Exam 6: Applied Respiratory Physiology

Question 1

What is the inspired PO2 at an atmospheric pressure of 155 mmHg? What would be the percent oxygen quivalent at sea level? What would predict would happen should an animal or human become exposed to this atmospheric pressure?

Answer 1

32. 55 mmHg
    (32. 55 mmHg / 155 mmHg) x 100 = 21
    a. Results in acute hypoxic state and rapid unconsciousness. You would have to drastically increase respiratory rate and depth to compensate.

Question 2

Why do stored red blood cells not function as well as fresh red blood cells? What is missing?

Answer 2

Banked blood has low levels of S-nitroso hemoglobin (SNO-Hb) which is a vasodilator. When this is missing, vessels tend to vasoconstrict thus oxygen cannot be delivered well to the tissues.

Question 3

Is breathing 100% oxygen the same as hyperbaric oxygenation?

Answer 3

No

Question 4

How does hyperbaric oxygen improve tissue oxygenation?

Answer 4

Hyperbaric oxygen increased PO2 in blood, but reduces tissue blood flow by means of O2-induced vasoconstriction

Question 5

Are there any side effects or dangers associated with hyperbaric oxygen?

Answer 5

Associated with significant oxygen toxic seizures
No long-term improvement in healing ulcers; questionable benefit for surgical healing
Not useful for treating sprains or muscle soreness

Question 6

What happens to mental function when PaCO2 is more than 80 mmHg?

Answer 6

Serious effects and possible mortality may start to occur

Question 7

How do anesthetic drugs affect the response to CO2?

Answer 7

Decrease the response to CO2; pulmonary system becomes unresponsive

Question 8

How do anesthetic drugs affect the response to O2?

Answer 8

Dull the response or eliminate it completely, even when PO2 is less than 60-70 mmHg

Question 9

What are 4 things that can lead to hypoxemia during anesthesia?

Answer 9

Decreased minute ventilation
Increased shunt fraction
Increased dead space ventilation
Decreased FRC (lung volume)

Question 10

Describe how positive pressure ventilation affects venous return

Answer 10

Positive pressure ventilation forces air in rather than letting it flow in on its own, so we are compressing the vessels and reducing venous return which decreases cardiac output

Question 11

What happens to pleural pressure during positive-pressure ventilation? Venous return?

Answer 11

Causes an increased in intrapleural pressure which will increase alveolar pressure and has negative effects on cardiovascular system
Positive pleural pressure with decreased venous return

Question 12

How do whales stay active underwater for prolonged periods of time?

Answer 12

Diving mammals have myoglobin levels 30 times greater than terrestrial mammals which enables extended dive times (>1 hour)
Myoglobin acts as a facilitator for dissolved oxygen from blood to mitochondria, so by having more of it, diving mammals are able to stay under water for longer without coming up for air