The eerie whistle of a mortar round pierces the calm as the unmistakable cracks of incoming rounds augment the disarray that surrounds you.

To the seasoned combat veteran, the experience of a fight and years of training to acclimate to the sights and sounds of battle can allow that Soldier to operate at peak performance.

However, one sound alone has the ability to rattle nerves and send fear into even the most seasoned Soldier.

"Medic!"

Amid the chaos, a voice sends the alarm that a comrade is down. Instantly, with no regard for his own safety, the medic moves through harm's way to get to his fallen brother.

Now is the time to put his years of training and experience to use. It is time to save a life.

It was with this scenario in mind that U.S. Army South recently conducted a tactical combat lifesaver course subject matter expert exchange with Paraguayan military forces June 16-27. The course was broken into two separate two-week classes focusing on tactical combat casualty care guidance and casualty evacuations under fire.

Paraguay sent more than 80 special forces soldiers and members of the National Anti-Drug Secretariat, Paraguay's anti-narcotics department of the national police, to take advantage of the knowledge U.S. medics acquired during their experiences in Iraq and Afghanistan.

"They're doing plenty of real-world missions right now and this training will greatly assist the Paraguayan forces in saving lives and maintaining a combat-ready force," said Sgt. 1st Class Efrain Perez, operations and plans noncommissioned officer for U.S. Army South's assistant chief of staff for medicine.

The Paraguayan military and security forces maneuver routinely in operations against guerilla organizations such as the Paraguayan People's Army, an insurgency group operating in remote areas of the country, or against narcotics cartels.

In a struggle against deadly opposition, the Paraguayans hope the combat medical care knowledge gained in the exchange can literally be the difference between life and death.

Each 2-week class started with classroom instruction detailing critical skills such as checking a casualty for wounds, treating for shock, applying tourniquets and how to administer IVs. Later, the students were tasked with taking the knowledge learned and applying it in a simulated firefight.

"The Soldiers who are training in this exchange are teammates," said 1st Lt. Pablo Solis, Joint Battalion of Special Forces for Paraguay. "Within a team, trust is essential. This information they have learned during these classes will allow our Soldiers to operate with the utmost trust in each other's ability to perform expedient medical care in the event we sustain casualties during operations."

Moving in small, five-man teams, each group was asked to engage the enemy, move to a simulated casualty, assess the fallen soldier, and treat and evacuate him under fire.

To add to the reality of the training, the Paraguayan air force agreed to support the exchange by providing aerial MEDEVACs via a UH-1 Huey helicopter. The medics that boarded the aircraft with the simulated casualty were tasked with securing the wounded soldier, then administering an IV catheter while the helicopter was in flight.

In these scenarios, seconds mean lives. As the teams maneuvered through their tests, confidence grew and the actions performed became less about trying to solve a new puzzle, and more about muscle memory.

Army South conducts several medical SMEEs throughout the year with numerous partner nation forces within the command's area of responsibility. These exchanges allow each army to gain a deep appreciation for one another and build cohesive practices that allow for a smooth transition should the need arise for a multinational coalition force to deploy.

"It's important to conduct exchanges like this to maintain our relationship with Paraguay and at the same time pass along information that can make a significant impact for both of our countries," said Perez.

"New global challenges require combined efforts from different forces from different countries," said Solis. "This exchange provides us an opportunity to learn from each other so that we can work well together in the future."