus effect in semiquantitative approach

A

0.58 * (mid-normal [phosphorus] - measured
[phosphorus])

41
Q

Albumin effect in semiquantitative approach

A

3.7 * (mid-normal [albumin] - measured
[albumin])

42
Q

Lactate effect

A

-1 * [lactate]

43
Q

Sum of effects in semiquantitative approach

A

free water effect + chloride effect + phosphorus effect + albumin effect + lactate
effect

44
Q

Unmeasured ion effect

A

base excess - sum of effects

45
Q

Fractional excretion of sodium (FeNa)

A

FeNa = 100 * (Urine [Na] * Plasma [Creatinine] / Plasma [Na] * Urine [Creatinine])

46
Q

Transtubular potassium gradient

A

(Urine [K] * Plasma osmolality) / (Urine osmolality
* Plasma [K])

47
Q

Urinary free water clearance

A

urine volume * (1 - (Urine [Na] + Urine [K]) / Serum [Na])

48
Q

CVC collapsibility

A

CVC CI = CVCd max – CVCd min / CVCd max

49
Q

RER

A

70*(BW^0,75 ) /24 h

50
Q

Dehydratation deficit

A

body wt (kg) * % dehydration (as decimal) * 1000 (ml/L)

51
Q

Effective osmolality

A

[Na] + [glucose (mg/dl) / 18]

52
Q

Corrected sodium

A

Na(meas) + 1.6 ([measured glucose – 100] / 100)

53
Q

amended insulin/glucose ratio
(AIGR)

A

(insulin 100) / (plasma glucose - 30)

54
Q

Urinary clearance of free water (Cfw)

A

Vu * (1 – [([Na]u + [K]u) / [Na]p ])

Vu = urinary volume

55
Q

Monroe-Kelly doctrine

A

Vintracranial = V brain + V CSF + V blood + V mass/lesion

56
Q

Dog plasma volume

A

(1 – hematocrit) * (body weight [kg] * 85 ml/kg)

HCT in decimals

57
Q

Cat plasma volume

A

(1 – hematocrit) * (body weight [kg] * 55 ml/kg)

HCT in decimals

58
Q

mean arterial blood pressure

A

diastolic + (systolic - diastolic) / 3 + diastolic BP

59
Q

Pulse pressure variation (PPV)

A

PPV (%) = 100 * (PPmax - PPmin) / [(PPmax + PPmin) / 2]

60
Q

Systemic vascular resistance

A

1) SVR = (MAP - CVP) / CO
2) SVR (mmHg/ml/kg/min) = (MAP - CVP) / CI (ml/kg/min)
3) SVR (dynes * sec/cm^5 ) = ([MAP - CVP] * 79.9) / CI (L/min/m^2)

61
Q

Cardiac output (Fick method)

A

CO = VO2 / (CaO2 - CvO2)

62
Q

Functional SO2

A

[(HbO2)/(HbO2 + HHb)] * 100

63
Q

Fractional SO2

A

[(HbO2)/(HbO2 + HHb + COHb+1 MetHb)] * 100

64
Q

Colloid osmotic pressure

A

COP = 2.1P + 0.16P^2 + 0.009P ^3

P = Plasma protein

65
Q

Abdominal perfusion pressure

A

mean arterial pressure (MAP) - intraabdominal pressure (IAP)

66
Q

Filtration gradient

A

glomerular filtration pressure - proximal tubule
pressure = MAP - 2*IAP

67
Q

Urine volume on POCUS

A

Vurine (ml) = (L * W * (dl + DT)/2) * 0.52

L = length of the bladder (longitudinal)
W = width of the bladder (transverse)
dl = depth of the bladder (longitudinal)
DT = depth of the bladder (transverse)

68
Q

cardiac index (CI) (2)

A

1) CI (ml/kg/min) = CO (ml/min) / BW (kg)

2) CI (L/m^2/min) = CO (L/min) / body surface area (m^2)

69
Q

Oxygen consumption index (from Fick equation)

A

VO2 (ml/kg/min) = CI (ml/kg/min) * (CaO2- CmvO2 ) / 100

70
Q

Oxygen extraction ratio

A

OER (%) = (CaO2 - CmvO2) / CaO2

71
Q

Pulmonary vascular resistance (2)

A

1) PVR (mmHg/ml/kg/min) = (PAP - PAOP) / CI (ml/kg/min)

2) PVR (dynes*sec/cm^5) = ([PAP - PAOP] * 79.9) / CI (L/min/m^2)

PAP = pulmonary artery pressure
PAOP = pulmonary artery occlusion pressure

72
Q

Stroke volume (SV) (2)

A

1) SV (ml/beat/kg) = CI (ml/kg/min) / HR

2) SV (ml/beat/m^2) = CI (ml/min/m^2) / HR

73
Q

Fractional shortening

A

FS = [LVIDd - LVIDs] / LVIDd * 100

74
Q

Ejection fraction

A

EF = (LVVd - LVVs) / LVVd * 100

75
Q

Static compliance

A

C stat = VT / (Pplat - PEEP)

76
Q

Dynamic compliance

A

C dyn = VT / (PIP - PEEP)

77
Q

Inspired resistance

A

RI = (PIP - Pplat) / VT

78
Q

Transpulmonary pressure

A

TPP = Palv - Ppl

79
Q

Driving pressure

A

deltaP = Pplat - PEEP

80
Q

Osmole gap

A

measured osmolality - calculated osmolality

81
Q

Total body water

A

0 6 * BW (kg)

82
Q

Laplace law

A

P = 2t / r

t = wall thickness
r = radius

83
Q

Modified Bernoulli equation

A

deltaP = 4*V^2

84
Q

Poiseuille’s law

A

Resistance = (8 n * l) / (2pi*r^4)

n = viscosity
l = lenght
r = radius

85
Q

Reynolds number

A

Re = (D* rho* V) / n

D = diameter
rho = density
n = viscosity

86
Q

Wall stress

A

sigma = liniary correlated to (P * R) / 2t

sigma = wall stress
P = pressure
R = resistance
t = thickness