It's quite extraordinary how procedures in hospitals get adopted. Their very nature makes it almost impossible to test in a proper scientific trial; how do you carry out a double-blind placebo trial on open-heart surgery, for instance?
For this reason, well over 80 per cent of procedures you may encounter in a hospital have never been tested for their safety or efficacy.
One example of this is the pulmonary-artery catheter, given almost routinely to elderly, high-risk patients in intensive care. It's a very invasive and unpleasant procedure and, worse, consultants and nurses have noticed that patients given a catheter are more likely to die than those left alone.
So researchers from the University of Calgary decided to break with tradition, and test a hospital procedure. They observed the progress of 1,994 patients, half of whom were given a catheter before emergency surgery, and the rest had standard care.
The worst fears of the consultants were confirmed. Those given a catheter who more likely to suffer a pulmonary embolism although, thereafter, survival rates at six and 12 months were similar in both groups.
So what are the benefits of the catheter? None at all, say the researchers, and it's another invasive procedure that can be safely stopped.
(Source: New England Journal of Medicine, 2003; 348: 5-14).