Case Study 8: The Respiratory System at Altitude and Depth

Objectives:

• Understand what the normal partial pressures of gases in the circulatory system are and how they change with altitude and depth.
• Explain the physiological changes humans encounter at high altitudes and at depth.
• Evaluate physiological data in order to make a medical diagnosis.
• Understand the integration of the cardiovascular, respiratory, and nervous systems in regulating homeostatic variables such as blood gas levels, pH, etc.

These case studies are based on a real-life situations.

Instructions: there are two case studies – one on respiratory distress at altitude (Part 1) and one at depth (Part 2). Select one of the case studies to complete.

Respiratory System Part 2: At Depth

Dan, a 38-year-old experience diver, has spent a decade recreationally diving on coral reefs. Recently, he and his partner opened a charter business that involved taking clients out on shipwrecks. They have taken a group of four to explore the wreck of the SS Atlas, a freighter that was sunk by a torpedo in 1942 from a German U-boat. Dan briefed the group on the dive which would be in 80 feet of water and familiarized them with procedures during the dive and the layout of the wreck. Maximum decompression limit was 40 minutes, with 5 minutes to descend down to the anchor line to the wreck and 30 minutes exploring before returning to the surface. Below is a table with changes in lung volume, atmospheric pressure, and the partial pressures of O₂ and N₂ with increasing depth.

Question:

1. What are the consequences for divers as a result of changes in lung volume, atmospheric pressure, and the partial pressures of O₂ and N₂ with increasing depth? Hint: think about what is happening to the gases in the bloodstream at depth. What happens when the diver returns to the surface?
2. What is decompression sickness and what is the cause?
3. What are some common signs of decompression sickness?
4. What is the treatment for decompression sickness?
5. Once in the helicopter, the paramedics try to stabilize both patients. Would flying at a high altitude worsen their condition?
6. What are some of the long-term effects of decompression sickness? Is it life-threatening?

Case Study 8: The Respiratory System at Altitude and Depth Answer 

1. As divers go deeper into the sea, the atmospheric pressure increases which exerts a greater compressive force on their bodies, which causes the lung volume to decrease, as well as that of air in other parts of the body. The reduced lung capacity of the divers will require the them to take more breaths in order to deliver the needed amount of oxygen.