Hemodynamics

Test Your Hemodynamic Knowledge: Part I

Richard J. Merschen, EdS, RT(R)(CV), RCIS, Adjunct Assistant Professor, Jefferson School of Health Professions, Senior Staff Technologist, Pennsylvania Hospital Cardiac Catheterization Laboratory, Philadelphia, Pennsylvania

Richard J. Merschen, EdS, RT(R)(CV), RCIS, Adjunct Assistant Professor, Jefferson School of Health Professions, Senior Staff Technologist, Pennsylvania Hospital Cardiac Catheterization Laboratory, Philadelphia, Pennsylvania

Accurate interpretation of cardiac hemodynamics is foundational for cath lab practice. Over the past several months, the Cath Lab Digest Editorial Board has reached the consensus that reinforcing the basics of cardiac hemodynamics is apriority for all cath lab practitioners. In upcoming issues, there will be a series of initiatives, articles, and case studies presented to improve staff knowledge and reinforce cath lab fundamentals. 

Case

A 51-year-old white male presented to the cardiac cath lab with a recent, progressive history of shortness of breath, chest pain on exertion, and fatigue. The patient has a history of poorly controlled hypertension, hyperlipidemia, family history of coronary artery disease, and arthritis. Based on the patient history, a left and right heart catheterization and coronary angiography were ordered for the patient. The coronary arteries demonstrated no obstructive lesions. A left ventriculogram (LV gram) demonstrated an ejection fraction of 40%, with global hypokinesis.

More information:

  1. Weight 234 lbs
  2. Height 6’0”
  3. Hemoglobin 16.5
  4. Heart rate 110
  5. Pa Sat 52%
  6. Ao Sat 96%
  7. Creatinine 1.07
  8. Potassium 3.9
  9. Platelets 234
  10. INR 1.0
  11. Blood pressure 160/90mmHg
  12. Pulse ox 94%

Now, test yourself! Based on the hemodynamic study and the information provided, what is the most likely diagnosis for the patient? While you are considering the diagnosis, see if you can answer the 25 questions below.

Questions

1. What is the normal mean pressure range for the right atrium?

A.    2-6mmHg

B.    4-18mmHg

C.    25/5 mmHg

D.    12-16mmHg

2. What is this patient’s mean right atrial pressure?

A.    25mmHg

B.    10mmHg

C.    5mmHg

D.    100mmHg

3. What does the atrial A wave mean and which wave of the ECG does it follow?

A.    Passive filling of the ventricle. Found on the T wave.

B.    The atrial kick, found just after the P wave.

C.    The atrial kick. Found after the QRS complex.

D.    Contraction of the ventricle. Located at the ST segment.

4. What is the normal pressure for the right ventricle?

A.    12/16/14

B.    25/5

C.    75/15/15

D.    40/15

5. Which portion of the ventricular waveform represents the preload state?

A.    Systolic peak

B.    Beginning diastole

C.    End diastolic pressure

D.    The ventricular upstroke

6. What is the normal pressure for the pulmonary artery?

A.    45/10/40

B.    30/30/24

C.    25/10/15

D.    50/15/33

7. What is the patient’s pulmonary vascular resistance, in Wood units, based off of the hemodynamics and cardiac output?

A.    0.6

B.    1234 

C.    100H

D.    70

8. What is the patient’s pulmonary vascular resistance, based off of metric units?

A.    48 dynes•sec•cm−5

B.    1234 dynes-5/cm

C.    56 grays

D.    4.8 psi

9. What is a normal pulmonary capillary wedge pressure?

A.    12-16mmHg mean

B.    2-6mmHg mean

C.    10-30mmHg mean

D.    14-45mmHg

10. What is this patient’s mean pulmonary capillary wedge pressure?

A.    55mmHg

B.    10mmHg

C.    43mmHg

D.    6mmHg

11. What does the left ventricular end diastolic pressure (LVEDP) indicate?

A.    Afterload

B.    Preload

C.    Congestive heart failure

D.    The end of the systolic cycle

12. What is the Fick formula for cardiac output?

A.    Wt (kg) x 3/(Ao Sat - Pa Sat) x 1.36 x hemoglobin x 10

B.    Wt (lbs) x 3/Ao Sat x Pa Sat) x 1.36 x 10

C.    Height x weight/stroke volume x heart rate + hemoglobin

D.     Wt (kg) x body surface area/(Ao Sat + Pa Sat) x 80

13. Using the Fick equation and patient data, what is the cardiac output for this patient?

A.    3.34L/min

B.    5000mL/min

C.    5.0mL/hr

D.    6.0L/min

14. What is cardiac output?

A.    Weight in kg/heart rate x 1.36

B.    Stroke volume x heart rate

C.    Stroke volume x cardiac index

D.    Cardiac index x heart rate

15. Based on the heart rate and cardiac output, what is the patient’s stroke volume?

A.     333ml

B.     30.3ml

C.     8.5L/min

D.     200L/min

16. What is the formula for systemic vascular resistance?

A.    Mean PA pressure – mean RA pressure/cardiac output

B.    Mean Ao    pressure x mean RA pressure

C.    Mean Ao    pressure – mean RA pressure/cardiac output

D.    Mean Ao    pressure x cardiac index/5

17. What is the metric unit for vascular resistance? 

A.    dynes-5 /cm 

B.    dynes•sec•cm−5

C.    mmHg

D.    Cm2 x dynes x 5

18. Where, on the respiratory cycle, is the optimal measurement point for measuring atrial and wedge pressures?

A.    End inspiration.

B.    You need inspiration and expiration, and average them.

C.     End expiration.

D.     Either one is OK, as long as you adjust the measurement scale.

19. In which case might a thermodilution cardiac output be superior to a Fick?

A.     Low cardiac output state

B.     Tricuspid valve regurgitation

C.     Mitral valve stenosis

D.     High cardiac output state

20. In which case would a Fick cardiac output be superior to a thermodilution cardiac output?

A.    Low cardiac output state

B.    Tricuspid valve regurgitation

C.    Peripheral vascular disease

D.    A & B

E.     All of the above

21. What is the formula for calculating mean arterial pressures?

A.     3 systolic pressure + 1 diastolic/4

B.     2 systolic + 2 diastolic/4

C.     2 systolic + 1 diastolic/3

D.     2 diastolic + 1 systolic/3

22. What is the formula for calculating mixed venous saturations?

A.    3 SVC + 3 IVC/4

B.    3 IVC = 3/IVC

C.    3 SVC + Ao Sat/3

D.     3 SVC + 1 IVC/4

23. Which hemodynamic pattern aligns with primary pulmonary hypertension?

A.    Elevated right ventricle, large V wave in the right atrium.

B.    Elevated wedge pressure, normal pulmonary artery pattern.

C.    Elevated LVEDP, normal right-sided measurements.

D.    Normal wedge pressure and elevated pulmonary artery, right ventricle, and right atrial pressures.

24. Which hemodynamic pattern aligns to left heart failure?

A.    Elevated right atrial pressures

B.    Normal wedge pressure and elevated pulmonary artery, right ventricle, and right atrial pressures.

C.     Elevated A waves on the ventricular pressures.

D.     The wedge pressure, pulmonary artery pressure, right ventricular pressure, and right atrial pressure are elevated.

25. What is the most likely diagnosis for this patient, based off of the hemodynamic assessment?

A.    Left heart failure

B.     Pulmonary hypertension

C.     Mitral valve regurgitation

D.     Atrial septal defect

Click here for the Part II Answer Key and Discussion. 

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