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 Current Diving Research at DDRC - M St Leger Dowse - DDRC, Plymouth, UK

+44 (0)1752 209999,,,

Reporting Signs and Symptoms of Decompression Illness

What happens when a diver experiences signs & symptoms of DCI? Some divers wait several hours before seeking help, and some divers fail to seek help at all. We know there is a relationship between the time from onset of symptoms to time of treatment and lasting effects. "Denial" works against the successful outcome of a diving incident. Delayed treatment can result in residual effects because the trauma of bubbling is allowed to continue without check.

In 1992 a DDRC study showed 37% divers waited >6 hrs before seeking treatment for DCI. Early results in the current DDRC study so far show 38% divers waited >6 hrs before seeking help. Only 22% of >6hrs group identified the cause as DCI. 78% didn't know the cause or thought it some other factor, >72 % did not consider/know if the signs and symptoms were serious and/or life threatening and 50% thought the symptoms would go away.

In both groups, <6 hrs and >6 hrs, some explanations given by diver for the symptoms were: sea sickness, cramp, dehydration, low BP, hunger, prickly heat, water trapped in ear, arthritis, indigestion, trapped nerve, pulled muscle, old sporting injury, hot and tired, and hangover.

In both groups, <6 hrs and >6 hrs, some attitudes of the buddies were as follows: you just need some lunch, the sun, marks from sitting on a chair, wait to develop sufficiently to confirm DCI, wasting time.

In both groups, <6 hrs and >6 hrs, from a list of thought scenarios, the top three at the time of the onset of symptoms were as follows: 39% “This isn't happening to me I didn't do anything wrong on the dive”, 27% “Embarrassed calling out the emergency services in case it is a false alarm”, 24% “I may never be able to dive again”.

In both groups, <6 hrs and >6 hrs, if the diver identified the signs and symptoms as DCI

and the buddy thought it was "some other factor" there was a greater time to treatment from onset of symptoms. Therefore the buddy is influential in the initial DCI management. Divers as a group must assume responsibility for taking action to ensure the well being of a diver who displays possible signs and symptoms of DCI. Never assume the diver with the problem is in a position to make a reasoned judgement concerning management of the incident. The chances are he/she isn't!

Health of Divers

Diving has become a "sport for all" and is now open to a greater spectrum of the population.

The DDRC want to know the current state of health of divers, smoking and alcohol use, prescription and over the counter drug use, and recreational drug use.

The data collected so far in the Health of Divers study show divers have reported the following: 29% back problems, 22% ear problems, 14% asthma,10% migraines, 9% depression, and a number of other illnesses. These data are in line with a previous 1992 DDRC study and reflect some of the national trends. Cigarette smoking is down in divers to11% (vs 28% 1992) the most cigarettes smoked a week being 140. 76% (vs 78% 1992) divers admitted to consuming alcohol regularly, with up to 35 units per week reported. 21% of divers consumed alcohol frequently 12 hrs or less before diving, and 35% reporting they sometimes consumed alcohol 12 hrs or less before diving.

24% divers are currently taking physician prescribed drugs, with a number reporting medications for cardiac problems. 52% have taken "over the counter" drugs within 4 to 6 hours of diving, these were mainly paracetamol, ibuprofen, sudafed, and otravine.

In the 1992 DDRC study 4% of divers reported taking recreational drugs in their diving career. These were cocaine, LSD, amphetamines, derivatives of cannabis. In the UK population as a whole, the 2006/07 British Crime Survey showed that >35% of 16 to 59 year olds have used one or more illicit/recreational drugs in their lifetime, with 10% using one or more in the last 12 months, and >5% in the last month. Cannabis the most used, 8% in the last 12 months.

Data so far in the DDRC Health of Divers study shows that >18% of 16 to 60 year olds have used one or more recreational drugs during the time they have been diving as a sport. Of that group 24% used drugs 48hrs or less before diving, >17% 12hrs before diving, with the least time reported being 5 mins before diving. Drugs used were: Cocaine (A), Cannabis (B/C), Magic Mushrooms (A).

Many divers and the educators in the industry are unfamiliar with the classification and/or the effects of drugs:

Class A Cocaine powder, Crack cocaine, Ecstasy, LSD, Magic mushrooms, Heroin, Methadone

Class A/B Amphetamines

Class B/C Tranquilisers

Class C Anabolic steroids, Cannabis (since 2004, to be reclassified to B Jan 09)

STIMULANTS: Amphetamines (including Ecstasy), Cocaine. These change the way you think, and information handling processes. Can cause an overestimation of one's abilities. High doses may cause high body temperature, irregular heartbeat, heart failure, seizures or death! Detection/residual time up to 4 days after single dose

HALLUCINOGENS: LSD (Lysergic Acid Diethylamide), Cannabinoids, Phencyclidine.

These change a person's perception of reality the way you see, hearing, sense of time, lost inhibitions, distance. Time and objective reality are warped. Serious injury and accidental death are real risks. Detection/residual times up to 3 weeks after last dose.

In the study so far the percentages of recreational drug types reported by divers are : 41% Cannabis (C/B), 20% Ecstasy (A) and/or Magic Mushrooms (A), 19% LSD (A) and/or Amphetamines (A/B),14% Cocaine (A). In total so far >50% drug types are from class A. The effect of drugs (prescribed, over the counter or recreational) may be understood in a surface environment….but we do not fully understand how the hyperbaric (diving) environment may change the drug effects.

If a diver’s abilities to estimate time, carry out complicated tasks or react to a life threatening situation are impaired or changed by a drug how is this going to affect the ability to track air consumption, estimate decompression limits or stops, locate a surface party, or gain control over a diving incident? Unlike alcohol, the drug effects can last a lot longer, for example, 12 hrs approximately for alcohol Vs up to 3 weeks for drugs. Any drug (prescribed, over the counter, recreational) may make a diver less aware of his/her surroundings and fail to recognise the onset of the "Incident Pit", it is also likely to enhance nitrogen narcosis.


Doing drugs and diving is possibly putting yourself and your buddy at risk. It is the same as driving a car under the influence of alcohol but possibly worse. Think before you snort a line or roll a joint …..and go diving!

Philip Robertson (Historic Scotland's Senior Inspector of Marine archaeology) outlined why Scotland's underwater heritage is important and described some of the most important historic shipwrecks that exist around Scotland's waters. Philip outlined a three stage approach - 'Respect, Report, Record' - which Historic Scotland would like to encourage recreational diving groups to follow when diving in Scotland. He provided a range of case-studies to underpin this message, which illustrated how recreational divers had made very positive contributions to the investigation, recording and stewardship of Scotland's underwater heritage.'

Marine Toxins – the Algae Strikes Back

Dr Gary Caldwell

School of Marine Science and Technology, Newcastle University

All the seafood that we eat has at some point come into contact with microscopic algae (microalgae). Often the algae is a direct food source for herbivorous animals such as mussels, oysters and scallops. In other cases it is the herbivores that become food for predators, including fish, marine mammals, sea birds and humans. The common opinion of algae is that it is the ‘grass of the sea’, basically that its purpose is to grow and be eaten. However, if you ask an algal biologist what they think, one of the responses you will get is that microalgae are phenomenal little chemical factories that produce wonderfully interesting, yet potentially highly dangerous chemicals as part of their everyday biology. In this presentation I will introduce you to a number of these chemicals and their biological effects once they get into the food chain. I will be concentrating primarily on human health impacts by exploring a number of common, yet threatening seafood poisoning syndromes.