A Canadian man undergoing surgery surprised doctors recently when they opened him up to find that he had green blood!
A report published by Alana Flexman from the University of British Columbia describes how the man, a 42 year old smoker, was due to undergo emergency surgery to relieve a condition called "compartment syndrome", which had been brought on when he fell asleep in a sitting position for several hours. This had triggered swelling and subsequent vascular problems in his legs, which the surgeons were seeking to relieve by cutting through some of the tough connective tissue, called fascia, which surrounds the muscles in the legs. But when the man was taken to the operating theatre and a tube was inserted into an artery to remove a blood sample, the anaesthetist was surprised to see green blood coming out.
It turned out that the man was suffering from a condition called sulphaemoglobinaemia, which is when sulphur groups become chemically bonded to haemoglobin, the iron-containing protein found in red blood cells that carry oxygen around the body. The patient had been using large amounts of an anti-migraine drug called sumatriptan, which contains sulphur compounds called sulphonamides. The doctors think that this had become linked to his haemoglobin, causing it to change colour. This is probably correct because after he stopped taking the drug the levels of sulphaemoglobin fell and five weeks later his blood was red again!