Earl Wood Explained

Earl H. Wood
Birth Date:1 January 1912[1]
Birth Place:Mankato, Minnesota
Death Place:Rochester, Minnesota
Citizenship:United States
Nationality:American
Alma Mater:Macalester College
University of Minnesota
Thesis Title:The Distribution of Electrolytes and Water Between Cardiac Muscle and Blood Serum with Special Reference to the Effects of Digitalis
Thesis Year:1942
Known For:Invention of the G-suit, Development of cardiac catheterization into a clinical service, Invention of the ear oximeter, Co-inventor of the first dynamic (high speed) volumetric x-ray computed tomography system
Awards:Presidential Certificate of Merit from Harry Truman-1947; Macalester College honorary degree of D.Sc.-1950; American Heart Association's "Career Investigator" 1962; Distinguished Citizen Award-1974; honorary member of the Royal Netherlands Academy of Arts and Sciences-1977; honorary member American College of Cardiology - 1978; honorary degree, doctor of medicine, from the University of Bern, Switzerland - 1978; Humboldt Prize for Senior U.S. Scientists by the government of West Germany - 1979; John Phillips Memorial Award of the American College of Physicians - 1979; President of the American Physiological Society - 1980-81; President of the Federation of American Societies for Experimental Biology (FASEB) - 1981-82; John Phillips Memorial Award of the American College of Physicians 1982; Aerospace Medical Association's Lyster Award for outstanding achievement in Aerospace medicine 1983; Ray G. Daggs Award for his distinguished long-term service to the science of physiology and, in particular, to the American Physiological Society - 1995; Street in Rheinfelden, Germany dedicated as "Earl H. Wood Strasse" - 2002.
Field:Cardiovascular, Respiratory, Aerospace Medicine and Cardiovascular and Pulmonary Dynamics
Work Institutions:Mayo Clinic
Rochester, Minnesota

Earl Howard Wood (January 1, 1912  - March 18, 2009) was an American cardiopulmonary physiologist who helped invent the G-suit, brought heart catheterization into a clinical reality and introduced dynamic volumetric computed tomography for the study of the heart and lungs.[2] [3]

Career

G-Suit

Shortly after receiving an M.D. and PhD in physiology from the University of Minnesota medical school under the mentorship of Professor Maurice B. Visscher, MD,[4] Wood became a key member of a team, working in a laboratory at the Mayo Clinic, tasked with helping military pilots and flight crew survive and function in high G-force environments. Based upon extensive physiologic testing via use of the human centrifuge installed at the Mayo Clinic, it was determined that blackout and then unconsciousness was caused by reduction of blood flow to the eyes first and then the brain.[5] The solutions the team arrived at were the M-1 breath hold maneuver[6] [7] and the G-suit.[8] [9] The M-1 maneuver consisted of a strained exhalation effort against a closed glottis designed to increase left ventricular pressure. (Although the references given are dated 1946-7, the work was performed much before then. In, see the acknowledgments section explaining the closed nature of the research with restrictions placed on publication during the war. During the war effort the Mayo Clinic laboratory was operating with government Confidential secrecy.) The G suit was a garment, produced by the David Clark Company, which has air bladders situated at the calves, thighs, and abdomen of the wearer. The bladders inflate as the G-force acting on the aircraft increase, constricting the wearer's arteries, hence increasing blood pressure and blood flow to the brain.

The G-suit was a superior solution to another alternative (a water-filled suit) being tested at the time, which was considered impractically heavy and cumbersome. The water-filled, pulsatile pressure suits were developed to effect venous return. However, Wood and colleagues' detailed physiologic measurements demonstrated that what was required was augmentation of arterial pressure.

Wood himself regularly tested the flight suits, taking many turns in a human centrifuge and plane dubbed the "G-wiz." He calculated that during more than a thousand rides, he had lost consciousness for an aggregate of at least fifteen minutes (without any observed lasting damage). Wood was awarded a Presidential Certificate of Merit by Harry Truman in 1947.

The G-suit was adopted in the 1940s. The current models are based on the pattern Wood and his colleagues designed. Following World War II, Wood was recruited to participate in what was known as "Operation Paperclip"[10] The goal was to keep the top German scientists away from Russia and working for the United States.

In 1962, Wood was the tenth scientist to be named "Career Investigator," of the American Heart Association.[11] These funds allowed Wood considerable flexibility in regards to the directions of his research.

Other work

After his work on the G-Suit, Wood worked on techniques for measuring cardiac blood flow. He was granted a patent for the ear oximeter, an optical instrument that measures blood oxygen levels without taking blood by examining the variation of light absorption as a function of oxygen saturation of hemoglobin. Integral to the work leading to the development of the G suit was the perfection of vascular catheterization methods needed to understand the distribution of blood pressure and flow. Shortly after the end of World War II, open-heart surgery emerged with the Mayo contribution[12] to the development of the heart-lung bypass machine initially developed by Gibbons[13] and perfected by Wood and colleagues.[12] [14] Wood's work at the Mayo Clinic lead to the development of many technologies allowing for the assessment of the heart and lungs including dye dilution methods serving to characterize cardiac output,[15] methods for the assessment of central blood volume,[16] the calculation of pulmonary vascular resistance (known as the "Wood Unit" and calculated by subtracting pulmonary capillary wedge pressure from the mean pulmonary arterial pressure and dividing by the cardiac output), analog subtraction angiography, and eventually the Dynamic Spatial Reconstructor (DSR), a predecessor to modern high speed volumetric computed tomography (CT) allowing for the evaluation of the beating heart and breathing lungs. The DSR comprised 14 X-ray tubes and a hemicylindrical fluorescent screen imaged by 14 associated television cameras.[17] [18]

In all, Wood is noted for his contributions (together with members of the Biodynamics Research Unit (BRU), under his direction, within the physiology and biophysics department at the Mayo Clinic) in the following areas:

Wood's publication list, with more than 700 entries, is a testament to the number of fellows who trained under him and who became prominent researchers in their own right.

Early life

Earl Wood was born to Inez Goff and William Clark Wood in Mankato, Minnesota on January 1, 1912 and started life on a subsistence farm.[53] William Wood, in addition to farming, was a real estate businessman. Earl Wood earned a B.A. in Mathematics and Chemistry from Macalester College in 1934, and his MD degree and a PhD degree in physiology from the University of Minnesota. Earl was one of 5 brothers (Earl, Chester, Delbert, Harland and Abe) and a sister, Louise.

Family

All of Earl Wood's siblings grew up to be highly accomplished.[11] Louise A. Wood was awarded the Medal of Freedom by President Truman for her services as overseas director of the American Red Cross during World War II. and became the executive director of the Girl Scouts of the USA from 1961 to 1972. Harland G. Wood was the first director of the department of biochemistry at the school of medicine and dean of sciences, Case Western Reserve University. As a biochemist, he was notable for proving in 1935 that animals, humans and bacteria utilized carbon dioxide[54] and received the National Medal of Science. Chester was a teacher and a university administrator; Delbert was, in succession, a lawyer, a Federal Bureau of Investigation agent, and a railway executive; Abe was an internist and founder of a Colorado-based medical clinic. Not surprisingly, in 1950, Earl Wood's mother, Inez, was awarded the title of "Minnesota Mother of the Year."[11] Earl and his wife, Ada, had a daughter, Phoebe and three sons, Mark, Guy and E. Andrew.

Notes and References

  1. Minnesota, Birth Index, 1900-1934
  2. News: Earl H. Wood Is Dead at 97; Helped Invent G-Suit. Jeremy. Pearce. March 26, 2009. March 27, 2009. The New York Times.
  3. News: A Research Physician's Innovations Bore Fruit in Unexpected Ways. Stephen. Miller. Wall Street Journal. 28 March 2009. www.wsj.com.
  4. Fox. JJ. Maurice B. Visscher at seventy-five--a life in the service of humanity. Circ. Res.. September 1976. 39. 3 . 295–296. 782741. 10.1161/01.res.39.3.295. free.
  5. Wood. EH. Lambert. EH. et al.. Effects of acceleration in relation to aviation. Fed. Proc.. September 1946. 5. 327–344. 20999477.
  6. Wood . EH . 1947 . Use of the Valsalva maneuver to increase man's tolerance to positive acceleration . Fed. Proc. . 6 . 1 Pt 2 . 229 . 20342926 .
  7. Wood . EH . Hallenbeck . GA . 1946 . Voluntary (self-protective) maneuvers which can be used to increase man's tolerance to positive acceleration . Fed. Proc. . 5 . 1 Pt 2 . 115 . 21066535 .
  8. Wood . EH . Lambert . EH . 1946 . The effect of anti-blackout suits on blood pressure changes produced on the human centrifuge . Fed. Proc. . 5 . 1 Pt 2 . 115 . 21066536 .
  9. Lambert . EH . Wood . EH . Jul 1946 . The problem of blackout and unconsciousness in aviators . Med Clin North Am . 30 . 4. 833–44 . 20992942 . 10.1016/s0025-7125(16)35922-3 .
  10. Web site: INSIDE Inventor had a life outside of science. Post-Bulletin. 27 October 2008. Jeff. Hansel.
  11. Burchell . HB . Wood . Earl H. . May 1987 . outstanding twentieth century investigator of the heart and circulation . Clin Cardiol . 10 . 5. 372–4 . 3297443 . 10.1002/clc.4960100518. free .
  12. Kirklin. JW. Dushane. JW. Patrick. RT. Donald. DE. Hetzel. PS. Harshbarger. HG. Wood. EH. Intracardiac surgery with the aid of a mechanical pump-oxygenator system (gibbon type): report of eight cases. Proc Staff Meet Mayo Clin. May 18, 1955. 30. 10. 201–206. 14371757.
  13. Stokes. TL. Gibbon. JH Jr.. Experimental maintenance of life by a mechanical heart and lung during occlusion of the venae cavae followed by survival . Surgery, Gynecology & Obstetrics. August 1950. 91. 2. 138–156. 15442833.
  14. Gibbon. JH. Application of a mechanical heart and lung apparatus to cardiac surgery. Minn Med. 37. 3. 171–185. 1954. 13154149.
  15. Grace. JB. Fox. IJ. Crowley. WP Jr. Wood. EH. Thoracic-aorta flow in man. J Appl Physiol. November 1957. 11. 3. 405–418. 13480951. 10.1152/jappl.1957.11.3.405.
  16. Bowers. D. Shepherd. JT. Wood. EH. A constant-rate indicator-infusion technic for the measurement of central vascular volume in man. Can J Biochem Physiol. May 1955. 33. 3. 340–348. 14364323. 10.1139/o55-045.
  17. Ritman . EL . Kinsey . JH . Robb . RA . Gilbert . BK . Harris . LD . Wood . EH . Oct 1980 . Three-dimensional imaging of heart, lungs, and circulation . Science . 210 . 4467. 273–80 . 7423187 . 10.1126/science.7423187 . 1980Sci...210..273R .
  18. Robb . RA . Sinak . LJ . Hoffman . EA . Kinsey . JH . Harris . LD . Ritman . EL . Dec 1982 . Dynamic volume imaging of moving organs . J Med Syst. . 6 . 6. 539–54 . 10.1007/BF00995505 . 7183727 . 24043369 .
  19. Wood . EH . Oct 1986 . Contributions of aeromedical research to flight and biomedical science . Aviat Space Environ Med . 57 . 10. A13–23 . 3778400 . . Erratum in: Aviat Space Environ Med 1987 Jul;58(7):706.
  20. Wood . EH . Jul 1987 . Development of anti-G suits and their limitations . Aviat Space Environ Med . 58 . 7. 699–706 . 3304268 .
  21. Wood . EH . Feb 1987 . Development of methods for prevention of acceleration induced blackout and unconsciousness in World War II fighter pilots. Limitations: present and future . Physiologist . 30 . 1. S27–30 . 3550843 .
  22. Burchell. HB. Wood. EH. Remarks on the technic and diagnostic applications of cardiac catheterization. Proc Staff Meet Mayo Clin. February 1, 1950. 25. 3. 41–48. 15404372.
  23. Burchell. HB. Helmholz Jr.. HF. Wood. EH. Over-all experiences with cardiac catheterization. Proc Staff Meet Mayo Clin. February 11, 1953. 28. 3. 50–57. 13014125.
  24. Ellis. EJ. Gauer. OH. Wood. EH. An intracardiac manometer: its evaluation and application. Circulation. March 1951. 3. 3. 390–398. 14812668. 10.1161/01.cir.3.3.390. free.
  25. Wood. EH. Leusen. IR. Warner. HR. Wright. JL. Measurement of pressures in man by cardiac catheters. Circ Res. July 1954. 2. 4. 294–303. 13172871. 10.1161/01.res.2.4.294. free.
  26. Wood . EH . Sep 1978 . Evolution of instrumentation and techniques for the study of cardiovascular dynamics from the Thirties to 1980, Alza lecture, April 10, 1978 . Ann. Biomed. Eng. . 6 . 3. 250–309 . 367231 . 10.1007/bf02409346. 13444980 .
  27. Wood. EH. Geraci. JE. Groom. DL. Photoelectric determination of blood oxygen saturation in man. Fed Proc. March 1948. 7. 1 Pt 1 . 137. 18934670.
  28. Wood. EH. Geraci. JE. Photoelectric determination of arterial oxygen saturation in man. J Lab Clin Med. March 1949. 34. 3. 387–401. 18113925.
  29. Connolly. DC. Kirklin. JW. Wood. EH. The relationship between pulmonary artery wedge pressure and left atrial pressure in man. Circ. Res.. September 1954. 2. 5. 434–440. 13190627. 10.1161/01.res.2.5.434. free.
  30. Swan. HJ. Burchell. HB. Wood. EH. Effect of oxygen on pulmonary vascular resistance in patients with pulmonary hypertension associated with atrial septal defect. Circulation. July 1959. 20. 1. 66–73. 13663195. 10.1161/01.cir.20.1.66. free.
  31. Shepherd. JT. Wood. EH. The role of vessel tone in pulmonary hypertension. Circulation. May 1959. 19. 5. 641–645. 13652355. 10.1161/01.cir.19.5.641. free.
  32. Ritman. EL. Earl Wood--a research career noted for development of novel instruments driven by the power of the indicator dilution concept. J Appl Physiol. November 1, 2014. 117. 9 . 945–956. 10.1152/japplphysiol.00491.2014. 25190740.
  33. Sass. DJ. Ritman. EL. Caskey. PE. Banchero. N. Wood. EH. Liquid breathing: prevention of pulmonary arterial-venous shunting during acceleration. J Appl Physiol. April 1972. 32. 4. 451–455. 10.1152/jappl.1972.32.4.451. 4503080.
  34. Sass. DJ. Nolan. AC. Wood. EH. Digital computer analysis of circulatory and respiratory pressures in water-immersed dogs breathing liquid in force environments of 1 and 7 G. Aerosp. Med.. January 1974. 45. 1. 1–11. 4521228.
  35. Banchero. N. Schwartz. PE. Tsakiris. AG. Wood. EH. Pleural and esophageal pressures in the upright body position. J Appl Physiol. August 1967. 23. 2. 228–234. 10.1152/jappl.1967.23.2.228. 6031193.
  36. Rutishauser. WJ. Banchero. N. Tsakiris. AG. Wood. EH. Effect of gravitational and inertial forces on pleural and esophageal pressures. J Appl Physiol. June 1967. 22. 6. 1041–1052. 10.1152/jappl.1967.22.6.1041. 6027051.
  37. Rutishauser. WJ. Banchero. N. Tsakiris. AG. Edmundowicz. AC. Wood. EH. Pleural pressures at dorsal and ventral sites in supine and prone body positions. J Appl Physiol. September 1966. 21. 5. 1500–1510. 5923220. 10.1152/jappl.1966.21.5.1500.
  38. Hoffman. EA. Behrenbeck. T. Chevalier. PA. Wood. EH. Estimation of regional pleural surface expansile forces in intact dogs. J Appl Physiol Respir Environ Exerc Physiol. September 1983. 55. 3. 935–948. 10.1152/jappl.1983.55.3.935. 6355027.
  39. Hoffman. EA. Ritman. EL. Heart-lung interaction: effect on regional lung air content and total heart volume. Ann. Biomed. Eng.. 1987. 15. 3–4. 241–257. 3662146. 10.1007/bf02584282. 22676532.
  40. Warner. HR. Wood. EH. Simplified calculation of cardiac output from dye dilution curves recorded by oximeter. J Appl Physiol. September 1952. 5. 3. 111–116. 12990551. 10.1152/jappl.1952.5.3.111.
  41. Shepherd. JT. Bowers. D. Wood. EH. Measurement of cardiac output in man by injection of dye at a constant rate into the right ventricle or pulmonary artery. J Appl Physiol. May 1955. 7. 6. 629–638. 14381340. 10.1152/jappl.1955.7.6.629.
  42. Hetzel. P. Swan. HJ. Ramirez de Arellano. AA. Wood. EH. Estimation of cardiac output from first part of arterial dye-dilution curves. J Appl Physiol. July 1958. 13. 1. 92–96. 10.1152/jappl.1958.13.1.92. 13563349.
  43. Fox. IJ. Wood. EH. Indocyanine green: physical and physiologic properties. Proc Staff Meet Mayo Clin. December 7, 1960. 35. 732–744. 13701100.
  44. Edwards. AW. Isaacson. J. Sutterer. WF. Bassingthwaighte. JB. Wood. EH. Indocyanine green densitometry in flowing blood compensated for background dye. J Appl Physiol. November 1963. 18. 6. 1294–1304. 14080764. 2997752. 10.1152/jappl.1963.18.6.1294.
  45. Williams. JC. Sturm. RE. Tsakiris. AG. Wood. EH. Biplane videoangiography. J Appl Physiol. May 1968. 24. 5. 724–727. 5647655. 10.1152/jappl.1968.24.5.724.
  46. Sturm. RE. Wood. EH. The video quantizer: an electronic photometer to measure contrast in roentgen fluoroscopic images. Mayo Clin. Proc.. November 1968. 43. 11. 803–806. 5711440.
  47. Greenleaf. JF. Ritman. EL. Wood. EH. Robb. RA. Johnson. SA. Dynamic computer-generated displays of data from biplane roentgen angiography for study of the left ventricle. Ann. Biomed. Eng.. March 1974. 2. 1. 90–105. 4596338. 10.1007/bf02368088. 13112148.
  48. Smith. HC. Sturm. RE. Wood. EH. Videodensitometric system for measurement of vessel blood flow, particularly in the coronary arteries, in man. Am J Cardiol. August 1973. 32. 2. 144–150. 4578631. 10.1016/s0002-9149(73)80112-2.
  49. Wood. EH. Ritman. EL. Robb. RA. Harris. LD. Ruegsegger. P. Noninvasive numerical vivisection of anatomic structure and function of the intact circulatory system using high temporal resolution cylindrical scanning computerized tomography. Med. Instrum.. May 1977. 11. 3. 153–159. 875764.
  50. Johnson. SA. Robb. RA. Greenleaf. JF. Ritman. EL. Lee. SL. Herman. GT. Sturm. RE. Wood. EH. The problem of accurate measurement of left ventricular shape and dimensions from multiplane roentgenographic data. Eur J Cardiol.. March 1974. 1. 3. 241–258. 4613557.
  51. Wood. EH. The dream of a dynamic, high-fidelity, synchronous, volumetric imaging system and the road to its realization. Herz. August 1985. 10. 4 . 183–192. 3899883.
  52. Book: Ritman. EL. Robb. RA. Harris. LD. Imaging Physiological Functions: Experience with the Dynamic Spatial Reconstructor. Greenwood Publishing Group. 1985. 0030693527.
  53. Inventing the G-suit: The Life Story of Dr. Earl Wood. Bill. Bonde. Karen. Bonde.
  54. Wood . HG . Utter . MF . 1965 . The role of CO2 fixation in metabolism . Essays Biochem . 1 . 1–27 . 4880809 .

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