Hypobaric and Hyperbaric Physiology

Question 0

Compression on Descent

Answer 0

Increased pressure => Decreased volume

*Mask squeeze=negative pressure causes capillary rupture and conjunctiva hemorrhage
Ear drum rupture=canal blocked by cerumen

Question 1

Boyle’s Law

Answer 1

P1V1=P2V2

*Is why pressure increases by 1ATA every 10m underwater

Question 2

Expansion on Ascent

Answer 2

Decrease pressure => increase volume

Causes pneumothorax, gas emboli, death

Symptoms= dyspnea, bloody sputum, chest pain

*SCUBA DIVERS MUST EXHALE ON ASCENT

Question 3

O2 toxicity

Answer 3

Causes alveolar and endothelial membrane damage; can be caused my normal air at 6 ATA

*Use He mixtures in diving tanks to prevent

Question 4

N2 toxicity

Answer 4

Acts as an anesthetic, much like ETOH

*Dissolves into the lipid membranes of the CNS; can cause decompression sickness as N2 will bubble

Question 5

Acclimation to Altitude

Answer 5

Hyperventilation-peripheral chemoreceptors sense decreased PO2 and increase the ventilation of CO2

Erythropoesis-increases Hcrt and blood volume

Increased capillary growth in tissue

Reduced plasma volume

Question 6

Acute Mountain Sickness

Answer 6

5hrs-5 days @ >8,000ft

Headaches, nausea, weakness, dyspnea

*Treat w/ diuretics

Question 7

High Altitude Cerebral Edema

Answer 7

Ataxia = cardinal sign

Swelling of brain can => herniation and ischemia

Question 8

High Altitude Pulmonary Edema

Answer 8

Occurs in young, male athletes and is aggravated by exercise; MOST serious altitude pathology

• Will present w/ hemoptysis
• INDIVIDUAL MUST RETURN TO LOWER ALTITUDE