High Altitude and Diving

Question 1

How does the body acutely adapt to high altitude?

Answer 1

Increased CO; quick HR increase, then SV from systemic vasodilation and decreased afterload. Returns within days.
Minute ventilation increase via carotid body response for weeks (hyperventilation).

Question 2

How does the body chronically adapt to high altitude?

Answer 2

Increased hemoglobin content via erythropoietin release. Constitiutional “left shift” for saturation.
Chronic respiratory alkylosis.
Higher resting ventilation
More myoglobin for skeletal muscle, higher capillary density.

Question 3

Describe Acute Mountain Sickness (AMS)

Answer 3

Headache, nausea, malaise, insomnia, anorexia.

Can prevent with dexomethasone or acetazolamine.

Question 4

Describe High Altitude Cerebral Edema (HACE)

Answer 4

Early AMS leading to ataxia, confusion, combativeness, hallucinations, coma.
Treat with oxygen, descent, ventilation, dexamethasone.

Question 5

Describe High Altitude Pulmonary Edema (HAPE)

Answer 5

After 2 days, cough with pink frothy sputum, SOB, fatigue. Includes exuberant PHTN.
Treat with descent, oxygen, vasodilators (nifedipine).

Question 6

Describe Chronic Mountain Sickness

Answer 6

Low birth weight infants, more pre-eclampsia.

Polycythemia and PHTN (Monge’s Disease) leads to more stroke and HF.

Question 7

How do you treat decompression sickness (Bend’s)?

Answer 7

Hyperbaric chamber

Question 8

How do you prevent nitrogen narcosis?

Answer 8

Use helium when deep sea diving?

Question 9

What disease predispose worse symptoms at altitude?

Answer 9

Pulmonary fibrosis, COPD, obesity

Question 10

What condition makes diving more dangerous?

Answer 10

Asthma