US military looks underground to protect wounded troops as drones force changes to wartime medicine

Editor’s Note: This story includes images and descriptions of military medical simulations that may be disturbing for some readers.

“What happened to my leg?”

The young soldier looked down to gauze soaked in fake blood wrapped around his knee, where his left leg now ended. His eyes squeezed shut as he threw his head back and groaned.

A group of US soldiers leaned over him, calling out updates: blood pressure, injuries, status. He’d been rushed from the front lines, helmet still strapped under his chin as he laid on a military stretcher.

The medical personnel were told the soldier, and his dark-furred animatronic working dog that laid a few feet away, missing part of his own left limb and whining, had been injured in an improvised explosive device blast. After a quick triage both the man and the pup were lifted on stretchers and rushed into an empty building nearby that had become a makeshift emergency room with small teams swarming the wounded. Less than an hour later, after being sedated and stabilized, they were loaded into a Humvee barreling back from the front lines to a field hospital set up underground.

The hope was that the subterranean medical location would protect them from enemy drones or missiles, threats that have become ubiquitous on the modern battlefield. Nearly half of the American casualties in the war with Iran have been the result of drone attacks, and in the Ukraine war, Russian forces have repeatedly targeted medics, suggesting medical personnel may not be deemed off-limits by a potential adversary.

Without solutions to protect the wounded and those caring for them, future wars could see massive increases in casualties and claw back decades of medical progress that have saved countless lives.

Just hours prior to the scene of medical triage, the wounded soldier had been in a tent down the road at Fort Hood, Texas, getting Hollywood-like makeup applied to his leg, which was bent at the knee to give the impression of an amputation.

On a whiteboard near the back of the tent, a casualty schedule of sorts was filled out with dry-erase marker. “DRONE STRIKE” was written in blue at the top of the board, scheduled for 4:00pm that day. On the far left, various injuries were jotted out: “Burns,” “blunt chest,” “eye injury.”

The elaborate simulation was a key part of the expansive training exercise last month run by the III Armored Corps' 1st Medical Brigade, aimed at enveloping troops in a realistic scenario to help soldiers prepare for future wars, or even wars already started. Everything from helicopters to fake bodily organs doused in blood were included to try to prepare soldiers for what they might face on the battlefield. The exercise held on Fort Hood from March 23 to April 1 — called Operation Silver Lightning — sought to practice new techniques largely pulled from watching recent conflicts.

During active operations in the first six weeks of the Iran war, US medical personnel were moved around repeatedly to protect them and their operations, a source familiar with the situation told CNN. And the regular drone and missile attacks made it difficult for US forces to conduct what would otherwise be routine transfers of wounded personnel to Landstuhl Regional Medical Center in Germany.

In prior campaigns, the military had learned that rapid medical care and evacuation from the front lines, treating troops in the “golden hour” after they sustain injuries, saves lives. The wars in Iraq and Afghanistan included the development of sprawling field hospitals fed by ready evacuation in operations where the US had near total control of the skies. That apparatus saved countless service members, but with cheap drones likely a fixture of future wars and recent evidence that medical personnel might be targeted, the Army is being forced to consider new ways of providing rapid medical care.

“We’re not going to enjoy the same advantages that we did in the Middle East, and primarily in Iraq and Afghanistan,” Maj. Gen. (Ret.) Paul Friedrichs, a doctor and former Joint Staff Surgeon, told CNN.

Col. Werner Barden, commander of the 1st Medical Brigade which conducted the exercise at Fort Hood, told CNN that watching the conflicts in Ukraine and Iran has proven military combat medicine has to adapt. The footprint must be smaller and more dispersed — no more sprawling field hospitals. And soldiers and leaders alike will have to work to lower their electromagnetic and thermal signatures, the kind of tell-tale markers radiated by machines and bodies that militaries can easily track.

“In today’s world, it takes one person, one drone, to create an event…that could disrupt the way we do things,” Barden told CNN. “So — hide in plain sight.”

At the heart of the underground field hospital set up for the exercise was a team best described as the real-life version of the popular 1970s television show, MASH.

The 555th Forward Resuscitative Surgical Detachment was running the emergency and operating rooms, which were not so much rooms but areas mere feet away from one another in a tunnel crammed with hospital beds and surgical equipment.

Lt. Col. James Gragg, commander of the 555th and an emergency room doctor, hovered around the operating table where role playing volunteers lay under a small tub of “organs” that had been laid on top of them, giving the doctors simulated internal injuries to sort through.

While soldiers clad in surgical gear and scrub caps worked on one patient undergoing “surgery,” Gragg, with a handgun holstered on his hip, walked over with a large syringe full of red liquid, spraying it into the tub to simulate internal bleeding.

“He’s bleeding out!” Gragg yelled, stepping back as the doctors swarmed.

The 555th, nicknamed the “Triple Nickel,” is one of the Army’s surgical detachment teams that deploy alongside other units and brings extensive surgical and trauma capabilities nearer the front lines in a conflict.

Unlike the wars in Iraq and Afghanistan, where US aircraft could typically fly anywhere without substantial risk, future conflicts will almost certainly see threats to planes and helicopters that make it difficult to quickly evacuate wounded troops. Bringing the life-saving capability of the 555th and units like it as close to the front lines as possible could be the difference between life and death.

Doing that, however, could also mean creating a target for an enemy and further exposing medical troops to threats of constant drone attacks. One solution the Army is trying is using makeshift underground spaces like the one employed for this exercise.

“The new assumption moving forward is, it’s possible to be in contact with enemy forces regardless of your position if you’re deployed,” George Barros, director of innovation and open-source tradecraft at the Institute for the Study of War told CNN. “There’s not going to be a permanently safe ‘Green Zone’ like in the GWOT (Global War on Terror) days, because the adversary’s ability to reach out persistently has grown substantially.”

The evolution of the drone threat was displayed early in the conflict between the US and Iran, when an Iranian drone struck a tactical operations center in Kuwait and killed six US soldiers. While senior Pentagon officials said at the time that the building was fortified, a source familiar with the site said it was only surrounded by concrete barriers that would provide protection from car bombs but had nothing to shield it from drones or missiles.

Protecting medical forces and the troops they’re treating requires not only in some instances going underground but also lowering their electronic signatures — a challenge in an environment where service members need to use things like X-ray and CAT scans to treat patients. Being underground helps reduce that signature, but it’s still something the Army is working to improve.

Soldiers are also taking a cue from how Ukrainian forces have tried to counter Russian attacks.

Between the start of the war in Ukraine in 2022 to April 2025, there were nearly 2,000 attacks on Ukrainian health care infrastructure, and 428 attacks on medical evacuation vehicles, the World Health Organization estimated according to a report released by the Army in 2025.

It’s “a documented fact,” Barros said, that Russia “does not play by the same rules or have the same level of respect for laws of armed conflict.” Marking emergency medical vehicles with red crosses, for example, only draws more attention and could make those personnel a target — as could erecting large medical facilities in the field.

“We have gotten very comfortable in the last 10 to 20 years sitting at these huge hospitals … But what we discovered in the most current conflicts, over the last five to seven years, is we’re a big target,” Barden said. In Ukraine and in Iran, he said, “we’ve realized that the enemy is targeting those nodes.”

Ukrainian medical units have been “working out of basements of building and stuff that one, provide a layer of protection, but two, kind of mask who they are and what they’re doing,” Barden explained.

“So,” he said, “we are doing the same thing.”

Pushing some field hospital capabilities underground is one way to address concerns about drones and missiles — but it comes with its own challenges. Some possible solutions tested out by the troops at Fort Hood were quite simple: soldiers rode bikes down the long tunnel between the treatment area underground and where casualties were being delivered outside both to save time and space as something like a golf cart could take up too much valuable room in the tunnel. Barden explained that the unit pulled out an old field telephone that could be used to better communicate as there was no cellular or satellite reception deep in the tunnels.

And while some changes seem simple, long-term success will require collaboration with the defense industry and “investment in new capabilities,” Friedrichs said. Better communication devices, for example, and medical equipment that “can be used without putting out a radar signal” that the enemy can trace are crucial for military medicine in future conflicts.

But the budget for military medicine has been “essentially a flat line” for years, Friedrichs said. The need to adapt major platforms like ships, fighter jets, and tanks has won out in the heavily bureaucratic budgeting process, he said, and investing in medical capabilities that may not seem necessary now but would be literally the difference between life or death later have in many ways fallen by the wayside.

Adjusting how military medical forces protect themselves and their patients has emerged as one of the most pressing needs for new battlefields. A report released by the Army in 2025 outlining medical lessons learned from the war in Ukraine says the “widespread use of drones” coupled with “blatant disregard for the Geneva Conventions protecting medical personnel and facilities” indicates a dire need to prioritize protecting medical assets.

In addition to working in new and creative spaces, medical personnel also need to prepare themselves for the types of injuries and treatment they’re likely to face in a war littered with drones.

It’s crucial that the injuries they practice on be as realistic as possible, Maj. Kelly Wood, the officer overseeing the mock injuries and wounds — called moulage — in the Fort Hood exercise told CNN, to ensure the medical personnel in the field are getting as close as possible to what they could experience on a real-life battlefield.

“The more high-fidelity training we can provide to our medical teams, the more successful they’ll be in those real-life scenarios,” Wood said.

While soldiers were finishing applying a different soldier’s amputated leg earlier in the day, as he stood on crutches, sitting across from him was another young soldier getting a fake abdomen with internal organs spilling out tied around her torso. Each role player — in this exercise, volunteers from throughout III Corps at Fort Hood — had a sheet of paper with them, outlining their injuries and giving them directions on how to act.

“Make wet gurgling sounds,” one said.

After the role players had their moulage done they were taken out to an urban training environment on Fort Hood that simulated mobile field medical treatment area. That area marks the first stop back from the front lines where a wounded service member would receive damage control surgery or resuscitative care. In a simulated village — meant to look like it’s located in the Middle East reflecting past training for the US’ wars in Iraq and Afghanistan — soldiers with 61st Multifunctional Medical Battalion would triage the wounded before loading them up and sending them back for further care.

In the dusty training area, it wasn’t just combat medics jumping in to help. Anyone with a free hand pitched in to carry a casualty or clear an area for the medical providers to treat patients. And when the sun went down, the soldiers worked in the glow of red lights on their helmets — an attempt to lower their visibility to the enemy while providing critical care.

When the wounded service members were stabilized, they were quickly loaded onto medical transportation Humvees and driven towards the larger field hospital for treatment. In another instance, the Humvees drove to an open field and waited to load the injured onto a HH-60 medical evacuation Blackhawk helicopter, shielding their patients as dust swirled from the rotor wash.

This field hospital would normally have been a mass of tents and structures above ground. Instead, medical personnel were spread throughout a sprawling subterranean network of decommissioned nuclear tunnels that run under Fort Hood.

The space was a stand in for a potential subway tunnel, a basement, or other subterranean areas that could provide some protection in the future.

At the tunnels’ entrance, netting was draped across the opening in an effort to “camouflage” the area and to physically block enemy drones from entering.

For the medical personnel, part of the practice is just remembering to rely on their regular medical training despite the surroundings. There’s the mental checklist to tick through when treating the patient in front of you; the chaos of the moment that cannot be processed until later; the individual mental routines a soldier uses to focus only on the life they’re working to save.

For Gragg, it’s a deep breath, a reminder that patients “die in minutes, not seconds,” and leaning on the routine treatment algorithm to help calm his nervous systems. For Sgt. 1st Class Daniel Hurst, a combat medic and detachment sergeant of the 555th, it’s silently singing a song — any song that pops into his head — to himself.

“It’s something I’ve taught my guys, and it doesn’t have to be a song,” said Hurst, who previously deployed to Iraq and Afghanistan. “Find something that brings you back to center and start again.”