Hello johnr:
Answers are for information only, do not imply diagnosis or treatment and should always be used in conjunction with advice from your personal physician.
One almost fears to write anything negative on this board for fear of being 'flamed' - but here goes!
Spontaneous pneumothorax is an inherited disease which leaves some people with weakened areas of the pleural lining of the lung, called blebs or blisters. These can occasionally burst, the lung collapses and causes air to leak from the lung to the chest cavity, resulting in a pneumothorax ('air in the chest'). It is 'spontaneous' in the sense that there was no trauma or surgical cause of the ruptured bleb. It can occur when the individual is exercising, straining, or performing some other physical task, but most of the time it just happens. If one spontaneous pneumothorax has occurred, there is a 33% chance that another will occur within 2-3 years; 30% will have a recurrence after 3 years, and there is a 60% long term risk for another pneumothorax.
When a lung collapses while diving, the air in the chest cavity is at the ambient pressure of the dive depth. Upon ascending, the air in the chest cavity expands, and further compresses the lung (tension pneumothorax), often pushing the heart over into the other side of the chest, severely compromising cardiopulmonary function. This is a life-threatening situation and is one of the main reasons that a history of spontaneous pneumothorax is an absolute contra-indication to diving since most divers and dive boats are not prepared to provide first aid to a diver with pneumothorax. One of the symptoms of a small pneumothorax is a voice change after a dive. This would raise a warning flag about further diving as there might be a small pneumothorax which in itself is not harmful, but which will cause a serious problem if the diver does another dive.
You cannot assume that you are at no risk because you have not had problems in a long time - the blebs that you describe would surely burst under the tremendous changes in pressure of diving. Also, nothing in diving is invariable but there would be considerable risk of a tension pneumothorax on ascent after a sizable spontaneous collapse of your lung at depth. There has been a special instrument developed, called the "McSwain dart" for use on dive boats for this situation. This can be obtained at most surgical supply houses. A 14 gauge needle/catheter assembly will often do just as well until the diver reaches an emergency facility.
Gas embolism with air getting into the arterial circulation is another serious outcome that can happen, often with brain and cardiac symptoms, and possible death.
Surgical procedures called pleurodesis (scarring the lung surface) and pleurectomy (excision of the pleura, a thin covering of the lungs) are commonly performed for recurrent collapsed lungs. There is a recurrence rate of 8 percent following pleurodesis. Recurrence is rare following pleurectomy. Even if recurrence of collapsed lung does not occur, the underlying cystic lung disease of the other lung remains, with the inherent danger now being pulmonary barotrauma with air embolism. The following are absolute contraindications to diving:
Diving within three months after any type of collapsed lung.
Spontaneous collapsed lung in beginners.
Expert divers with recurrent collapsed lung after pleurectomy.
If you feel that you will continue your quest to dive regardless of the risk, Spiral CT scans of your lungs should be performed so as to detail the degree of risk involved.
Best advice here would be not to dive until you have had a pleurectomy (both sides, if necessary)and have been cleared to dive by your personal chest physician.
Best regards:
Ern Campbell, MD, FACS
Diving Medicine Online
http://www.scuba-doc.com/
