Scuba Diving Safety Diving 5 — Questions and Answers
Question 1: A diver surfacing from a deep dive suddenly loses consciousness at the surface. The most likely cause is:
- Arterial gas embolism (AGE) from lung overexpansion (Correct answer)
- Exhaustion from long swimming distance
- Dehydration-induced syncope
- Sunstroke from surface exposure
Correct answer: Arterial gas embolism (AGE) from lung overexpansion
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)?
- Holding the breath during ascent (Correct answer)
- Breathing continuously through the regulator
- Ascending at 30 feet per minute
- Performing a safety stop at 15 feet
Correct answer: Holding the breath during ascent
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:
- Behind the victim to avoid being grabbed and pulled under (Correct answer)
- Directly in front to make eye contact and reassure them
- The side with their dominant hand free
- Underwater from below to push them up
Correct answer: Behind the victim to avoid being grabbed and pulled under
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:
- Lowers CO2 below the level that triggers the urge to breathe, risking shallow water blackout (Correct answer)
- Increases nitrogen absorption in the tissues
- Causes oxygen toxicity at shallow depths
- Overinflates the lungs and increases squeeze risk
Correct answer: Lowers CO2 below the level that triggers the urge to breathe, risking shallow water blackout
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?
- That it is a diving accident, depth and duration of the dive, and symptoms present (Correct answer)
- The brand of equipment the diver was using
- The exact GPS coordinates of the dive site only
- The diver's certification level and agency
Correct answer: That it is a diving accident, depth and duration of the dive, and symptoms present
EMS dispatchers need to know it's a dive-related injury to send appropriate resources including hyperbaric specialists or DAN referral.
Question 6: A diver notices their air consumption is much higher than normal at the same depth. The most likely explanation is:
- Increased exertion, cold water, or anxiety elevating breathing rate (Correct answer)
- A faulty depth gauge reading shallower than actual depth
- Over-weighted configuration reducing buoyancy control effort
- Incorrect nitrox blend requiring more breaths
Correct answer: Increased exertion, cold water, or anxiety elevating breathing rate
Higher-than-normal air consumption at depth is almost always tied to increased work of breathing from exertion, cold stress, or anxiety.
Question 7: What does the term 'task loading' refer to in scuba diving safety?
- Having so many tasks to manage simultaneously that situational awareness breaks down (Correct answer)
- The weight added to a diver's BCD by equipment
- The mental fatigue from extended decompression calculations
- Overloading a dive bag beyond safe carrying capacity
Correct answer: Having so many tasks to manage simultaneously that situational awareness breaks down
Task loading occurs when multiple simultaneous demands (navigation, buoyancy, photography) overwhelm the diver's attention and degrade safety awareness.
Scuba Diving Safety Diving 5
A diver surfacing from a deep dive suddenly loses consciousness at the surface.
The most likely cause is: