Ok for those interested........
The pressure inside the brain is normally controlled. If you have a head injury, are sedated or anaesthetised, this regulatory mechanism is disabled. Any bleeding inside the skull will then be catastrophic, but also if you put the patients head down in relation to the body blood will flow into the head increasing pressure. Moreover if we accelerate the patient feet first the pressure inside the brain goes up, and falls as you brake. If you move the patient head first it is the other way round.
The rise in pressure cuts off the blood and thus oxygen to the brain, and in particular the penumbra or area around the injury. It lasts longer than the period of pressure and can kill.
So moving these patients can literally kill them. This is why we put patients on a ventilator before moving them, as over breathing them restricts the blood vessels in the brain and provide some protection. We have to anaesthetise the patient, but the drugs we use are also protective
When we then put the patient in a land vehicle or fixed wing we have little control over the destructive forces - some of you may recall ambulances travelling at 10 miles an hour, but suspension movements are still destructive.
The helicopter is unique in providing a protective attitude. Flown correctly for the patient, a patient loaded feet first will go head up as they accelerate. The two forces cancel each other out. Deceleration is the same. A balanced turn applies no forces. The helicopter really is a life saver - we published evidence of this when moving intensive care patients 25 years ago - possibly the only evidence of reducing mortality due to mode of transport as opposed to cutting time to treatment
Sadly in the UK the NHS has refused to continue to pay for dedicated inter hospital ITU helicopter transfers. HEMS helicopters obviously provide the benefits detailed above, but lack the very specialised equipment and medical staf that should be part of the package
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