From the G-suit to the Space Race, from cardiac technology to medical imaging, this Mayo researcher made it possible

In the tales that came out of the last century, one stock character was the white-coated scientist working in a secluded lab on top-secret projects. That researcher invented the technology that “helped us win the war” or get us into space or solve the critical problem at just the right time. That character is found in journalism, history, novels, and science fiction. The archetype for all of them could easily have been Earl Wood, M.D.

Charles Lindbergh reportedly saved himself in mid-air because of a technique he learned from Dr. Wood. Test pilots and Mercury astronauts benefited from Dr. Wood’s work, as did airmen fighting over Europe a generation before. Yet few people knew about him. Even after the restrictions of government security were lifted, Dr. Wood remained typically low-key, crediting his team, encouraging his students and focusing on discovering solutions through biomedical engineering.

“He always told us ‘Don’t hide your light under a bushel!’” says Barry Gilbert, Ph.D., about his mentor. “Yet that’s just what he did.” Modest, but brilliant, Wood could have been wealthy but chose to continue working at a medical facility aiding patients. In the days before intellectual property was a byword in science, Wood’s inventions found their way into the products of major industries or in the hands of the government. In his own way, his main concern was translation, making sure his discoveries reached the people who needed them.

“Dr. Wood was unassuming and easy going. His personality reminded me of the “aw shucks” persona of Jimmy Stewart in the movies of that day,” says science writer Ken McCracken, who knew him well and wrote about him often.

It’s a toss up as to which is more surprising – that one man accomplished so much or that he did it here, at Mayo Clinic. From arriving at Mayo in 1942 (he’d been here as a fellow earlier) to his death March 18 at the age of 97, Dr. Wood either spearheaded or collaborated on a collection of medical advancements that are viewed as commonplace elements of critical care and treatment.

Directly or in part, Dr. Wood was responsible for:

• The first practical G-suit — a flight suit outfitted with air-filled bladders and a system of valves to protect pilots during high-speed maneuvers by encouraging greater blood flow to the brain.
• Modification of an aircraft air pressure gauge into an instrument that became the standard tool for measuring arterial blood pressure.
• The first human diagnostic cardiac catheterization.
• The M-1 maneuver, a voluntary exhaling technique used by pilots to prevent blackouts, developed by Dr. Wood.
• Instrumentation and multi-channel recordings that monitored the amount of oxygen present in the blood throughout a surgical procedure.
• Refinement of the heart-lung bypass machine, which Mayo used to become the first medical center to perform open-heart surgery as a routine procedure.
• Development of indocyanine green dye, the favored method for measuring heart pump function and diagnosing congenital heart disease for many years and is still used in some applications today.

A Career Like No Other

Dr. Wood was born January 1, 1912, in Mankato, Minn. A 1934 graduate of Macalester College, he also earned an additional bachelor's degree, master's degree, as well as Ph.D. and M.D. degrees from the University of Minnesota. After serving as a National Research Council fellow at the University of Pennsylvania, he taught Pharmacology at Harvard University where he met Charles Code, M.D., who offered him a position at Mayo Clinic.

From 1942, Dr. Wood was an integral member of the Mayo Clinic Aero Medical Unit, which developed the first civilian human centrifuge in the United States. The centrifuge was used to test human reactions to high levels of gravitational (G) forces. The team of Drs. Wood and Code, and Drs. Edward Lambert and E.J. Baldes tested the centrifuge themselves, risking their personal safety to safeguard others involved in their research. They followed the same "do no harm" approach when, later, they tested equipment inside aircraft. Barry Gilbert, Ph.D., a Mayo physiologist who worked with Dr. Wood, says this group didn't hesitate to be their own "guinea pigs."

"People need to appreciate that for four years Dr. Wood and his colleagues got up every day and risked their lives in the service of their country," says Dr. Gilbert. He estimates Dr. Wood spent a total of 15 minutes in unconsciousness due to the many times he tested himself in the human centrifuge and in dive bombers.

In large part, their top-secret work laid the foundation for the science behind modern aerospace physiology and made travel possible in the upper levels of the atmosphere and outer space. WWII bomber pilots, jet fighter pilots, the test pilots who broke the sound barrier, and today's astronauts wore the suit, in various versions.

The group quickly gained an international reputation that extended to heart, lung and blood physiology and cardiac catheterization. "Dr. Wood was absolutely instrumental in the development of cardiopulmonary bypass, a technology that saves hundreds of thousands of lives every year," says Thoralf Sundt III, Mayo Clinic surgeon.

In 1958, research using the centrifuge got a second boost when the U.S. Air Force and NASA requested that Dr. Wood continue his studies on G forces. He and his team tested prototypes of the Project Mercury astronaut couches on Mayo's centrifuge.

Dr. Wood headed Mayo Clinic's Cardiovascular Laboratory and became a Career Investigator of the American Heart Association in 1962. Countless fellows, visiting scientists and clinicians came to study in his lab and learn new techniques. He was chairman of the Biodynamics Research Unit from 1975 to 1976 and advanced through the academic ranks to become a professor in the Mayo Graduate School of Medicine in 1951 and Mayo Medical School in 1973. Dr. Wood was a prolific contributor to the literature in Medicine, Aerospace Medicine, Cardiology, Physiology and Video Densitometry as well as advanced X-ray imagery of the heart, lungs and circulation leading to the development of the Dynamic Spatial Reconstructor, a 3-D, real-time, X-ray-based computed tomography machine that evolved into the Imatron CT scanner technology.

Dr. Wood published over 700 articles and numerous book chapters. He was president of the American Physiological Society from 1980 to 1981, and president of the Federation of American Societies of Experimental Biology. He was a fellow of the National Research Council. Dr. Wood retired from Mayo Clinic in January 1982.