Clearing Hospitals

A Forgotten Link in Large-Scale Evacuation Strategy

By Sanders Marble, PhD

Article published on: August 1, 2025, in the August 2025 Issue of The Pulse of Army Medicine.

Read Time: < 5 mins

ABSTRACT:

The AMEDD plays a key role in clearing the battlefield to get patients to hospitals; however, the system beyond that is under strain. Large Scale Combat Operations (LSCO) will generate casualty volumes greatly exceeding current evacuation capacities. Historical evacuation methods, including hospital trains, ship platoons, and WWII air evacuation squadrons, demonstrated scalable solutions capable of moving large numbers of patients efficiently. Today’s small-unit air evacuation cannot meet the demands of LSCO alone. The Army must revisit mass evacuation concepts now or risk overwhelmed hospitals and stalled casualty care in future conflicts.

The AMEDD helps clear the battlefield to enable maneuver, which gets patients to a hospital. I use the word “helps” because CASEVAC has been needed in the past and may well be needed in the future; however, CASEVAC is a line responsibility.

That’s important, but it represents only part of the hospitalization and evacuation system. A 100-bed hospital with 100 patients has very little to offer to the 101st patient. LSCO casualty estimates reach tens of thousands during just an eight-day exercise. This estimate translates into hundreds of casualties per day per division. Therefore, the hospitals need to evacuate both promptly and in large volumes. Are we prepared for that?

CURRENT CAPABILITY GAPS

U.S. Air Force Critical Care Air Transport Teams (CCATT) can move a finite number of high-acuity patients while air evacuation squadrons move a larger number of lower acuity patients. As Air Force units, they operate when air evacuation is feasible. Walking wounded generally needs little en-route medical care; however, over long distances, patients will need feeding and basic assistance.

Historically, the Army maintained three types of evacuation units for air, land, and sea patient evacuation. These units were designed to evacuate large numbers of patients from Role III hospitals back to Role IV hospitals in theater-rear. While four-patient ground ambulances were fine for tactical evacuation, they were not ideal for mass patient movement. They lacked the speed of air evacuation and could not operate over water.

HISTORICAL MODELS FOR LARGE-SCALE EVACUATION

AIR EVACUATION: MEDICAL AIR EVACUATION SQUADRONS (MAES)

During WWII, Medical Air Evacuation Squadrons (MAES) were established. These units consisted of a handful of physicians to screen patient stability for air evacuation. At the time, air evacuation had less en-route care than surface evacuation, typically one nurse and one enlisted technician per aircraft, with limited medical supplies. Selecting which patients to not evacuate was important to the excellent safety record of the MAES. Air evacuation proved to be the fastest method and could move decent volumes of stable patients - about 20 litter patients per plane.

RAIL EVACUATION: HOSPITAL TRAINS

From the Civil War into the 1980s, the AMEDD used hospital trains. During WWI and WWII, they were the standard method for transporting large numbers of patients over substantial distances – even as short as 20 miles. Trains offered better en-route care due to higher-skilled medical staff, smoother rides that reduced patient discomfort, and the added benefit of freeing up roadways for other military vehicles. Hospital trains could be purpose-built and shipped overseas or adapted from local cargo or passenger cars.

Patients being evacuated from Okinawa. The medical crew could do more than just fruit juice, but the patients were stable, after being hospitalized several days. ACHH collection.

They required a modest personnel investment – typically one physician, two to four nurses, and around 20 enlisted men, including approximately 10 medics. These trains were equipped with laboratories, small pharmacies, and even operating tables. A single hospital train could carry roughly 400 wounded patients, complete with medical and kitchen facilities, and travel several hundred miles over several days. In contrast, transporting that many patients by road, at 4 patients per ambulance, would have needed more resources and posed greater risks to patient well-being.

Improvised hospital train (note rough and ready carpentry) used in Italy, February 1944. ACHH collection.

SEA EVACUATION: HOSPITAL SHIPS AND SHIP PLATOONS

The Army also organized units for water evacuation. During World War I and World War II, a limited number of Army hospital ships were used; however, all of them were decommissioned after the wars. These ships offered excellent medical facilities, had physicians for the highest level of en-route care, and were protected under the Geneva Convention. However, the number of hospital ships was never sufficient. Rather than hold patients overseas, the Army Medical Department (AMEDD) developed Hospital Ship Platoons.

Hospital ship platoons could work on any transport ship to provide enroute care. Like air evacuation planes, there was no Geneva Convention protection. U.S. Navy photo.

These platoons ranged in capacity from 25 to 500 patients and could operate on pretty much any kind of transport ship, including Landing Ship Tank, to provide en route care for moderate- and low-acuity patients. Every transport ship was allotted a modest supply of medical material, including non-perishable Class VIII items and durable equipment, allowing a platoon to be attached as needed. This effectively transformed it into a “hospital transport,” which, unlike hospital ships, was not protected under the Geneva Convention. Some of these transports were attacked, but they played a critical role in patient movement. They were especially important during the early stages of amphibious landings, before air evacuation became operational, yet their importance persisted throughout the conflict given the sheer given the sheer volume of patients requiring transport, either to a rear-area hospital in a theater of operations or back to the U.S.

These units were all small and required minimal specialized equipment. By clearing the hospitals, they helped streamline the entire evacuation chain. While these formats are not likely to be effective in a future large-scale combat operation, the Army should still consider the underlying challenges they address.

LESSON LEARNED: NO SYSTEM; NO SPACE

Clearing hospitals is more than just a back-end task; it’s what keeps the whole evacuation system moving. A 100- bed hospital can’t help the 101st patient if there’s no way to move the first 100. In LSCO, with casualty estimates in the thousands over just a few days, evacuation needs to happen quickly and at scale. The current system, built around small-unit air evacuation, wasn’t designed for this kind of volume. Historical models hospital of trains, ship platoons, and air evacuation squadrons weren’t perfect, but they worked. They moved large numbers of patients using modest quantities of personnel and adaptable platforms. That capacity helped clear hospitals and maintained the flow of care. We’re not going back to WWII hospital trains or improvised sea evacuations. However, the Army needs to revisit the problem again. If we don’t build a system that can handle the numbers, we will end up with hospitals full of patients and no way to help the next patient who comes through the door.