Although evidence‑based medicine now condemns the sort of bloodletting that Rush indulged in, it is important to point out that evidence‑based medicine also means remaining open to new evidence and revising conclusions. For example, thanks to the latest evidence from new trials, bloodletting is once again an acceptable treatment in very specific situations–it has now been demonstrated, for instance, that bloodletting as a last resort can ease the fluid overload caused by heart failure. Similarly, there is now a role for leeches in helping patients recover from some forms of surgery. For example, in 2007 a woman in Yorkshire had leeches placed in her mouth four times a day for a week and a half after having a cancerous tumour removed and her tongue reconstructed. This was because leeches release chemicals that increase blood flow and thus accelerate healing.
Despite being an undoubted force for good, evidence‑based medicine is occasionally treated with suspicion. Some people perceive it as being a strategy for allowing the medical establishment to defend its own members and their treatments, while excluding outsiders who offer alternative treatments. In fact, as we have seen already, the opposite is often true, because evidence‑based medicine actually allows outsiders to be heard–it endorses any treatment that turns out to be effective, regardless of who is behind it, and regardless of how strange it might appear to be. Lemon juice as a treatment for scurvy was an implausible remedy, but the establishment had to accept it because it was backed up by evidence from trials. Bloodletting, on the other hand, was very much a standard treatment, but the establishment eventually had to reject its own practice because it was undermined by evidence from trials.
There is one episode from the history of medicine that illustrates particularly well how an evidence‑based approach forces the medical establishment to accept the conclusions that emerge when medicine is put to the test. Florence Nightingale, the Lady with the Lamp, was a woman with very little reputation, but she still managed to win a bitter argument against the male‑dominated medical establishment by arming herself with solid, irrefutable data. Indeed, she can be seen as one of the earliest advocates of evidence‑based medicine, and she successfully used it to transform Victorian healthcare.
Florence and her sister were born during an extended and very productive two‑year‑long Italian honeymoon taken by their parents William and Frances Nightingale. Florence’s older sister was born in 1819 and named Parthenope after the city of her birth–Parthenope being the Greek name for Naples. Then Florence was born in the spring of 1820, and she too was named after the city of her birth. It was expected that Florence Nightingale would grow up to live the life of a privileged English Victorian lady, but as a teenager she regularly claimed to hear God’s voice guiding her. Hence, it seems that her desire to become a nurse was the result of a ‘divine calling’. This distressed her parents, because nurses were generally viewed as being poorly educated, promiscuous and often drunk, but these were exactly the prejudices that Florence was determined to crush.
The prospect of Florence nursing in Britain was already shocking enough, so her parents would have been doubly terrified by her subsequent decision to work in the hospitals of the Crimean War. Florence had read scandalous reports in newspapers such as The Times, which highlighted the large number of soldiers who were succumbing to cholera and malaria. She volunteered her services, and by November 1854 Florence was running the Scutari Hospital in Turkey, which was notorious for its filthy wards, dirty beds, blocked sewers and rotten food. It soon became clear to her that the main cause of death was not the wounds suffered by the soldiers, but rather the diseases that ran rife under such squalid conditions. As one official report admitted, ‘The wind blew sewer air up the pipes of numerous open privies into the corridors and wards where the sick were lying.’
Nightingale set about transforming the hospital by providing decent food, clean linen, clearing out the drains and opening the windows to let in fresh air. In just one week she removed 215 handcarts of filth, flushed the sewers nineteen times and buried the carcasses of two horses, a cow and four dogs which had been found in the hospital grounds. The officers and doctors who had previously run the institution felt that these changes were an insult to their professionalism and fought her every step of the way, but she pushed ahead regardless. The results seemed to vindicate her methods: in February 1855 the death rate for all admitted soldiers was 43 per cent, but after her reforms it fell dramatically to just 2 per cent in June 1855. When she returned to Britain in the summer of 1856, Nightingale was greeted as a hero, in large part due to The Times ’s support:
Wherever there is disease in its most dangerous form, and the hand of the spoiler distressingly nigh, there is that incomparable woman sure to be seen; her benignant presence is an influence for good comfort even amid the struggles of expiring nature. She is a ‘ministering angel’ without any exaggeration in these hospitals, and, as her slender form glides quietly along each corridor, every fellow’s face softens with gratitude at the sight of her.
However, there were still many sceptics. The principal medical officer of the army argued that Nightingale’s higher survival rates were not necessarily due to her improved hygiene. He pointed out that her apparent success might have been due to treating soldiers with less serious wounds, or maybe they were treated during a period of milder weather, or maybe there was some other factor that had not been taken into account.
Fortunately, as well as being an exceptionally dedicated military nurse, Nightingale was also a brilliant statistician. Her father, William Nightingale, had been broadminded enough to believe that women should be properly educated, so Florence had studied Italian, Latin, Greek, history, and particularly mathematics. In fact, she had received tutoring from some of Britain’s finest mathematicians, such as James Sylvester and Arthur Cayley.
So, when she was challenged by the British establishment, she drew upon this mathematical training and used statistical arguments to back her claim that improved hygiene led to higher survival rates. Nightingale had scrupulously compiled detailed records of her patients throughout her time in the Crimea, so she was able to trawl through them and find all sorts of evidence that proved that she was right about the importance of hygiene in healthcare.
For example, to show that the filth at Scutari Hospital had been killing soldiers, she used her records to compare a group of soldiers treated at Scutari in the early unhygienic days with a control group of injured soldiers who at the same time were being kept at their own army camp. If the camp‑based control group fared better than the Scutari group, then this would indicate that the conditions that Nightingale encountered when she arrived at Scutari were indeed doing more harm than good. Sure enough, the camp‑based soldiers had a mortality rate of 27 deaths per 1,000 c ompared with 427 per 1,000 a t Scutari. This was only one set of statistics, but when put alongside other comparisons it helped Nightingale to win her argument about the importance of hygiene.
Nightingale was convinced that all other major medical decisions ought to be based on similar sorts of evidence, so she fought for the establishment of a Royal Commission on the Health of the Army, to which she herself submitted several hundred pages of detailed statistics. At a time when it was considered radical merely to include data tables, she also drew multicoloured diagrams that would not look out of place in a modern boardroom presentation. She even invented an elaborate version of the pie chart, known as the polar area chart, which helped to illustrate her data. She realized that illustrating her statistics would be enormously helpful in selling her argument to politicians, who were usually not well versed in mathematics.