Ralph Milton Waters (October 9, 1883 – December 19, 1979) was an American anesthesiologist known for introducing professionalism into the practice of anesthesia.
Waters attended Western Reserve University Medical School and started a private practice focusing on obstetrics in Sioux City, Iowa upon graduation.
In 1919, he published the landmark paper, "Why The Professional Anesthetist", describing the inadequacies of anesthetic practices across the country.
Among his contributions to the field were the development of the gas cyclopropane for clinical use, beginning in the 1930s; the carbon dioxide absorption method; and endobronchial anesthesia for thoracic surgery.
[2] Waters was instrumental in outsourcing his resident training model to other universities and hospitals, including Bellevue Hospital, where he sent his assistant, Emery Rovenstine in 1935; and the University of Pennsylvania, where his protege Robert Dripps implemented the model.