Decompression Illness (DCI) encompasses:
- Decompression Sickness (DCS)
- Arterial Gas Embolism (AGE)
Decompression Sickness (DCS): Time spent diving causes an excess of inert gas, such as nitrogen, to dissolve in the body. When a diver surfaces this dissolved gas may form bubbles, which then cause local damage to body tissues or obstruct small blood vessels. This can result in a wide range of symptoms including pain, weakness, dizziness or tingling.
Arterial Gas Embolism (AGE): Most commonly occurs when diving as a result of lung over-expansion injury, also known as pulmonary barotrauma. Air passes directly from the lungs into the arteries, blocking them. This causes a variety of sudden onset, stroke-like symptoms depending on the site of the blockage, such as one sided weakness or loss of consciousness.
Common symptoms and mechanisms of DCI
- Limb pain – Vague pain in a joint or limb that is typically described as like a tooth ache
- Back pain/pain across the abdomen
- Nerve symptoms – Tingling in skin, weakness in the muscles, difficulty expressing oneself or not behaving normally, poor co-ordination, loss of bowel or bladder control, changes in hearing or eyesight, memory loss, unconsciousness
- Ear problems (Staggers) – Sense of spinning and inability to stand up due to dizziness. Hearing loss. Ringing in the ears, nausea and vomiting
- Chest Pain or breathing difficulties (Chokes)
- Rash –Take a picture of the rash and send it to a hyperbaric centre as it may have disappeared by the time the diver reaches a chamber. Divers commonly believe the skin rash is of no consequence but other signs are often apparent when they are examined fully by a diving doctor. Ignoring a rash could lead to significant disease if not treated correctly
- “Not quite right” – constitutive symptoms such as headache, apathy, inappropriate fatigue, malaise, loss of appetite, difficulty in carrying out simple arithmetic and word blindness
How is DCI diagnosed?
Currently, there are no specific diagnostic tests, investigations or imaging techniques which can confirm or deny a diagnosis of DCI. It is therefore up to a qualified diving doctor to take a history, examine the diver and then decide clinically whether it is DCI or not.
How is DCI treated?
First Aid: First principles in any first aid situation are to assess for a safe approach to the casualty, look for and treat in order or concurrently: catastrophic haemorrhage (bleeding), airway, breathing, circulation, disability and exposure. The well-known mnemonic is cABCDE which all divers should be familiar with.
Oxygen: Administer 100% oxygen immediately and continuously.
Fluids: Give fluids if the diver is conscious and able to swallow. Give water or cold drinks.
DO NOT give Entonox (50% nitrous oxide/50% oxygen) under any circumstances to anyone who has recently dived as the nitrous oxide is highly soluble and will increase the inert gas load, making the symptoms of DCI worse. It can also expand within the air filled spaces of the body and cause barotrauma to the lungs, ears, sinuses or gut.
DO NOT give pain killers unless you have a very long transfer to a chamber, and only after discussion with a diving doctor.
Hyperbaric Chamber Treatment
If the diver has chest pain, breathing difficulties, is unconscious or has a rapidly progressing neurological DCI or AGE they should be taken to the nearest Emergency Department for assessment.
Divers without the above symptoms can brought to DDRC Healthcare where the duty doctor will see and examine them immediately.
What can I do to stop myself getting DCI?
This list is not exhaustive but covers some of the main ways to reduce risks. Remember that computers give an average decompression profile for your dive but you may not be an average diver!
- Dive well within your computer and/or table limits, don’t miss deco.
- If you are using a computer add on extra conservative settings to limit yourself.
- Dive with Nitrox (if trained to do so).
- Stay shallow.
- Keep hydrated.
- Keep warm.
- Dive in a buddy pair.
- Don’t drink alcohol.
- Don’t use recreational drugs.
- Look after your health generally. Eat a healthy balanced diet and do regular exercise and keep your weight within normal limits.
- If you have a health problem, then please declare it on your medical form and seek a dive doctor’s opinion well before you dive.
- Dive safe. “Plan your dive and dive your plan”. Add in levels of safety along the way and establish good signals so you can communicate underwater.
- Dive within your limits of safety and what you feel comfortable with. If you don’t feel comfortable at a dive site, then don’t get in the water. Panic due to anxiety can be a major cause of DCI.
- Keep your kit serviced and in full working order. Kit failures are often a reason for rapid ascents.
- Diving with a buddy who knows you well is always better if possible. If you don’t know your buddy, make sure you communicate well and dive the plan you make.
- If you are diving on holiday, consider taking a day to off gas. There is no hard and fast rule about this, but certainly 4 dives a day for 6 days in a row will give you a significant nitrogen load.
- Be wary diving at altitude and follow your training organisation’s guidelines strictly.
- Adhere to safety stops on top of decompression stops.
A note about health insurance
Treatment for DCI in the UK is free but if you are diving abroad you must ensure you have adequate insurance cover. Companies specialising in dive trip insurance are widely available via the internet or dive magazines. Many divers use their bank’s travel insurance to cover them for trips abroad but read the small print as there is often a depth limit. They will not cover you if it can be shown you have exceeded the depth limit agreed, by even a tiny amount.
I think I may have Decompression Illness
Even if you just have a nagging little doubt about possible DCI symptoms, do call us for some advice, or follow our emergency procedures, as appropriate.
On average, only around a third of the divers that we speak to or assess, actually require treatment in our hyperbaric chambers.