Scuba Diving Safety Diving 5

Question 1

A diver surfacing from a deep dive suddenly loses consciousness at the surface. The most likely cause is:

Accepted Answer

Arterial gas embolism (AGE) from lung overexpansion

Answer

Sudden loss of consciousness on surfacing is a hallmark of AGE, where expanding gas emboli enter the bloodstream and block cerebral circulation.

Question 2

Which action significantly increases the risk of arterial gas embolism (AGE)?

Accepted Answer

Holding the breath during ascent

Answer

Holding the breath while ascending allows expanding air to over-inflate and rupture lung tissue, sending bubbles into the arterial circulation.

Question 3

When assisting a distressed diver at the surface, the rescuer should approach from:

Accepted Answer

Behind the victim to avoid being grabbed and pulled under

Answer

Approaching from behind prevents a panicking victim from grabbing the rescuer and endangering both divers.

Question 4

Hyperventilation before a breath-hold dive is dangerous because it:

Accepted Answer

Lowers CO2 below the level that triggers the urge to breathe, risking shallow water blackout

Answer

Hyperventilation purges CO2, delaying the breathing urge while oxygen depletes to unconscious levels — this is called shallow water blackout.

Question 5

What is the most important information to relay when calling emergency services after a diving accident?

Accepted Answer

That it is a diving accident, depth and duration of the dive, and symptoms present

Answer

EMS dispatchers need to know it's a dive-related injury to send appropriate resources including hyperbaric specialists or DAN referral.

Scuba Diving Practice Test