Question 1

Which of the following can be used to estimate the contractility of the ventricles?

Accepted Answer

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.

Question 2

While attempting to draw blood from an indwelling arterial catheter,the respiratory therapist notices a dampened waveform and has difficulty withdrawing blood for sampling.What should the respiratory therapist's immediate action be?

Accepted Answer

The presence of both a persistently dampened waveform and difficulty withdrawing blood indicate that there is a clot.To avoid any adverse effects the catheter should be removed.Flushing the catheter could cause the blood clot to move into the patient's circulation and has the potential to cause an infarction in the brain,heart or lungs.Repositioning the catheter will not remove the clot.Recalibrating the transducer will not remove the clot.

Question 3

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.

Accepted Answer

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.

Question 4

The measurement that can be used to estimate right ventricular preload is which of the following?

Accepted Answer

Central venous pressure (CVP)is used to estimate the right ventricular preload.Pulmonary artery occlusion pressure (PAOP)reflects the preload of the left ventricle.The pulmonary artery pressure is generated by the right ventricle ejecting blood into the pulmonary circulation,which acts as a resistance to the output from the right ventricle.The pulmonary artery pressure (PAP)is a measurement of right ventricular afterload.Cardiac output is the amount of blood that the heart pumps out each minute.

Question 5

The main component of a hemodynamic monitoring system is which of the following?

Accepted Answer

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.

Question 6

Absolute confirmation of placement of a central venous pressure catheter is done with which of the following?

Accepted Answer

A chest x-ray is used most often to confirm the placement of the central venous pressure (CVP)catheter.Checking the centimeter mark may be deceiving because the catheter may be curling up inside a vessel.Ensuring the waveform is not always accurate because other values may be low enough to appear to be a CVP measurement.Due to arterial blood gas acid-base changes and oxygenation problems,the blood sample drawn may appear to be mixed venous,when in fact it is not.

Question 7

An increase in systemic vascular resistance will cause which of the following to occur?

Accepted Answer

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.

Question 8

The most determining factor for preload is which of the following?

Accepted Answer

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.

Question 9

During the insertion of a pulmonary artery catheter,the balloon needs to be inflated with air when it enters which of the following?

Accepted Answer

The balloon must be inflated as soon as it enters the intrathoracic vessel so that the catheter may be flow-directed by the balloon through the blood into the right atrium,right ventricle and into the pulmonary artery.The inflation of the balloon also protects the heart from endocardial and pulmonary artery damage and ventricular arrhythmias.

Question 10

The filling pressure of the ventricle at the end of ventricular diastole is known as which of the following?

Accepted Answer

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

Question 11

During the introduction of a pulmonary artery catheter the waveform seen in the figure is visible on the monitor.This waveform represents which of the following locations?

Accepted Answer

This figure shows a pressure range of 2 - 6 mm Hg which is consistent with the right atrium.It also shows the characteristic respiratory fluctuations.The systolic pressure for the right ventricle is as high as 25 mm Hg,which is not seen in the figure.The systolic and diastolic ranges for pulmonary artery pressure are 15 to 35 mm Hg and 5 to 15 mm Hg respectively.This is higher than what is shown in the figure.Pulmonary capillary pressure when wedged is usually between 5 to 12 mm Hg,which is somewhat higher than what is shown in the figure.

Question 12

The respiratory therapist preparing to insert an arterial line in the right radial artery performs an Allen's test.The result of the Allen's test is 20 seconds.The respiratory therapist should do which of the following?

Accepted Answer

The purpose of the Allen's test is to assess the adequacy of the collateral circulation to the hand,specifically ulnar circulation.A positive Allen's test is a refill time of 5 to 10 seconds.This patient has a negative Allen's test (23 seconds).Therefore,ulnar collateral circulation is insufficient and the right radial artery of this patient must not be cannulated.Another site,the left radial,should be assessed for collateral circulation.

Question 13

The complications that may occur during the insertion of a central venous pressure line include all of the following except:

Accepted Answer

It usually takes several hours to days for an infection to develop,so infection would not occur during the insertion of the central venous pressure (CVP)catheter.Bleeding,pneumothorax and vessel damage are all complications that may occur during the insertion of the catheter.

Question 14

Calculate the ejection fraction of a female patient with a stroke volume of 40 mL and an end-diastolic volume of 125 mL.

Accepted Answer

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.

Question 15

The function of the transducer in the invasive vascular monitoring system is to do which of the following?

Accepted Answer

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.

Question 16

Left ventricular afterload is indicated by which of the following?

Accepted Answer

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.

Question 17

Which measurement is typically used to indicate right ventricular preload?

Accepted Answer

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.

Question 18

The vessels that often require a surgical cut down when used for pulmonary artery catheter access include which of the following?
1)Femoral vein
2)Subclavian vein
3)Internal jugular vein
4)Antecubital vein

Accepted Answer

The subclavian,internal jugular,external jugular,femoral,or antecubital veins may be used for access for pulmonary artery catheters.A surgical cut down is often necessary when the subclavian or antecubital veins are used.This is done so that the vein may be visualized directly to facilitate catheter entry.It is especially useful in cases of hypovolemic shock and trauma when peripheral cannulation is difficult or impossible.

Question 19

Common complications of systemic artery catheterization include all but which of the following?

Accepted Answer

Phlebitis is inflammation of a vein.Since the catheter in this situation is in an artery,phlebitis is not possible as a result of a system artery catheterization.Ischemia,hematoma,and hemorrhage are all complications of systemic artery catheterization.

Question 20

While checking an indwelling central venous pressure (CVP)catheter the respiratory therapist observes that the transducer is at the epistatic line.The respiratory therapist should do which of the following at this time?

Accepted Answer

The epistatic line is located at the mid-thoracic line.The central venous pressure (CVP)transducer needs to be placed at this line to accurately measure CVP.The epistatic line is located about 5 cm behind the angle of Louis.This is the place where the transducer must be zero-balanced.Since the transducer is at the epistatic line in this question the pressure measured will be accurate and should be accepted.

Quiz 11: Hemodynamic Monitoring