Dear All, Over the last few weeks, I have had a chance to see various medical offices and hospitals in action.
All, and I repeat all, of these used sphygmomanometers (blood pressure gauges) filled with elemental mercury, a known nerve poison*. Knowing that it is relatively easy to construct a mercury free pressure gauge (begin your search at your local tyre supplier) I began to wonder why the medical profession preserves these old and dangerous devices. Could it be that the old unit name (millimetres of mercury = mmHg) is the culprit. Because the medical profession is using mmHg for blood pressure it must feel right to actually use mercury in a glass tube to measure it. I believe that use of the unit mmHg is holding back progress in this area, and causing the medical profession to cling to old and dangerous technology because they have yet to find a way to change to the pascal, the SI unit for pressure, including blood pressure. * In humans, mercury binds to molecules in the central nervous system and can cause behavioural problems. Common symptoms of mercury poisoning are anxiety, depression, dexterity problems, hostility, insomnia, irritability, memory loss, nerve damage, and tremor. Low level mercury poisoning is suggested as a contributor to many conditions including autism and chronic fatigue syndrome. Cheers, Pat Naughtin CAMS Geelong, Australia
