I'm pretty sure jcot is aware of the problemmatic theoretical foundations for historic bloodletting, and the attending reputation that persists. However the int

I'm pretty sure jcot is aware of the problemmatic theoretical foundations for historic bloodletting, and the attending reputation that persists. However the interesting part is that it could have therapeudic uses, but physicians are understandably adverse to performing a procedure considered typical of medieval quackery. Here's an excerpt from the BMJ: >Bloodletting was done by the barbers in England at the request of patients and must, therefore, have had some beneficial effect even if it was just a placebo effect. It is very possible, however, that there were very real benefits in selected patients especially those in left ventricular or congestive cardiac failure. In withdrawing blood the venular outflow pressure from capillaries and cardiac filling pressures would have been immediately reduced. The pressure gradient between capillary and interstitial fluid may have been decreased or even reversed if it was elevated(6,7). A reversal of the pressure gradient in oedematous patients would have promoted the mobilisation of oedema fluid and excretion in urine provided renal function was normal. Bloodletting would also have improved capillary blood flow, which can be severely disturbed in septic patients, by decreasing viscosity and improving the rheological chacteristics. >Repeated epsiodes of bloodletting will cause anaemia which is an independent risk factor for adverse outcome in patients with heart failure (8). As heart failure may cause anaemia by compromising the synthesis in the Krebs cycle of substrate needed for haemoglobin synthesis and blood formation in the bone marrow this risk might be a consequence of the heart failure rather than the cause. In adequately nourished and oxygenated bone marrow haemoglobin pools should be replenished by resynthesis unless the bloodletting was repeated too often. >In the short term bloodletting achieves what the venodilators glyceryl trinitrate and isosorbide mononitrate achieve, a reduction in venular outflow pressure in capillary beds. In patients with heart failure venodilators improve exercise performance and reduce mortality (9). Whilst ACE inhibitors, angiotensin II receptor agonists and beta blockers may also decrease mortality in patients in heart failure, partly or wholly by similar mechanisms, inotropes and beta agonists may increase mortality from heart failure. These medications have not been established to improve disability-adjusted or un-adjusted longevity. >Bloodletting might have been much more effective than venodilators and as effective as diuretics for in increasing th tone of the precapillary sphincters and establishing a pressure gradient between interstitium and capillary the excretion of oedema fluid would have been promoted. If in inducing a gastric intramucosal acidosis bloodletting were also to induce preconditioning by, for example, activating anf K(atp) channel, bloodletting might even have had extended benefits not seen with medical therapy. [1] I wouldn't agree that patients' requests meant that it must have been beneficial, since people willingly do all sorts of crazy things to their bodies based on the most tenuous new age theories. It also doesn't make sense that regular bloodletting would be beneficial to an already healthy subject, since we'd presumably have evolved with a mechanism to dispose of excess "bad humors". However, as an alternate mechanism for achieving results that treat a condition like congestive heart failure, it seems a lot like drilling a hole in your head to treat a head injury — ridiculous sounding, but effective in certain cases. [1] http://www.bmj.com/rapid-response/2011/10/29/treating-heart-failure-and-sepsis-bloodletting-and-leeches http://www.bmj.com/rapid-response/2011/10/29/treating-heart-...