Chapter 42 Test Flashcards
Overall goal of O2 therapy
- maintain adequate tissue oxygenation
- minimizing cardiopulmonary work
Clinical objectives for O2 therapy
- correct documents or suspected acute hypoxemia
- decrease symptoms of chronic hypoxemia
- decrease workload of cardiopulmonary system
What is hypoxemia
low O2 levels in the blood
3 basic ways to know if patient needs O2 therapy
- ABGs or other lab measures
- patients specific clinical problem or condition such as exacerbation of asthma
- perform patient assessment to identify need for O2
Common Hazards for O2 therapy
- Fire hazard
- O2 toxicity
- Depression of Ventilation
- Retinopathy of Prematurity (ROP)
- Absorption Atelectasis
Fire Hazard
O2 is nonflammable but gas supports combustion
O2 toxicity
High levels of O2 in the blood
two factors to determine:
- PaO2
- exposure time
O2 toxicity “circle”
O2 toxicity > Increased shunting > Low PaO2 > Increased FiO2
Type I alveolar cells
where gas exchange occurs
Type II alveolar cells (septal cells)
secrete alveolar fluid (surfactant)
Alveolar dust cells
wandering macrophages remove debris
Depression of Ventilation
When SOME COPD patients are placed on high levels of O2, it suppresses their chemoreceptors which depresses ventilatory drive
Retinopathy of Prematurity
abnormal eye condition in premature or low-weight babies who receive supplemental O2
Absorption Atelectasis
Breathing high levels O2 quickly depletes N2 levels. as N2 decreases, venous gases decrease
AARC develop guidelines for each procedure
- indication
- contraindication
- precautions
- possible complications
Low Flow Device
referred as a variable performance device, low flow cannot meet patients inspiratory flow demand (variable)
Nasal Cannula Flow Rate and FiO2
1 lpm = 0.24
2 lpm = 0.28
3 lpm = 0.32
4 lpm = 0.36
5 lpm = 0.40
6 lpm = 0.44
Advantages of Nasal Cannula
- can be used on adults, children, and infants
- easy to use
- disposable
- doesn’t cost very much
- very well tolerated (eat, sleep)
Disadvantages of Nasal Cannula
- unstable, easily dislodged
- uncomfortable at high liter flow
- can cause dryness, bleeding, polyps
- mouth-breathing may reduce FiO2
Simple Mask Flow Rate and FiO2
5 lpm = 0.35
6-7 lpm = 0.40
8-9 lpm = 0.45
10 lpm = 0.50
Simple mask cannot go below ____ l/min or the patient may be at risk for CO2 retention
5 L/min
Advantages of using a simple mask
- can be used on adults, children, and infants
- quick and easy to apply
- disposable
- inexpensive
Disadvantages of using a simple mask
- uncomfortable, claustrophobia
- must be removed for eating
- prevents radiant heat loss
- risk of aspiration if patient vomits
- masks cannot be humidified
Partial Rebreather Mask Flow Rate and FiO2
10-11 lpm = 0.40-0.50
11-12 lpm = 0.50-0.60
12-13 lpm = 0.60-0.70
13-14 lpm = 0.70+
14-15 lpm = 0.70+
Advantages of using PRB mask
- can be used on adults, children, and infants
- quick and easy to apply
- disposable
- inexpensive
- can provide moderate to high FiO2
Disadvantages of using a PRB mask
- uncomfortable, claustrophobia
- must be removed fro eating
- prevents radiant heat loss
- risk of aspiration if patient vomits
- masks cannot be humidified
- potential suffocation hazard
Nonrebreather Mask Flow Rate and FiO2
10-11 lpm = 0.60
11-12 lpm = 0.60-0.70
12-13 lpm = 0.70- 0.80
13-14 lpm = 0.80+
14-15 lpm = 0.80+
Advantages of using a NRB mask
- can be used on adults, children, and infants
- quick and easy to apply
- disposable
- inexpensive
- can provide high FiO2
Disadvantages of using a NRB mask
- uncomfortable, claustrophobia
- must be removed for eating
- prevents radiant heat loss
- risk of aspiration if patient vomits
- mask cannot be humidified
- potential suffocation hazard
3 things used in the initial selection or change in O2 delivery
purpose, patient, and performance
What is purpose of O2 therapy
to increase the patient’s FiO2 sufficiently to correct arterial hypoxemia and or minimizing cardiopulmonary work
What things are you looking at on a patient for O2 therapy
- severity and cause of hypoxemia
- patient age group
- degree of consciousness and alertness
- presence or absence of tracheal airway
- stability of minute ventilation
- mouth breathing vs. nose breathing
What is the performance for O2 therapy
O2 systems vary according to actual FiO2 delivered and stability of FiO2 under changing patient demands.
according to AARC guidelines for O2 therapy for adults, how often should O2 delivery systems be checked?
Once a day
High Flow Device
device that is able to meet or exceed the patient’s inspiratory flow demands so the patient does not have to entrain room air (fixed)
High Flow Devices:
- Air-entrainment mask (AEM)
- Air-entrainment nebulizer (AEN) or Large Volume Nebulizer (LVN)
- High flow nasal cannula
The smaller the orifice, the greater the ____ of O2 and more ___ is entrained
velocity, air
To increase total flow for a LVN you can:
-Connect 2 or more nebulizers together (double flow)
- set nebulizer to a low concentration and bleed-in O2
- add open reservoir to expiratory side of T-tube
4 types of interface used with AEN/LVN
- aerosol mask
- face-tent
- tracheostomy collar
- t-tube or t-piece
2 major problems with LVNs
- ensuring adequate flow at moderate to high FiO2s
- Downstream resistance affects the FiO2 device
Why do we do a double flow system?
so air to O2 ratio meets the fiO2 requirements along with more liter flow
Low Flow Devices
- nasal cannula
- simple mask
- partial rebreather
- non-rebreather
What are you partially rebreathing with a PRB
Headspace gas and mostly O2
Explain how a Venturi mask works
devices have a simple restricted orifice or jet through which O2 flows at high velocity. air is entrained by shear forces at the boundary of jet flow
Venturi mask FiO2 range
0.24 - 0.55
LVN FiO2 range
0.28 - 0.98-1.0
Why do we test an O2 analyzer?
to make sure the analyzer can go all the way up to proper FiO2 delivering to patient
