Dr Ian Sibley-Calder has been a GP since 1988, is a medical referee for the UK Sports Diving Committee and is involved with hyperbaric medicine and commercial diving activities. He is a BSAC Advanced Diver and Club Instructor.
Outlook for anxious and depressed
hspace=5 I found the letter Brain Storm At Sea in Off-Gassing in March slightly worrying. I have been prescribed a 10mg dose of Escitalopram for depression, and feel it would be very difficult to cope without it.
I have tried herbal remedies but suffered anxiety attacks as a side-effect.
I normally dive around the UK, well within my training limits (PADI Advanced, 100-plus dives), and I am now concerned about any possible

The letter was certainly interesting, because of the current debate among diving doctors about fitness to dive while on anti-depressants.
With any such drug we have to consider why it was prescribed, its side-effects at the surface and any known or predicted side-effects under water.
We must also consider how long the drug has been on the market, because new drugs are not fully evaluated, and sometimes late side-effects occur.
In common use are tricyclic anti-depressants (the oldest group, including amitriptyline and dosulepin - often very sedating); selective serotonin re-uptake inhibitors or SSRIs (newer drugs that include fluoxetine, citalopram and paroxetine); and serotonin and noradrenalin re-uptake inhibitors or SNRIs (even newer powerful drugs that include venlafaxine and mirtazapine).
It is generally accepted that divers are unfit to dive on tricyclic anti-depressants, because of the excessive side-effects - drowsiness, dry mouth, blurred vision and others.
The same goes for SNRIs, very powerful drugs often used second or third line, and reserved for severe cases of anxiety and depression. Marked side-effects include increasing blood pressure, dizziness and cardiac problems.
SSRIs are more difficult. They can cause quite marked side-effects in some people, but others seem to experience few or none.
The other problem is the condition itself. Anxiety is often a major factor in depression.
It causes the person to release large amounts of adrenalin, leading to panic attacks, hyperventilation and rapid heartbeats. It also affects the person mentally, making decision-making more difficult, particularly under stress.
I have no doubt that people suffering from anxiety and depression should not dive until they are fully back to normal.
They are a risk to themselves and to their buddies and other divers, because of their potential to panic and make inaccurate decisions.
The area that causes considerable difference of opinion among diving doctors is where the patient is apparently back to normal and on maintenance therapy. This can be an extended period, consolidating the medication and the condition before attempting to wean off, during which the patient is often back to all normal activities.
I know that a lot of divers are diving on SSRIs, but none of these has been tested under pressure, so their side-effects when diving are largely unknown.
Depressed and anxious divers are not always the best people to assess their recovery realistically. Third-party information from colleagues, family and friends should be obtained, and the maintenance dose should be the lowest possible.
Diving on anti-depressants makes the divers into guinea pigs. They may feel fully recovered, but diving is not always stress-free, and medication effects vary from person to person. There may be unknown consequences for them, for their buddies and for their rescuers if the experiment fails.

Heart surgery
I recently had to visit my GP for a dive medical, as I am a 53-year-old male and a smoker. The doctor said I had a heart murmur and referred me to a cardiologist as a precaution. After an echocardiogram and an ECG, I was told that I have a moderate/severe leaking mitral valve and have had a heart attack in the past 12 months, longer ago than six weeks. I have had to stop diving pending further tests and the inevitable surgery, but would I then be fit to dive

After mitral valve surgery, diving may well be possible. It would require an individual assessment by a dive doctor, ideally interested in cardiology, and would depend on type of valve, efficiency of repair and any medication such as warfarin.
The heart attack is more difficult and would depend on further investigations, any treatment and the medication used.
To be fit following a heart attack there must have been minimal damage to the heart, full recovery (especially to heart function) and normal-exercise ECG. Any medication used must also be compatible with diving.
You cannot even be assessed for some considerable time, and would then require close examination of your risks by an experienced dive doctor.
It is thought that one of the commonest causes of death under water from a medical problem is by heart attacks and ischemic heart disease.
This is a problem that dive doctors take seriously, and it is increasing. Fitness to dive is not automatic once problems occur.

Fully certificated
I suffered from pneumothorax six months ago following a bicycle accident in which I broke three ribs and a rib punctured my lung. I know that traumatic pneumothorax (which I assume mine is) is better than a spontaneous pneumothorax in terms of diving again, as there was at least a reason for it.
When I was discharged from hospital, the doctor told me not to dive for six months. Now the time is up, what must I do to be able to dive again Do I need to see a diving doctor, and should I take some kind of confirmation with me whenever I go diving somewhere, as I will presumably have to tick the box saying I have had a lung injury in the past when I do the paperwork prior to diving

You are correct that the prognosis for traumatic pneumothorax and diving is better than that for spontaneous pneumothorax. This relates to the underlying structure of the lungs.
In traumatic pneumothorax, the lung was normal until injury. In spontaneous pneumothorax, there is a weakness in the lungs that causes the leak and collapse.
Careful assessment regarding fitness to dive needs to be made regarding spontaneous pneumothorax, and often the individual cannot dive again, or may require operations to prevent the lung collapsing again.
In traumatic pneumothorax, all that is required is an assessment that the lungs have recovered. This may need a follow up X-ray, although often flow volume loop spirometry is all that is done.
Your second point about paperwork is very valid. A lot of divers simply omit the relevant information, but this is a mistake, because it could invalidate their insurance and leave them with an expensive bill should problems arise.
Have a medical with an accredited diving doctor and get a certificate of fitness to dive regarding the problem. This will keep the insurance companies happy and give you peace of mind.

Recently I have had severe pneumonia.
I am told that I will make a full recovery but are there are any special steps I need to take before I resume diving

A lot would depend on the type of pneumonia, how unwell you were and what lung tissue was involved.
In general I would like to see full X-ray resolution of the pneumonia and then full spirometry with flow volume loops to check that the lungs are working normally.
It may well be prudent to do a before and after exercise spirometry as well, if there is any residual coughing, in case of post-infective inflammation giving rise to an asthma-like reaction, and increased risk of air-trapping.

Scar tissue and DCI
Scarred knees are at more risk from finning stresses than from DCI
After crashing my motorbike I needed serious reconstruction work on a damaged knee. I had a posterior cruciate ligament implant made from synthetic polyethylene attached into the bone, with a graft made from my own hamstring material to rebuild the posterolateral corner. I also have large areas of scar tissue, in and around the knee joint, cartilage damage and soft-tissue damage.
Am I more likely to suffer a bend from this type of injury Do implants or plastic grafts present any issues to off-gassing, and will this prevent me from doing any serious diving

There is a theory that scar tissue releases nitrogen more slowly, which is reasonable in view of its poorer blood supply.
Whether this causes any practical problems is more debatable.
For scar tissue around the spinal cord (as in back surgery) there may well be grounds for being cautious in diving.
As for scarring around other areas such as the knee, however, I am not convinced that there is any evidence that it increases DCI risk.
As to the grafting, again I am not aware of problems with slow releasing of nitrogen
and increase of DCI.
I would be more concerned regarding the stresses put on the knee while finning, and would recommend that you try different fins to help off-load work from the knee.

Double time
I had surgery on an umbilical hernia and the doctor has signed me off for four weeks. How soon could I dive again

Umbilical hernia repairs are simple operations that do not involve major cuts, only stitches around the weakness around the umbilicus, with possible introduction of a mesh to help it seal.
Diving can be considered once the scar and deeper tissue have fully recovered. I would leave it eight weeks or so to be sure.