A major advance in anesthesia during the 20th century was the development of curare as a muscle relaxing agent. For many operations it is advantageous for the muscles to be sufficiently relaxed so they can be easily separated for surgeons to work in the gaps between them.
Surgical technique advanced rapidly once hygienic principles and anesthesia had been firmly established - the one removed the ever-present spectre of infection while the other gave the surgeon more time to work.
Although this can be achieved with general anesthetics, high doses are required, with all their attendant hazards. The profound muscle relaxation provided by curare removed for all time the need for deep anesthesia and led to a dramatic decrease in the number of pneumonias and other complications following surgery. Once again, self-experimentation played a part (6) in defining the actions of purified curare but not before clinical studies had proved its value during operations.(21)
The idea to use curare originated from Lewis Wright, a medical consultant to Squibb, who noted that the Nebraska State Mental Hospital employed the drug to facilitate pelvic examinations in disturbed patients. Experiments in which animals were dosed with ether and curare ended in disaster with all of the cats dying and the dogs becoming deeply distressed. Although the animal tests were abandoned, Wright pursued his idea and eventually persuaded Harold Griffith, an anesthetist at the Homoeopathic Hospital in Montreal, to try the drug on patients anesthetized with cyclopropane. Fortunately, Griffith's wide experience with cyclopropane convinced him that patients should also be kept on artificial respiration and so he unwittingly overcame the main problem with curare - that it paralyzes the respiratory muscles and therefore necessitates artificial respiration. The outcome of tests with a 20-year-old undergoing an appendectomy were so encouraging that Griffith went on to inject curare into a further 25 patients undergoing anesthesia. Within 18 months, this and other clinical trials confirmed the revolutionary role of the drug in making operations safer.(21)
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