| What’s in a name? | | | | - Rapid ascents – as a result of tangling with |
| Decompression illness, commonly known as "the | | | | surface marker buoys (SMB’s), problems with |
| bends" is caused by gas bubbles absorbed into tissues | | | | buoyancy control in dry suits, running out of air etc |
| whilst breathing under pressure, typically underwater. | | | | - Staying too long at depth – with resulting |
| Construction workers working on large bridge building | | | | increased gas load |
| projects and the like at the turn of the century were | | | | - Missing planned decompression stops |
| breathing air under pressure for the duration of their | | | | - Equipment problems |
| work shifts, the modern equivalent would be diving to a | | | | - Bounce diving – repeated ascents/descents |
| similar pressure or depth for several hours. | | | | increase risk |
| When the shifts were completed and the workers | | | | How can decompression illness (the bends) be |
| would emerge from the tunnels, many would be seen | | | | treated? |
| to be bent over double in considerable pain – hence | | | | Ultimately, decompression illness is treated in |
| the term "the bends." | | | | hyperbaric chambers. Once assessed, a diver will be |
| During every dive, the diver is breathing compressed | | | | placed inside a hyperbaric chamber where the |
| breathing gases at the chosen depth for the duration | | | | pressure will be increased, they will be "recompressed." |
| of the dive. | | | | As the pressure is increased the offending gas |
| During this time elements of the gas are absorbed into | | | | bubbles reduce in size. This in itself is often enough to |
| the diver’s tissues – the rate being dependent | | | | promote an improvement in the diver’s symptoms. |
| on a number of factors such as the depth, the gas in | | | | Oxygen or oxygen rich gases are breathed, which |
| question, the time spent at depth and so on. This | | | | depends on treatment depth. This, combined with the |
| dissolved gas has to come out later on and if all goes | | | | reduction in bubble sizes, allows the diver to quickly get |
| to plan – a controlled ascent, followed by | | | | rid of dissolved gas bubbles, as well as helping repair |
| ‘decompression stops’ where the diver | | | | any damage they may have caused. |
| continues to breath their diving gas at a specified | | | | Treatment itself consists of several hours inside a |
| depth to for several minutes - the dissolved gas | | | | hyperbaric chamber, with oxygen or other gas |
| generally has enough time to dissolve back into the | | | | breathing sessions interspersed with "air breaks". Slow |
| bloodstream, pass through the lungs and be expired. | | | | controlled ascents are used throughout the treatment |
| Problems can occur though if there is just too great a | | | | where required by the protocol. |
| gas load and the diver cannot get rid of enough of it | | | | Divers are assessed throughout the treatment to |
| during the ascent. Equipment failure at depth, or any | | | | monitor progress and if treated rapidly following the |
| other problems encountered which lead to a rapid | | | | dive, one treatment is usually all that is required. In |
| ascent increase the likelihood of suffering | | | | some cases, either those involving spinal |
| decompression illness dramatically – as the body | | | | decompression illness or delay to recompression, one |
| has not had the opportunity to rid itself of the dissolved | | | | or more further short treatment tables of around 90 |
| gases. | | | | minutes may be required. |
| Tiny bubbles are present following all dives, but there is | | | | A final medical review is carried out and as long as a |
| a point at which either the number of bubbles present | | | | full recovery has been made, divers are usually |
| and/or their size, is enough to cause symptoms. What | | | | advised that a return to diving will be possible after 4 |
| symptoms are experienced will in large part depend on | | | | to 6 weeks – though local policies vary. In some |
| amount and position of those bubbles, which are of | | | | cases divers may be advised to have follow up |
| course numerous. | | | | checks, or potentially even advised not to dive again if |
| What causes decompression illness (the bends)? | | | | it is felt that it is not safe to do so. |
| Common causes of decompression illness are: | | | | |