Ch 6 Pinsky Hemodynamic Monitoring

Question 1

What is the purposes of hemodynamic monitoring?

Answer 1

To characterize the cardiovascular state of the individual, identify cardiovascular insufficiency and its most probable causes, and monitor response to targeted therapies aimed at restoring cardiovascular sufficiency.

Question 2

T or F: The basic tenet of resuscitation is to provide adequate oxygen (02) delivery (DO2) to meet metabolic demand and reverse any existing tissue hypoperfusion.

Answer 2

True

Question 3

T or F: In general, noninvasive continuous monitoring, if available and accurate, is preferred to invasive intermittent monitoring.

Answer 3

True

Question 4

What are the principal hemodynamic monitoring biomarkers?

Answer 4

Arterial pressure, central venous pressure, pulmonary artery pressure and its occlusion pressure, estimates of cardiac output (CO), and the various ways of assessing oxygenation.

Question 5

What is required for hemodynamic monitoring?

Answer 5

An open tubing system without obstruction at the tip (often due to blood clots), elimination of air bubbles in the tubing that dampen the signal, and hydrostatic zeroing to the isosbestic point (5 cm below the manubrium sterni) in order to measure dynamic and mean pressure and arterial pressure-derived estimates of CO.

Question 6

What is the primary force driving blood pinto the tissues?

Answer 6

Arterial blood pressure.

Question 7

What is Systolic pressure?

Answer 7

The maximum pressure during ventricular ejection/

Question 8

What is Diastolic pressure?

Answer 8

The lowest pressure in the blood vessels between heartbeats during ventricular filling as the stored arterial blood runs off into the periphery.

Question 9

What is the difference between the systolic and diastolic pressures called?

Answer 9

Pulse pressure and is determined by left ventricular stroke volume, central arterial capacitance, and to a certain extent the rate of LV ejection.

Question 10

T or F: Systolic pressure usually decreases from central to peripheral sites whereas diastolic pressure increases slightly.

Answer 10

False. Systolic pressure usually increases from central to peripheral sites whereas diastolic pressure decreases slightly.

Question 11

What is the primary driving pressure for cerebral and peripheral organ perfusion?

Answer 11

Mean Arterial Pressure (MAP)

Question 12

Mean Arterial Pressure (MAP) is estimated how?

Answer 12

As the sum of diastolic pressure plus one-third of the pulse pressure.

Question 13

What is the most common way of measuring arterial pressure?

Answer 13

Sphygmomanometer

Question 14

What are some issues of Sphygmomanometer use?

Answer 14

It often gives slightly higher systolic pressure and lower diastolic pressure than those reported from simultaneous direct measurement using an intra-arterial catheter.

Question 15

T or F: Intra-arterial catheterization is the reference method for blood pressure measurement and should be used in all hemodynamically unstable patients in whom accurate and continuous measures of arterial pressure and required.

Answer 15

True.

Question 16

What does intra-arterial catheterization provide?

Answer 16

Instantaneous measures of MAP, arterial pulse pressure, pulse pressure variation, and CO with newer transducer technologies.

Question 17

What does hypotension do to a person’s body?

Answer 17

Decreases oxygen perfusion pressure and blood flow, stimulating a sympathetic response to increase vasomotor tone, heart rate, and contractility.

Question 18

What is a reasonable target MAP?

Answer 18

Between 90-60 mm Hg, although the optimal MAP will vary depending on the underlying cause of hemodynamic instability. When MAP decreases below 65 mm Hg in a previously nonhypertensive patient, organ perfusion becomes compromised.

Question 19

What is the target MAP for traumatic brain injury?

Answer 19

90 mm Hg

Question 20

Is it okay to use CVP for assessing intravascular volume?

Answer 20

No, CVP is not a measure of central blood volume nor can its values be used to determine whether a patient will be volume responsive.

Question 21

What do high CVP values (> 12 mm Hg) indicate?

Answer 21

A larger than normal mean systemic pressure allowing an adequate perfusion pressure gradient to sustain venous return.

Question 22

What is a noninvasive way to measure CVP?

Answer 22

Through inspection of the jugular venous pulsation.

Question 23

Where is CVP measure from?

Answer 23

The IJ or subclavian vein.

Question 24

All intrathoracic vascular pressures should be measured when?

Answer 24

At end-expiration to minimize the pressure artifact.

Question 25

How is Pulmonary artery pressure measured?

Answer 25

It is measured from the tip of a nonoccluded pulmonary artery catheter once this catheter has been floated past the pulmonic valves into the main pulmonary arteries.

Question 26

What is pulmonary artery occlusion pressure used for?

Answer 26

To assess PVR, pulmonary edema, intravascular volume status and LV preload, and LV performance.

Question 27

What happens with increased pulmonary arterial pressure?

Answer 27

Increased pulmonary arterial pressure impedes right ventricular ejection, causing RV dilation and decreased CO.

Question 28

What contributes to pulmonary hypertension?

Answer 28

An increase in pulmonary vasomotor tone, pulmonary vascular obstruction or passive increases in Ppao due to LV failure.

Question 29

What causes pulmonary edema?

Answer 29

Elevations of pulmonary capillary pressure, increased capillary or alveolar epithelial permability, or a combination of both.

Question 30

What are the primary determinates of LV performance?

Answer 30

Preload (LV end diastolic volume), afterload (LV wall stress), heart rate, and contractility.

Question 31

What are the most commonly used noninvasive techniques to measure cardiac output?

Answer 31

Echocardiography, pulsed esophageal Doppler, and continuous wave suprasternal notch ultrasound.

Question 32

How does Esophageal Doppler ultrasound work?

Answer 32

It uses an esophageal probe similar in size to a nasogastric tube to measure descending aortic flow as it parallels the esophagus. A Doppler transducer probe is inserted orally or nasally to midthoracic level and rotated until the probe senses a characteristic aortic velocity signal profile.

Question 33

How does Transcutaneous Doppler US work?

Answer 33

It uses a handheld probe placed at the suprasternal notch with the transducer aimed downward at the aortic valve. This technique is easy to learn and gives accurate measures of LV stroke volume and CO.

Question 34

What is the primary invasive measurement used to measure CO?

Answer 34

Pulmonary artery catheter.

Question 35

T or F: An increase in CO of greater than 15% after a fluid challenge has been considered the gold standard reflecting fluid responsiveness.

Answer 35

True.

Question 36

Hypoxemia is usually defined as a SPO2 less than ___.

Answer 36

90%