Inventor of G-Suit Dies

Earl Wood, M.D., Ph.D., the Mayo Clinic investigator credited with inventing the high-altitude pressure suit worn by pilots and astronauts, died March 18 in Rochester, Minn. He was 97.

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. In large part, their 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 ‹ including innovations still used in heart bypass surgery and the practice of Cardiology. Directly or in part, Dr. Wood was responsible for:

• The first 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 by Dr. Wood, the favored method for measuring heart pump function and diagnosing congenital heart disease for many years and is still used in some applications today.

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 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.

He is survived by four children, Phoebe Busch, Denver, Colo.; Mark Wood, Fresno, Calif.; Guy Wood, Corvallis, Ore.; and Andy Wood, Rochester, Minn.; and by four grandchildren.

Dr. Wood’s work is highlighted in a documentary entitled, Reaching New Heights: Secret Stories of the Mayo Clinic Aero Medical Unit, which is embedded below. Journalists may request access to broadcast-quality excerpts via email.

Part 1:

Part 2:

Photo of Dr. Wood (click to enlarge and/or download):

Share/Bookmark