London Hyperbaric Chamber

Well, while Britain shivered in the big freeze and only the brave were getting wet, Aquapigs from Essex took the wise decision of getting their diving fix without having to put on layers of undersuits by taking part in a dry dive.

Wayne Ford hosted the enthusiastic bunch on Sunday February 12th at our London Hyperbaric Chamber and everyone was glad to get in out of the cold.

After an orientation to the dive chamber, everyone went inside to experience going to 40 metres in a very different way to usual.

Once ‘down’ everyone was able to feel the effects of pressure and nitrogen narcosis on their bodies and have a bit of a laugh at each others’ expense as well.

After returning to the ‘surface’ everyone chatted about the changes to their voices, how they felt and the tests they had done at depth.

Aquapigs had a great time, we thank them for coming and hope to see them again soon.

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On Sunday the 22nd January 2012, the hyperbaric chamber once again played host to a group of divers wanting to experience a dry dive.

The group came from Planet Scuba and included Rebecca Heanes, Debbie Schwaner, Angela  & Jade Allen, Steve Cox, Paul Bennett, Simon Heanes and Peter Jacks.

After a safety briefing and tour, the group went in the chamber and were taken down to 40 metres. As always, the squeaky voices and compulsory outfits combined with the effects of nitrogen narcosis had everybody smiling, although many serious facts were learnt at the same time.

Instructor Wayne Ford said ” Once again Steve Manton sent an enthusiastic group of divers and thanks to their great attitude and sense of fun, a great time was had by all”

Don’t forget, more details about dry dives are on our website under  dry diving

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Weil’s Disease

This is a bacterial infection resulting from exposure to the Leptospira interrogans bacteria, and therefore is also known as leptospirosis. The vast majority of cases are mild and recovery is complete. This is fortunate as the there are millions of infections every year worldwide as it is probably the most common infection passed from animals to humans. Thankfully this infection is rare in the UK and only the severe form is generally known as Weil’s disease.

Infection is caused by exposure to the bacteria in drinking water or while swimming in freshwater, usually in the presence of urine from an infected animal. The bacteria enter at certain locations, including broken skin, membranes lining the airway, mouth, lungs and sometimes via sexual intercourse. Dry undamaged skin is a good barrier to the bacteria and the risks from saltwater are almost nil.

Human leptospirosis can be difficult to recognise as symptoms can vary considerably between patients, depending on their age and health, the strain of bacteria and the amount of bacteria that enter the body. The time from infection to symptoms is typically 3 to 21 days, with most patients developing illness after about 3 to 14 days. The symptoms classically then occur in 2 phases and affect the whole body.

In mild cases the infection is similar to flu, with both phases lasting 3-5 days with slight recovery in the middle. Not all symptoms may be present but a severe headache is common and other symptoms include: sore throat, dry cough, red eyes, muscle pains, fatigue, fast heart rate, nausea and vomiting. There may also be symptoms similar to that of meningitis. These include a red non blanching rash anywhere on the body, neck stiffness and an aversion to light similar. To tell whether the rash is non blanching, push a glass against it and if it is non blanching then the rash will not become paler under the glass. This is the same for the rash in meningitis. Both conditions need immediate medical assessment.

In severe cases, the illness develops rapidly and there may or may not be a period of apparent recovery. Symptoms include severe forms of the above and also jaundice (yellowing of the skin and whites of the eyes), chest and abdominal pain, kidney and liver problems and psychological changes, such as depression and agitation. Bleeding from mouth and eyes, organ failure and death can also occur, but with medical treatment the chances of survival are good.

On average in Europe and mainland USA about 20% of wild rats carry strains of leptospira, but other rodents can be carriers. The single most important factor in avoiding infection is knowing where infection is likely and avoiding these locations. Hence local knowledge is important, but also infection requires close contact to infected water. Simply being near and infected animal carries no risk. Where someone has a ‘risk exposure’ and then shows characteristic illness during the incubation period (3 to 21 days), a blood test for leptospirosis should be requested and antibiotics started at the same time.

Remember that water can also enter the mouth via the hands, so even when preparing for a dive in at risk areas, when washing equipment or wading through shallow water, good hygiene and covering broken skin with waterproof dressings should be followed.

1. Where can I find more information on leptospirosis?

More information can be found at:

http://www.leptospirosis.org/

http://www.who.int/zoonoses/diseases/leptospirosis/en/

http://www.cdc.gov/leptospirosis/index.html

2. What is a Lyme disease?

This is a tick borne bacterial infection. Early symptoms can also include fever, headache, fatigue, depression but an entirely different characteristic circular skin rash called erythema migrans. (Picture ) Again the infection can be treated successfully with antibiotics, especially if caught early. However, if not treated, symptoms may affect the joints, heart and central nervous system.

3. Why are rats the main culprits?

Rats are naturally incontinent. Therefore they spread more urine more widely than any other rodent.

4. Can I take any prophylaxsis against leptospirosis, just in case?

Doxycycline can be used, but the best method is to avoid at risk areas. There is no vaccine against leptospirosis.

5. Can you tell me more about the life cycle of a leptospirosis?

For more information on this, have a look at this picture:

Thank you to The Leptospirosis Information Centre and Wikipedia for information and pictures.

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Diving Doctor Oliver Sykes Discusses the impact of asthma on diving – “ASTHMA: Why Can I Not Dive?”

Asthma is similar to having an allergy. There are triggers, such as cold, exercise and emotion induced asthma, the attacks are intermittent and can vary in severity. At a cellular level, there are complex inflammatory interactions that are incompletely understood. However ultimately, the responses to asthma and allergies do not improve survival chances.

While most cells in the lungs are pneumocytes, that exchange CO2 for O2 with every breath, there are also mucus secreting cells and muscle cells, which widen and narrow the diameter of the conducting tubes. Mucus helps remove foreign material and wider diameter tubes are required to exchange more gas during exercise.

Asthma has 2 effects during an attack. There is more mucus production and there is significant airway constriction. As air passes through narrowed tubes, further obstructed with mucus, there is wheeze, chest tightness and shortness of breath. Wheeze means air trapping in the lungs, which can lead to pulmonary barotrauma, pneumothorax and air embolism. Some of the most feared complications in diving. While the extent of an attack varies hugely, from barely noticeable to life threatening, divers die every year due to asthma.

How can we make sure it’s not you? People with cold, exercise or emotion induced asthma must avoid diving altogether. While a little wheeze can be annoying while playing football, there are additional factors that make scuba diving completely different from the usual sports. For example dry gas and salt water aspiration act as additional triggers for asthma and make asthma attacks worse. There may well be a decompression obligation, meaning a controlled emergency swimming ascent, or immediate surfacing, is not safe during an attack, especially with the additional gas trapping. However most importantly, an asthma attack reduces exercise tolerance and can turn a dangerous situation into a life threatening emergency. Unlike football, with scuba diving, you cannot simply stop play and call for help.

The UK Sports Diving Medical Council has been instrumental in creating guidelines to allow some asthmatics to dive. Look under medical standards, then respiratory and then asthma at www.uksdmc.co.uk. Previously any history of wheeze meant no diving. Currently the guidelines state:

Asthmatics may dive if they have allergic asthma but not if they have cold, exercise or emotion induced asthma.

All asthmatics should be managed according to British Thoracic Society guidelines

Only well controlled asthmatics may dive

Asthmatics should not dive if he/she has needed a therapeutic (required for symptom control) bronchodilator in last 48hrs or has had any other chest symptoms, such as cough or chest tightness.

A puff or 2 of ventolin, often the blue inhaler, before a dive TO RELIEVE SYMPTOMS is not safe. As prevention however, 2 puffs of ventolin before a dive is acceptable. The bottom line is that asthma can be life threatening under water and must be taken seriously.

Question1:

I play football 2 or 3 times a week, I wheeze a little when it’s cold, but my asthma does not stop me doing anything. Can I still dive?

This is a common question and people are often surprised at being told they cannot dive because of asthma, which may not limit their other activities. However breathing compressed gas at depth provides a number of triggers that are not present on land, so an attack may be more severe than expected, and help is more difficult to provide, as diving is usually remote and ascent is dangerous. Unfortunately asthma can also be stable for months and years and then flare up with an acute attack. So no diving with exercise, cold or emotion induced asthma.

Question2:

I take a steroid (brown) inhaler along with my ventolin (blue) inhaler. Can I still dive?

You need assessment from a diving doctor. You may, or may not, be able to dive safely.

Question3:

Why do diving doctors vary their requirements for a diving medical for asthma?

All diving medicals for asthma should include taking down a history of your asthma and an exercise test. There is no point in having a medical if you have exercise, cold or emotion induced asthma, as these prevent safe diving. If you are going for a medical, remember that everyone with asthma is affected differently and the doctor needs to be sure that your will not have a life threatening asthma attack under water. You will be asking the doctor to take some responsibility for your health, so the doctor will want to be as stringent as he/she feels necessary.

Question4:

How can I improve my asthma control?

Primarily, make sure that you have a doctor in charge of you asthma, take the medications as directed by them andavoid triggers. The treatment may include inhalers, nebulisers or tablets, but unfortunately if you are on tablets or nebulisers, then your asthma is too severe to consider diving. Stopping smoking and weight loss can help too. If you are prescribed a steroid (brown) inhaler, remember to take it. This is a preventer medication and takes days/weeks to work. Once taken regularly, there should be fewer symptoms, less ventolin required and therefore less air trapping and safer diving.

Question5:

I have been assessed as fit to dive with my asthma, but how do I know if my asthma is good enough to dive?

If there is any cough, wheeze or chest tightness, then you should not dive. If you have needed medications, including inhalers, for any chest symptoms then no diving again for 48hrs from last dose. Monitoring your own peak expiratory flow rate (PEFR, peak flow) can help you gain control of your asthma and balance the need for treatment. However it is not possible to give an absolute figure for peak flow for safe diving, as asthma can vary considerably and the presence of symptoms is much more important.

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We are excited to finally announce the lucky winner of our competition held at our stand at DIVE 2011 Birmingham.

Over 500 divers took part and Monty Halls very kindly drew the winner on Sunday afternoon.

Simply Scuba had kindly provided the prize of £200 of vouchers for dive equipment from the UKs leading online dive store and the winner is David Morgan from Swindon.

David tells us “Wow, that is certainly out of the blue. Thank you, my wife has already decided what to spend the money on, and it is even for me!”

If it wasn’t you, better luck next time at LIDS!

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On Saturday we played host to another excited bunch who wanted to join us in the chamber for a dry dive. Joining instructor Wayne Ford and the rest of the team were some members of Harlow BSAC Club, Kay Mcginley, John Skipper, Alan Harman, Nick Costen, Paul Surridge and Lorna Crump, plus David Watchorn and Carman Devlin from Luton BSAC.

During the session the divers had a briefing covering safety and what they could expect, then went in the chamber to a depth of 40m and underwent tests to see what level of impairment they experienced from nitrogen narcosis.

As usual there were many laughs but some valuable lessons were also learnt.

David sent us this email:

“Hi Wayne, Just a quick note to thank you for Saturdays dry dive. Carmen and I found it both great fun and useful. I have spoken to a number of other divers, and recommended that they also partake in the session. They seem very interested, Carmen, even wants to come again!”

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Wow, what a fantastic and utterly exhausting weekend at the Dive Show in Birmingham!

The Divers Emergency Service stand was mobbed all day every day and as always, it provided a great opportunity to chat to old friends, make new friends and as we were running a campaign to ‘like’ our facebook page, it also allowed us to educate people in the wonders of smart phones and modern technology! If you haven’t liked us on facebook yet, make sure you do……

Over 500 of you entered the competition to win £200 vouchers from Simply Scuba and the winner was drawn at 5pm on Sunday at the show by the delightful and always helpful Monty Halls.  Once the winner has been contacted, we will post details on here so watch this space. If you weren’t lucky, don’t worry, we are going to be back at the next show in the spring with more great giveaways and chances to win.

Thanks again for making the show great and if you weren’t there, we hope to see you soon.

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Skin Bends

Skin bends may not be seen as part of decompression illness.

Rashes are common and determining whether a skin bend is present can be difficult. A skin bend is a rash with poorly defined edges, there may be varying degrees of redness, it may be itchy, may make the skin seem more like marble and may occur in a single area or in multiple areas. Finally the rash of a skin bend is not caused by sunburn, suit squeeze, harness straps, skin infections, bites or scratching, although all these may be present and confuse the picture. Simple cases of itching, burning and increased warmth occur after many dives and probably should not be recompressed, but should still be discussed with a diving doctor. In terms of severity, next comes cutis marmorata. This is described as marbling of the skin. Blood vessels constrict and dilate in different areas over a small patch of skin, producing areas of pale skin and redder areas. This then looks like marble and should certainly be discussed with a diving doctor.

At the other end of the scale, livedo reticularis is the most severe form, as seen in the picture above, and involves patchy, reddish-purple mottled areas, especially around the shoulders and trunk. This can be intensely itchy, due to a local vascular reaction from bubbles in the tissues below the dermis, and is clearly a systemic manifestation of DCS. These divers must be treated. Another skin symptom to take seriously occurs with blockage of the lymphatics with bubbles, resulting in swelling and a peculiar pitting of the skin called peau d’orange (meaning skin of the orange) and again is evidence of a more serious form of DCS, known as lymphatic decompression sickness.

In the past skin bends on the limbs were not considered severe enough to warrant treatment. However all symptoms that start after decompression has begun, however minor, can herald severe DCI and must be assessed by a diving doctor. There have also been recent reports of an association with skin bends with patent foramen ovale (PFO) and there are now recommendations that some divers with this condition be checked for PFO.

In order to help us improve our recognition of skin bends, please help us with our Skin Bend Image and Information Bank. Scroll down the page to find the forms at the bottom of this article. Please print off and fill in the consent form and questionnaire and send these to the address given. Finally please email the relevant photos to the secure NHSMail email address: o.sykes@nhs.net. This will in no way affect your treatment by the Divers Emergency Service or London Hyperbaric Medicine.
We do need written consent, not emailed consent. Sorry!

Picture reprinted from The Lancet, Vol. 377, Vann RD, Butler FK, Mitchell SJ, Moon RE, ‘Decompression Illness,’ Pages 153-64, 2011, with kind permission from Elsevier.

Information for Participants
Research study: Skin Bend Image and Information Bank

We would like to invite you to be part of this research project.
You should only agree to take part if you want to and it is entirely up to you. If you choose not to take part there won’t be any disadvantages for you and choosing not to take part will not affect your access to treatment or services in any way. Please read the following information carefully before you decide to take part; this will tell you why the research is being done and what you will be asked to do if you take part. Please ask if there is anything that is not clear or if you would like more information. If you decide to take part you will be asked to sign the attached form (below) to say that you agree. You are still free to withdraw at any time and without giving a reason.

Details of study:
There are many reasons for rashes after diving, but sometimes these are due to decompression illness (The Bends). We at London Hyperbaric Medicine (LHM) would like to collect anonymous images and information on rashes that occur up to 72 hrs after diving in order to form a bank. This will be published on the LHM web site and blog, in a Sport Diver article, for teaching purposes, in a medical journal and in The Anaesthesia UK Image Bank, if accepted for publication. This will form very useful resources for doctors and divers.

Every effort will be made to ensure that you are unrecognizable from the pictures. However this cannot be absolutely guaranteed. Once the pictures are on the web site, you may request for yours to be removed at any time.

Cautions:
If you think you may have skin decompression illness, any other form of decompression illness or serious cause for a rash, then contact the Divers Emergency Service immediately on:
+44 (0)7 999 292 999
In order to help maintain your safety and confidentiality, the images will not be free for all to use. LHM will need to hold the copyright to the images, but will not use the images in any other fashion without express prior consent from you.

Forms to download

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Recently,  Divers Emergency Service recompression chamber unit at Whipps Cross Hospital, London was pleased to welcome Morne Christou, a Chamber Operator Instructor Trainer for DAN (Divers Alert Network). Morne visited us to gain experience, so we were in fact training the trainers so to speak!

He was to get some more experience in how a large HBO chamber runs its treatments and also get an insight into some of the maintenance work we do. He spent the week under the watchful eye of Lee Griffiths and got the chance to work with all our staff.

It was a busy week when he was here, with 7 divers and 6 ‘routines’ (non-diving and non-emergency medical treatments) being treated. Morne did very well and was impressed by what we did.

His comments on the visit:

“Please accept my compliments for the supportive role you played when I visited the London Hyperbaric Centre  at the Whipps Cross University Hospital in September to learn more about your facility. Your effort to further my knowledge is greatly appreciated and will definitely help my efforts to improve the competence of chamber attendants & operators at remote chamber locations. If every chamber facility were to commit themselves with the same level of enthusiasm you expressed during my visit, DAN would undoubtedly have confidence to refer injured divers to more chamber locations.

Having been guided by you around your chamber facility, I must say that I am thoroughly impressed with your operations and personnel. On rare occasions have I ever viewed a more efficient, smooth running, and clean chamber facility such as yours. I was particularly impressed with the procedures you have implemented to monitor safety and provide a professional emergency service to divers in need.

All your staff members were extremely courteous and enthusiastic to teach me as much as possible within a short period of time. I would be most appreciative if you would extend a special thank you from me to all the staff.

Thank you for giving your time! It has been a great help to me and will definitely benefit DAN in the future.

Yours in safe diving, Morne Christou”
This was an important visit for us as we are a DAN Preferred Provider and have close working links with them. DAN are often the first name that comes up when divers are asked about emergency planning and a name that is familir to divers all over the world.

Morne Christou also commended our emergency hotline for divers, which operates nationally providing 24 hour advice and referral for divers who suspect DCI.

For more information about DAN courses provided by DES or our status as a DAN preferred provider, please contact us.

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Oxygen is necessary for life, but as divers we are exposed to higher partial pressures of oxygen (pO2 or ppO2) than normal. A partial pressure is simply the fraction of the total pressure that an individual gas takes up in a mixture of gases. Therefore 21% oxygen at sea level has a pO2 of 0.21 bar.
There are 2 main types of oxygen toxicty that we need to limit, which are pulmonary (lung) and neurological oxygen toxicity. In order to obtain energy from food, oxygen is used to break strong molecular bonds at the cellular level and is necessarily a fairly reactive species. As humans, we have evolved to use oxygen at 0.21 bar and even a pO2 of 0.5 bar begins to overwhelm the body’s repair mechanisms very slightly. This pO2 is only 50% O2 at sea level or 25% O2 at 2 bar or 10m. Therefore 50% oxygen is not recommended for over 24hrs in healthcare settings due to lung oxygen toxicity, unless absolutely necessary.

With much larger increases over shorter periods, such as a pO2 of over 1.4 bar during diving, neurological oxygen toxicity becomes the main worry. This is manifested in violent fitting (uncontrolled movements of the arms and legs) and is often fatal when diving. Unfortunately drowning is common and ascent is dangerous due lung barotrauma from a closed wind pipe. Therefore even a full face mask is not safe and the only treatment is to reduce the high pO2. Unfortunately stressors make neurological oxygen toxicity more likely during diving and include exercise, cold, poor vis, nitrogen narcosis, raised blood carbon dioxide levels and psychological stress. These are present on all dives and for everyone to some degree.
During recompression treatment, the chamber environment does not risk drowning and we minimise the stressors. We also use air breaks to limit the time spent at high pO2 levels and therefore use 100% O2 to greater depths than in water.
Overall, neurological oxygen toxicity is a very rare event in chambers and simply requires the diver to be taken off oxygen. Given that recompression is a treatment, the additional risk from oxygen toxicity is therefore acceptable and the pO2 limit is significantly higher in chamber treatments. But only with good reason.

Question 1:
What do you do if a diver fits underwater?
100% O2 should not be breathed below 4-6m, as this gives a pO2 of 1.4 to 1.6 bar. If a diver is using breathing gas mixes enriched with oxygen and then fits at depth, the cause is likely to be oxygen toxicity and switching to the wrong mix can cause this. Ascent is clearly dangerous due to lung over expansion injury, but may be the only way to ensure help can be given. Make sure you are aware of this problem and are able to cope with it. Essentially, follow the guidence from your training agency at all times.

Question 2:
Are there any preceding symptoms prior to an oxygen toxicty fit?
Yes there are. These include blurred vision, ringing in the ears, nausea, twitching, irritability (anxiety, restlessness) and dizziness, which can progress to convulsions (fitting). These can be remembered with the letters VENTID-C  and can be difficult to pick up when diving. (Vision, Ears, Nausea, Twitching, Irritability, Dizziness, Convulsions)

Question 3:
What happens if someone has an oxygen fit in the chamber?
Our chamber attendants are trained to recognise the preceding symptoms and will take the diver off oxygen. If there is a convulsion, then they will pad the moving limbs and the fit will stop once off oxygen. Chamber pressure must not be altered during a fit. There is no long term damage, it is not epilepsy and has no impact on future diving or driving. We would then decide whether to continue the treatment or shorten it, depending on the reason for treatment and the state of the patient.

Question 4:
What is pulmonary (lung) oxygen toxicity?
The airways become narrower as a result of inflammation. There is often midline chest pain, cough and reduced lung function tests. Diving is unlikely to produce sufficient oxygen exposure. However some of the more extensive treatments for decompression illness may cause a degree of pulmonary oxygen toxicty. Thankfully this is often completely reversible.

Question 5:
Are air breaks useful in preventing oxygen toxicity at sea level?
Important: Do not use air breaks when using oxygen at the surface in an emergency situation, this is unnecessary and deprives the diver of a very important treatment.

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