Pilbeams Mechanical Ventilation 5th Edition By Cairo -Test Bank

Chapter 11; Hemodynamic Monitoring
Test Bank

MULTIPLE CHOICE

1. The filling pressure of the ventricle at the end of ventricular diastole is known as which of the following?
a. Preload
b. Afterload
c. Dicrotic notch
d. Ejection fraction

ANS: A
The definition of preload is the filling pressure of the ventricle at the end of ventricular diastole.

DIF: 1 REF: pg. 200

2. Which measurement is typically used to indicate right ventricular preload?
a. Right atrial pressure (RAP)
b. Pulmonary artery occlusion pressure (PAOP)
c. Right ventricular end-diastolic pressure (RVEDP)
d. Ejection fraction

ANS: C
Preload is the filling pressure of the ventricle at the end of ventricular diastole and is estimated by measuring the end-diastolic pressures. In the case of right ventricular preload the measurement would be right ventricular end-diastolic pressure.

DIF: 1 REF: pg. 200

3. Which of the following can be used to estimate the contractility of the ventricles?
a. Ejection fraction
b. Systemic vascular resistance
c. Pulmonary vascular resistance
d. Right and left ventricular end-diastolic pressure

ANS: A
The ejection fraction is a way of estimating the force that the ventricle generates during each cardiac cycle. It is calculated as the ratio of the stroke volume to the ventricular end-diastolic volume. Systemic vascular resistance is used to describe the afterload that the left ventricle must overcome to eject blood into the systemic circulation. The pulmonary vascular resistance reflects the afterload that the right ventricle must overcome to eject blood into the pulmonary circulation. The right ventricular end-diastolic pressure is used as an indicator of the right ventricular preload and the left ventricular end-diastolic pressure is used to indicate left ventricular preload.

DIF: 1 REF: pg. 200

4. Calculate the ejection fraction of a female patient with a stroke volume of 40 mL and an end-diastolic volume of 125 mL.
a. 0.32
b. 3.1
c. 85
d. 165

ANS: A
Ejection fraction is calculated using the ratio of stroke volume to the ventricular end-diastolic volume. In this case the ejection fraction is 40 mL/125 mL = 0.32.

DIF: 2 REF: pg. 200

5. Left ventricular afterload is indicated by which of the following?
a. Ejection fraction
b. Systemic vascular resistance
c. Pulmonary vascular resistance
d. Left ventricular end-diastolic pressure

ANS: B
The systemic vascular resistance is the resistance the left ventricle must contract against to eject blood into the systemic circulation. Ejection fraction is a measurement of contractility. Pulmonary vascular resistance is the resistance the fight ventricle must contract against to eject blood into the pulmonary circulation. Left ventricle end-diastolic pressure (LVEDP) is used to estimate left ventricular preload.

DIF: 1 REF: pg. 200

6. The most determining factor for preload is which of the following?
a. Contractility
b. Venous return
c. Ejection fraction
d. Vascular resistance

ANS: B
Preload, the filling pressure of the ventricle at the end of ventricular diastole is dependent on the level of venous return and in addition the compliance of the ventricles. Contractility is the force that the ventricle generates during each cardiac cycle and is estimated using the ejection fraction. Vascular resistance is a measurement used to determine the afterload of a ventricle, or the force the heart needs to overcome to eject the blood from the ventricles.

DIF: 1 REF: pg. 200

7. An increase in systemic vascular resistance will cause which of the following to occur?
a. Decrease left ventricular preload
b. Increase right ventricular preload
c. Increase left ventricular afterload
d. Decrease right ventricular afterload

ANS: C
Afterload is increased when aortic pressure and systemic vascular resistance are increased, by aortic valve stenosis, and by ventricular dilation. When afterload increases, there is an increase in end-systolic volume and a decrease in stroke volume. Afterload does not immediately alter preload; however, preload changes secondarily to changes in afterload. Increasing afterload reduces stroke volume and increases left ventricular end-diastolic pressure (LVEDP) (i.e., increases preload). This occurs because the increase in end-systolic volume is added to the venous return into the ventricle and this increases end-diastolic volume. This increase in preload activates the Frank-Starling mechanism to partially compensate for the reduction in stroke volume caused by the increase in afterload.

DIF: 2 REF: pg. 200

8. The main component of a hemodynamic monitoring system is which of the following?
a. Plethysmograph
b. Pneumotachometer
c. Sphygmomanometer
d. Strain gauge transducer

ANS: D
Hemodynamic monitoring systems consist of equipment that detects small physiological signal (vascular pressure) changes and converts them to electrical impulses, which can then be amplified and recorded on a cathode ray tube (CRT) monitor or strip chart recorder. A strain gauge transducer is utilized to measure vascular pressure.

DIF: 1 REF: pg. 202

9. The function of the transducer in the invasive vascular monitoring system is to do which of the following?
a. Measure the flow of fluid in the catheter.
b. Convert the fluid pressure to an electrical signal.
c. Connect to the thermistor to measure cardiac output.
d. Amplify the electrical signal so it may be seen on the monitor.

ANS: B
The transducer has two main compartments. One, called the dome, contains the fluid that enters it from a plastic line connected to the indwelling catheter. The dome is separated from the electrical portion of the transducer by a flexible diaphragm. Changes in fluid pressure results in movement of the diaphragm, which causes an increase or decrease in the length of the wires of the Wheatstone bridge contained in the electrical portion of the transducer. The transducer is therefore able to detect small physiological signal changes and convert it to an electrical impulse or signal.

DIF: 1 REF: pg. 202

10. Which of the following is true concerning the insertion of a radial arterial line?
1. The catheter tip must face upstream.
2. The catheter tip must face downstream.
3. The transducer must be higher than the catheter tip.
4. The transducer must be level with the catheter tip.
a. 1 and 3 only
b. 1 and 4 only
c. 2 and 3 only
d. 2 and 4 only

ANS: B
When a catheter faces the source of blood flow it is “looking” upstream. An arterial line placed in the radial artery needs to face the blood flow to accurately measure pressures that are a result of left heart work. If the catheter faces downstream it reads the pressures ahead of it. To accurately measure pressure, the transducer needs to be at the same height or level with the tip of the catheter. If the transducer is higher than the catheter tip the fluid will be flowing away from the transducer and will produce a reading lower than the actual pressure.

DIF: 1 REF: pg. 205