PADI Dive Physiology and Health 5 — Questions and Answers
Question 1: Which medical condition is an absolute contraindication to scuba diving?
- Well-controlled type 2 diabetes (insulin-independent)
- Spontaneous pneumothorax history without surgical correction (Correct answer)
- Mild seasonal allergies
- Previous broken arm fully healed
Correct answer: Spontaneous pneumothorax history without surgical correction
A history of spontaneous pneumothorax without surgical correction is a standard absolute contraindication because of the high risk of recurrence under pressure.
Question 2: Immersion pulmonary edema (IPE) in divers is characterized by:
- Dry cough only at the surface
- Coughing up pink frothy sputum and difficulty breathing underwater (Correct answer)
- Joint pain and skin mottling
- Tunnel vision and convulsions
Correct answer: Coughing up pink frothy sputum and difficulty breathing underwater
IPE involves fluid accumulating in the lungs during immersion, causing respiratory distress, coughing, and frothy sputum, particularly in cold water or with heavy exercise.
Question 3: How does cold water immersion affect a diver's risk profile?
- Reduces DCS risk by slowing nitrogen absorption
- Increases cardiovascular stress and can accelerate heat loss leading to incapacitation (Correct answer)
- Has no physiological effect beyond slight discomfort
- Prevents nitrogen narcosis
Correct answer: Increases cardiovascular stress and can accelerate heat loss leading to incapacitation
Cold water causes vasoconstriction, increased cardiac workload, and accelerated core heat loss, all of which elevate dive risk.
Question 4: A diver who takes certain antihistamines before diving should be aware that these drugs may cause:
- Increased buoyancy
- Sedation that can impair underwater judgment and mask DCS symptoms (Correct answer)
- Protection against nitrogen narcosis
- Enhanced night vision
Correct answer: Sedation that can impair underwater judgment and mask DCS symptoms
First-generation antihistamines cause sedation and can interact with nitrogen narcosis, impairing performance and masking medical symptoms.
Question 5: Which physiological effect of diving increases urine production and can lead to dehydration?
- Immersion diuresis due to central blood volume shift (Correct answer)
- Increased salt intake from seawater
- Breathing dry compressed air only
- Elevated cortisol from task loading
Correct answer: Immersion diuresis due to central blood volume shift
Water pressure causes blood to shift centrally, triggering the kidneys to produce more urine (immersion diuresis), which can dehydrate divers.
Question 6: Patent foramen ovale (PFO) is a diving risk because it:
- Increases oxygen consumption at depth
- Allows venous bubbles to bypass the lungs and enter arterial circulation (Correct answer)
- Prevents equalization of middle ear pressure
- Reduces hemoglobin binding capacity
Correct answer: Allows venous bubbles to bypass the lungs and enter arterial circulation
A PFO is an opening between heart chambers that allows venous nitrogen bubbles to enter arterial blood, increasing DCS and AGE risk.
Question 7: A diver with a recent ear infection should:
- Dive only in warm, shallow water
- Postpone diving until fully recovered and cleared by a physician (Correct answer)
- Use decongestants and dive normally
- Avoid only deep dives above 18 m
Correct answer: Postpone diving until fully recovered and cleared by a physician
Ear infections can impair Eustachian tube function, making equalization impossible and risking middle ear barotrauma or perforation.
PADI Dive Physiology and Health 5
Which medical condition is an absolute contraindication to scuba diving?