Happy New Year!

To my readers, I know there’s been a drought of my scribblings over the past some time. But now I’ve passed most of my Naval Order responsibilities off to an energetic and capable successor, and already this ancient brain is beginning to swirl with ideas for new posts. Let’s hope some mental alchemy yields nuggets of gold from the lead that’s been mouldering in the depths and is just now getting some agitation!

My older son James gave me as a holiday gift Admiral Jim Stavridis’s 2017 book, Sea Power (New York, Penguin Press). In what I see as the Admiral’s combination memoir and strategic reflection, I encountered (for the first time in my consciousness) the term “medical diplomacy”.

Bingo! The subject of my next post – in a few days.

For now, my standard New Years mantra: may 2018 meet or exceed your expectations!


Thanksgiving 2012

I wrote this greeting 5 years ago. I still like it. Best wishes to my historical friends.

Of Ships & Surgeons

The cornucopia – horn of plenty – symbolizing the abundance of a good harvest, comes down to us from the ancient Romans. Americans have traditionally associated the symbol with Thanksgiving.

We have the great good fortune to live in a nation that is wealthy enough to be able to support a robust historical establishment. University programs and fellowships produce their own cornucopiae of newly minted historians each year. Many if not most cities and communities sponsor or at least encourage local historians to accession and preserve their communities’ stories. Some corporations have historians on staff (I retired from Kaiser-Permanente, a company that does this). Even our popular culture embraces – and purchases – the works of excellent historians who have plumbed the far reaches, and the nooks and crannies of our national history. The instant popularity of Jon Meacham’s biography of Thomas Jefferson is but the most recent example of this.

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Navy Medicine in Araby (Episode 8, the Final)

In seven previous episodes, I’ve told the story of combat casualty and general medical care given our sailors in conflicts in “Araby”, starting with 19th century battles against the Barbary States and finishing with our current military activities in Iraq and Afghanistan. Herewith is the final episode, in which I describe the truly innovative aerial ICUs of the U.S. Air Force.


The final 21st century iteration of an earlier concept is the Air Force’s Critical Care Air Transport Team. The first reported aeromedical evacuation was during the Franco-Prussian War of 1870-71, when 160 French casualties were evacuated by observation balloons from Paris, then under siege. Fixed wing aircraft soon followed, and by the end of WW I, the British were using aircraft specifically modified for medical applications. The United States Army Air Corps created Medical Air Ambulance Squadrons starting in 1942, and by the end of WW II more than a million patients from both theaters of war had been evacuated by these means. The concept of critical care evacuation – that is, transporting medically unstable patients requiring such support as respirators and intensive physiological support (IVs, transfusions and blood pressure sustaining drugs and the like) – evolved quickly after Operation Desert Storm, when it was discovered that such a capability simply did not exist. This lack of capability at the time forced the Army and Navy to utilize huge and semi-permanent Field Hospitals in or near the theater of operations. Prior to 1994, aeromedical transport teams typically consisted of two or more nurses, sometimes with critical care training, and several medical technicians. In 1994, the Air Force launched a formal Critical Care Air Transport Team program. These teams include critical care physicians, critical care nurses, respiratory therapists and the required medical supplies to support what are essentially flying ICUs. This concept has permitted medical planners to reduce the size of in-theater medical facilities while enhancing their flexibility and mobility to keep them as close as possible to zones of combat. [1],[2] Once wounded warriors receive emergency stabilizing surgeries, they can be rapidly evacuated to more definitive care settings in Kandahar & Bagram in Afghanistan, or to Landstuhl Germany or even to the specialty care facilities like the Brooke in San Antonio.

flying ICU.jpg

Intensive Care Unit in an Airplane (Credit: http://www.dodlive.mil)

In conclusion, there really is no comparison between the medical care offered our sailors in the Barbary Wars and that provided today. Hippocrates, the Greek father of western medicine wrote in ‘On the Surgery”, “He who desires to practice surgery must go to war”, and it is cliché’ nowadays to say that the surgical art and science advance with every war. The evolution of that art is clearly seen in this story of Navy medicine across three centuries. From bleeding and purging to antibiotics and transfusions, from amputations in the cockpit to damage control surgery in the field and intensive care in airplanes, the sophistication of knowledge and the resources brought to bear for the care of combat casualties are beyond comparison.

The one common thread throughout this story, however, is the dedication of medical people to the care of their sick and wounded military compatriots.

[1] Air Transport of the Critical Care Patient, http://www.cs.amedd.army.mil/FileDownloadpublic.aspx?docid=57ab806b-df57-42d7-85b4-5f96907faf92, accessed 5 October 2016.

[2] U.S. Air Force Website, Gulf War Created Need for Better Critical Care, http://www.af.mil/News/ArticleDisplay/tabid/223/Article/643126/gulf-war-created-need-for-better-critical-care.aspx?source=GovD, accessed 5 October 2016.

Veterans’ Day Greeting

Today, I wrote this to Naval Order Companions of the San Francisco and Continental Commanderies, and the members of the Albany Medical College – Military Affinity Group. I send the greeting now to followers of Of Ships and Surgeons, with my best wishes:

Inline image 1
The word “service” comes to us from the Latin servus / servitium, meaning “slave” and “slavery”. By the 13th century, the old French servise had come to mean “labor undertaken for or at the direction of another”. The Roman and “Scholastic” notion of work with body or hands as dishonorable servitude underwent further modification under the influence of the Enlightenment so by the early 1700s, the association of “service” with military duty, at least for higher ranks, was seen as completely honorable. The need for larger “citizen” militaries probably completed the transition to a view of “honorable” service being performed by all ranks.
Let us salute each other on this day set aside especially to honor the service and sacrifice of the Veterans among us. 
Very Respectfully,
Tom S
Tom Snyder MD ’69

Captain, Medical Corps, US Navy (Ret​.​)
Commander, San Francisco and Continental Commanderies,
Naval Order of the United States
Founder / Coordinator
Albany Medical College – Military Affinity Group


Navy Medicine in Araby (Episode 7)

I’m posting this episode a day or two early because I’ll be away from my PC for the next several days to attend the annual Congress of the Naval Order of the United States, this year in Jacksonville, FL.

The Naval Order is the oldest Naval historical organization in the country, founded in 1890. It Mission is to preserve, promote and support research in the history of our maritime uniformed services (Navy, Marine Corps, Coast Guard, Public Health Service and NOAA). One of my favorite features of our Congresses is that the local organizers try to highlight the military history of their locale. So in Jacksonville this week, we’ll have talks on “Rising Seas in Naval Cities”; “Doolittle’s Raiders”; “History of Florida in World War II”; “Maritime History of Jacksonville”; “Sinking of the Gulf America”; “”A History and Future of ASW in the Atlantic”; and “St John’s Bar Pilots”. You can see that there’s a broad sweep here, and likely something of interest to almost everyone in attendance.

Now, “Navy Medicine in Araby”, Episode 7 of 8.

In 2006, when the war in Afghanistan was being run by NATO, the Canadian Forces Health Services stood up a combat casualty facility at the Kandahar air base in southern Afghanistan. Initially an Echelon 2 facility – limited to one operating room and very basic radiology and laboratory – the facility was expanded physically and by capability so that by the time it was turned over to U.S. Navy command in 2009, it boasted of 2 CT scanners, a robust blood bank and concomitant surgical capabilities. By the time the Canadians turned over command, the hospital and staff had performed more than 6700 procedures for more than 4100 patients. The mission of the hospital, from its beginning was three-fold; to treat coalition soldiers, to treat civilians injured as a result of the conflict, and to treat any civilians who presented with any life- limb- or eye-threatening medical problems.[1] The U.S. Navy retains overall command of the facility, though the staff is multinational.

The value of putting surgical assets very close to the area of combat became fully established during World War II, but as often happens, this idea was lost in time, especially as helicopter and other evacuation techniques came on line. Adding wartime experience and modern medical understanding has led to the system of echelons of care described earlier. Based on the notion of the “Golden Hour” – the critical time required for the best chances for successful combat casualty management – Forward Surgical Teams now accompany troops to positions very close to active combat – being placed in tents or other “shelters of opportunity”[2]so casualties can receive skilled stabilization and life-saving “damage-control” surgery at least theoretically within minutes of injury. Casualties are then evacuated in a stepwise fashion to more sophisticated levels of care, ultimately, when necessary, arriving in high-level specialty, research and teaching hospitals in the U.S.[3] Brooke Army Burn Center in San Antonio is a key example of this: all warriors – Army, Navy or Marine – who suffer significant burns receive the most advanced available care in this high level specialty, research and teaching hospital.

[1] Can J Surg. 2011 Dec; 54(6 Suppl): S124–S129

[2] Frosolone, op. cit.

[3] Frosolone, op. cit.

Navy Medicine in Araby (Episode 6)

Gina and I have been away, culminating a 6 month-long celebration of our 50th wedding Anniversary, this time with a couple of couple-friends. We cruised the Seine to Normandy, where we walked the long flat beaches and appreciated what our men faced as they came ashore. The American Cemetery is a quietly majestic reminder of the sacrifices made there. We also visited Giverny, the living memorial to Claude Monet, and then later, the l’Orangerie museum that houses 8 very large Monet renderings of his famous water lillies. They brought tears to my eyes.

Now, back to part 6 of my 8 part series on Navy medicine in the middle east.

As a result of past experience and from learning in our middle east combat zones, the system of levels of care has evolved as follows: Level 1 is the simplest and most basic care; our soldiers and Marines each carry a tourniquet with them, and are taught how to apply it to stop bleeding from injured extremities. Level 2 facilities, located as close to the combat zone as is safe, offer basic capabilities to provide what is referred to as “damage-control” surgery. Level 3 facilities are fully capable hospitals with most major specialties, ICUs, and specialized nursing care. Level 4 facilities are specialized hospitals, research facilities and teaching hospitals with the highest levels of sophistication of care and facilities available.[1]


Medical facilities aboard U.S. ships range from simple sick bays in Destroyers and  Frigates that have nothing more than an examining table, rudimentary instrument sets and an autoclave for sterilizing dressings and instruments. With perhaps two navy corpsmen aboard, medical capabilities in these smaller ships is limited to simple surgical procedures, routine care of simple medical problems like upper respiratory infections, and first aid – echelon 1 level care – for more serious industrial-type and combat injuries. Patients in these ships would need to be evacuated by helicopter or boat to larger, more capable ships or facilities ashore. Our aircraft carriers and amphibious landing ships can offer, when fully staffed, Echelon 2+ to Echelon 3 levels of care. They have complete surgical teams aboard, in the instance of U.S.S. Nimitz, 2 General Medical Officers, a General Surgeon, 2 Registered Nurses (one trained in intensive care, one an anesthetist), a psychologist, physical therapist, 20 corpsmen and a dental department. [2] Patients treated there would need transport to higher levels of care only if their recovery time exceeds the time permitted by local so-called evacuation policy, or if they have suffered massive injuries that will require prompt advanced surgical and medical management.

The U.S. has two hospital ships in active service. USNS Comfort, homeported in Baltimore at the outset of the wars in the Middle East, but now in Norfolk; and the USNS Mercy, homeported then in Oakland, and now in San Diego. Each has a bed capacity of 1000, both have 12 operating rooms and a radiology suite including CT scanners. They are kept in custodial status with skeleton crews, but can be activated on a five-day schedule, their medical staffs brought together from military hospitals throughout the U.S. Both ships deployed to the Persian Gulf during Operation Desert Storm / Shield. Between them, they admitted nearly 1400 patients and performed over 600 surgeries during their 6 month deployments. Comfort again deployed in 2003 to support Operation Iraqi Freedom. In her 56 days in the Persian Gulf, she cared for 700 patients, performing 590 surgeries and administering 600 units of blood. Her medical staff also cared for nearly 200 Iraqi civilians and POWs. These floating hospitals are capable of Echelon 3 level care.


Navy Fleet Hospitals began during WW II as tent hospitals set up on remote Pacific Islands to provide definitive care for injured and sick warriors in theater. The fleet hospital concept grew as medical care became more sophisticated, and Fleet Hospitals became large, heavy hospitals-in-shipping-containers that could be prepositioned, then moved to places of need. In August 1991, FHs 3, 5 and 15, each with 500 beds, were mobilized to support Operations Desert Shield / Storm. By the time they were demobilized eight or nine months later, the medical people assigned to them had cared for more than 32,000 patients, most importantly providing top level combat casualty care.[3]

By 2003, the Fleet Hospital concept had evolved to smaller, more easily transportable modular hospitals that could be configured for specific missions. Between April and July 2003, Four Fleet Hospitals were stood up to support Operation Iraqi Freedom. Fleet Hospital 3, designated an Expeditionary Medical Facility of 116 beds, was the first such Echelon 3 hospital to be set up in a theater of combat, in southern Iraq. Within two weeks of its opening, its 300 personnel had already cared for 500 patients and performed more than 280 surgical operations.[4] A second Expeditionary Medical Facility, FH 8, was located in Rota Spain to provide Echelon 3 care as well. Later expanded to a 250 bed Fleet Hospital, its medical personnel cared for 1400 patients and performed around 250 surgical operations in support of Operations Enduring Freedom and Iraqi Freedom.[5]

[1] Pruitt, Basil A, Combat Casualty Care and Surgical Progress, Ann. Surg., 2006, Jun; 243 (6): 715-729.

[2] Frosolone, Charles A, General Surgery in the United States Navy, slide show presentation, http://washington.providence.org/~/media/files/providence/hospitals/wa/phc/conference%20handouts/general%20surgery%20in%20the%20us%20navy.pdf/, no date, accessed 27 September 2016.

[3]Navy Expeditionary Medical Support Command, Williamsburg, VA, Command History, Fleet Hospitals – the Beginning, http://www.med.navy.mil/sites/nemscom/CommandInfo/Pages/history.aspx, accessed 30 September 2016.

[4] Website “America’s Navy”, Fleet Hospital 3 – Best Care in Iraq, http://www.navy.mil/submit/display.asp?story_id=7056, accessed 30 September 2016

[5] Website “America’s Navy”, Ten Year After – Fleet Hospital 8 Returned Home to Naval Hospital Bremerton, http://www.navy.mil/submit/display.asp?story_id=75648, accessed 30 September 2016.

Navy Medicine in Araby (Episode 5)

This is instalment 5 of a series of 7, wherein I endeavor to contrast medical care of sailors of the 19th century with that of today.

Before I discuss our Navy’s medical assets, I must discuss the concept of Levels, Echelons or Roles of Care in today’s combat casualty care environment. Combat casualty care has evolved significantly since the Barbary Wars. The Napoleonic surgeon Larrey made a significant first step toward modernity when he established a system of horse-drawn “flying ambulances” to move casualties – who heretofore may have lain for days in the field without care, food or water – to facilities where prompt care of their wounds could be given. Modern combat casualty care started in the U.S. Army during the Civil War as a result of a series of reforms brought forth by the Lincoln-appointed Sanitary Commission led by Frederick Olmstead. Basing many of its recommendation on learnings from the Crimean War, the Commission and the Army built hospitals, established a system of evaluation of prospective Army doctors (the Navy already had such a system in place) and provided supplies and equipment. Under this system, Army Surgeon Jonathan Letterman established an ambulance corps to effect prompt evacuation of field casualties to facilities in the rear; he also established an early system of echelons of care with field dressing stations on the battlefield, field hospitals for definitive surgery located in nearby homes, churches or barns, and larger hospitals in the rear for longer term treatment. While more advanced surgical technique and evacuation by ambulance were utilized in World War I, it wasn’t until World War II that an appreciation of the need for rapid surgical intervention in injured soldiers was institutionalized with the development of mobile surgical teams attached to division level field hospitals. Shortly after our entry into the war, it became clear that transfusion of flood was an essential element in the resuscitation and ongoing management of men who suffered extensive wounding, and the robust system of blood collection that I described earlier was implemented. In the Korean War, an emphasis on the treatment of shock with IV fluids and transfusions saved many additional lives, and the forward care surgical facilities referred to as MASH units plus the use of helicopters for casualty movement further improved outcomes for injured warriors. During the Vietnam war, emphasis was put on shortening the time from injury to surgical care by keeping medical facilities close to the area of combat and by using helicopter transport.

©2016, 2017 Thomas L Snyder

Navy Medicine in Araby (Episode 4)

This is instalment 4 of a 7 segment article comparing combat casualty care in the Navy of the 19th century with that of the 21st.

My original intent here was to compare and contrast Navy medical care between the 19th and the 21st centuries. However, it soon became clear to me that there really is no comparison, only contrast. So much has changed, at so many levels of endeavor, to have changed Navy medicine almost completely. First is the matter of physical diagnosis – the interpretation of symptoms (what the patient reports) and signs (what the physician observes) to diagnose illness. The system of physical diagnosis began with the 1760 discovery of percussion – the tapping of certain body parts, say the chest, to determine if fluid is where it doesn’t belong. Next came the stethoscope in 1816; this permitted physicians to listen for abnormal sounds in the lungs, the heart and vessels, and the abdomen, and to interpret them. The inventor, Laennec, was also the first to correlate his physical findings with autopsy examinations, thereby beginning a system of thought about disease processes and their diagnosis. The so-called German School of the mid-to-late 19th century added laboratory examinations to the diagnostic set. The ophthalmoscope (1850) permitted physicians to peer into the eye, called the window to the body because many illnesses cause changes that can be seen there. The thermometer was invented in 1871, and all understand the importance of that device. Conrad Roentgen discovered x-rays in 1895, and immediately appreciated their implications for medical diagnosis. Just three years later, American surgeons used the x-ray apparatus extensively for localizing bullets in wounded soldiers during the Spanish-American War.[1] Radiologic diagnosis took a major leap forward with the introduction of CT scanning in the mid-1970s; the technique creates essentially 3-d views of the inside of the body, permitting much more precise diagnosis in most cases.

The role of bacteria in causing wound infections was elucidated by Pasteur and others from about 1861. This work prompted the German army to adopt antibacterial surgical techniques, the effectiveness of which to reduce wound infection rates was proven in the Franco-Prussian War. The bacterial theory of disease was advanced throughout the early 20th century, and the role of viruses in causing such diseases as smallpox, poliomyelitis and yellow fever was worked out the 1920s and 1930s. Public health and preventative medicine – for example the role of immunizations against epidemic diseases – played a huge role in reducing morbidity and mortality in military organizations thereby keeping more soldiers on the battlefield more of the time. Once again, the Germans led the way with mandatory vaccination: in the Franco-Prussian War, the immunized Germans suffered 4835 cases of smallpox with a mortality rate of 0.5%, compared with the unimmunized French POWs who experienced 14,178 cases with a mortality rate of nearly 14%.[2]

The notion of replacing blood lost as a result of wounding and injury gained credibility only after a system of blood typing was worked out by Karl Landsteiner in 1901. While transfusions from one man to another had been tried before (transfusions from animals had been tried, too) – all with disastrous results – it was only after transfusion of matching blood became possible that the procedure could be safely carried out. Transfusion was used during World War I, British surgeons commonly using the man-to-man technique in the early part of the war. The American Army physician Oswald Paterson came up with the idea of banking blood during the war. This played a major role in combat casualty care, but only after technical problems- such as keeping collected blood from clotting, preserving it, and of practical transfusion set-ups – were solved. Transfusion of banked blood became commonplace near the end of the war. The technical and practical approaches to the handling and banking of blood were refined in the inter-war period, so by the outbreak of WW II, mass collection, banking and transport of blood to theaters of war were instituted. Some elements of the German army had their members’ blood type tatooed on them; these men became part of a walking blood bank – men, who as in World War I, could be called upon to give blood on the spot, when needed. Our Navy still uses the walking blood bank concept today, as a supplement to the blood banking system, but without that particular type of tatoo. Finally, the advent of anesthesia permitting major surgical operations without pain came in the 1870s. This single advance permitted a vast refinement in surgical techniques that are applied to this day. Compare the image of the sole ship’s surgeon and his assistants, with no anesthesia, working in a dark cockpit with modern combat casualty care where two or more surgical teams are working on a patient while the anesthetist is responsible not just for administering the anesthesia, but also administering blood and blood products, fluids and a multitude of drugs to support a patient who has been gravely injured.

[1] Gabriel, Richard A. and Karen S. Metz, A History of Military Medicine, Vol II, New York, Greenwood Press, 1992, pp 221, 222.

[2] Gabriel and Metz, op. cit., pp 108, 109.

©2016, 2017 Thomas L Snyder

Navy Medicine in Araby (Episode 3)

This is part 3 of a 7 part series contrasting 19th century Navy medicine with the care today’s navy medical team provides our sailors, Marines and soldiers.

Probably the first-ever designated hospital ship in the U.S. Navy started her life as a ketch built in France in 1798 for service in Napoleon’s Egyptian campaign. Later, she was sold to the Bey of Tripoli and took part in the capture of USS Philadelphia in October 1803. Subsequently taken by LT Stephen Decatur while transporting a cargo of female slaves, she was commissioned into the US Navy as USS Intrepid. She lived up to her name participating in Decatur’s daring action to retake and burn Philadelphia in February 1804. Mediterranean squadron Commodore Edward Preble noted in a diary entry dated 9 July that he had designated the ketch as a hospital ship[1]. According to the ship’s history, this was from 1 June. She served in this role through July,[2] by which time Commodore Preble likely had in hand the Secretary of the Navy’s instructions authorizing him to establish a Naval Hospital ashore, at Syracuse, Malta or some other agreeable place.[3] Thus was the very short career of the first known U.S. Navy hospital ship.

After several months of considering ideal sites (many were rejected because of the ease with which sailors could desert from them), a house large enough to accommodate 100 men was secured in Syracuse, Sicily. Surgeon Cutbush was put in charge of the place in November 1804. About 100 men – sailors, Marines and other soldiers – received their treatment there. A treaty of peace with Tripoli in 1805 made the hospital redundant, and Cutbush was ordered to close the facility in April 1806,[4]

Upon cessation of the War of 1812, the Navy returned to the Mediterranean because the Algerians had resumed their depradations upon American merchant shipping. Navy Secretary Crowninshield intended that a Naval Hospital be established early on. Commodore Chauncy fancied Port Mahon on the island of Menorca off the southeastern coast of Spain, but the Spanish government waxed and waned in its support of the notion. Accordingly, a “hospital of sorts” was established there during the American squadron’s winter-over in 1816-17, only to be taken down when the Spanish essentially kicked us out due to our support of South American independence movements. A hospital established on the River Arna at Pisa, Italy lasted only a short while because it was too far from most Naval activity; it closed late in 1821. Meanwhile, by 1825, relations between the U.S. and Spain warmed sufficiently that a naval base was established at Port Mahon, and with it, a Naval Hospital on Quarantine Island there. This hospital – recently celebrated as the first ever permanent overseas U. S. Naval Hospital – remained in business for nearly 20 years.[5]

The only record of navy medical interaction with the inhabitants of the Barbary states that I’ve been able to find is borne in the journal of Dr Jonathan Cowdery, a Navy surgeon, held captive after the Tripolitan capture of the USS Philadelphia. Within two months of his capture, Dr Cowdery had been summoned to care for the Pascha and his officers, and by early February 1804, was requested to be physician to the Pascha’s family. So impressed was the Pascha with Dr Cowdery’s cure of his very sick son, that Cowdery worried that he would not be released with the rest of the Americans come the time the U.S. government paid the required ransom. At one point, he purposefully bungled a finger amputation on one of the Pascha’s soldiers in hopes that the Pascha would lose faith in his skills. It didn’t work, and in fact, so pleased was the Pascha with Cowdery’s work overall that he at one point he told the doctor he would not take $20,000 for his release, by comparison with $50 for each of the other prisoners, officers and men. Cowdery never mentions caring for Tripolitan commoners but seemed quite comfortable rubbing elbows with Tripolitan aristocracy.[6]

[1] Roddis, Louis H, Naval Medicine in the Early Days of the Republic, Journal of the History of Medicine, V 16 (1961), pp 103-123.

[2] Naval History and heritage Command website, article “Intrepid I (Ketch), http://www.history.navy.mil/research/histories/ship-histories/danfs/i/intrepid-i.html, accessed 1 September 2016.

[3] Roddis, op. cit.

[4] Langley, op. cit., p 97-102.

[5] Langley, op. cit., pp 267-270.

[6] Cowdery, Jonathon, “American Captives in Tripoli”, in Narratives of Barbary Captivity, Allison, RobertJ., ed., Lakeside Press, Chicago, 2007, pp 123-177

(c)2017 Thomas L Snyder

Hypoxia and Aviation

A passel of recent headlines (here, here and here, for instance) have highlighted a persistent hypoxia problem facing pilots of jet aircraft in both the Air Force and the Navy. These or similar episodes, designated “physiological episodes”, are blamed for the deaths of four Naval aviators over the past several years.

“Mountain sickness”, that is, the effects of altitude, were first written about in western literature in the 16th century, most particularly in a description of the syndrome by Father Jose de Acosta, who, in 1590, published his observations on the effects of altitude on men and animals in the Andes mountains of Peru. The British scientist Robert Boyle was the first to identify a vital factor in air that was lacking at altitude. Joseph Priestly identified that vital factor in 1774, and Antoine Lavoissier named it “oxygen” in 1777.

There the matter lay until men started going up in balloons, although apparently the first recorded “altitude-related” hypoxic deaths resulted when three men (two of whom died) were subjected to a simulated altitude of 28,000 feet in a pressure chamber developed by French physiologist Paul Bert, in 1875. As a result of these and other experiments, Bert was able to show that the breathing of supplemental oxygen could prevent the physiological ill effects of altitude.

With the advent of fixed wing aviation, and in particular, military aviation in World War I, the main thrusts of aviation medical research involved the physical safety of pilots (restraining apparatus and the like), and dealing with the cold of altitude. The use of supplemental oxygen apparently was a given, and both gaseous and liquid O2 were used.

Aviation medicine research between the wars depended on a few unsung stalwarts who responded to queries concerning the physiological effects – now including loss of consciousness while pulling gs – from the aviators and engineers who designed ever more capable aircraft. That said, developing oxygen delivery systems for aircraft expected to operate at high altitudes for hours at a time – bombers – was a critical matter. The advent of high performance jet aircraft in the late 1940s led to significant improvements in aircraft oxygen systems.

Physiologists now break the effects of hypoxia out in “stages”, viz.,


  1. INDIFFERENT STAGE – The only adverse effect is on dark adaptation.
  2. COMPENSATORY STAGE – Physiological compensations provide some defense against hypoxia so that the effects are reduced unless the exposure is prolonged or unless exercise is undertaken. Respiration may increase in depth or slightly in rate, and the pulse rate, the systolic blood pressure, the rate of circulation, and the cardiac output increases.
  3. DISTURBANCE STAGE – In this stage the physiological compensations do not provide adequate oxygen for the tissues.
    Subjective symptoms may include fatigue, lassitude (state of exhaustion), somnolence (drowsiness, sleepiness), dizziness, headache, breathlessness, and euphoria.
    Objective symptoms include:
        Special Senses – Both the peripheral and central vision are impaired and visual acuity is diminished. 
        Extraocular muscles are weak and incoordinate
     – Touch and pain are diminished or lost. Hearing is one of the last senses to be impaired or lost.
        Mental Processes – Intellectual impairment is an early sign and makes it improbable for the individual to comprehend his own disability. Thinking is slow. Calculations are unreliable.
    Memory is faulty. Judgment is poor. Reaction time is delayed.
        Personality Traits – There may be a release of basic personality traits and emotions as with alcoholic intoxication (euphoria, elation, pugnaciousness, overconfidence, or moroseness).
    Hyperventilation Syndrome
     – Over-breathing due to excitement or stress. Cyanosis – Blue discoloration of the skin.
  4. Critical Stage – In the critical stage consciousness is lost. Death follows shortly.

Source: http://www.mountainflying.com/pages/mountain-flying/hypoxia.html, accessed 31 July 2017

Which brings us to today. Modern jet combat aircraft – including the T-45 trainer, Navy F/A-18s and E/A-18s, and all F-35s – have very sophisticated on-board oxygen generation systems. Engineers’ attention is now being directed to this commonality, the “OBOGS”, among the aircraft where the “hypoxia-like” episodes have happened. Another factor seems to be altitude: all reported episodes appear to be have occurred above 25,000 feet, and engineers now suspect a malfunction in the oxygen metering device in these systems at these altitudes.

Until the engineers find a solution to the problem, the services are limiting operations in OBOGS-bearing aircraft to below 25,000 feet, introducing oxygen monitoring devices and beefed up supplemental oxygen supplies, and giving aviators additional training in how to recognize symptoms of hypoxia before they reach the “disturbance” stage.

(c)2017 Thomas L Snyder