Diving with a spontaneous pneumothorax is not recommended. First aid is needed to evacuate air if a lung collapses while diving, for which most divers and dive boats may not be prepared. Spontaneous pneumothorax is an inherited disease where some areas of the lung’s pleural lining are weak.
In the past few years, we have witnessed a relaxation of many of the rules about diving with medical disorders. We now allow some individuals with heart conditions to dive after a careful medical evaluation and there are many people with mild asthma who are diving safely. Each question that arises about diving with a medical disorder has been subjected to medical review, a statement has been made about the limits of capability with the disorder and some information is provided about how to determine whether diving will be safe. In the case of asthma, for example, there have been several seminars and workshops about defining the limits of asthma that would not compromise diving safety. New guidelines will soon be available for asthmatics who wish to dive. There is now a group of expert physicians examining diabetes and a similar outcome is expected.
Questions about diving with a spontaneous pneumothorax are increasing because of the number of people with this disorder and their increasing interest in diving.
Lung collapse occurs when the airtight integrity of the lining of the chest cavity is broken. The chest cavity is filled with the lungs, heart and the major blood vessels. The lungs remain in the expanded state because they are held against the inside of the chest by a vacuum created in a thin layer of fluid between the lining of the chest and the lining of the lung. These two linings are called pleura. The vacuum that holds the lungs in an expanded state is created by the elastic recoil of the lungs. Because the pressure within the chest cavity is negative, damage to either of the linings will cause air to leak into the chest cavity outside the lungs and break the vacuum that holds the lungs in an expanded state. This condition is called a pneumothorax.
The lungs expand during inspiration because the muscles of the chest and the diaphragm force the chest to expand. As the chest expands, the vacuum inside increases and pulls the lungs along with the expanding chest. Expiration is accomplished when the muscles in the chest relax and the elastic energy of the expanded lungs pulls the chest cavity back to a smaller size. All of this results in air moving into and out of the lungs. During inspiration, the vacuum in the chest increases and, if a leak is present, air will be sucked into the chest cavity. In most instances, the air will leave the cavity during expiration but there are occasions when the leak acts as a one-way valve and air enters but does not leave. In this case, the chest cavity fills continuously with air, causing the lung to collapse. The collapsed lung does not allow air to be exchanged and shortness of breath follows. This makes the person breathe harder, creating a larger vacuum and drawing more air into the chest cavity, making the pneumothorax worse. Fortunately, the chest is separated into two pleural spaces separated by the heart and blood vessels, so when damage to one side of the pleura occurs, collapse of only one lung is likely. Complete collapse of both lungs is usually fatal if not rapidly corrected.
The issue raised in diving is spontaneous pneumothorax, an inherited disease that leaves some individuals with weak areas of the pleural lining. These may take the form of small blisters or outpouchings of the lung called blebs, which are weaker than the normal lining of the lung and can occasionally break and cause air to leak from the lung to the chest cavity, resulting in a pneumothorax. The disorder is called spontaneous because the collapse can occur without provocation or warning. Most people with blebs who experience spontaneous pneumothorax can relate some activity to the event. Often the individual is exercising, straining while lifting or performing some other physical task but many times nothing out of the ordinary is being done. About 80 percent of people with a spontaneous pneumothorax have blebs on the lung surface. Most of the remaining 20 percent who have no blebs will usually be smokers. Thus, presence of blebs and smoking seem to be risk factors. If one spontaneous pneumothorax has occurred, there is a 30 percent chance another will occur within two to three years.
When a lung collapses while diving, the air in the chest cavity is at ambient pressure. When the diver ascends, the air in the chest cavity expands and further compresses the lung. The expanding air may cause total collapse of the lung on one side, then continue to expand and push the heart and blood vessels into the opposite side of the chest. Continued expansion can collapse veins in the chest and cause a blockage of blood flow into the heart. Obviously, none of these events is good for the diver and, in some cases, may be life-threatening. There have been cases reported where the diver needed immediate insertion of a needle into the chest to evacuate the air and restore the lung and heart to normal. Most divers and dive boats are not prepared to provide this type of first aid to someone with pneumothorax.
A spontaneous pneumothorax that occurs at one atmosphere does not cause an expanding gas problem. Indeed most are self-limiting and do not cause total lung collapse. A partial pneumothorax may not even be noticed save for a vague feeling of discomfort in the chest on the side of the partial lung collapse. It is mainly in the diving environment that a spontaneous pneumothorax can cause a life-threatening situation. Thus, persons with a history of spontaneous pneumothorax should not dive.
The symptoms of spontaneous pneumothorax vary widely. One person may feel nothing, may have a vague feeling of discomfort in the chest on the side of the collapsed lung, may become short of breath and may develop shock if the air expands and compresses the veins in a way that prevents the normal flow of blood through the heart. Pain may be a component of the pneumothorax. This is usually sudden in onset, sharp and often made worse by breathing. A feeling of shortness of breath may occur because the pain prevents normal breathing or because the lung collapse does not allow enough oxygen to get to the blood. If the pressure within the chest cavity increases, owing to expanding gas on ascent, air may find its way into the tissues of the neck and subcutaneous emphysema will accompany the pneumothorax. In some cases, air surrounds the larynx (the voice box) in the neck and causes abnormal function of the vocal cords resulting in a change in the voice. A voice change following a dive should raise special concern because there may be a small pneumothorax that in itself is not harmful but will cause a serious problem if another dive is made.
Individuals who have a history of a spontaneous pneumothorax have asked if there is any way to determine who will be at risk and whether there is any method to correct the problem. The presence of lung blebs is usually not known until a pneumothorax occurs. As noted above, 30 percent of people with one pneumothorax will have another in two to three years and a further 30 percent will have a recurrence after three years. Thus, there is a 60 percent long term risk for another pneumothorax. These statistics are related to the finding that a person who has pleural blebs usually has more than one and all of the blebs are prone to leak at one time or another.
Some people with spontaneous pneumothorax have frequent events that may cause numerous hospitalizations. Treatment for a small pneumothorax (10 percent collapse or less) is usually minimal to no therapy, as the gas in the chest will be reabsorbed in a few days. When all blebs are treated, the recurrence rate can be as low as two percent (versus 30 percent in untreated cases). In the future, it may be possible for those with spontaneous pneumothorax to dive if they have identified blebs on the lung, the blebs are all repaired and sometime elapses to be sure a recurrence will not occur.
At present, diving trained physicians will not recommend diving for anyone who has had a spontaneous pneumothorax. Advances in surgical therapy in the future may provide the opportunity to change this standard but diving is not recommended at this time.