49: Therapeutic Gases - Duric

Question 1

O2 delivery to the tissues is inadequate to meet metabolic need

Answer 1

hypoxia

Question 2

failure of the respiratory system to oxygenate arterial blood or a decreased carrying apacity of the blood

Answer 2

hypoxemia

Question 3

3 causes of hypoxia

Answer 3

• hypoxemia
• impaired blood flow
• dysoxia

Question 4

inability of the cardiac system to adequately deliver blood to the tissues

Answer 4

impaired blood flow

Question 5

impaired ability for tissue to utilize oxygen

Answer 5

dysoxia

Question 6

impaired ability of oxygen to diffuse across the alveolar-capillary membrane

Answer 6

v/q mismatch

Question 7

anatomic shunt example

Answer 7

blood bypasses lungs like in bronchial circulation

Question 8

cyanide posioning is an example of …

Answer 8

dysoxia

cellular use of oxygen is abnormally decreased

Question 9

primary response to hypoxia

Answer 9

increased cardiovascular workload

Question 10

___ of air at sea level is oxygen

Answer 10

21%

Question 11

_____ of room air is _______ but partial pressure is proportional to atmospheric pressure

Answer 11

FiO2

constant

Question 12

most common therapy to treat hypoxia/hypoxemia

Answer 12

oxygen therapy

Question 13

indications for adult and children hypoxemia oxygen treatment

Answer 13

PaO2 less than 60 torr

SaO2 less than 90%

Question 14

indications for neonate hypoxemia treatment

Answer 14

PaO2 less thann 50 torr

SaO2 less than 88%

Question 15

pathological responses to oxygen

Answer 15

• damage to the capillary endothelium
• thickening of the alveolar-capillary membrane
• alveolar exudate and consolidation causing physiological shunting
• at end stage pulmonary fibrosis and hypertension

Question 16

why does oxygen-induced hypoventilation sometimes happen?

Answer 16

central response to CO2 is blunted –> primary stimulus to breathe is oxygen deprivation (hypoxemia) –> high blood O2 levels suppress peripheral chemoreveptors and depress ventialtroy drive

Question 17

condition of the eye affecting premature/low-birth weight infants

Answer 17

retinopathy of prematurity

excessive blood-oxygen levels produce retinal vasoconstriction causing necrosis of the blood vessels –> new vessels form and increase in number –> hemorrhage of these new vessels causes scarring behind the eye’s retina leading to retinal detachment and blindness

Question 18

describe absorption atelectasis

Answer 18

nitrogen, the primary gas in teh alveoli, is “washed out” by oxygen

results in increased physiologic shunt because alveoli are perfused but not ventilated

Question 19

for every liter increase, increase FiO2 __ %

Answer 19

4%

ex 1L = 24% or FiO2 0.24

2L = 28 etc…

Question 20

indications for hyperbaric oxygen therapy

Answer 20

air embolism
carobon monoxide poisoning
wound therapy

makes more oxygen available in the blood and not just on hemoglobin

Question 21

less than ___ helium is not therapeutic

Answer 21

60%

delivered in parts per million up to 80ppm - standard dose is 20 ppm

Question 22

how does helium-oxygen therapy work?

Answer 22

low-density gas which lowers the work of breathing - promotes laminar flow in large airways

Question 23

FDA approved indication for nitric oxide therapy

Answer 23

persistent pulmonary hypertension of the newborn

treats by dilating the pulmonary blood vessels