CINCU, Romania -- Army combat medics live by a creed of trust.Those who have proven their skills under fire and put their lives before others receive the nickname "Doc." From the moment soon-to-be medics give their first IV at Fort Sam Houston, Texas, to the day they hang up their aid bag, they will endure blood, sweat and guts to maintain that title.With 17 years of experience and two deployments, Army Staff Sgt. Brad Foster, with the Oregon Army National Guard's Headquarters and Headquarters Company, 3rd Combined Arms Battalion, 116th Heavy Brigade Combat Team, from Pendleton, Oregon, has earned the right to be called "Doc" several times over.Foster, along with his unit, recently spent three weeks training with active-duty U.S. Army units and troops from nine partner nations during Exercise Saber Guardian 16, a multinational exercise designed to develop joint combat readiness.He spent most of the exercise training combat medics in his platoon to save lives. During training and war, combat medics prevent fatalities.UNDER FIRE"Doc" recalled the fateful day he tested his mettle and steady skills and earned his title.In 2004, while he was deployed to Iraq with the 1st Battalion, 6th Field Artillery Regiment,a rocket-propelled grenade hit the rear vehicle in his convoy during a routine mission. Under a rain of enemy fire, Doc Foster ran to two soldiers with life-threatening wounds, dragged them to safety and patched them up.But not even the memory of receiving the Combat Medic Badge for his heroic acts elicits from him the same smile as when he hears a soldier call out, "Hey, Doc Foster!"Combat medicine is much more than repairing limps and treating sickness; it is a social game of trust. If soldiers trust their medics to treat them in any situation, they will have the confidence to do higher-tempo missions without worrying about the potential for serious injury. Like a rock climber's harness, medics make the soldiers feel safe.REAL CONSEQUENCES, EVEN DURING TRAININGIt was early in the morning, but the sun was already sucking the moisture from the muddy ground, the consistency of brownie batter. The day would be hot and humid, and Doc Foster was already thinking about what that might mean for his soldiers."Did you drink at least a liter of water since waking up?" he asked a soldier who walked in for sick call, while handing him a two-liter bottle.During this exercise, Foster supported the 140 soldiers of Bravo and Charlie Companies, 116th HBCT, and there were no heat casualties or serious injuries. Last year, he was with the same group at the National Training Center in California, and it was a very different story."I've never seen so many heat casualties in my whole career," Foster said. "I think a lot of our medics at our [National Training Center] rotation realized how viable our training is. It woke up a lot of people -- making sure they're trained up."Foster maintains high expectations of everyone in the battalion aid station, said Army Spc. Gaige Spencer, a combat medic who works for Doc Foster. During this year's rotation, soldiers were performing 14-hour missions in temperatures exceeding 115 degrees. But because of Foster's work ethic and care for his soldiers, there were no heat casualties in his company.Doc Foster credits junior leaders, the combat medics working with him, or the lucky stars for the achievement, despite all indications pointing to the influence of his leadership and medical expertise.CARING FOR ALL TROOPSHis care for soldiers extends to non-U.S. troops as well, having served all over the world, including South Korea, Germany and two tours in the Middle East. Saber Guardian saw a total of 2,800 soldiers from 10 countries, and for Foster, the wealth of culture and diversity was priceless."When I was in Afghanistan, I met some really great friends in the Canadian army," Foster said. He said he played hockey with the Canadians and even started a ball-hockey league. For Foster, hockey has always been a door to interact with local people and experience the culture."When I was stationed in Korea, I got to play hockey with the locals and was invited to their homes," he said. "[At Saber Guardian] we are all from different countries, but military guys have similar experiences. There is camaraderie no matter what country you are from. You may not speak the same language, but deep down you know that you experience similar things. … It's kind of unspoken, but it's great."When Foster isn't training or deployed with the National Guard, he works as a Veterans Affairs housing support specialist for homeless veterans in Richland, Washington. "I love to work with vets, to find homes and get them stable so they can be safe," he said. "It's the most rewarding work I've ever done."The Army prepared him to solve problems and think outside the box, Foster said. "Every day is a different day," he added. "The scenarios are all different to get these guys taken care of."Foster said he sympathizes with the men and women who served and now suffer from post-traumatic stress disorder, and he was shocked when he found out how many of his neighbors had served and didn't have homes."They trust me because of my experience being a veteran medic," he said.