Dominique Jean Larrey put light sprung wagons into the fighting line in the 1790s so that wounded French soldiers could be collected during an engagement instead of after it, and he treated them in the order of how badly they were hurt rather than by what rank they held. Most of what an American EMS crew does at a multi-patient scene descends from that decision and from the systems built on top of it over the next two centuries. This piece follows the line from the flying ambulance through Letterman’s ambulance corps, the First World War clearing chain, helicopter evacuation in Korea and Vietnam, and the return of the tourniquet to civilian streets.

Larrey, Percy, and the wagons that went forward

Eighteenth century European armies kept their medical trains well behind the fighting because the baggage regulations put them there, which meant a wounded man normally lay where he fell until the engagement ended and somebody came looking, often the following day. Larrey, serving with the French Army of the Rhine in the early 1790s, watched the horse artillery move guns quickly across a battlefield and concluded that casualties could be moved the same way. He organized light two-wheeled and four-wheeled carriages on springs, with assigned drivers, litter bearers and surgeons, and took them forward with the troops so that collection began while the fighting was still going on.

The word ambulance at that time meant the mobile field hospital as an organization rather than the vehicle, and Larrey’s ambulance volante was a manned and equipped unit with a table of personnel, not a cart. That distinction matters more than the hardware, because the thing he invented was a deployable medical element with its own transport, its own supply and its own command relationship to the division it supported. Pierre-Francois Percy, working in the same armies, built a parallel arrangement around a long wagon that carried surgeons and dressing supplies directly to the line, and between the two of them the French established that surgical capability travels toward the casualty.

Larrey also wrote down the rule that governs the profession to this day. In Richard Willmott Hall’s 1814 English translation of Larrey’s memoirs, the passage usually quoted says that those who are dangerously wounded should receive the first attention, without regard to rank or distinction, and that the less seriously injured can wait. Larrey did not use the word triage the way we use it, and he did not publish a category scheme, so it is fair to say he established the ethical principle while the vocabulary and the categories arrived later.

What sorting actually decides

Triage comes from the French verb trier, to sort, and it entered English-language military medicine during the First World War, when British and American medical officers working alongside French units picked up the term for the sorting station at the casualty clearing station. The modern categories that most American agencies use, some version of immediate, delayed, minimal and expectant, describe how a fixed set of resources gets allocated across a patient load that exceeds them. The expectant category is the one that separates disaster triage from everything else in clinical practice, because it exists only when the arithmetic will not close and it disappears the moment enough surgeons, blood and operating rooms are available.

In routine practice the sickest patient gets the most resources, and any paramedic or physician assistant works that way without thinking about it. Under scarcity the objective changes to producing the largest number of survivors from what you actually have on the ground, and that can mean walking past the most severely injured person on the scene. Crews find this genuinely difficult, and no algorithm removes the difficulty, because the algorithm is only a fast proxy for a judgment about who will die without immediate intervention and who will survive without it.

The field algorithms in common use are recent. START was developed in 1983 through work by Hoag Memorial Hospital Presbyterian and the Newport Beach Fire Department in California, JumpSTART was published by Lou Romig in the mid 1990s to correct START’s poor fit to pediatric physiology, and SALT was published in 2008 by a national working group convened through the American College of Surgeons Committee on Trauma with federal support. The published evidence for how accurately any of them predicts outcome is thinner than most instructors admit, and the persistent operational problem is over-triage, which Eric Frykberg examined in his work on bombing incidents published in the Journal of Trauma in 2002.

Letterman’s ambulance corps and the tiered American system

The American failure case is Second Bull Run in August 1862, where Union ambulances were driven by civilian teamsters under quartermaster rather than medical control, drivers left the field, vehicles were diverted to haul other cargo, and wounded men lay on the ground for days after the battle. Jonathan Letterman took over as medical director of the Army of the Potomac that summer and issued an order in August 1862 that pulled ambulances and their crews under the medical department, assigned them by division, trained the crews, and forbade the use of ambulance wagons for anything other than casualties. The reform was administrative rather than clinical, and it worked because it fixed who owned the vehicles and who could task them.

Letterman also built the echelon structure that American emergency medicine still runs on. Wounded men were stabilized at a dressing station near the regimental line, moved to a division field hospital where surgery was performed, and then evacuated by wagon, rail or steamer to general hospitals in the rear, with a medical supply system that pushed materiel down to the divisions instead of waiting for requisitions to climb up. Antietam on 17 September 1862 produced something on the order of 23,000 casualties in a single day, and the standard accounts credit Letterman’s organization with clearing the Union wounded from the field within roughly twenty-four hours, a claim that rests largely on Letterman’s own report. Congress extended the system to all Union armies by law in March 1864.

The mortality figures for that war remain disputed, and the dispute is worth knowing because it shows how casualty counts get made. The traditional figure of about 620,000 deaths on both sides comes from nineteenth century compilations by William F. Fox and Thomas Livermore, while J. David Hacker, working from census data and published in the journal Civil War History in 2011, estimated roughly 750,000 with a plausible range of about 650,000 to 850,000. Both ends agree that disease killed roughly twice as many soldiers as combat did, which is the finding that later drove military sanitation, water discipline and immunization as hard as it drove surgery.

The First World War chain and the casualty clearing station

By 1916 the British Expeditionary Force on the Western Front was running a defined chain with named nodes, and the terminology is worth learning because it is the direct ancestor of a modern trauma system. A wounded soldier was carried by regimental stretcher bearers to a regimental aid post within a few hundred yards of the line, moved back to an advanced dressing station and then a main dressing station operated by a field ambulance unit, carried by motor ambulance convoy to a casualty clearing station several miles to the rear, and moved from there by ambulance train or canal barge to a base hospital near the coast. Each transfer had a defined distance, a defined transport mode and a defined receiving unit, so the chain could be reinforced at whichever node was backing up.

The casualty clearing station is where sorting and surgery both happened, and it is where the word triage lodged itself in English. A designated officer met incoming casualties and split them into those needing immediate operation, those who could be moved onward without surgery, those with minor wounds who would return to duty, and those judged unlikely to survive. That officer was managing throughput as much as physiology, because a clearing station that operated on everyone in front of it stopped accepting new arrivals within hours, and the chain behind it seized up all the way to the aid posts.

The clinical advances of that war were real, and they were made possible by a system that concentrated enough casualties in one place to learn from. Oswald Hope Robertson, an American serving with the British in 1917, established stored citrated blood at casualty clearing stations in what is generally described as the first blood banking operation. Surgeons converted from closing contaminated wounds to excising devitalized tissue and irrigating, an approach associated with Alexis Carrel and Henry Dakin. The Thomas splint for femoral fractures is widely credited with cutting mortality from compound femur wounds from around eighty percent to around twenty percent, and while that pair of numbers appears throughout the orthopedic literature, I have never seen it traced convincingly to a single documented dataset, so treat it as a strongly held tradition rather than a measured result.

Korea: helicopters, MASH units, and arterial repair

Korea is remembered for the helicopter, and the helicopter genuinely mattered, but it mattered because of what sat at the far end of the flight. Bell H-13 aircraft with external litter panniers carried casualties from forward aid stations to Mobile Army Surgical Hospitals positioned close behind the line, and Army medical histories commonly put the total number of patients moved by helicopter during the war somewhere in the range of roughly 17,000 to 21,000, with sources differing on the count and on which categories they include. The MASH itself was the innovation that the aircraft made usable, since a surgical hospital with operating capacity that could relocate with the front line gave the flight somewhere worth going.

The most measurable clinical change in Korea was vascular. Standard practice through the Second World War was to ligate a damaged major artery, which stopped the bleeding and frequently cost the limb, and US Army surgical teams in Korea, including work associated with Carl Hughes, moved to repairing arteries instead. The amputation figures that came out of that work, commonly cited as roughly half of major arterial injuries in the ligation era against something near thirteen percent once repair became routine, are among the cleanest before-and-after numbers in military surgery, and they came out of deliberate registry-style data collection by the surgical research teams rather than from anybody’s impression.

The published died-of-wounds percentages for the twentieth century wars point in a consistent direction, declining from the First World War through the Second, Korea and Vietnam, but the specific figures differ by source and, more importantly, by how the denominator is defined. Some series count deaths among all wounded, others count only those who reached a medical treatment facility alive, and a system that gets more critically injured patients to a hospital alive will look worse on some measures and better on others. When I use these figures I give the direction of travel and say plainly that the exact percentages are not settled.

Vietnam: Dustoff, and what the time figures mean

Vietnam moved air ambulance work from an improvisation to a service. Dedicated medical evacuation units flying the UH-1 operated on published radio frequencies under the call sign Dustoff, ground units could request a lift directly, and aircraft went into unprepared landing zones with a crew chief and a medic aboard. Army histories commonly put the total number of patients moved by air ambulance across the war at roughly 850,000 to 900,000, a figure that includes allied military and Vietnamese civilian patients as well as American wounded, and the various published totals do not agree precisely.

The time figures cited for the three wars, on the order of ten hours or more from wounding to surgery in the Second World War, a few hours in Korea, and well under an hour in much of Vietnam, are drawn from Army medical department histories and are averages across very different tactical situations. What made those Vietnam times achievable was a set of conditions that no civilian agency and no future conflict can assume: uncontested airspace, dedicated aircraft that flew no other mission, surgical hospitals positioned forward, and a radio system that connected the man on the ground to the aircraft without a relay. Take away air superiority and the same medical doctrine produces very different numbers.

The transfer to civilian practice was immediate and personal, because the pilots, crew chiefs and medics came home. Maryland State Police began flying medical missions in 1970 with a program built around Cowley’s shock trauma work, and St. Anthony Hospital in Denver started Flight For Life in 1972 as the first civilian hospital-based helicopter program in the country. Vietnam corpsmen and medics also walked into the earliest paramedic programs with skills that no civilian curriculum yet taught, which is one reason the American paramedic scope of practice looks the way it does.

1966: the white paper that built American EMS

In 1966 the National Academy of Sciences and the National Research Council published Accidental Death and Disability: The Neglected Disease of Modern Society, usually called the white paper, and it described an American prehospital system that barely deserved the name. Ambulance service in much of the country was provided by funeral homes using hearses, attendants had no required training, equipment lists did not exist, and there was no mechanism for a state to say who could operate. The report made the comparison that gave it its force by observing that a soldier wounded in Vietnam had better odds of surviving than a person injured in a highway crash in the United States, and Congress passed the Highway Safety Act the same year, which gave the Department of Transportation the authority that made a national curriculum possible.

What followed came fast for federal policy. J.D. Farrington published Death in a Ditch in the Bulletin of the American College of Surgeons in 1967, the ACS Committee on Trauma issued essential equipment lists for ambulances, DOT published the national standard curriculum for the EMT-Ambulance in 1971, and the Emergency Medical Services Systems Act of 1973 funded regional systems and defined the components each one had to contain. In Pittsburgh, the Freedom House Ambulance Service operated from 1967 until 1975 with crews recruited from the Hill District and trained under Peter Safar, and it demonstrated that laypeople could be trained to a level of prehospital care that physicians would accept.

The structural inheritance from the military is the echelon. A modern trauma system routes patients to facilities verified at defined levels of capability, keeps a receiving facility list, and moves a patient onward when the first hospital cannot finish the job, which is Letterman’s dressing station, field hospital and general hospital wearing a different vocabulary. The National Academies returned to the theme in its 2016 report on integrating military and civilian trauma care, arguing for a national system aimed at eliminating preventable deaths after injury, and that report is worth reading directly rather than in summary.

The tourniquet comes home

American prehospital teaching through most of the second half of the twentieth century treated the tourniquet as a device of last resort that would probably cost the limb, and generations of EMTs were taught direct pressure, elevation and pressure points first, with the tourniquet mentioned mainly as a decision you would have to justify. That doctrine rested on institutional memory of poorly designed devices left on for many hours during long evacuations, and it was carried forward for decades without anybody measuring the outcomes it was supposed to prevent.

The reversal came out of Tactical Combat Casualty Care, laid out in a 1996 paper in Military Medicine by Frank Butler, John Hagmann and George Butler, and institutionalized through the Committee on Tactical Combat Casualty Care in the early 2000s. Manufactured windlass tourniquets were issued down to the individual soldier in Iraq and Afghanistan, and Kragh and colleagues published a series in Annals of Surgery in 2009 reporting a survival association with prehospital tourniquet application, particularly when the device went on before shock developed, with limb loss attributable to the tourniquet itself occurring rarely. The reason those findings exist at all is the Joint Trauma System and its trauma registry, which captured injury, intervention and outcome across the whole force so that doctrine could be revised against data rather than against opinion.

Civilian adoption followed through a deliberate policy channel. The American College of Surgeons convened the Hartford Consensus in 2013 after the Sandy Hook shooting, chaired by Lenworth Jacobs, which recommended that hemorrhage control be treated as a public responsibility comparable to CPR, and the Stop the Bleed campaign launched from the White House in 2015 built the public course and the kit placement program around that recommendation. Tourniquets now ride on patrol officers, in school and stadium wall cabinets and in every ambulance I have worked out of, prehospital tranexamic acid and prehospital whole blood programs have followed the same military-to-civilian path, and the practical instruction belongs in a hands-on course rather than in an article.

What to do at your agency

• Have the training officer physically count the triage tags on every first-out unit this month and compare the total to the largest patient count in your mass casualty annex, because the plan that assumes fifty tags and the apparatus that carries twelve are a documented gap.
• Ask your EMS medical director for a written statement of which tourniquet models the agency has approved, when they were last inventoried, and whether any of the stock has passed a manufacturer expiration or shows strap or windlass damage.
• Run a five minute triage sort during a shift drill that is already on the calendar, using your adopted algorithm and real tags, then calculate the over-triage rate from the tags afterward and put that single number in the training record.
• Add one item to the next officer meeting that already meets: name the person who fills the transportation group supervisor position at a multi-patient incident and the person who keeps the patient destination log, and write both assignments into the mass casualty annex.
• Have your communications officer test the hospital alerting path end to end, on a specified date with the receiving facilities notified, and confirm that somebody at each hospital answers, that the bed count comes back, and that the result is documented.
• Ask the regional trauma coordinator or state EMS office for the current trauma center designations and capability list for your region, verify that the version posted in dispatch matches it, and replace it if it does not.
• Schedule one Stop the Bleed course through a named instructor for a specific public audience in your jurisdiction, such as school staff or a large employer, and record the completion count.

Takeaways

• Larrey’s ambulance volante of the 1790s was a manned and equipped medical unit with its own transport rather than a vehicle, and the principle of treating by severity rather than by rank appears in the 1814 Hall translation of his memoirs, while the word triage and the modern category scheme arrived later, largely through the First World War.
• Jonathan Letterman’s 1862 reform succeeded because it fixed ownership and tasking authority for ambulances rather than because it introduced any new clinical technique, and Congress extended it to all Union armies in March 1864.
• Civil War death totals are genuinely disputed, with the traditional figure of about 620,000 coming from Fox and Livermore and J. David Hacker’s 2011 estimate in Civil War History running near 750,000 within a range of roughly 650,000 to 850,000.
• The First World War chain from regimental aid post through advanced dressing station and casualty clearing station to base hospital is the direct ancestor of tiered trauma systems, and the clearing station taught that sorting is throughput management as much as clinical judgment.
• Helicopter evacuation in Korea and Vietnam worked because forward surgical capability and uncontested airspace existed at the far end of the flight, and the commonly quoted time and mortality figures vary by source and by how the denominator is defined.
• The golden hour is a planning heuristic rather than a measured threshold, with Newgard and colleagues finding no association between EMS intervals and mortality in a 2010 Annals of Emergency Medicine cohort and Kotwal and colleagues finding lower case fatality after the 2009 evacuation mandate in a 2016 JAMA Surgery paper.
• The 1966 NAS and NRC white paper, the Highway Safety Act of that year, and the EMS Systems Act of 1973 converted military lessons into a regulated civilian system with training standards, equipment lists and regional structure.
• The return of the tourniquet came from Tactical Combat Casualty Care doctrine published in 1996 and from a military trauma registry that measured outcomes, and it reached the public through the Hartford Consensus in 2013 and the Stop the Bleed campaign launched in 2015.