Flashcards in Oxygen Therapy Deck (68):
What is ventilation?
Bringing in air from the environment to the lungs
What is diffusion?
Moving air from the alveoli to the capillaries
What are the factors that determine the amount of oxygen absorbed from the pulmonary system?
What are the factors that determine the amount of oxygen delivered from the capillaries to the tissues?
Tissue oxygen use
What percent of oxygen is dissolved in plasma?
What are the factors that shift the oxygen-Hb saturation curve to the left? (temp, 2,3, BPG, pH, and CO)
Decreased 2,3 BPG
What is the definition of hypoxia?
O2 delivery to the tissues is inadequate to meet metabolic needs
What is the definition of hypoxemia (arterial PO2 levels for adults and neonates)?
-Arterial PO2 less than 60 mmHg
-Less than 50 mmHg for neonates
What is Dysoxia?
Impaired ability for tissues to utilize oxygen
What are the three major causes of hypoxia?
-Impaired blood flow
What are the two major causes of impaired alveolar-capillary diffusion?
-Inadequate time for PO2 to equilibrate
-Severe thickening of the membrane
What is a common cause of dysoxia?
What is the normal V/Q ratio in the apices? Bases?
Apices = 3
Bases = less than 1
What is the V/Q ratio of dead spaces?
How does aging lower the V/Q ratio?
Lowers the elasticity of the alveoli
What is an anatomic shunt?
Right to left shunt that does not participate in gas exchange (bronchiolar capillaries)
Do anatomic shunts change with respiratory therapy?
What is the anatomic dead space?
What are alveolar dead spaces? Do these respond to oxygen therapy?
Poorly perfused alveoli that do respond to oxygen therapy
What is the effect of hypoxemia on pulmonary artery pressures? What, then, is the effect of the heart?
-Increased workload of the heart
How does hypoxemia result in impaired renal function?
Decreased blood flow
What is the effect of hypoxemia on the cerebral blood flow?
What is the normal percent of oxygen in RA?
What is the major, overall goal of oxygen therapy?
To maintain adequate tissue oxygenation
What are the physiologic effects of being exposed to 100% O2 for 0-12 hours?
-Substernal chest pain
What are the physiologic effects of being exposed to 100% O2 for 12-24 hours?
Decreased vital capacity
What are the physiologic effects of being exposed to 100% O2 for 24-30 hours?
-Decreased lung compliance
-Decreased exercise PO2
What are the physiologic effects of being exposed to 100% O2 for 30-72 hours?
Decreasing diffusing capacity
What are the two major organs that are primarily affected with oxygen toxicity?
CNS and lungs
When is the CNS affected with oxygen therapy?
With oxygen therapy greater than 60% at 1 ATM
What is the MOA of oxygen damage to the lungs and CNS?
Free radical generation
What is the pathological response to oxygen toxicity?
-Damage to capillary endothelium
-Thickening of the alveolar-capillary membrane
-Alveolar exudate and consolidation
-Pulmonary fibrosis and HTN
What happens to the central response to CO2 with oxygen therapy? What does this lead to?
Blunted response, leading to a depressed respiratory drive
What is the MOA of retinopathy of prematurity with oxygen therapy?
Excessive blood oxygen levels produce retinal vasoconstriction, causing necrosis of blood vessels. This causes a proliferation of new blood vessels, which hemorrhage and damage retina further.
What is the MOA of absorption atelectasis with oxygen therapy?
oxygen levels above 50% depletes both alveolar and blood nitrogen, which is the main alveolar dilator. This can cause atelectasis.
Above what oxygen saturation level should you attempt to keep neonates above? Adults?
Neonates = 88%
Adults = 90%
How is oxygen ordered? (2)
What are the clinical guidelines for oxygen therapy?
Give the minimum dose needed to obtain the desired result
What are the two things that you should monitor when administering oxygen?
What is the MOA of hyperbaric oxygen therapy?
Increased atmospheric pressure increases partial pressure,
What are the pressures used for hyperbaric oxygen supply?
What are the indications of hyperbaric oxygen therapy? (3)
What are the two major complications that can occur with hyperbaric oxygen therapy?
What are the high flow delivery devices for oxygen therapy?
What are the two enclosures that can be used to deliver oxygen?
-Oxygen tents and hoods
What are the four major low flow oxygen delivery systems?
-Simple O2 mask
What are the disadvantages to NC use?
-Cannot deliver high [O2]
-Requires adequate ventilation patterns
-High flow rates not tolerated
What is the major disadvantage of a nasal catheter?
Can direct gas into the stomach
True or false: the flow rate and FiO2 for a nasal catheter is similar to the nasal cannula
The flow rate with a simple oxygen mask should not go below what level? Above what
What is the major downside in terms of FiO2 with a simple oxygen mask?
What is the flow rate of a NC?
What are the flow rates for a partial rebreathing mask?
8 or 10-12
What are the three precautions that should be taken with administration of oxygen with a partial rebreathing mask?
-Must keep reservoir filled
-Maintain good seal
What are the flow rates that can be given with non-rebreather masks?
What is the major downside of non-rebreather masks?
Higher potential for oxygen toxicity
What are venturi masks?
High flow oxygen system that consists of a mask with an orifice, to allow for some RA to enter
What are the two major advantages of a venturi mask?
-Delivers exact FiO2
-FiO2 independent of ventilation rate
What is the max flow rate with an aerosol mask?
What are aerosol masks?
Face mask that provided humidified and heated air
How does hyperbaric oxygen therapy treat an air embolism?
Decreases air bubble size
What is an oxygen tent?
An enclosure that surrounds the entire body to deliver high rates of oxygen (10-12 L/min)
What is the max FiO2 with a NC?
Why is it important to ensure that the partial rebreather mask is 2/3 full? What level of oxygen flow will prevent this?
If not, then will be breathing in CO2
When is humidified air absolutely necessary?
When you bypass the naso/oropharynx
Do oxygen tents and hoods require humidified air?
What are the three major clinical goals of oxygen therapy?
-Reduce cardiopulmonary workload