Traumatic Brain Injury In Veterans Could Be Made Worse by Air Evacuation
When soldiers fall in battle, they need immediate medical attention in a safe area as soon as possible, so airlifting soldiers from combat when they are severely wounded makes sense. However, one of the most prevalent forms of injury that veterans suffer is traumatic brain injury, or TBI, which has numerous causes in combat situations, and a new study suggests that airlifting patients with TBI could make the problem worse.
The University of Maryland School of Medicine conducted a study involving combat veterans that suggested rapid air evacuation had the potential to cause more damage to patients with traumatic brain injuries. Researchers involved with the study used rats, giving the animals a traumatic brain injury and then placing them in pressure chambers that simulated the changes in air pressure in emergency military transport aircraft. The pressure in such military aircraft when at full altitude is around 9,000 feet above sea level, while a civilian airliner pressurizes to 6,000 feet.
“What we found is that they were materially worse at the end,” said Alan Faden, a professor of anesthesiology at the University of Maryland School of Medicine. “They were worse in behavioral terms, and when we looked at the brains, they lost cells in the critical hippocampal regions, where one makes memories.”
The tests also found that brain inflammation after a head injury was “substantially enhanced” after the rats underwent air pressure changes. Faden and his team also put rats in pressurized cabins two days after they suffered a brain injury and simulated the travel and pressurization from Afghanistan to Germany, then Germany to the US, which wounded and discharged service members might undergo. Faden found that the pressure caused mild TBI to get worse as the pressure changes compounded the injury to mimic a larger TBI.
The rats were given oxygen to ensure normal blood levels, further simulating combat transportation and real-world medical treatment.
“What we showed is that if you give 100 percent supplemental oxygen in this condition of air evacuation pressure, it was worse than just giving enough oxygen to normalize the oxygen tension,” Faden said.
More than 330,000 veterans of the recent Afghanistan and Iraq conflicts suffer mild TBI, which for many leads to severe disability and inability to work, and for some leads to premature death. If medical transport compounds those injuries, then the idea of airlifting injured troops must be reevaluated to help prevent or reduce the impact of concussions and traumatic brain injuries. Faden hopes that the Air Force and medical teams will find better ways to stabilize patients on the ground before transport, as well as find ways to lessen the effects of pressurization on wounded troops. He also suggested that post-evacuation care would become hugely important for service members suffering traumatic brain injury, and the military must find not just better methods of treatment on the field, but also, as the wounded are returned home, in a safer manner.
“This research has the potential to connect bench to bedside in an important, potentially lifesaving way,” said Dean E. Albert Reece, MD, PhD, MBA, who is also Vice President of Medical Affairs at the University of Maryland and the John Z. and Akiko Bowers Distinguished Professor.
