Avoiding and Treating Reverse Block During Scuba Diving Ascent
A reverse block may occur upon ascending to the surface, as air expands in our tissues. It’s pretty rare to experience a reverse block. Most divers would not experience reverse block while scuba diving as long as taking the right measures to prevent it from happening.
Depth, pressure and volume. Some background:
The deeper we get the more pressure is applied on our body. These changes are more drastic at shallow water, where even a small change in depths can be easily felt. Every 10m/33ft of salt water adds 1bar/atm of pressure to the ambient pressure applied on us. Adding 1atm/bar of pressure due to the air pressure and you’ll experience 2 bars at 10m/33ft, 3bars at 20m/66ft and so on.
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As we ascend air bubbles that were dissolved in our tissues will expand. Under normal circumstances air will simply escape our tissues to our bloodstream and out it goes when exhaling.
A reverse block is caused by mucus blocked sinuses that prevent these air bubbles from escaping our body. Upon ascending, trapped bubbles press on the sinuses which cause serious pain above the eyes, around the chicks, and all the way down to the teeth.
How to avoid a reverse block?
Luckily, reverse block can be easily avoided for most divers:
- Those with chronic sinus problems should not dive, unless checked by a dive physician.
- Never Dive with a cold. Diving with a cold increases your chances of experiencing a reverse block, which is something I don’t recommend trying to temper with. When having a cold you may have your sinuses blocked which can make it difficult to equalize upon descent and even more serious, experiencing a reverse block upon ascent.
- You may use decongestion drugs, as long as you make sure these will not ware out during the dive, or else you’ll find yourself stuck at mid-water struggling with a reverse block.
What do I do if I experience a reverse block?
- Relax. All you have to do is to stop your ascent and signal to your body you have some problems and you need to take your time ascending to the surface.
- Descend a few feet/meters, that increases water pressure and shrinks those trapped air bubbles, which decreases the pressure on your tissues and may relieve the pain.
- Take your time. Equalizing reverse block may take some time, so make sure you and your buddy have enough air left in the tank. Some reverse block cases are only solved after 10-15 minutes so be patient and don’t force your ascent.
Treating Reverse Block
If you do ascent to the surface while experiencing a reverse block your condition mat only get worse. It may also lead to sinuses rapture, which on a minor scale may lead to some nose bleeding, but may also lead to sinuses infection if left untreated.
look for some professional help if experiencing serious reverse block.