Charity Number: 279652

DDRC diver swimming

26 February 2018

Diving Accident Scenario

A 45 year old experienced diver was diving in a quarry. He performed two dives over the day wearing a dry-suit and using a manifolded twinset filled with air.

Dive 1: Max depth 38m for 40 minutes. Normal dive profile with no mandatory decompression stops incurred and a safety stop was performed. Surface interval of 2 hours.

Dive 2: Max depth 35m for 45 minutes, followed a normal dive profile with no decompression stops required. The dive went well, until during ascent.  The diver indicated to his buddy that he wanted to go straight up, rather than do a safety stop. The ascent rate was quick but not uncontrolled. After a short surface swim, the diver became very short of breath and started coughing. Upon exiting the water with assistance the diver vomited and collapsed.

What has happened? What would you do?

As divers you may well be the first on scene, responding to a dive casualty. We have deliberately left the scenario quite open to interpretation to facilitate some thoughts and discussion at this point.

Feedback from Facebook

Originally this scenario was posted on Facebook, in installments over a few days, prompting some discussion and debate. In response to this, it was agreed that no tables created would allow you to undertake these dive profiles without incurring significant decompression. In order to complete this profile the diver has either planned a multi-level dive profile, or they have been diving with a computer, as was the case with this diver.

In the absence of a detailed dive plan, it is entirely appropriate to assume the worst case scenario, in that they have done square profiles. This case demonstrates that when transferring a dive casualty to a recompression chamber, it is really very important to send the dive computer with the diver, whenever possible. This prevents information from being lost. It allows the treating doctor to see their exact profile and gauge their inert gas loading. It also shows whether there have been any rapid ascents that could contribute to the problem.

There was much debate around In Water Recompression (IWR). There are certain situations where, with an appropriately trained casualty, appropriate support divers, equipment and conditions it may be appropriate. Within the UK you are very rarely more than 4 hours away from your nearest chamber.  Any water you put a diver back into is at the very least going to be cold. Add into the mix some current with sub-optimal visibility and the risks of things going wrong climb rapidly. The diver in the scenario is showing signs of lung involvement. Any diver with respiratory distress would not be a candidate for IWR.

The Scenario Continues…

Call 999 for help. This is a life threatening emergency.

At sea, contact the coastguard on VHF Channel 16.

Also call the National Diving Accident Helpline on 07831 151 523 in England and Wales. In Scotland call 0345 408 6008.

Assessing the Dive Casualty

When assessing a diver, start with the ABCDE approach. The DDRC Healthcare flow chart  can help when dealing with an incident.

After a brief loss of consciousness the diver regains consciousness, but is unable to stand. He is answering questions but seems drowsy and confused. He has several further episodes of vomiting.

Airway – The diver is talking and the airway can therefore be considered clear.

Breathing – Look, listen, feel for 10 seconds. In this scenario the diver is breathing but it is rapid and shallow. He appears to be in pain from his breathing and is coughing. Feeling around his neck the skin feels abnormal, like bubble wrap.

*** Oxygen should always be given to a diver, even if their oxygen saturation levels are measuring normal ***

Circulation – our diver is talking and breathing with no evidence of bleeding. He has a good pulse at his wrist with a rate of 90 beats per minute. He is likely to have adequate circulation.

Disability – The AVPU scale (alert, voice, pain, unresponsive) is useful and simple to assess overall consciousness. The diver, whilst drowsy, is responding when you talk to him. If the diver is well enough, use the DDRC 5 Minute Neurology Exam to assess his neurological state. This provides a useful benchmark to track any potential deterioration. After a quick assessment you notice that his eyes are rapidly flickering from side to side. He is also suffering from weakness and numbness in both legs. This is known as ‘nystagmus’.

Exposure – check the diver for any wounds, rashes or surgical emphysema. Bear in mind that full exposure on a boat or pontoon may not be advisable on a cold day!

In this scenario our diver has a clear airway, but is vomiting. He is coughing and has painful, rapid, shallow breathing with a bubble wrap texture around his neck. He has no circulatory compromise currently. He is only responding to voice and is showing evidence of neurological disturbance.

He should be put into the recovery position and given high flow oxygen.

It is important to regularly re-assess ABCDE whilst help is on the way.

It is also important to keep a close eye on the diver’s buddy. Are they also unwell?

What is your Diagnosis?

What is your diagnosis of the casualty in this diving accident scenario? What do you think has happened and what evidence do you have to support that?

Time to reflect, discuss and consider this scenario again.


The Scenario Concludes…

This diver has suffered lung barotrauma on his ascent. This may be due to breath holding, or in this circumstance due to an undiagnosed, underlying lung condition. He has then suffered a subsequent cerebral arterial gas embolism (CAGE).

The barotrauma is evident by his painful breathing and the bubble wrap feeling around his neck. This is subcutaneous emphysema or air within the skin tissues. In divers it is diagnostic of a collapsed lung, also known as a pneumothorax.

The rapid onset of vomiting and collapse, coupled with abnormal eye movements and lower limb weakness and loss of sensation, are all serious neurological signs. They indicate that as a result of his pneumothorax air has entered his arterial circulation and traveled to his brain. A cerebral gas embolism.

In conjunction with the on-call Diving Doctor, this diver was evacuated by helicopter to the Emergency Department for a chest x-ray and chest drain insertion. He was then transferred to DDRC Healthcare’s Hyperbaric Medical Centre in Plymouth, for emergency recompression using a Comex 30 treatment table as initial therapy.