| This was asked of me at a recent beach diving get | | | | injury are panic and ignorance. Other less common |
| together. I believe this is important to be aware of | | | | causes are choking, nausea, carelessness, and even |
| overexpansion lung injuries (from an uncontrolled | | | | smoking. Smoking can destroy the surfactant which |
| ascent) and secondary pulmonary embolism (air in the | | | | keeps the lungs from sticking shut when they are |
| bloodstream from insulted lung tissue). | | | | vented. This can cause the parts of the lungs to |
| Lung over-expansion injury occurs when a SCUBA | | | | stick shut and simulate holding ones breath. |
| Diver holds their breath when ascending underwater. | | | | How to avoid |
| This can be as little as a 1.5 meter ascent near the | | | | Never hold your breath while using SCUBA equipment. |
| surface. | | | | - Never give a "puff" of air to a free diver when |
| How it happens (The technical reason) | | | | using SCUBA equipment underwater. The free diver |
| When using SCUBA equipment underwater, the diver | | | | may not be aware of the problem of lung |
| is breathing compressed air at a pressure equal to | | | | over-expansion injury and ascend without releasing |
| that of the water around him/her. This means the air | | | | their breath. |
| entering their lungs is at the same pressure as the | | | | - Avoid diving while having chest congestion problems |
| water. When the diver ascends, according to Boyle's | | | | (eg colds, flu's, etc). |
| Law, the air expands due to reducing hydrostatic | | | | - Smokers should not smoke for several hours |
| pressure, (the shallower the depth, the less the | | | | before a dive. (Good luck convincing them of that! So |
| pressure) causing the lungs to over-inflate. | | | | do NOT dive if you are a heavy smoker and have |
| The lung does not burst like a balloon when | | | | had a cold or flu recently). |
| over-inflated, instead it tears. However the tear itself | | | | - See a diving-aware doctor before learning to dive, |
| is not so much a problem as the resulting air entering | | | | and if you have any injury to your lungs or chest, |
| the tissues and bloodstream. The result of such a | | | | see the doctor again. What to do The most |
| rupture causes the pulmonary capillaries and alveoli to | | | | common, and biggest warning sign of a lung |
| rupture mixing blood and air into the lungs usually | | | | over-expansion injury is coughing up blood. Other |
| causing the diver to cough up blood. (A definite alert | | | | indications include chest pains and difficulty breathing. |
| sign) The rupture can also cause one of four injuries: | | | | If you suspect such an injury immediately consult an |
| Air embolism, pneumothorax, mediastinal emphysema, | | | | emergency medical specialist. If you want to know |
| and subcutaneous emphysema. | | | | the nitty gritty more, please ping me at a local dive |
| Why it happens (The human factor) | | | | get together. All that medical school needs to be |
| The most common causes of lung over-expansion | | | | used somehow! |