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CVPR 360 ECMO > Ch 7 VV ECMO & VA ECMO > Flashcards

Ch 7 VV ECMO & VA ECMO Flashcards

1
Q

VV ECMO does not decrease what ?

A

RV Preload
Pulmonary blood flow
LA return
LV output

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2
Q

VA ECMO decreases the following ?

VA ECMO increases the following ?

A

RV Preload
Pulmonary blood flow

LV Afterload

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3
Q

A change in left ventricular afterload seen in VA ECMO may lead to what syndrome ?

A

Left ventricular stun

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4
Q

Occasionally some patients on VV ECMO may develop what syndrome ?
What do these patients develop ?

A

Right ventricular stun

Severe PPHTN
RV Dilation > Bowing of the ventricular septum into the LV = Reduced filling & compromised C.O.

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5
Q

How can you reverse right ventricular stun without the need to convert to VA ECMO?

A

Careful management of:

  • Preload
  • Afterload
  • Myocardial contractility
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6
Q

In VV ECMO, high O2 saturated blood is being delivered to the RA. This high mixed venous saturation in the pulmonary arteries may do what?

A
  • Decrease PVR

- Decrease RV afterload

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7
Q

What can a pulsitile flow achieve ?

A
  • Decreases SVR
  • Decreases afterload
  • Improves organ perfusion
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8
Q

Blood interpretation is different in VV ECMO do to what?

A
  • Recirculation
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9
Q

VA ECMO is described as ?

A

Partial Bypass

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10
Q

During VA ECMO, the effect of pump flow can have dramatic effect on what ?

A
  • BP
  • C.O
  • Heart function in general
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11
Q

The effect of VA ECMO is reflected on what ?

A
  • Pulse contour

- Pulse pressure

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12
Q

During total bypass, why would you see an occasional pulsatile beat ?

A

LV gradually distends due to thebesian and venous return.

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13
Q

Typically on VA ECMO we can achieve what % of normal resting cardiac output?

A

60 - 80%

this allows for 20% to pass though the lungs and left heart

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14
Q

Pulsatile or non-pulsatile perfusion does not differ as long as what ?

A

adequate blood flow of:
> 100 mL/Kg/min &
Adequate mean pressure exists.

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15
Q

In regards to pulsatility, the kidney is more sensitive to what?
How can we overcome the effects ?

A

Non-pulsitile flow

Diuretics

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16
Q

on VA ECMO, forward flow results from what ?

A

ECMO pump contribution + LV C.O.

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17
Q

A reduction in preload leads to what?

A
  • Inadequate forward flow

- Hypotension

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18
Q

What hemodynamic data is used to reflect LV preload ?

A
  • LA Pressure

- PCWP

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19
Q

What hemodynamic data is used to reflect RV preload ?

A
  • CVP
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20
Q

Why is the CVP during ECMO not an accurate indicator of intravascular volume status?

A

due to the continuous draining of blood from the RA. A low CVP could be inaccurately interpreted as decreased intravascular volume or decreased RV preload.

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21
Q

The unloading of the LA results in what ?

A
  • Decreased filling of the LV, or
  • Decreased LV preload
  • Decreased preload = Decreases native cardiac output
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22
Q

During VA ECMO, blood is returned to the aortic arch, and is directed towards the aortic valve. What may this lead to ?

A
  • Increase afterload on the LV
  • LV has difficulty ejecting effectively
  • Results in over distention of the LV
  • C.O is compromised
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23
Q

In the presence of adequate preload and adequate forward flow ( C.O + pump output ), what could the probable cause of a hypotensive patient?

How can we manage this patient ?

A
  • Drop in SVR
  • Increase ECMO flow rate
  • Increase preload in the system (intravascular volume)
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24
Q

How can we achieve higher MAPs ?

A
  • Increase LV afterload

- Increase SVR

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25
Q

What hemodynamic data is a direct measurement of afterload ?

A

MAP

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26
Q

Drugs that increase afterload include inotropes such as ?

A
  • Dopamine

- Vasoconstrictors such as: Epinephrine & Norepinephrine

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27
Q

RV afterload is usually elevated on VA ECMO due to what ?

A
  • Lung collapse
  • Pulmonary arterial constriction
    = Increases PVR
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28
Q

RV afterload is usually elevated on VA ECMO, this would obviously lead to what?

How can we manage this ?

A
  • Decrease RV output
  • Decrease cardiac output
    = Decreased MAPs

Decrease afterload by vasodilation, thus improving C.O and MAPs.

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29
Q

4 Drugs that decrease afterload ?

A
  • Dobutamine
  • Nitroprusside
  • Milrinone
  • Priscoline
30
Q

Pressure =

A

Flow X Resistance

31
Q

C.O =

A

HR X Stroke Volume

32
Q

In infants and neonates, how is cardiac output increased given the developmental constraints on increases in stroke volume ?

A

Increasing the HR

33
Q

What is the key to managing a patient on VA ECMO?

A
  • Maintaining a normal mean BP
  • Balancing Preload & Afterload
  • Adequate contractility
34
Q

If the left side of the heart becomes over-distended, what can occur?

Usually not a problem with neonates on VA ECMO due to a PDA, but it is a huge problem with the older population.

A
  • Cardiac Damage

- Pulmonary edema

35
Q

LV Stun should be suspected in the absence of the following ?

How can it be diagnosed ?

What is the wrong thing to do ?

A
  • Hypovolemia
  • Pneumothorax
  • Pneumopericardium
  • Hemothorax
  • Hemopericardium

Echo that shows little LV wall motion.

Increase pump flow to improve oxygen delivery.

36
Q

During VA ECMO, what effects do we cause ?

Inpatients with cardiac stun, these effects can cause what?

A
  • Decrease in ventricular preload
  • Increase in LV afterload
  • Increase in myocardial oxygen consumption
  • LV to dilate
  • Mitral Valve to become insufficient
  • Increased risk of pulmonary hemorrhage.
37
Q

LV stun often resolves over a 48 hr period. Failure to see improvements after 4-5 days of ECMO, it is a clear sign and suggests what ?

At this point, what is crucial in preventing irreversible damage to the LV and the lungs ?

A
  • Myocarditis
  • Myocardial Infarction
  • Surgical decompression of the overdistended LV via a balloon septostomy or an LA or LV vent to the ECMO circuit.
38
Q

VV ECMO does not decrease what, since the volume of blood drained is equal the volume returned?

A
  • RV preload
  • Pulmonary blood flow
  • LA return
  • LV output
39
Q

Who are the neonates that develop RV stun ?

A

Neonates that have severe pulmonary hypertension before initiation of ECMO.

40
Q

Is a PaO2 or Oxygen saturation reliable indicators of sufficient tissue oxygenation during VA-ECMO ?

A

NO

41
Q

In VA ECMO, how is oxygen sufficiency evaluated?

A

MVO2 and content returning to the right heart.

42
Q

Mixed venous specimen taken from the PA is know as what ?

A

“True end organ perfusion” or “What is left over”

43
Q

Normal PA saturations ?
PA saturations in this range indicate the tissues and organs are receiving and utilizing enough oxygen to maintain normal state of health.

A

65 - 75%

44
Q

PA saturations

A

O2 demads are not being satisfied

45
Q

Where can we draw a specimen that is the closest to mixed venous saturations ?

A

Pre-membrane saturations are monitored on VA ECMO, not the patients arterial saturations or PaO2s to evaluate adequate oxygen delivery.

46
Q

It should be noted that oxygentation is significantly effected by the patients lungs on low ventilator settings while on ECMO. As the patients lungs contribute progressively more to oxygentaion, venous saturation will continue to increase.
A PA saturation > 85% would be suggestive of what?

A

lungs are healing, we can cut down on ECMO flows till we reach 65-75%

47
Q

How can oxygenation be optimized during VV ECMO ?

A
  • [Hgb] ~ 15 grams/dL
  • Recirculation fraction is low
  • Venous catheter is large enough to achieve 120-140 mL/Kg/min pump flow
48
Q

What are the 4 factors that can be used to monitor oxygen saturation during VV ECMO ?

A
  • Arterial O2 saturation
  • Pre-Oxygenator PO2 or saturation
  • Central venous O2 saturation
  • Calculated VO2 across the oxygenator
49
Q

What is a good reflection of oxygen sufficiency during VV ECMO ?

A
  • Arterial oxygen saturation via blood gas or pulse ox.

-

50
Q

During VA ECMO the pre-oxygenator saturation is used as what?

A

MVO2

51
Q

An increase in the pre-oxygenator saturation can occur in what settings?

A
  • Improving patients

- Deteriorating patients (due to recirculation)

52
Q

How would we measure oxygenation during DL VV ECMO ?

A

Cephalad drain in the jugular venous bulb

53
Q

What is a 4th method to monitor oxygentation during VV ECMO ?

A

Calculate oxygen uptake across the oxygenator

54
Q

How would recirculation present itself during a clinical setting?

A
  • Decreasing patient arterial saturations
  • Increasing pre-membrane saturations
  • Decreasing AVDO2
  • Color of blood draining from the RA = Color of blood returning from the pump.
55
Q

Recirculation formula ?

A

S preOx - SvO2
_________________
S postOx - SvO2

56
Q

Saturation postOx will always be ?

A

100%

57
Q

What is considered typical recirculation for VV ECMO?

A

30%

58
Q

What are the 4 factors that can effect recirculation?

A
  • Pump flow
  • Catheter Position
  • C.O.
  • RA size or (intravascular volume)
59
Q

Effective Flow formula =

A

Total flow - (Total flow X Recirculation fraction)

60
Q

Ideal pump flow provides what?

A
  • Highest effective flow at lowest RPMs

- While yielding the best O2 delivery

61
Q

As pump flow increases ?

A
  • Effective flow first increases
  • Stabilizes
  • Then decreases
62
Q

The use of a cephalad venous catheter has been shown to ?
Blood draining from this catheter is more desaturated than the blood in the RA. This catheter was originally employed to achieve what?

A
  • Decrease recirculation
  • Increase the amount of oxygen that can be added to the blood
  • Decompress the cerebral venous circulation.
63
Q

What total of ECMO flow can be obtained from a well placed cephala cannula?

A

1/3 - 1/2

64
Q

From a practical standpoint, compare the color of blood draining from the cephalad to the color of blood draining from the RA.
If the colors are similar? =
If the colors are very different? =

A

If the colors are similar? = Recirculation is low

If the colors are very different? = (Cephalad dark or blue & RA is bright or red) Recirculation is high

65
Q

How can we manage a patient in SVT or VT ?

A
  • Adenosine

- Cardioversion

66
Q

3 limiting factors for VV ECMO ?

A
  • Inadequate size of the jugular vein
  • Excessively prominent 1st rib
  • Mediastinal shift due to congenital diaphragmatic hernia
67
Q

In neonates, it is assumed that the site of cannulation for ECMO will be ?

A

Neck

68
Q

What are the most common vessels used in neonates for VA ECMO ?

A

Internal jugular vein
Common Carotid

In larger patients, femoral veins & arteries may be used.

69
Q

What are the most common vessels used in neonates for VV ECMO ?

A

Internal jugular vein (DL catheter), ascending internal jugular, cephalad vein.

70
Q

Ideally, the tip of the DL catheter should be placed in ?

Placement of the catheter too high in the RA will result in what?

A

Lower 1/3 of the RA

Arterialization (increased redness) of the venous drainage from recirculation effect.

71
Q

What should our blood prime for ECMO consist of ?

A
  • Fresh blood,
72
Q

Addition of what other drugs will make our prime more physiologic to initiate ECMO?

A 
40 mL  25% Albumin 
25 mL THAM
10 mEq NaHCO3
100 u/Heparin 
300 mg Calcium Gluconate

Circulate

Add an additional
300 mg Calcium Gluconate

CVPR 360 ECMO (13 decks)

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