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Year 2 Respiratory > Oxygen therapy > Flashcards

Flashcards in Oxygen therapy Deck (30)
1

decreased body temp
decreased 2,3-BPG
decreased pH
CO

what do these do to the oxyHb binding curve?

left shift

2

increased body temp
increased 2,3-BPG
increased pH

what do these do to the oxyHb binding curve?

right shift

3

what are three causes of hypoxia?

hypoxemia
impaired blood flow
dysoxia

4

definition: hypoxemia

failure of respiratory system to oxygenate arterial blood

5

what are causes of hypoxemia?

low ambient pO2
hypoventilation
Hb deficiencies
impaired A-a diffusion
V/Q mismatch
shunts

6

cyanide poisoning causes what type of hypoxia?

dysoxia

7

what are causes for a V/Q mismatch?

gravity
lung disease
shunts
alveolar dead space
aging

8

does an anatomic shunt respond to oxygen therapy?

no

9

what is the effect of hypoxia in the brain?

cerebral vasodilation - increased cerebral blood flow

10

what is the goal of oxygen therapy?

maintain adequate tissue oxygenation

11

what are the clinical objectives / indications for oxygen therapy?

1. correct hypoxemia
2. relieve symptoms of hypoxia / hypoxemia
3. prevent / minimize increased cardiopulmonary workload associated with hypoxia / hypoxemia

12

what are the physiologic effects of breathing 100% inspired oxygen at atmosphere pressure for 0-12 hours?

normal pulmonary function
tracheobronchititis
substernal chest pain

13

what are the physiologic effects of breathing 100% inspired oxygen at atmosphere pressure for 12-24 hours?

decreasing VC

14

what are the physiologic effects of breathing 100% inspired oxygen at atmosphere pressure for 24-30 hours?

decreasing lung compliance
increasing pO2 (A-a)
decreasing exercise pO2

15

what are the physiologic effects of breathing 100% inspired oxygen at atmosphere pressure for 30-72 hours?

decreasing diffusion capacity

16

oxygen toxicity primarily affects which organs?

lungs
CNS

17

oxygen toxicity is primarily determined by what factors?

PO2 and exposure time

18

the pathology of oxygen toxicity is thought to be caused by what process?

oxygen free radicals

19

what is the pathological response of oxygen toxicity (4)?

1. damage to capillary endothelium
2. thickening of alveolar-capillary membrane (interstitial edema)
3. alveolar exudate and consolidation causing physiological shunting
4. end stage - pulmonary fibrosis and HTN

20

what are the effects of oxygen induced hypoventilation of COPD patients with chronic hypoxemia and hypercapnia?

1. central response to CO2 is blunted
2. primary stimulus to breathe is oxygen deprivation (hypoxemia)
3. high blood O2 levels suppress peripheral chemoreceptors and depress ventilatory drive

21

when delivering oxygen therapy to patients with COPD and high CO2, how much oxygen should be used?

lowest level possible to maintain saturation (mid 80s)

22

what is the pathophysiology of retinopathy of prematurity?

1. excessive blood-oxygen levelsl produce retinal vasoconstriction causing necrosis of blood vessels
2. new vessels form
3. hemorrhage of new vessels - scarring, detachment, blindness

23

what is the pathophysiology of absorption atelectasis?

nitrogen, the primary gas in the alveoli, is "washed out" by oxygen

1. inspired oxygen above 50% depletes both alveolar and blood nitrogen within minutes
2. removal of nitrogen from blood lowers total pressure of gases in venous system
3. large pressure gradient occurs between pulmonary capillary blood and alveoli
4. in obstructed alveoli, oxygen continues outward movement without repletion causing alveolar collapse
5. increase in physiologic shunt (alveoli are perfused but not ventilated)

24

what are the clinical guidelines for oxygen therapy (3)?

1. give minimum dose needed to obtain desired result
2. ordered in liters/minute and/or percent FiO2
3. ongoing assessment and titration

25

what is the normal oxygen range for blood gas analysis?

80-100 mm Hg

26

what is the MOA of hyperbaric oxygen?

1. increased atmostphere pressure = increased partial pressures
2. decreased air bubble volume
3. increased oxygen content in blood available for use by tissues (in PLASMA)

27

what are the indications for hyperbaric oxygen therapy?

air embolism
CO poisoning
wound therapy

28

what are complications of hyperbaric oxygen therapy?

barotrauma caused by high pressure
CNS, lung toxicity

29

venturi mask: advantages

delivers exact FiO2
FiO2 independent of ventilation rate

30

which mask is good for COPD patients / SOB?

venturi