Hemodynamic monitors & equipment 3 Flashcards

1
Q

When does pulmonary artery occlusion pressure overestimate left ventricular end-diastolic volume? (Select 2)
a. PA catheter tip in West zone 3
b. PEEP
c. Diastolic dysfunction
d. aortic insufficiency

A

b. PEEP
c. diastolic dysfunction

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2
Q

Conditions where PAOP overestimates LVEDP include

A

mitral valve disease
COPD
pulmonary hypertension
PEEP
non West zone 3 placement of PAC
impaired LV compliance (ischemia)
left-to-right cardiac shut
tachycardia
PPV

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3
Q

_________ causes PAOP to underestimate LVEDV

A

Aortic insufficiency

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4
Q

Which situation underestimates cardiac output obtained by the thermodilution method?
a. over warmed injectate
b. right-to-left intracardiac shunt
c. high injectate volume
d. partially wedged pulmonary artery catheter

A

c. high injectate volume

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5
Q

_________ is the most common method of measuring cardiac output.

A

The thermodilution method

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6
Q

Cardiac output is underestimated when

A

the injectate volume is too high or the injectate solution is too cold

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7
Q

Cardiac output is overestimated when

A

the injection volume is too low, the injectate is too hot, the PAC is partially wedged, or there’s a thrombus on the tip of the PAC

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8
Q

Advantages of continuous cardiac output monitoring includes

A

providing continuous data & avoiding inaccuracies from the human element

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9
Q

The major drawback of continuous cardiac output monitoring includes

A

slower response time & the data is typically averaged over time

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10
Q

An injection of _______________________ is bolused through _____________- for the thermodilution method

A

5% dextrose or 0.9% NaCl of known quantity & temperature is bolused through the proximal port on the PAC

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11
Q

Each injection should occur during

A

the same phase of the respiratory cycle and be completed in <4 seconds

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12
Q

If CO is high, the injectate

A

rapidly travels towards the distal tip of the PAC

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13
Q

The area under the curve will be _______________, if CO is higher.

A

smaller

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14
Q

These conditions can make it difficult to predict the accuracy of CO:

A

intracardiac shunt
tricuspid regurgitation

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15
Q

When would it be preferential to measure CO using the standard thermodilution technique over continuous cardiac output?

A

in a hemodynamically unstable patient (due to a delay time between measurement and the data appearing on the monitor)

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16
Q

Factors that increase mixed venous oxygen saturation include: (select 2)
a. thyroid storm
b. sodium nitroprusside toxicity
c. anemia
d. sepsis

A

b. sodium nitroprusside toxicity
d. sepsis

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17
Q

SvO2 is a function of four variables:

A

cardiac output
arterial oxygen saturation
amount of hemoglobin
oxygen consumption

18
Q

When Hgb, SaO2, and VO2 are held constant, then SvO2 becomes an indirect monitor of

A

cardiac output

19
Q

Factors that decrease SvO2 can be split into two categories:

A

increased O2 consumption
decreased O2 delivery

20
Q

Examples of increased O2 consumption include

A

stress, pain, thyroid storm, shivering, fever

21
Q

Examples of decreased O2 delivery include

A

Decreased SaO2, Hgb, or CO

22
Q

Factors that increase SvO2 can be split into two categories:

A

decreased O2 consumption
increased O2 delivery

23
Q

Examples of decreased O2 consumption include

A

hypothermia
cyanide toxicity

24
Q

Examples of increased O2 delivery include

A

O2 therapy
increased Hgb
increased CO

25
Q

Normal SvO2 is

A

65-75%

26
Q

The equation for SvO2 is

A

SaO2 - (VO2)/(CO x 1.34 x Hgb x 10)

27
Q

Why do you need a PA catheter to measure SvO2?

A

a true mixed venous sample must contain blood returning from the superior vena cava, inferior vena cava, and the coronary sinus & the PA artery is the best place to get the sample

28
Q

Preload responsiveness is expected to be present if a 250 mL fluid bolus increases the stroke volume in excess of:

A

10%

29
Q

____________ analysis provides a measure of preload responsiveness

A

Pulse contour analysis

30
Q

Methods of pulse contour analysis include

A

plethysmogroapthy variability index (requires pulse ox)
stroke volume variation (requires esophageal doppler)
systolic pressure variation (requires direct arterial pressure)
pulse pressure variation (requires arterial pressure)

31
Q

To ensure accuracy of pulse contour analysis, the patient must be receiving

A

positive pressure ventilation

32
Q

As a general rule, preload responsiveness can be assumed when a 200-250 mL fluid bolus improves SV more than

A

10%

33
Q

Factors that reduce the accuracy of pulse contour analysis include

A

spontaneous ventilation
open chest
RV dysfunction
dysrhythmias
small tidal volume
PEEP

34
Q

A _____________- patient will have a greater degree of stroke volume variation through the respiratory cycle as a function of __________________________

A

hypovolemic; intrathoracic pressure’s effect on RV filling & function

35
Q

Which conditions limit the reliability of the esophageal Doppler monitor? Select 2
a. hypovolemia
b. aortic stenosis
c. aortic cross-clamp placement
d. esophageal disease

A

b. aortic stenosis
c. aortic cross-clamp placement

36
Q

What can the esophageal doppler measure?

A

stroke volume
stroke index
stroke volume variation
stroke distance
peak velocity
flow time

37
Q

The esophageal Doppler can help you determine if you should treat with

A

fluid
vasopressors
or inotropes

38
Q

Where should the esophageal Doppler be positioned?

A

~35 cm from the incisors (T5-6)

39
Q

The position of the probe is based on

A

the sound and waveform quality

40
Q

The esophageal Doppler should not be used if the patient has

A

esophageal disease

41
Q

Factors that reduce the reliability of the esophageal doppler data include

A

aortic valve disease
aortic cross-clamping
disease of the thoracic aorta
pregnancy
after CPB