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Hemodynamics Flashcards

1
Q

What is the formula for Fick CO?

A

CO = O2 consumption (mL/min) / VO2 difference (mL/100mL blood) x10

  • O2 consumption estimated using 3 mL O2/kg or 125 mL/min/m2
  • VO2 difference = difference (0.95 - 0.65) x 1.36 x Hgb x 10

**** Larger difference between A and V O2 content –> lower CO

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2
Q

What is the formula for cardiac index (CI)?

A

CI = CO (L/min) / BSA (m2)

  • normal = 2.5 - 4 L/min/m2
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3
Q

When is Fick (CO) most accurate?

A
  • low output states (valvular heart disease)
    • TR
    • multivalvular heart disease
  • steady state
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4
Q

What is the problem with Fick (CO)?

A

estimate of O2 consumption

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5
Q

What PA sat correlates with low CO (on Fick)?

A

< 65%

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6
Q

What are quick estimates of Fick (CO) utilizing PA sats?

A
  • PA sat 70-80% –> Normal CO
  • PA sat < 65% –> Low CO
  • PA sat > 80% –> High CO (or L-R shunt)
    • AV graft for HD
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7
Q

When is TD (CO) more accurate?

Least accurate?

A
  • Most accurate –> High Output States
  • Inaccurate –> TR or AF
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8
Q

What is the formula for PVR (pulmonary vascular resistance, Woods units)?

A

PVR = mPAP - mPCWP / CO

**Normal range = 80-130 dynes

***Woods units x 80 = dynes

**** TPR = mPAP / CO

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9
Q

What is the formula for SVR (systemic vascular resistance)?

What is normal range?

A

SVR = mean systemic arterial pressure - mRAP x 80 / CO

  • Normal range = 700-1600 dynes-sec/cm5
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10
Q

Describe the finding

A

Severe TR

  • monophasic “CV” wave
    • CV wave lifted completely off the baseline
    • monophasic event in systole, occurring within the RA
  • ventricularization of RA waveform
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11
Q

What constitutes a pathologic or abnormal “v” wave in PCWP tracings?

What are causes?

A
  • “v” wave more than 10 mmHg than PCWP
  • PCWP “v” waves
    • MR
    • VSD
    • Noncompliant LA
      • previous A-fib ablation procedures
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12
Q

Describe the findings

A

Pericardial Tamponade

  • Rapid x only
  • Blunted ‘y’ descent (no early diastolic RV filling)
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13
Q

Describe the findings

A

Pericardial constriction

  • Rapid x and y descents
    • y = early rapid diastolic RV filling
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14
Q

Describe when step-up O2 saturations are significant?

What does this imply?

A

Intra or Extra cardiac shunt may be present

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17
Q

Describe the findings

A
  • a = atrial systole
  • x = atrial relaxation, decrease of pressure
  • c = closure of the TV
  • v = ventricular systole, atrial diastole
  • y = passive filling of the RV
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21
Q

Describe the findings

A

HOCM - Brockenbrough sign

  • PVC –> ventricular contraction will be more forceful, and the pressure generated in the LV will be higher
    • reduction in pulse pressure in a post-PVC beat
      *
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22
Q

How can you differentiate AS and HOCM on intracardiac pressure tracings?

A

Post-PVC

  • Pulse Pressure
    • HOCM –> decrease
    • AS –> increase

Valsalva

  • Gradient
    • ​HOCM –> increase
    • AS –> decrease
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23
Q

Describe the findings

A

AS

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24
Q

Describe the findings

A

HOCM: L heart pullback

25
Q

Describe the findings

A

Provocable Gradient: Valsalva Maneuver

26
Q

Describe locations for mixed venous O2 sats in shunt calculations:

  • No L-R shunt
  • L-R shunt present
  • ASD
  • No R-L shunt
A
  • No L-R shunt
    • Mixed venous = PA sat
  • L-R shunt present
    • Mixed venous = O2 sat in chamber proximal to shunt
  • ASD
    • Mixed venous = Caval O2 sat = (3 x SVC) + (1 x IVC) / 4
  • No R-L shunt
    • Mixed venous = PV O2 sat = FA O2 sat
27
Q

What is a normal BP response to exercise?

A

25-70 mmHg

28
Q

Describe the findings

29
Q

Describe the findings

A

AR

  • Corrigan’s pulse
  • absence of dicrotic notch
31
What is the Gorlin formula?
Area (cm2) = value flow (mL/s) / K x C x √MVG * K = constant = 44.3 * C = empiric constant * AV, TV, PV = 1 * MV = 0.85 \*\*\*MV flow = CO / DFP x HR \*\*\*AV flow = CO / SEP x HR
32
What is the simplified Gorlin or Hakki formula? When does this formula differ?
AVA = CO / √MG * differs by 18% +/- 13% from real formula * Bradycardia * Tachycardia * Low flow states --\> overestimate severity of AS * CO \< 2.5 L / min --\> constants should be used
33
When is the Gorlin formula inaccurate?
* Regurgitation (concomitant) * moderate or more AI * Low output states * Tachy/Brady cardia \*\*\*Assumes steady state and fixed orifice
39
What are factors that can increase the gradient in HOCM?
* increased contractility * decreased preload * volume depletion * decreased afterload
40
What are factors that can decrease the gradient in HOCM?
* decreased contractility * increased preload * increased afterload * phenylephrine
41
What is a normal LVOT VTI?
18-22 cm * important to avoid PISA / flow convergence --\> leads to overestimation
42
Calculate MVA?
MVA = 220 / PHT * PHT = deceleration time x 0.29 * PHT = the time required for the velocity to drop to 1/2 the peak pressure
43
What is the grading severity of mitral stenosis?
44
What is the diagnosis? * 65 year old man * severe exertional dyspnea
**severe AS** * delayed aortic pressure uprise * PVC with compensatory pause --\> increase in aortic pulse pressure
45
Describe the findings and key to differentiation
**Pulse pressure change on post-PVC beat** * Severe AS * increase in PP --\> increased filling and more flow across the valve * HOCM ("Brockenbrough-Braumwald" sign) * decrease in aortic pulse pressure * increased intracellular calcium --\> contractility * aortic pressure runoff --\> decreased afterload --\> worsening obstruction
46
Describe the findings
Post-PVC aortic pulse pressure tracings * severe AS * HOCM
47
Describe the findings
**Severe AR**
48
Describe the findings
**Acute severe AR** * diastolic equalization of pressures between LV and aorta
49
Describe the findings
**Severe AR** * early closure of the Mitral valve * well before onset of systole * elevated LVEDP
50
Describe the findings and diagnosis
* Mitral inflow * Inspiration --\> decrease in mitral inflow velocity * Expiration --\> increase in mitral inflow velocity
51
Describe the findings and diagnosis
**Effusive constrictive pericarditis** * Pericardial tamponade --\> * pericardiocentesis --\> * Constrictive pericarditis
52
Describe the findings and diagnosis
Mitral annular velocity --\> important measure for differentiation
53
Describe the findings, diagnosis, treatment
Constrictive pericarditis --\> Pericardiectomy * Diastolic equalization of pressures * Diastolic pressures elevated * Ventricular discordance * Enhanced ventricular interaction
54
What are key hemodynamic criteria to differentiate RCM and CP?
* LVEDP - RVEDP * Constriction * Restriction \> 5 * RVSP * Constriction \< 50 * Restriction \> 50 * RVEDP/RVSP * Constriction \> 0.3 * Restriction \< 0.3
55
Describe the findings, diagnosis, treatment
Severe MS --\> PMBV --\> **Pericardial tamponade** * **Pericardiocentesis**
56
Calculate the Qp/Qs * High SVC 67% * IVC 75% * RA 87% * RV 88% * PA 89% * PCWP 99% * CO 5 L/min * Hgb 12 g/dl
Qp/Qs = 3.0
57

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