I have been thinking about lung function just recently because of a chest infection picked up on an airline flight. It started as ‘flu but soon went to my bronchi causing bronchitis. It has surprised me how much my exercise tolerance has been reduced, and I’m still hoping for a quick recovery. Today’s artwork arises out of these thoughts.
Asterixis, (meaning unable to keep still) is a medical term for flapping of the hands seen in metabolic diseases affecting the brain – encephalopathy – it is commonly seen in liver failure due to cirrhosis but can be due to respiratory failure.
The sight of a man – it was usually a man – lying in bed with hands flapping like little wings, gasping for breath, was one of the more disturbing sights I encountered as medical registrar in a respiratory unit. Chronic obstructive airways disease or emphysema; strongly associated with smoking tobacco, with congenital abnormalities of lung, and lung metabolism causes progressive damage to lung tissue with loss of ability to exchange Oxygen (O2) for Carbon Dioxide (CO2).
Slow loss of lung function means increasing breathlessness until the person comes to a point where the balance of O2 input to CO2 output is marginal. It only requires a small infection to knock them over into negative balance; they absorb only just enough O2 to survive and they cannot easily eliminate CO2.
After exercise anyone will be familiar with the sensation of increased drive to breathe more quickly. This reflex is largely due to rapid rise in CO2 in the blood that stimulates the brain to increase the breathing rate (it’s also due to other things, but I’m trying to keep this simple). But when that CO2 rise is gradual over years due to progressive lung damage the response is blunted. That means low oxygen levels become the main driver to control breathing rates. If Oxygen treatment is given to such a person, increased O2 in the brain takes away the stimulus to breathe, respiration slows, CO2 is not exhaled, allowing more to accumulate in the body. Eventually enough CO2 mounts up to cause brain toxicity. Hence asterixis – the brain toxicity of too much carbon dioxide.
This is a paradox. Of course if someone is desperately short of breath it is natural to give them Oxygen. BUT NOT in this situation because it can kill them.
There was one small comfort. A man would come to our ward in extremis, apparently massively distressed, in anguish, gasping for air. After treatment and before discharge I would ask what he could remember of his admission. The event and the suffering had always been wiped from his mind. That is one small blessing.
The X-ray in this image shows a man with chronic emphysema. A child can be seen running through the picture chasing her breath.