Therapeutic Innovations Related to Respiration
Therapeutic Innovations Related to Respiration
During the first half of the twentieth century, several great innovations designed to treat respiratory failure were developed. The emerging fields of bioengineering and biomaterials developed devices to assist in medicine and therapy. One of the great bioengineering feats was the development of the "iron lung" to assist breathing. Invented by Philip Drinker (1894-1972) in 1927, this device provided respiration for those whose lungs could not breathe on their own. Drinker's machine, originally made from a household vacuum cleaner, some materials from the laboratory, and a large steel box, was used to treat one of the most frightening conditions of the day—infantile paralysis, now called poliomyelitis.
With the aim of treating people who were dying from drowning or other interruptions of breathing, Edward Sharpey-Schafer (1850-1935), an English physiologist, decided that a mechanical method or artificial respiration could start breathing until the lungs of the person could take over. He described the first pronepressure method of artificial respiration that became known as the Schafer method. In addition, John Scott Haldane (1860-1936), a British physiologist known for his work on respiration, first introduced modern oxygen therapy.
These pioneering innovations have been refined in the last part of the twentieth century. Some of the inventions and methods are no longer used, however, they once saved many lives and led to new improvements in the treatment of respiratory failure.
The study of respiration developed as part of the physiology of chemistry. Gases necessary for life were studied by many chemists and physiologists who formed the basis of the science of biochemistry. Gases necessary for life—mainly oxygen and carbon dioxide—were known in earlier centuries.
Asphyxia, unconsciousness caused by oxygen deprivation, had long been recognized as the most common cause of death. Oxygen can be deprived in several ways, each occurring when respiration is slowed or stopped.
In the early days of the twentieth century, poliomyelitis was a disease that caused paralysis to the lungs. Also called, infantile paralysis, the condition is caused by a virus that injures the upper part of the spinal cord and then causes difficulty in breathing. When breathing is affected, the person requires mechanical help or will die.
Asphyxiation also may occur when normal respiration is ineffective because the person is in an atmosphere where there is little oxygen. Examples are unventilated or poorly ventilated enclosed spaces such as mine tunnels, sewers, and industrial tanks where oxygen may be replaced by other gases. Many of these gases are odorless. Methane, for example, may accumulate in coal mines or come from decomposing sewage. People may or may not be aware of breathing these poisonous gases.
Another form of asphyxiation occurs when respiration is interfered with by gases like carbon monoxide that impede the oxygen-carrying ability of the cells. Carbon monoxide combines with hemoglobin, the substance in red blood cells that carries oxygen to the body tissues. The carbon-monoxide-hemoglobin combination does not allow the red blood cells to carry oxygen, so the body does not get the oxygen it needs. This condition may cause problems even though normal oxygen is present.
The idea of an apparatus to help breathing had been the dream of many people. In 1670 a scientist named John Mayow (1641-1679) built a model consisting of bellows and a bladder to pull in and expel air. Inspired by the death of his son from respiratory failure, Alexander Graham Bell (1847-1922), inventor of the telephone, designed a vacuum jacket in 1892. Throughout the nineteenth century, physicians and engineers experimented with External Negative Pressure Ventilator devices (ENPV).
Few people can imagine the terror of polio during the early days of the twentieth century. Patients with anterior polio affecting cervical and thoracic areas of the spinal cord might only have a few hours between the onset of the disease and death. Children who were afflicted would smother and drown in their own saliva. In 1926 Philip Drinker, a chemical engineer, was employed to teach applied physical science at Harvard. In 1926 he was asked by a committee of the Rockefeller Research Institute to study methods of resuscitation. He happened to observe an experiment conducted by his brother Cecil, and another physiologist Louis Shaw. The two measured the respiration of a cat by putting it in a sealed box with only its head sticking out.
Drinker reasoned that perhaps a similar design could help one breath. He injected a cat with curare, a poison and muscle relaxant, to slow down breathing. He modified the box so that he could manipulate a syringe to increase or lower the air pressure. He successfully ventilated the animal for several hours until the drug wore off.
Drinker concluded that if it worked for a cat, it could also work for a human being. He recruited a tinsmith to build a metal cabinet, to which he added a vacuum cleaner blower and some valves from the laboratory. The patient would slide into the respirator on a creeper, the device that wheels a mechanic under a car to work on it. The end point is secured at the feet and a rubber collar is slipped over the person's head. Drinker climbed into the respirator while his brother and Shaw worked the ventilation machine. For four minutes they pumped additional air into his lungs. At the end of 15 minutes he was so hyperventilated that it took four minutes for him to regain normal breathing. But the machine was a success; it had breathed for him.
In 1928 an eight-year-old girl who was in a coma from lack of oxygen was placed in the machine, and it started breathing for her. She regained consciousness and in a few minutes was asking for ice cream.
Another opportunity to use the device arose when Harvard senior Barret Hoyt was dying in the Peter Bent Brigham Hospital. His physician called Drinker to bring the machine over to the hospital. The machine would not fit into the taxi he had called, and there was no time to find a truck; the machine was finally tied to the top of the taxi. After a stay in the machine for four weeks, Hoyt lived, finished college, and worked for 30 years as a successful insurance agent.
The iron lung also became an extravaganza. Department stores—wanting to show their support for polio research—would display the instrument in their windows. Machines were invented that would hold a group of people, and these would be shown with several of the large iron boxes stacked on top of each other with multiple heads sticking out. The machine was then sent to Europe, and over the years was improved and imitated. Actually, it was a great tool against the dreaded disease. When the polio vaccine was developed in 1955, the machine—no longer needed—was relegated to museums.
Edward Albert Sharpey-Schafer was an English physiologist and inventor of the Schafer method of artificial respiration. He was the first student to hold a scholarship under Dr. William Sharpey; to honor his teacher, he attached his surname to his own to become Sharpey-Schafer.
A professor named Sylvester had devised a method of reviving a person who was drowning by laying the patient on his or her back and working the arms sideways from straight down to up above the patient's heart to pump air into the lungs. Schafer turned the patient face down to let the water drain out of the lungs. The operator kneeled across the back pressing down and counting "one two three" then relaxing counting "one-two-three."
The Schafer method became generally accepted by the medical profession and was taught to Scouts, first aid professionals, and people throughout the world. Although the procedure has been replaced by cardiopulmonary resuscitation (CPR), it is still credited to saving many lives.
British physiologist John Scott Haldane discovered in 1905 that breathing is regulated by the concentration of carbon dioxide in the respiratory center of the brain. He devised an apparatus for the analysis of blood gas called a hemoglobinometer and an apparatus for the analysis of a mixture of gases. In 1911 he led an expedition to Pike's Peak to study the effect of low barometric pressure on breathing.
Going into the depths of coal mines, he found that carbon monoxide and other dangerous gases were causing the deaths of miners. Taking a clue from French physiologist Claude Bernard (1813-1878), who showed that carbon monoxide combined with hemoglobin, Haldane found that rats survived carbon monoxide poisoning when placed at 2 atmospheres of pressure. Carbon monoxide deaths were occurring in many places because of illuminating gas and gas heaters. In 1927, for example, 611 carbon-monoxide related deaths occurred in New York City.
Haldane's innovative thinking related to his study of blood gases. He noted that divers who ascended in stages could avoid the nitrogen accumulation in the blood commonly called the "bends." Haldane used experimental animals, especially goats because their respiratory systems are similar to humans. Haldane also carried out an experiment in which a goat was decompressed to a low pressure using a mixture of helium and oxygen, then given pure oxygen to speed up recompression. The pioneering work of Haldane would lead to the first clinical use of the hyperbaric chamber in 1960.
The work of these three innovative pioneers—Drinker, Sharpey-Schafer, and Haldane—proved essential to the development of a variety of treatments for respiratory ailments in the second half of the century.
EVELYN B. KELLY
Porter, Roy. The Greatest Benefit to Mankind: A Medical History of Humanity. New York: W. W. Norton, 1997.
Porter, Roy. Medicine: A History of Healing. New York: Barnes & Noble, 1997.