It is your first night as a resident in the cardiothoracic intensive care unit.

Question

It is your first night as a resident in the cardiothoracic intensive care unit. A patient with severe biventricular systolic failure has just come out of the operating room, where both a left ventricular assist device (LVAD) and right ventricular assist device (RVAD) were implanted in their heart. When the attending physician comes in the morning you get berated, as it appears the patient has developed pulmonary edema overnight while you weren’t paying attention. Which of the following factors could have caused this?

I More output from the LVAD than the RVAD

II More output from the RVAD than the LVAD

III Aortic valve insufficiency (“leakiness”) with LVAD output=RVAD output

IV Pulmonary valve insufficiency (“leakiness”) with LVAD output=RVAD output

a. I and II

b.III and IV

c.I and IV

d. II

e. II and III

f. I, II, III, IV

My reasoning so far: Because pulmonary edema results from left ventricular failure, a buildup of blood in the left ventricle would result and therefore, RVAD output would be greater than LVAD output. However, I am unsure as to whether aortic valve insufficiency would have any effect on pulmonary edema.

WHEN ANSWERING PLEASE PROVIDE YOUR REASONING AS WELL!

Explanation / Answer

Pulmonary oedema happens when your left hear is unable to pump out adequate blood into system. So there is rise in left ventricle ----> incresed pressure in left atrium ------------> capillary bed in lung trnsudate into lung alveoli----->pulmonary oedema happens.

So the main cause congestive heart failure.

I : if LVAD is acting more there is no chance of pulmonary oedema, as left ventricular function is normal in this case.

II : If RVAD acts more than LVAD then there is circulation mismatch. Right heart acting more compared to left heart, so there will be rise in pressure pulmonay capillary bed causing pulmonary oedema. So you are right RVAD output need to be more to cause pulmonary oedema.

III : Aortic valve insufficiency (LVAD = RVAD) will cause regurgitation of blood into left ventricle from systemic circulation. It will cause increase in the pressure in left ventricle -----> increased pressure in left atrium eventually ------------> pulmonary oedema. This is a sudden cause of pulmonary oedema.

IV: Pulmonary valve insufficiency means there is regurgitation of blood from pulmonary vuscular bed to right ventricle, so there is reduced pressure in capillary bed of lung---> so no pulmonary oedema. This option can cause right heart failure and therby left heart failure, but that is only possible in chronic case not in overnight condition.

So you see, condition II and III can cause pulmonary oedema.

So answer is : e.) II and III

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