RGI 4 Notes

Flashcards covering key concepts related to barotrauma, decompression sickness, gas laws, and diving safety.

What is barotrauma?

A type of injury caused by abnormal air pressure.

What are the major conditions associated with barotrauma?

Mediastinal emphysema, cerebral embolism, pneumothorax.

What does the total pressure formula Ptot = Patm + pgh represent?

Total pressure increases by 1 atmosphere for every 10m of depth.

What is the purpose of a self-contained underwater breathing apparatus (SCUBA)?

Delivers air at ambient pressure, combining atmospheric and gauge pressure.

What is decompression sickness (DCS)?

A condition resulting from the formation of bubbles due to rapid ascent to the surface.

What is Henry's Law?

The concentration/solubility of a gas in a liquid is proportional to its partial pressure above the liquid.

What happens to gas solubility during a dive?

Solubility of O2 and N2 increases in body tissues and blood.

What can happen if a diver ascends too quickly?

Bubbles form in the body as gases come out of solution.

What are common symptoms of decompression sickness?

Joint pain, muscle spasms, and other neurological symptoms.

What is the recommended speed for an ascent to prevent DCS?

No faster than 10m per minute.

What is the main treatment for decompression sickness?

Administration of O2 and immediate transport to a recompression chamber.

What is the equivalent seawater pressure for hyperbaric treatment of DCS?

Usually at 18.5m of seawater pressure.

How long after a dive can symptoms of DCS appear?

Symptoms can take up to 24 hours to appear.

What gases do commercial divers use for deep dives?

Heliox or Tri-mix gases.

What is Caisson Disease?

The early name for decompression sickness, related to construction work in pressurized environments.

Why should sport divers avoid flying after diving?

To prevent DCS due to residual nitrogen in the body.

How does nitrogen narcosis affect divers?

It has an intoxicating effect that impairs motor function and decision-making.

At what nitrogen partial pressure does nitrogen narcosis occur?

It occurs at pressures greater than 3.2 atm.

What is the danger of oxygen toxicity?

It can become toxic for any pO2 greater than 1.6 atm.

What are the symptoms of oxygen toxicity?

Convulsions and potential fatality underwater.

What is the equivalence of nitrogen narcosis to alcohol?

Approximately 1 unit of alcohol for every 10m of depth.

In what conditions can decompression sickness occur outside of scuba diving?

Sudden loss of cabin pressure in airplanes.

What historical event is associated with the first documented cases of DCS?

Construction of the Brooklyn Bridge.

What does “The Bends” refer to?

Decompression sickness resulting in bubble formation in the body.

What part of the body is often affected by gas bubbles during DCS?

Joints, muscles, cerebrospinal fluid (CSF), bloodstream, and capillary beds.

What physiological mechanism is limited in removing excess nitrogen?

The body can't expel nitrogen bubbles effectively.

What pressure is required for pure O2 to be safe while diving?

Safe at depths of 6m for pure O2.

How do divers use gas mixtures to prevent DCS?

By diluting nitrogen with helium or argon.

What is the risk of nitrogen narcosis correlated with?

Depth of the dive.

How is decompression sickness managed once diagnosed?

Immediate referral for treatment in a recompression chamber.

Why is it important to ascend slowly during diving?

To avoid rapid decompression and the formation of harmful gas bubbles.

What medical facility specializes in treating decompression sickness in Ireland?

The Department of Underwater Medicine at University College Hospital, Galway.

What has been noted about the incidence of DCS in recent years?

There has been an increase in the incidence of DCS in Ireland.

What must all divers equipped with specialized diving equipment recognize?

Abnormal physiological conditions associated with their diving.

What physical experience indicates a diver may be suffering from DCS?

Assuming a fetal position due to spasms caused by gases in joints.

What common pressure is found in SCUBA diving at typical depths?

Ambient pressure plus gauge pressure.

What are the long-term risks of DCS if not treated properly?

Chronic pain and mobility issues.

What has the Department of Underwater Medicine done to improve patient outcomes?

Early recognition and referral for treatment.