final exam for rc176

The affinity of Hb for carbon monoxide (CO) is approximately how many times greater than its affinity for oxygen?

200 or greater

What cylinder factor is used to compute the duration of flow for a 244 cu/ft (H/K) O2 or air cylinder?

3.14

What is a normal end-tidal PETCO2 range

35 to 43 mm Hg

A patient has a whole-body oxygen consumption of 320 ml/min and a measured CaO2-CvO2 of 8 ml/dl. What is the cardiac output?

4.0 L/min

If you want the flow at the patient to be 9 L/min with a heliox mixture of 80:20, how much flow should you set the flow meter to

5 L/min

What is the normal range of PAO2-PaO2 for healthy young adults breathing room air?

5 to 10 mm Hg

Large piston air compressors used in bulk supply systems typically can provide working pressures of

50 psi

You are asked to calibrate an O2 analyzer. Which of the following gases would you use for this procedure?

50% oxygen

You obtain a SpO2 reading of 90% using an oximter with an approximate accuracy of 5%. This could indicate a PO2 as low as what level?

55 mmhg

A normal person breathing 100% oxygen at sea level would have PAO2 of about what level?

670 mmhg

The expected PaO2 for an 80-year-old man is otherwise in good health and breathing room air is about what level?

75 mmHg

Pulse oximeter readings are generally unreliable at saturations below what level

80%

What is the U.S. Food and Drug Administration (FDA) purity standard for O2

99%

A patient's P50 is 37 mm Hg. Which of the following conditions could be responsible?

Hypercarbia

Which of the following would be considered clinical manifestations of carbon dioxide toxicity?

Hypertension Bounding pulse PaCO2> 70 mm Hg Multiple premature ventricular contractions

When oxygen uptake by the tissues is abnormally low, as occurs in certain forms of dysoxia, what would you expect to find?

Increased CvO2

Which of the following variables will lead to an increase in turbulent airflow?

Increased radius of the conducting tube

In the presence of an acutely reduced arterial oxygen content (hypoxemia), normal oxygen delivery to the tissues can be maintained by which of the following?

Increasing the cardiac output

Which of the following will increase the flow of a gas across a semipermeable membrane, according to Fick's law of diffusion?

Increasing the partial pressure gradient of the gas across the membrane

In which of the following forms is carbon dioxide transported by the blood?

Ionized as bicarbonate (HCO3-)

Which of the following is true regarding properly applied O2 therapy

It can decrease the work of breathing.

Which of the following are true regarding fetal Hb (HbF)

It delivers more oxygen to tissues at low PaO2 than normal Hb

Which of the following is an indication for NO therapy?

It has been used successfully to treat persistent pulmonary hypertension of the newborn. It can be used as an adjunct to the treatment of congenital cardiac defects

Which of the following statements about He is true

It is nonflammable It is odorless It is an inert gas

You are preparing to conduct a complex transport of a patient receiving O2, and you expect to have to alter O2 flows during the transport. Which of the following devices would best meet your needs?

Bourdon gauge

Which of the following medical gases does not support combustion

CO2

Which of the following is classified as a nonflammable gas that does not support combustion?

Carbon dioxide

To measure PO2, blood gas analyzers use what electrode?

Clark

A patient rescued from a house fire is brought into the ER. The patient is suspected of suffering from CO poisoning, which device can help monitor CO levels?

Co-oximeter

To validate patient readings obtained from a transcutaneous blood gas monitor, what should you do?

Compare the monitor's readings to those obtained with a concurrent ABG sample

What safety system is designed to prevent accidental interchanging among low-pressure (less than 200 psig) connectors such as those found on flowmeters and ventilators?

DISS

Which of the following are potential causes of hypoxia?

Decrease in arterial PO2

Which of the following does NOT increase the affinity of Hb for oxygen?

Decreased PCO2

A patient has a P50 value of 29mmHg. What does this indicate?

Decreased affinity of Hb for oxygen

Why is the presence of carbonic anhydrase in RBCs so crucial for CO2 transport?

Drives the hydrolysis reaction that forms HCO3-

An abnormal metabolic state in which the tissues are unable to utilize the oxygen made available to them best describes which of the following?

Dysoxia

The conversion of HbO2 to deoxygenated Hb does which of the following

Enhances CO2 loading on Hb

3 strategies that can be used to protect patients from electrical hazards

Ensuring that all devices attached to patients are electrically grounded Ensuring that equipment circuit interrupters are functioning Ensuring that all electrical devices used with a microshock-sensitive patient are well-insulated and connected to outlets with a common, low-resistance ground

Who sets the purity standard for medical gases?

FDA

Medical gas cylinders are color coded for easy identification. E cylinders of carbon dioxide are painted

Green

A blood gas analyzer measures all of the following except:

HCO3-

The largest percentage of CO2 transported in the blood occurs as which of the following?

HCO3-

The largest percentage of carbon dioxide transported in the blood occurs as which of the following?

HCO3-

The influence of oxyhemoglobin saturation on CO2 dissociation is called the what?

Haldane effect

When Hb saturation with oxygen is high, less CO2 is carried in the blood. What is this relationship called?

Haldane effect

When a Hb molecule accumulates excessive amounts of HCO3-, it is expelled from the cell in exchange for Cl-. What is this called?

Hamburger phenomenon

What is the most important component in the oxygen transport system?

Hb

What is the primary determinant of the PAO2?

PO2 in the inspired gas

A patient breathing 40% oxygen at sea level has a PaO2 of 50 mmHg, a PCO2 of 30 mmHg, and a PAO2-PaO2 of 250 mmHg. When the FiO2 is raised to 0.7, the PaO2 rises to only 58 mmHg. Hypoxemia is primarily due to which of the following?

V/Q imbalance

What is the most common cause of hypoxemia in patients with lung disease?

V/Q mismatch

According to Poiseuille's law, the gas flow through a tube is inversely proportional to the:

Viscosity of the gas

Under which of the following conditions may CO2 removal be impaired

When a V/Q imbalance exists

Why is it necessary to keep the patient's PaO2 greater than 60 mm Hg?

a level of 60 mm Hg marks the beginning of the steep part of the O2Hb dissociation curve

What is the measurement of CO2 in respiratory gases called?

capnometry

Which of the following gases would diffuse fastest across the alveolar-capillary membrane

carbon dioxide

Which of the following can cause false high readings when using a pulse oximeter?

carboxyhemoglobin

The highest PCO2 levels are found in what location

cells

How is the vast majority of oxygen carried in the blood?

chemically combined with Hb

Which of the following are common sites for transcutaneous blood gas electrode placement

chest abdomen lower back

Which of the following devices would you select if the goal was to accurately meter the flow through a jet nebulizer?

compensated Thorpe tube

Which of the following conditions must exist for gas to move between the alveolus and pulmonary capillary?

difference in partial pressures (pressure gradient)

What role does the Bohr effect play in oxygen transport?

enhances oxygen delivery to tissues and oxygen pickup at lungs

The NFPA standard for bulk liquid O2 systems requires that the reserve supply be which of the following?

equal to the average gas use of 1 day

What is the greatest hazard to pulse oximetry?

false results leading to incorrect decisions

Cylinders of liquid gases are filled according to what specification?

filling density

If you have to deliver medical gas to a patient from a compressed gas cylinder, which of the following devices would you select to control gas flow?

flowmeter

By what means is air for medical use in a hospital most commonly produced?

fractional distillation

On what does the movement of gases between the lungs and the body tissues mainly depend?

gaseous diffusion

A patient with a normal PaO2 and cardiac output is exhibiting signs and symptoms of tissue hypoxia. What is most likely the cause?

hemoglobin deficiency

A patient breathing room air at sea level has the following arterial blood gases: PaO2 = 62 mm Hg; PCO2 = 75 mm Hg. When the FIO2 is raised to 0.28, the PaO2 rises to 95 mm Hg. What is the most likely cause of the hypoxemia?

hypoventilation

What is the greatest potential problem with quick-connect DISS systems (such as Ohio, NCG, or Puritan)?

incompatibility among different manufacturers

Specific clinical objectives of oxygen (O2) therapy all of the following except:

increase the workload hypoxemia imposes on the lungs

Assuming a constant FIO2 and carbon dioxide production, which of the following statement are correct?

increases in VA decrease the PACO2 and increase the PAO2

During a single-breath capnogram, the sharp downstroke and return to baseline that normally occurs after the end-tidal point indicates what?

inspiration of fresh respiratory gas

Which of the following statements about CO2 is true?

it is odorless and colorless it does not support animal life it is heavier than air

All of the following are ways in which blood can carry oxygen except

leukocyte

What key property of He makes it useful as a therapeutic gas?

low density

Which of the following is not considered a therapeutic gas?

n2o

Compared to portable cylinders, a centrally located, piped-in bulk O2 system has all of the following advantages except

no need for a backup or reserve system

When full, a gas cylinder registers a pressure of 2200 psig. After a few hours of use, the pressure gauge reads 550 psig. The cylinder is now how full?

one fourth

What does V/Q mismatch have the biggest impact on

oxygenation

Which of the following mechanisms do all compressed gas cylinders use to avoid excessively high buildup of cylinder pressure?

pressure-relief mechanism on the valve stem

The time available for diffusion in the lung is mainly a function of which of the following?

rate of pulmonary blood flow

In clinical practice, how is a positive identification made of the contents of a medical gas cylinder?

reading the cylinder label

Compressed gas cylinders are manufactured from which of the following?

seamless steel

An area of the lung has no blood flow but is normally ventilated. All of the following statements are true about this area except:

the PO2 will go toward 0 and the PCO2 will go toward 150

Regarding pulmonary blood flow in the upright lung, which of the following statements is true?

the bases receive about 20 times more blood flow than the apexes

When is the rate of gaseous diffusion across a biological membrane decreased?

the partial pressure gradient is low

What is the primary purpose of indexed connector systems?

to prevent inadvertent misconnections between equipment

To accurately determine the remaining contents of a liquid-filled CO2 cylinder, what would you do?

weigh the contents of the cylinder

At body temperature, how much oxygen will physically dissolve in plasma at a PO2 of 40 mm Hg

0.12 ml/dl

Under normal physiologic circumstances, how many milliliters of oxygen are capable of combining with 1 g of Hb?

1.340 ml

How much flow actually leaves the flowmeter with a 70:30 mixture of heliox set at 10 L/min

16 L/min

You are planning a patient transport that will take about 1.5 hours. The patient requires manual ventilation with 10 L/min of O2. What is the minimum number of full E cylinders you would take with you?

2

You are called to prepare an E-cylinder of oxygen for a patient. Which pinhole locations on a regulator should be used?

2 and 5

What is the appropriate interval for changing the site for a transcutaneous blood gas monitor sensor

2-6 hours

Alternating supply systems for medical gases that are used in hospitals should include a reserve supply for oxygen in case the primary system fails. How much reserve oxygen should be available?

An average day's supply

Which of the following equations best describes oxygen delivery to the tissues?

Arterial oxygen content x cardiac output

Which of the following statements is true regarding the Haldane effect?

At high SaO2 levels, the capacity of blood to hold CO2 decreases

Which of the following conditions is associated with an acute respiratory acidosis?

Barbiturate intoxication

Hypoxia is best defined as a condition in which what occurs?

Blood Hb levels are less than normal

What are the consequences of maintaining the temperature of the PtCO2 probe at 48 degree Celsius?

Malignant hyperthermia

According to the U.S. Department of Commerce, a gas cylinder that is color coded blue should contain which of the following?

N2O

Which of the following statements are true regarding NO therapy?

NO is a potent vasoconstrictor

You are asked to administer a helium-oxygen mixture to an asthmatic patient who is admitted to the emergency department with acute respiratory distress. Which of the following devices is the most appropriate method of delivering this form of medical gas therapy?

Nonrebreathing mask

Which of the following would you expect to find with "oxygen debt"?

Oxygen demand exceeds oxygen delivery

When carbogen is administered, which of the following vital signs should be monitored?

Pulse Blood pressure Respirations Mental status

To measure PCO2, blood gas analyzers use what electrode?

Severinghaus

Which of the following patient conditions would you expect to be hypermetabolic (elevated VO2)

Starvation

What occurs in the bases of the upright lung?

The V/Q is lower than the average.

The percentage of oxygen delivery provided by molecular sieve O2 concentrators depends on which of the following factors?

The age of the sieve beds

The pressure inside a cylinder increases dramatically when the cylinder is exposed to extremely high temperatures. What prevents cylinders with frangible disks from exploding when exposed to extremely high temperatures?

The frangible disk ruptures from the increased pressure, allowing gas to escape from the cylinder

A respiratory therapist is having trouble attaching a regulator to an E cylinder. One possible cause might be:

The pin positions of the regulator are not the same as those on the cylinder

Before using an H cylinder of oxygen, a respiratory therapist opens it, and gas at high pressure comes out of the cylinder outlet. Which of the following statements is true?

This action clears debris from the connector.

Interpret the following ABG findings:pH: 7.50 PaO2: 60 mm Hg PaCO2: 30 mm Hg HCO3-: 24 mEq/L

acute respiratory alkalosis with mild hypoxemia

Benefits of properly applied O2 therapy in patients with chronic hypoxemia include which of the following?

decreased right ventricular workload