Flebotomía

La sangría (o sangría ) es la extracción deliberada de sangre de un paciente para prevenir o curar enfermedades. La sangría, ya sea realizada por un médico o con sanguijuelas , se basaba en un antiguo sistema de medicina en el que la sangre y otros fluidos corporales se consideraban " humores " que debían mantenerse en equilibrio para conservar la salud. Fue la práctica médica más común realizada por cirujanos desde la antigüedad hasta finales del siglo XIX, un periodo de más de 2000 años. ^{[ 1 ]} En Europa, la práctica siguió siendo relativamente común hasta finales del siglo XIX. ^{[ 2 ]} La medicina moderna la ha abandonado, salvo en algunas afecciones médicas muy específicas . ^{[ 3 ]} A principios del siglo XIX, algunos estudios comenzaron a mostrar los efectos nocivos de la sangría. ^{[ 4 ]}

El término moderno flebotomía se refiere a la extracción de sangre para análisis de laboratorio o transfusión sanguínea . ^{[ 5 ]} La flebotomía terapéutica se refiere a la extracción de una unidad de sangre en casos específicos como hemocromatosis , policitemia vera , porfiria cutánea tarda , etc., para reducir el número de glóbulos rojos . ^{[ 6 ] [ 7 ]} La práctica médica tradicional de la sangría se considera una pseudociencia , ^{[ 8 ]} aunque el método todavía se usa comúnmente en formas de medicina alternativa .

Passages from the Ebers Papyrus may indicate that bloodletting by scarification was an accepted practice in Ancient Egypt.^[9][10][11] Egyptian burials have been reported to contain bloodletting instruments.^[12] According to some accounts, the Egyptians based the idea on their observations of the hippopotamus,^[13] confusing its red secretions with blood and believing that it scratched itself to relieve distress.^[14][15]

In Greece, bloodletting was in use in the 5th century BC during the lifetime of Hippocrates, who mentions this practice but generally relied on dietary techniques.^[16]Erasistratus, however, theorized that many diseases were caused by plethoras, or overabundances, in the blood and advised that these plethoras be treated, initially, by exercise, sweating, reduced food intake, and vomiting.^[17] But his student Herophilus supported bloodletting.^[18] A contemporary Greek physician, Archagathus, one of the first to practice in Rome, also believed in the value of bloodletting.

"Bleeding" a patient to health was modeled on the process of menstruation. Hippocrates believed that menstruation functioned to "purge women of bad humors". During the Roman Empire, the Greek physician Galen, who subscribed to the teachings of Hippocrates, advocated physician-initiated bloodletting.^[19]

La popularidad de la sangría en el mundo mediterráneo clásico se vio reforzada por las ideas de Galeno, tras descubrir que no solo las venas , sino también las arterias, estaban llenas de sangre, y no de aire como se creía comúnmente en aquella época. ^{[ 20 ] [ 21 ]} Su sistema de sangría se basaba en dos conceptos clave. El primero era que la sangre se creaba y luego se consumía; no circulaba , por lo que podía estancarse en las extremidades. El segundo era que el equilibrio humoral era la base de la enfermedad o la salud, siendo los cuatro humores sangre, flema, bilis negra y bilis amarilla, relacionados con los cuatro elementos clásicos griegos de aire, agua, tierra y fuego, respectivamente. Galeno creía que la sangre era el humor dominante y el que más necesitaba control. Para equilibrar los humores, el médico extraía el exceso de sangre (plétora) del paciente o le administraba un emético para inducir el vómito o un diurético para inducir la micción.

Galeno creó un sistema complejo sobre cuánta sangre debía extraerse según la edad del paciente, su constitución, la estación del año, el clima y el lugar. Se desarrollaron instrucciones de sangría "hágalo usted mismo" siguiendo estos sistemas. ^{[ 22 ]} Se creía que los síntomas de la plétora incluían fiebre, apoplejía y dolor de cabeza. La sangre que se debía extraer era de una naturaleza específica determinada por la enfermedad: arterial o venosa , y distante o cercana al área del cuerpo afectada. Vinculó diferentes vasos sanguíneos con diferentes órganos , según su supuesto drenaje. Por ejemplo, se extraía sangre de la vena de la mano derecha para problemas de hígado y de la mano izquierda para problemas del bazo . Cuanto más grave era la enfermedad, más sangre se extraía. Las fiebres requerían grandes cantidades de sangría.

1335-1340, Inglaterra. Médico o barbero sangrando a un paciente.

Alrededor del año 1300 d. C., Alemania. Un médico sostiene el brazo del paciente extendido mientras la sangre fluye hacia un recipiente. El cuchillo utilizado para abrir la herida está sobre la mesa, y un torniquete en el suelo. El pie de foto hace referencia a sangre.

The Talmud recommended a specific day of the week and days of the month for bloodletting in the Shabbat tractate.^[23] During medieval times bleeding charts were common, showing specific bleeding sites on the body in alignment with the planets and zodiacs.^[22]Islamic medical authors also advised bloodletting, particularly for fevers. It was practised according to seasons and certain phases of the Moon in the lunar calendar. The practice was probably passed by the Greeks with the translation of ancient texts to Arabic and is different from bloodletting by cuppingmentioned in the traditions of Muhammad. When Muslim theories became known in the Latin-speaking countries of Europe, bloodletting became more widespread. Together with cautery, it was central to Arabic surgery; the key texts Kitab al-Qanun and especially Al-Tasrif li-man 'ajaza 'an al-ta'lif both recommended it. It was also known in Ayurvedic medicine, described in the Susruta Samhita.

Bloodletting became a main technique of heroic medicine, a traumatic and destructive collection of medical practices that emerged in the 18th century.^[24]

Even after the humoral system fell into disuse, the practice was continued by surgeons and barber-surgeons. Though the bloodletting was often recommended by physicians, it was carried out by barbers. This led to the distinction between physicians and surgeons. The red-and-white-striped pole of the barbershop, still in use today, is derived from this practice: the red symbolizes blood while the white symbolizes the bandages. Bloodletting was used to "treat" a wide range of diseases, becoming a standard treatment for almost every ailment, and was practiced prophylactically as well as therapeutically.

A number of different methods were employed. The most common was phlebotomy, or venesection (often called "breathing a vein"), in which blood was drawn from one or more of the larger external veins, such as those in the forearm or neck. In arteriotomy, an artery was punctured, although generally only in the temples. In scarification (not to be confused with scarification, a method of body modification), the "superficial" vessels were attacked, often using a syringe, a spring-loaded lancet, or a glass cup that contained heated air, producing a vacuum within (see fire cupping). There was also a specific bloodletting tool called a scarificator, used primarily in 19th century medicine. It has a spring-loaded mechanism with gears that snaps the blades out through slits in the front cover and back in, in a circular motion. The case is cast brass, and the mechanism and blades steel. One knife bar gear has slipped teeth, turning the blades in a different direction than those on the other bars. The last photo and the diagram show the depth adjustment bar at the back and sides.

Leeches could also be used. The withdrawal of so much blood as to induce syncope (fainting) was considered beneficial, and many sessions would only end when the patient began to swoon.

William Harvey disproved the basis of the practice in 1628,^[2] and the introduction of scientific medicine, la méthode numérique, allowed Pierre Charles Alexandre Louis to demonstrate that phlebotomy was entirely ineffective in the treatment of pneumonia and various fevers in the 1830s. Nevertheless, in 1838, a lecturer at the Royal College of Physicians would still state that "blood-letting is a remedy which, when judiciously employed, it is hardly possible to estimate too highly",^[25] and Louis was dogged by the sanguinary Broussais, who could recommend leeches fifty at a time. Some physicians resisted Louis' work because they "were not prepared to discard therapies 'validated by both tradition and their own experience on account of somebody else's numbers'."^[26]

During this era, bloodletting was used to treat almost every disease. One British medical text recommended bloodletting for acne, asthma, cancer, cholera, coma, convulsions, diabetes, epilepsy, gangrene, gout, herpes, indigestion, insanity, jaundice, leprosy, ophthalmia, plague, pneumonia, scurvy, smallpox, stroke, tetanus, tuberculosis, and for some one hundred other diseases. Bloodletting was even used to treat most forms of hemorrhaging such as nosebleed, excessive menstruation, or hemorrhoidal bleeding. Before surgery or at the onset of childbirth, blood was removed to prevent inflammation. Before amputation, it was customary to remove a quantity of blood equal to the amount believed to circulate in the limb that was to be removed.^[27]

There were also theories that bloodletting would cure "heartsickness" and "heartbreak". A French physician, Jacques Ferrand wrote a book in 1623 on the uses of bloodletting to cure a broken heart. He recommended bloodletting to the point of heart failure (literal).^[28]

Leeches became especially popular in the early 19th century. In the 1830s, the French imported about 40 million leeches a year for medical purposes, and in the next decade, England imported 6 million leeches a year from France alone. Through the early decades of the century, hundreds of millions of leeches were used by physicians throughout Europe.^[29]

One typical course of medical treatment began the morning of 13 July 1824. A French sergeant was stabbed through the chest while engaged in single combat; within minutes, he fainted from loss of blood. Arriving at the local hospital he was immediately bled twenty ounces (570 ml) "to prevent inflammation". During the night he was bled another 24 ounces (680 ml). Early the next morning, the chief surgeon bled the patient another 10 ounces (285 ml); during the next 14 hours, he was bled five more times. Medical attendants thus intentionally removed more than half of the patient's normal blood supply—in addition to the initial blood loss which caused the sergeant to faint. Bleedings continued over the next several days. By 29 July, the wound had become inflamed. The physician applied 32 leeches to the most sensitive part of the wound. Over the next three days, there were more bleedings and a total of 40 more leeches. The sergeant recovered and was discharged on 3 October. His physician wrote that "by the large quantity of blood lost, amounting to 170 ounces [nearly eleven pints] (4.8 liters), besides that drawn by the application of leeches [perhaps another two pints] (1.1 liters), the life of the patient was preserved". By nineteenth-century standards, thirteen pints of blood taken over the space of a month was a large but not an exceptional quantity. The medical literature of the period contains many similar accounts—some successful, some not.^[30]

Bloodletting was also popular in the young United States of America, where Benjamin Rush (a signatory of the Declaration of Independence) saw the state of the arteries as the key to disease, recommending levels of bloodletting that were high even for the time. George Washington asked to be bled heavily after he developed a throat infection from weather exposure. Within a ten-hour period, a total of 124–126 ounces (3.75 liters) of blood was withdrawn prior to his death from a throat infection in 1799.^[31]

One reason for the continued popularity of bloodletting (and purging) was that, while anatomical knowledge, surgical and diagnostic skills increased tremendously in Europe from the 17th century, the key to curing disease remained elusive, and the underlying belief was that it was better to give any treatment than nothing at all. The psychological benefit of bloodletting to the patient (a placebo effect) may sometimes have outweighed the physiological problems it caused. Bloodletting slowly lost favour during the 19th century, after French physician Dr. Pierre Louis conducted an experiment in which he studied the effect of bloodletting on pneumonia patients.^[32] A number of other ineffective or harmful treatments were available as placebos—mesmerism, various processes involving the new technology of electricity, many potions, tonics, and elixirs. Yet, bloodletting persisted during the 19th century partly because it was readily available to people of any socioeconomic status.^[33]

Barbara Ehrenreich and Deirdre English write that the popularity of bloodletting and heroic medicine in general was because of a need to justify medical billing. Traditional healing techniques had been mostly practiced by women within a non-commercial family or village setting. As male doctors suppressed these techniques, they found it difficult to quantify various "amounts" of healing to charge for, and difficult to convince patients to pay for it. Because bloodletting seemed active and dramatic, it helped convince patients the doctor had something tangible to sell.^[24]

Bloodletting gradually declined in popularity over the course of the 19th century, becoming rather uncommon in most places, before its validity was thoroughly debated. In the medical community of Edinburgh, bloodletting was abandoned in practice before it was challenged in theory, a contradiction highlighted by physician-physiologist John Hughes Bennett.^[34] Authorities such as Austin Flint I, Hiram Corson, and William Osler became prominent supporters of bloodletting in the 1880s and onwards, disputing Bennett's premise that bloodletting had fallen into disuse because it did not work. These advocates framed bloodletting as an orthodox medical practice, to be used in spite of its general unpopularity.^[35] Some physicians considered bloodletting useful for a more limited range of purposes, such as to "clear out" infected or weakened blood or its ability to "cause hæmorrhages to cease"—as evidenced in a call for a "fair trial for blood-letting as a remedy" in 1871.^[36]

Some researchers used statistical methods for evaluating treatment effectiveness to discourage bloodletting.^[32] But at the same time, publications by Philip Pye-Smith and others defended bloodletting on scientific grounds.^[35]

Bloodletting persisted into the 20th century and was recommended in the 1923 edition of the textbook The Principles and Practice of Medicine.^[37] The textbook was originally written by Sir William Osler and continued to be published in new editions under new authors following Osler's death in 1919.^[38]

Antiguamente se creía que la sangría reducía la inflamación, fortalecía el sistema inmunitario y mejoraba la circulación al favorecer la desintoxicación de la sangre que circulaba por el cuerpo. ^{[ 39 ]} Sin embargo, con el tiempo, los efectos nocivos de la sangría la convirtieron en una práctica médica menos recomendable. No solo era generalmente ineficaz, sino que también solía provocar una pérdida de sangre significativa. Esta gran pérdida de sangre hacía que los pacientes fueran altamente susceptibles a infecciones/ sepsis o a la formación de hematomas . ^{[ 40 ]} Además, la sangría también causaba anemia , lo que provocaba debilidad, cansancio e incluso pérdida del conocimiento. Los efectos nocivos no terminaban ahí; en casos graves, la sangría podía provocar un shock hipovolémico mortal . ^{[ 41 ]} Con el avance de la medicina, estos efectos mortales hicieron que la práctica de la sangría perdiera popularidad.

La flebotomía terapéutica se utiliza hoy en día en el tratamiento de algunas enfermedades, como la hemocromatosis , la anemia falciforme , la porfiria cutánea tarda , la enfermedad del hígado graso no alcohólico y la policitemia . ^{[ 42 ] [ 43 ]} La practican profesionales específicamente capacitados en hospitales que utilizan técnicas modernas y un procedimiento relativamente seguro que agota las reservas de hierro en el cuerpo. ^{[ 44 ]} En la mayoría de los casos, la flebotomía ahora se refiere a la extracción de pequeñas cantidades de sangre con fines diagnósticos y es un procedimiento importante en los EE. UU. Según un artículo académico publicado en el Journal of Infusion Nursing con datos publicados en 2010, el uso principal de la flebotomía es tomar sangre que se reinfundirá a una persona ( donación de sangre ). ^{[ 45 ]} Sin embargo, en el caso de la hemocromatosis , la sangría (por venopunción ) se ha convertido en la opción de tratamiento principal. ^{[ 46 ] [ 47 ]} La flebotomía terapéutica es una forma rentable de eliminar el exceso de hierro en la sangre para pacientes que tienen hemocromatosis . ^{[ 44 ]}

Therapeutic uses of bloodletting were reported in 60 distinct cultures/ethnic groups in the HRAF database, present in all inhabited continents. Bloodletting has also been reported in 15 of the 60 cultures in the probability sample files (PSF) list.^[48] The PSF is a subset of eHRAF data that includes only one culture from each of 60 macro-culture areas around the world. The prevalence of bloodletting in PSF controls for pseudo-replication linked to common ancestry, suggesting that bloodletting has independently emerged many times. Bloodletting is varied in its practices cross-culturally, for example, in native Alaskan culture bloodletting was practiced for different indications, using different tools, on different body areas, by different people, and it was explained by different medical theories.^[49]

According to Helena Miton et al.'s ^[48] analysis of the HRAF database and other sources, there are several cross-cultural patterns in bloodletting.

• Bloodletting is not self-administered. Out of 14 cultures in which the bloodletting practitioner was mentioned, the practitioner was always a third party. 13 out of 14 of the cultures had practitioners with roles related to medicine, while one culture had a practitioner whose role was not related to medicine.
• The idea of bloodletting removing "bad blood" that needs to be taken out was common, and was explicitly mentioned in 10 out of 14 cultures studied with detailed descriptions of bloodletting.
• Bloodletting is not thought to be effective against illness caused supernaturally by humans (e.g., witchcraft). This is surprising, because in most cultures witchcraft and sorcery can be blamed for ailments.^[50] But out of 14 cultures with detailed bloodletting descriptions, there was no evidence of bloodletting being used to cure witchcraft-related ailments, while bloodletting was recorded as a cure for ailments of other origins. The Azande culture has been recorded to believe that bloodletting does not work to cure human-related witchcraft ailments.^[51]
• Bloodletting is usually administered directly to the affected area, e.g. if the patient has a headache, a cut is made on the forehead. Out of 14 cultures with information on the localization of bloodletting, 11 at least sometimes removed blood from the affected area, while 3 specifically removed blood from a different area from the area in pain. Europe is the only continent with more instances of non-colocalized than colocalized bloodletting.

En un experimento de cadena de transmisión realizado con personas que viven en los EE. UU. a través de Amazon Mechanical Turk , las historias sobre sangrías en un área no afectada tenían muchas más probabilidades de transformarse en historias sobre sangrías administradas cerca del área dolorida que viceversa. ^{[ 48 ]} Esto sugiere que la sangría ubicada en el mismo lugar podría ser un atractor cultural y es más probable que se transmita culturalmente, incluso entre personas en los EE. UU. que probablemente estén más familiarizadas con la sangría no ubicada en el mismo lugar.

Se considera que la sangría, como concepto, es un atractor cultural, o un concepto intrínsecamente atractivo y transmisible culturalmente. Esto podría explicar su surgimiento transcultural independiente y sus rasgos comunes entre culturas. ^{[ 48 ]}

• Carter, K. Codell; Barbara R. Carter (2005). Fiebre puerperal. Una biografía científica de Ignaz Semmelweis . Transaction Publishers. ISBN 978-1-4128-0467-7.
• Carter, K. Codell (2012). El declive de la sangría terapéutica y el colapso de la medicina tradicional . New Brunswick y Londres: Transaction Publishers. ISBN 978-1-4128-4604-2.
• Kang, Lydia; Nate Pederson (2017). Charlatanería: Una breve historia de las peores maneras de curarlo todo . Workman Publishing Company.

• McGrew, Roderick. Enciclopedia de Historia de la Medicina (1985), breve historia, págs.  32-34.

• Historia y evolución de la sangría
• Antigüedades médicas: escarificación y sangrado
• Imágenes de instrumentos antiguos para sangrías.
• Red Gold: The Story of Blood de PBS (Archivado el 22 de julio de 2015 en Wayback Machine)
• Gran colección de instrumentos antiguos para sangrías
• "Respirando una vena" phisick.com 14 de noviembre de 2011