2 - Other

Question 1

Define barotrauma.

Answer 1

Injury/Pain caused by compression of tissue gases and spaces when the body is exposed to changing pressures.
Symptoms depend on location of gas pocket:
External Ear
Middle Ear and Sinus
Dental Pain
Pneumothorax
Air Gas Embolism

Question 2

What are some problems associated with tissue nitrogen when changing atmospheric pressure (diving/high altitude)?

Answer 2

Nitrogen Narcosis -> nitrogen saturates body tissue when under greater “atmospheric” pressure, as when diving. This causes anesthetic gas intoxication as N2 is absorbed by cells (specifically nerves). This creates a sense of euphoria, overconfidence, and loss of judgement.
Can happen at “shallow” depths -> as low as 75ft, but loss of consciousness are at 400ft.
Prevent is to replace N2 with He when diving to deep depths.

Question 3

What is oxygen toxicity?

Answer 3

Most adults can handle 100% O2 for 30 min at sea level before CNS toxicity and pulmonary toxicity is noted. At increased depths the effects occur more acutely.
Prevent by reducing O2 concentration or taking breaks on “room air.”

Question 4

What percentage of adults have patent foremen ovale?

Answer 4

25%

Question 5

What is the immediate treatment for significant decompression sickness?

Answer 5

O2
control for “optimal” hydration
Aspirin
–> get to hyperbaric chamber

Question 6

What is the affect of acetazolamide on Acute Mountain Sickness?

Answer 6

Acetazolamide is a carbonic anhydrase inhibitor. This decreases the amount of CO2 that can be transported in the blood. This will cause metabolic acidosis, relative hyperventilation, and improved oxygenation. This is especially true while sleeping.
Prophalxic/Initial tx for first week at altitude can reduce incidence of AMS by 75%.

Question 7

What is HACE?

Answer 7

High Altitude Cerebral Edema - cerebral edema is produced as a reaction to decreases atmospheric O2 content
As PO2 drops, blood flow is up-regulated to the brain to maintain cerebral O2 concentrations. However, this can cause excessive cerebral blood pressure and result in edema.
Symptoms: ataxic gait (confused stumbling), lassitude, drowsiness, headache, nausea, vomiting
Tx- O2 (hyperbaric if possible), decent ASAP, dexamethasone

Question 8

What is HAPE?

Answer 8

High Altitude Pulmonary Edema - pulmonary hypertension and edema due to low O2 ventilation
As PO2 in the lungs drops, the capillaries are constricted to match perfusion to ventilation. But since the whole lung is “poorly ventilated,” the complete pulmonary arterial constriction greatly increases pressure. This results in edema.
Symptoms - dyspnea at REST, dry cough, fever, cyanosis
Tx - descend ASAP, oxygen (in hyperbaric if possible), PDE inhibitor (Viagra) –> Cialis for prevention