1.3 Carbon Dioxide Toxicity

• What does properly designed diving gear prevent?

  CO2 toxicity due to depth
• Why does depth not increase CO2 partial pressure in the alveoli?

  Depth does not increase CO2 production rate
• What happens if a diver breathes normally at depth?

  Alveolar CO2 pressure remains normal
• What can happen with certain diving gear like rebreathers?

  CO2 can build up in dead space air
• What is the maximum increase in minute respiratory volume a diver can tolerate?

  8- to 11-fold increase
• What occurs when alveolar CO2 pressure exceeds 80 mm Hg?

  Respiratory center becomes depressed
• What symptoms does a diver experience beyond 80 mm Hg PCO2?

  Respiratory acidosis and lethargy
• What happens to nitrogen when a person breathes air under high pressure?

  Nitrogen dissolves in body fluids
• Why does nitrogen remain dissolved in body tissues?

  Nitrogen is not metabolized by the body
• How is nitrogen removed from the body after high pressure exposure?

  By reverse respiratory process
• How much nitrogen is dissolved in the body at sea level?

  1 liter
• How is nitrogen distributed in the body at sea level?

  Half in water, half in fat
• What is the volume of nitrogen dissolved at 100 feet?

  4 liters
• What is the volume of nitrogen dissolved at 200 feet?

  7 liters
• What is the volume of nitrogen dissolved at 300 feet?

  10 liters
• Why does nitrogen take hours to reach equilibrium in body tissues?

  Blood flow and diffusion are slow
• How does nitrogen saturation differ between body water and fat?

  Fat takes longer to reach equilibrium
• What happens if a diver stays at depth for only a few minutes?

  Not much nitrogen dissolves in tissues
• What happens if a diver remains at depth for several hours?

  Body water and fat become saturated