#23/24 Zhu - Pracical Applications in Respiratory Physiology

Question 1

Calculate the PO2 of air at 10,500 ft. Barometric pressure is 524 mmHg.

Answer 1

524 *0.21 = 110 mmHg

Question 2

Calculate the PO2 of inhaled air at 10,500 ft. Barometric pressure is 524mmHg.

Answer 2

(524-47)*0.21 = 100mmHg

Question 3

Calculate the PN2 of air at 10,500 ft. Barometric pressure is 524 mmHg.

Answer 3

524*0.79 = 414 mmHg

Question 4

Calculate the PN2 of inhaled air at 10,500 ft. Barometric pressure is 524 mmHg.

Answer 4

(524-47)*.79 = 377 mmHg

Question 5

As altitude increases does the composition of air change?

Answer 5

No, the composition of air does not change but density changes.

Question 6

During the 1st stage of acclimatization in high altitudes, which receptors are are most influential?

Answer 6

Peripheral (carotid and aortic)

Question 7

It is day 3 of your trip at Machu Picchu. (Elevation 7972 ‘) You have been huffing and puffing but now your kidneys have kicked in and you no longer suffer from respiratory (alkolosis/acidosis).

Answer 7

Alkalosis

Question 8

You are on a long term mission trip into the mountains of Peru (Elevation 11,500’). Your red blood cell count has increased and you have what type of shift of the O2-Hb dissociation curve?

Answer 8

Rightward shift

Question 9

You have been inspired to climb Mt. Kilimanjaro. (Elevation 19,341’) Unfortunately you got chronic mountain sickness. What aspects of pulmonary hypertension could be taking place?

Answer 9

Polycythemia - increased viscosity
Pulmonary vasoconstriction - insufficient gas exchange
Right-sided heart failure - right side of heart has to pump harder to get into pulmonary circulation.

Question 10

60 year old gets on a ride at Six Flags. After plummeting over 100 feet his retinas detach. Why?

Answer 10

He experienced negative G force with downward acceleration. As he went down, the blood pushed up and caused the retinal detachment. It can also create too much blood in the brain.

Question 11

You are a jet pilot and are reaching Mach 3. Why is your vision changing?

Answer 11

The positive G force is pulling your blood into your lower extremities away from your head and eyes.

Question 12

An astronaut friend of yours is returning from the space station. What has been happening to his bones and muscles and why?

Answer 12

Decalcification of bone and muscle atrophy due to deconditioning.

In space perfusion and ventilation became more uniform..
There is a decrease in blood volume, red cell mass, work capacity and maximum cardiac output.

Question 13

You are deep sea diving and you need to calculate the pressure that you are at. Your depth gauge says you are at 66 ft.

Answer 13

3 ATM

Question 14

At sea level, your amount of air is 1 L. You are now at 100 feet below sea level. What is the actual volume at 100 ft?

Answer 14

Actual: 1/4 liter

Question 15

You are busy following a beautiful manta ray and you forget to pay attention to your dive watch. You are at 160 feet under sea level. What is the inhaled PN2?

Answer 15

(4560-47) * 0.79 = 3565 mmHg

Question 16

At what point would you get oxygen toxicity?

Answer 16

760 mHg

Clinical - twitching

Question 17

Your friend did not time his ascent well and has ended up with the bends. You give him another air tank and send him back down to recompress. What happened to the N2 level in his body?

Answer 17

As the diver descended N2 dissolved into the tissue due to the increased pressure.

On ascent the N2 expands and is released from the tissue.

If his ascent is too fast the N2 is released too quickly causing the bends.

Question 18

Why is CO so dangerous as it relates to affinity for Hb?

Answer 18

CO (unlike CO2) binds to the heme group creating COHb. Not only does CO have 200x greater affinity for Hb but it also increases the O2 affinity for Hb. This makes it harder for O2 to unload in the periphery.

Question 19

It is winter time and the heater has been releasing CO into the air. How would you treat the carbon monoxide poisoning?

Answer 19

Hyperbaric O2 therapy