Altitude and Diving

Question 1

Relation of barometric pressure, FiO2, PaO2, and saturation to altitude

Answer 1

FiO2 stays the same as altitude increases but partial pressure decreases. This reduces both PaO2 and saturation.

Question 2

Adaptions to Altitude

Answer 2

Immediate: carotid bodies promote hyperventilation from low PaO2 (

Question 3

Acute Mountain Sickness: Pathology

Answer 3

18-42% of ski resort visitors develop HA w/ fatigue, insomnia, nausea, or malaise in response to cerebral edema caused by systemic hypoxic vasodilation.

Question 4

AMS prevention and treatment

Answer 4

Prevent with gradual ascent, lower altitude resorts, acclimitization
Treat with Dexamethasone, Acetazolamide, or ibuprofen

Question 5

High altitude cerebral edema

Answer 5

Severe form of AMS with symptoms of ataxia and mental changes. Treat with immediate descent, oxygen, and dexamethasone

Question 6

High Altitude Pulmonary Edema: Pathology

Answer 6

noncardiogenic edema caused by hypoxic pulmonary vasoconstriction, usually associated with pulmonary hypertension, short latent period, rapid progression, high recurrence

Question 7

HAPE Prevention and Treatment

Answer 7

Prevent by avoiding similar altitudes, PO vasodilators, steroids, and inhaled salmeterol
Treatment is descent, oxygen, vasodilators. NO DIURETICS

Question 8

Decompression Sickness

Answer 8

Inert gas (N2) partial pressure increases during deeper dives and can form bubbles with rapid surfacing. Adding helium to gas tank helps

Question 9

Hyperventilation and Submerging

Answer 9

Hyperventilation greatly decreases PaCO2 so that peripheral chemoreceptors will not cause dyspnea before PaO2 is low enough for unconsciousness.
PaCO2 increases 3-5mmHg/min w/ apnea so it would be

Question 10

Barotrauma

Answer 10

increased airway pressure causes air extravasation and can cause pneumothorax, pneumomediastinum or air embolism.