Does Early Anesthesia for Combat Injuries Ease Pain Later?

Steven Fox

April 06, 2011

April 6, 2011 (Washington, DC) — A major study is under way of combat injured soldiers, and its eventual aim is to assess how regional anesthesia, administered shortly after traumatic injury, affects later pain.

Although the study so far has yielded only preliminary data on other aspects of postinjury pain, it was the focus of much interest here at the American Academy of Pain Medicine (AAPM) 27th Annual Meeting.

The Regional Analgesia Military Battlefield Pain Outcomes Study (RAMBPOS) is a 4-year study that's a joint effort between the Veterans Administration (VA) and the US Department of Defense (DOD).

Col. Chester "Trip" Buckenmaier III, MD

"The eventual aim of the study is to look at advanced pain management techniques — specifically continuous peripheral nerve block — in soldiers out on the battlefield after they had sustained a traumatic amputation or injury to an extremity and compare them with soldiers who didn't get that care," study author Col. Chester "Trip" Buckenmaier III, MD, told Medscape Medical News in an interview.

Dr. Buckenmaier, a pain specialist at Walter Reed Army Medical Center in Washington, DC, emphasized that the data presented here are preliminary and represent results from the 2-year midpoint of the longitudinal 4-year study.

So far the results of the study demonstrate there are substantial variations in responses for pain outcomes and health-related quality of life. Overall, the trends of multivariable pain data obtained in the study show improvements in pain scores over time, Dr. Buckenmaier said. But for soldiers with these sorts of major traumatic injuries, psychosocial outcomes continue to be a problem, he added.

As to the principle aim of the study, Dr. Buckenmaier said, "We still don't have any information from this study on the major outcomes that I'm most interested in: What was the impact of more advance pain care modalities on these soldiers? Did it have an impact on their psychosocial outcomes? Did it have an impact on their overall pain? Did they do better in their rehabilitation? Those answers are in the future," he said.

Early Aggressive Regional Anesthesia

Not much is known about how early aggressive regional analgesia affects short- and long-term pain and psychological outcomes of soldiers with combat injuries.

"Those of us who treat these kinds of injuries have long believed that pain continues to be an issue long after the initial injury heals — both in terms of physical and psychological effects — and that early intervention can make a difference over time," Dr. Buckenmaier said. "But this is really one of the first studies that's going to give us hard data."

The presentation at this year's AAPM meeting included data from 180 combat-injured soldiers recruited via a joint effort of the Walter Reed Army Medical Center and the VA.

The principal investigator of the study, Rollin "Mac" Gallagher, MD, from the Philadelphia Veterans Hospital and the University of Pennsylvania, and Rosemary Polomano, MD, also from the University of Pennsylvania, directed the longitudinal follow-up team out of the Philadelphia VA.

In the study, the soldiers were assessed at regular intervals, via telephone interviews, for the presence and severity of pain and physical and psychological status. Investigators used several different assessment instruments to quantify their results, including the Brief Pain Inventory (BPI), Neuropathic Pain Scale (NPS), Treatment Outcomes in Pain Survey (TOPS), and the VA Behavioral Health Laboratory instruments for measures of mental health.

Preliminary findings thus far for the BPI pain intensity items show a statistically significant downward trend in average and worst pain over time compared with baseline scores collected at the time of discharge from acute care when aggressive rehabilitation was initiated.

The same was true for selected items on the NPS and the overall NPS score. On average, soldiers experienced clinically significant episodes of "worst pain" throughout their participation in the study, indicating the need for continuous attention to pain management in their longitudinal recovery.

Results of several of the 14 TOPS subscales collected during a 24-month period indicate that varying percentages of injured soldiers have outcomes similar to normative data from chronic pain populations, and for some TOPS outcomes were better and others worse.

Investigators found that a small number of soldiers in this study cohort reported issues related to their psychological health, which provides greater insight into their challenges in recovery after major limb injuries.

"On the whole, we found that measures of pain showed improvements over time," Dr. Buckenmaier said. "But psychosocial aspects of recovery continued to be a problem."

Traditionally, he said, physicians have thought of pain as a symptom of being injured — that it has no lasting consequences for the patient. "But now we're coming to understand that it really has tremendous impact, contributing to problems like PTSD [posttraumatic stress disorder], recovery from traumatic brain injury, substance abuse, and a whole host of other issues," he said.

We're finding that if you manage pain well, everything about that soldier's recovery gets better. If you manage pain poorly, everything about the soldier's recovery is worse.

"We're finding that if you manage pain well, everything about that soldier's recovery gets better. If you manage pain poorly, everything about the soldier's recovery is worse. But even though that's intuitive, we really didn't have any hard evidence to back up that intuition until we began getting data from this study.”

Useful Results

Asked for comment, Fred Defrancesch, MD, an associate professor at both Louisiana State University and Tulane Schools of Medicine, New Orleans, called this an "excellent" study.

"I've done some previous work with the VA and have seen a lot of veterans with these sorts of injuries and PTSD," he told Medscape Medical News. "I think any sort of study, such as this one, where you're trying to help these severely injured men and women decrease their pain and facilitate their return to society, is a valuable one, and the results will most likely be useful in managing other patient populations."

Along with Dr. Buckenmaier, Dr. Defrancesch identified some limitations of the study, the main one being that the data are incomplete.

"It's a preliminary study, so they're going to need to do more research and take this out further on the time line," he said. "But at the end of the 4 years we should have some good, hard information on how we can improve chronic pain outcomes by addressing acute pain more accurately and more aggressively."

Dr. Buckenmaier emphasized that one of the most notable aspects about the study was its cooperative design, teaming up efforts of the DOD and the VA.

"The DOD tends to lose track of soldiers after they leave the hospital," he said. "But in this case we were able to close the loop between the DOD and the VA and successfully follow these patients longitudinally for up to 2 years."

He said he hopes these sorts of cooperative efforts carry through to other studies.

Neither Dr. Buckenmaier nor Dr. Defrancesch has disclosed any relevant financial relationships.

American Academy of Pain Medicine (AAPM) 27th Annual Meeting: Poster 110. Presented March 25, 2011.

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