Oxygen Therapy

Question 1

Oxygen Delivery Equation

Answer 1

DO2= CO x Arterial O2 content

Question 2

Failure of O2 delivery can be d/t

Answer 2

hypotension
acidosis
coagulopathy

Question 3

Oxygen Use equation

Answer 3

VO2=CO x O2a-O2v

Question 4

Oxygen extraction ratio

Answer 4

normal 25%

heart has very high demand

Question 5

Hypoxemia definition

Answer 5

deficiency of O2 in the blood

Question 6

Hypoxia definition

Answer 6

O2 delivery to tissues not sufficient to meet metabolic demand

Question 7

Anesthesia Oxygenation goal

Answer 7

maintain oxygenation and ventilation

Question 8

Oxygen therapy is

Answer 8

the prevention and correction of hypoxemia and tissue hypoxia

Question 9

Surgical patients are at an increase risk of

Answer 9

hypoxia/hypoxemia

Question 10

Main causes of hypoxemia

Answer 10

V/Q mismatch (not enough blood flow or oxygen to the lungs)
R to L shunt (blood entering L side of heart w/o being oxygenated first
diffusion impairment (impaired movement of oxygen from the lungs into the bloodstream)
hypoventilation (shallow and ineffective breathing)
low environmental oxygen

Question 11

Main causes of hypoxia

Answer 11

any condition or event that reduces O2 intake
asthma
lung disease
heart disease
anemia
high altitudes
carbon monoxide or cyanide poisoning

Question 12

Hypoxic Hypoxia

Answer 12

pulmonary diffusion effect

Drug overdose, COPD, emphysema, asthma, ateletasis

Question 13

Hypoxia d/t circulatory

Answer 13

reduced CO

CHF or MI

Question 14

Hypoxia d/t Hemic

Answer 14

reduced hemoglobin content

carboxyhemoglobinemia, methemoglobinemia, anemia

Question 15

Hypoxia d/t demand

Answer 15

increased O2 consumption

fever, seizure, shivering, mH

Question 16

Hypoxia d/t histotoxic

Answer 16

inability of cells to utilize oxygen

cyanide toxicity

Question 17

Hypoxia Signs and Symptoms

Answer 17

vasodilation
tachycardia
tachypnea
cyanosis
confusion
lactic acidosis

Question 18

Methods to improve oxygenation of MV patients

Answer 18

treatment needs to be tailored to cause
increase Ve
increase CO
increase CaO2
optimize V/Q relationship
increase FiO2

Question 19

Supplemental O2 for non-intubated patients

Answer 19

nasal cannula
simple face mask
face mask with reservoirs
venturi masks

Question 20

Nasal cannula

Answer 20

flow rates 1-6L/min

FiO2 increases about 4% per L/Min

Question 21

Simple Face Mask

Answer 21

FiO2 40-60%
minimum 6L flow required to prevent rebreathing
Minimum is whatever patient’s Mventilation is

Question 22

Face mask with reservoirs

Answer 22

FiO2 60-100%

Question 23

Venturi Masks

Answer 23

more precise FiO2

24-50%

Question 24

Oxygen Toxicity

Answer 24

High FiO2 over long periods can be harmful to lung tissue

Question 25

What lung tissue damage is seen from O2 toxicity

Answer 25

decreased ciliary movement alveolar epithelial damage interstitial fibrosis

Question 26

O2 toxicity is dependent on

Answer 26

FiO2, duration and patient susceptibility

Question 27

safe vs toxic O2 therapy

Answer 27

Safe 100% O2 up to 10-20 hours | Toxic: 50-60% O2 for more than 24-72 hours

Question 28

High Risk O2 Toxicity Patients

Answer 28

> 70 Ys PMH: radiation to chest lunge glicomyocin

Question 29

S/S of Oxygen Toxicity

Answer 29

``` cough dyspnea rales hypoxia decrease diffusion increase in the arterial alveolar gradient ```

Question 30

Absorption Atelectasis

Answer 30

nitrogen is replaced by oxygen under ventilated alveoli have decreased volume due to greater uptake of oxygen increases pulmonary shunting

Question 31

Induced Hypoventilation

Answer 31

chronic CO2 retainers rely on hypoxic drive peripheral chemoreceptors are triggered by hypoxemia increased O2 can lead to hypoventilation

Question 32

Fire Hazard

Answer 32

O2 can support combusion | use extreme caution with head and neck cases

Question 33

Retinopathy

Answer 33

O2 therapy in neonates can lead to vascular proliferation fibrosis retinal detachment and blindness

Question 34

Population at risk for retinopathy

Answer 34

< 36 weeks gestational age weight <1500gm up to 44wks gestational age are considered high risk safe O2 administration PaO2 60-80mmHg

Question 35

hypercapnia

Answer 35

increased Co2 >45mmHG

Question 36

Causes of hypercapnia

Answer 36

increased Co2 concentration increased CO2 production increased alveolar dead space decreased alveolar ventilation

Question 37

Increased alveolar dead space

Answer 37

decreased alveolar perfusion interruptions in pulmonary circulation pulmonary disease

Question 38

Decreased alveolar ventilation

Answer 38

can be central or peripheral | respiratory depression most common cause in immediate postoperative period

Question 39

Clinical manifestations of Hypercapnia

Answer 39

directly produces vasodilation of peripheral vessels indirectly increase hR after catecholamine release produces effects due to acidotic state

Question 40

Nonspecific signs of hypercapnia

Answer 40

headache, N/V, sweating, flushing, shivering, restlessness

Question 41

CNS Considerations for hypercapnia

Answer 41

regulation of ventilatory drive | cerebral blood flow

Question 42

Cardiovascular considerations in hypercapnia

Answer 42

depression of smooth muscle and cardiac muscle increased catecholamine release vasodilation vs vasoconstriction

Question 43

pulmonary consideration in hypercapnia

Answer 43

increased RR increased pulmonary vascular resistance right shift in Hgb dissociation curve

Question 44

treatment of hypercapia

Answer 44

adjustment to the cause | increase minute ventilation

Question 45

hypocapnia

Answer 45

CO2 less then 35mmHg | cause is usually iatrogenic

Question 46

Manifestations of hypocapnia

Answer 46

decrease CBF cardiovascular decrease in CO, coronary constriction hypoxemia may result from hypoventilation

Question 47

treatment of hypocapnia

Answer 47

decrease minute ventilation