O2 Therapy

Question 1

Cardiopulmonary system compensates for hypoxemia by :

Answer 1

• increasing ventilation and cardiac output

Question 2

Hypoxemia causes:

Answer 2

• pulmonary vasoconstriction
• pulmonary hypertension

Question 3

three basic ways to determine whether a patient needs
O2 therapy :

Answer 3

• use of laboratory measures such as arterial blood gas testing
• based on the specific clinical problem or condition
• may cause tachypnea,
tachycardia, cyanosis, and distressed overall appearance, and
therefore bedside assessment can help identify such a need

Question 4

Laboratory measures for documenting hypoxemia include :

Answer 4

■ hemoglobin saturation
■ partial pressure of oxygen (PaO2),

Question 5

commonly a used threshold for hypoxemia:

Answer 5

PaO2 - <55 to 60 mm Hg
SaO2 - <87% to 90%

Question 6

condition formerly known as oxygen toxicity is currently termed

Answer 6

hyperoxic acute lung injury.

Question 7

Hyperoxia

Answer 7

PaO2 greater than 300 mm Hg

Question 8

In hyperoxia, threshold appears clinically important at

Answer 8

PaO2 of greater than 150 mm Hg

Question 9

Two factors determine the extent of harmful effects of O2:

Answer 9

• PaO2
• Exposure time

Question 10

The toxicity of O2 is caused by

Answer 10

Overproduction of O2 free
radicals

Question 11

Avoiding Oxygen Toxicity Limit patient exposure to 100% O2 to less than 24 hours whenever possible. High FiO2 is acceptable if the concentration can be decreased to 70% within 2 days and 50% or less in 5 days.

Question 12

High PO2 also is associated with

Answer 12

• retinopathy of prematurity (ROP)
• bronchopulmonary dysplasia in infants.

Question 13

Although the toxic effects of high
O2 concentrations can be serious, it is not FiO2 but rather PO2 that
results in such harmful effects

Question 14

Oxygen toxicity

Answer 14

■ Fio2 > 60% longer than 36 hrs
■ Fio2>80%longer than 24 hrs
■ Fio2>100%longer than 12hrs

Question 15

The user judges the performance of an O2 delivery system by answering two key questions:

Answer 15

● How much O2 can the system deliver (FiO2 or FiO2 range)
● Does the
delivered FiO2 remain fixed or vary under changing patient
demands?

Question 16

Typical low-flow systems provide supplemental O2 directly to the airway at a flow of

Answer 16

8 L/min or less

Question 17

Low-flow O2 delivery systems include:

Answer 17

■ nasal cannula
■ nasal catheter
■ transtracheal catheter

Question 18

-Most commonly used oxygen delivery device

Question 19

Nasal cannula

Answer 19

FiO2 Range : 22%–40%
Flow : 1/4 –6 L/min (adults)
≤2 L/min (infants)

● Flows greater than 6 to 8 L/min can cause patient discomfort
● should be replaced with a new one
(placed in the opposite naris) at least every 8 hours
● inappropriate for neonatal patients.

Question 20

soft plastic tube with several small holes at the tip that is inserted by gently advancing it along the floor of either nasal passage and visualizing it just behind and above the uvula

Answer 20

Nasal catheter

Question 21

Transtracheal catheter

Answer 21

thin polytetrafluoroethylene (Teflon) catheter inserted into the trachea
between the second and third tracheal rings

Question 22

Transtracheal catheter

Answer 22

● flow is so low, no humidification is needed.
● needs approximately half of
the O2 flow to achieve a given PaO2.

Question 23

Low-flow nasal systems provide O2 concentrations ranging from
22% to 45%

Question 24

Common problems with low-flow O2 delivery systems include:

Answer 24

■ inaccurate flow
■ system leaks and obstructions
■ device displacement
■ skin irritation

Question 25

Reservoir system

Answer 25

● incorporate a mechanism for gathering and storing O2 between patient breaths.
● generally provide higher FiO2 than low-flow systems
● can decrease
O2 use by providing FiO2 comparable with nonreservoir systems but at lower flow

Question 26

Reservoir system

Answer 26

■ reservoir cannulas
■ mask
■ non-rebreathing circuit

Question 27

Reservoir cannula

Answer 27

● designed to conserve O2 and are an alternative to the pulse-dose or demand-flow O2 systems
● nasal reservoir cannula operates by storing approximately
20 mL of O2 in a small membrane reservoir during exhalation
● pendant reservoir system helps overcome esthetic concerns by hiding the reservoir under the patient’s clothing on the
anterior chest wall

Question 28

Reservoir mask

Answer 28

most commonly used reservoir systems

Question 29

3 types of reservoir mask

Answer 29

■ Simple mask
■ partial rebreathing mask
■ non-rebreathing mask

Question 30

Simple mask

Answer 30

● disposable plastic unit designed to cover both the mouth and the nose
● If O2 input flow ceases, the patient can draw in air through these holes and around the mask edge.

● input flow range for an adult simple mask is 5 to 10 L/min

Question 31

Partial rebreathing mask

Answer 31

• Minimum of 10 L/min

Question 32

High flow delivery system

Answer 32

■ air entrainment mask
■ air entrainment nebulizer
■ high-flow nasal cannula