During diving, there are several factors that can affect the respiratory system. These include the environmental conditions and the diver’s age. Divers should be examined before they go diving. They should also report any pre-existing medical conditions. If they are experiencing breathing problems, they should stop diving.
The most common diving accident is an arterial gas embolism. This occurs when gas bubbles do not reach the alveoli and enter the mediastinum. This interferes with the delivery of blood to the vital organs. The resulting condition is mediastinal emphysema. This condition is often spontaneously reversible. However, it can lead to mediastinal emphysema, pulmonary edema, or both. Symptoms begin at depth and may include chest pain, dyspnea, and wheezing.
Divers’ CO2 levels are elevated due to the increased pressure of diving. This is not the cause of pulmonary barotraumas, however. These are caused by trapped air. When trapped air expands, it blocks blood flow and causes various types of damage.
Air sacs in the lungs are thin and are designed to hold air. However, when the pressure of the lungs increases, the air expands faster than it can exit the alveoli. Eventually, the air gets trapped in a balloon-like extension of the air sacs called BLEBs. This trapped air expands more rapidly than the alveoli and may burst, blocking the air from exiting.
In one study, scuba divers of the German Navy were compared with healthy controls. The subjects underwent high resolution computed tomography of their chest. Compared to the healthy controls, the scuba divers had minor lobular air trapping.