The battlefield can be a laboratory for assessing response of the human body to stress. Although scenes may differ, from musket volleys to a shattering car bomb, effects to the body and psyche are similar. "Every war stimulates medical research. It is sad, but true," says Frank Freemon, a semiretired neurologist from Vanderbilt University who earned a PhD in history at age 54 and is an authority on the Civil War.1
As recently as the last Gulf War in 1990–1991, health effects of combat were assessed in fuzzy hindsight. That approach is changing, beginning with symptom chronicling among troops now in Iraq and Afghanistan. And future soldiers may wear bio-monitoring outfits that will provide valuable new types of information based on real-time measurements.
"Tools embedded in soldiers' clothing and watch-like meters to monitor vital signs and exposures will allow us to know what an exposure is with much more certainty than in 1991, when we had to rely on soldiers' reports on what they think they might have seen," explains Charles C. Engel, director of the Department of Defense's deployment health clinical center at Walter Reed Army Institute of Research and assistant chair of psychiatry at the Uniformed Services University.
SURVEILLANCE AND MONITORING EVOLVE
Medical and scientific knowledge both arise from war and influence it. Recognition of the danger of sepsis and importance of public health measures halved the death rate from infection between the American Civil War and World War I, although infectious disease remains challenging (see sidebar below). Antibiotics slashed the risk further. And continuing analysis of health problems in Gulf War veterans is revealing potential dangers in current conflicts.
Information technology distinguishes what we are learning from war today compared to yesterday. "When Vietnam ended, we hadn't entered the automated age yet, and in the Gulf War we were just into it. We were not prepared for the need to have automated baseline health data on all troops," says Engel. In 1991, with the world interconnecting, the obsolescence of paper military records suddenly loomed. "Before we go off to war we need to have ways to automate databases on the health experience of each serviceperson deployed and follow up after they return to see how their health changes. We had to develop and implement baseline and longitudinal health data collection in military troops," he adds. Major efforts are underway now in the United States and the United Kingdom.
Record keeping also applies to the environment, as evidenced by a disaster in the Gulf War, with air so foul that matching symptom to pollutant was nearly impossible. In Operation Iraqi Freedom, the darkness following the "shock-and-awe" attack echoed conditions in the first Gulf War, but with more building materials than burning oil. As the dust settled, particulates and sand emerged as the biggest threat to respiratory health, as in Afghanistan.2 Yet the air quality problem in both places is eclipsed by contaminated food and water supplies and temperature extremes.
For tomorrow's soldier, information such as reported symptoms and environmental conditions will be wed to output from the US Army's Warfighter Physiological Status Monitoring (WPSM) system. This wearable, lightweight suite of sensors, currently being tested in a variety of settings, will send physiological data to commanders and medics, communicating danger instantaneously. Devices track skin and core temperature, heart and respiratory rate, sleep, cognitive state, hydration, body orientation, and wartime acoustics, such as bullet impact. "When we optimize the science, we will field-test it for user acceptance. If those assurances are good, we will go into the next generation of development. But it will still be several years" before it is ready for the battlefield, explains Christopher Joyce, technology transfer and marketing specialist at the US Army Research Institute of Environmental Medicine in Natick, Mass.
Data from the WPSM project are generating predictive models that will guide implementation.3 For example, hydration data for males and females are documented for mountain climbing, arctic field training, and reconnaissance and surveillance missions. Heart rate and temperature changes in response to heat come from studies at Fort Benning, Ga. A 58-day stint at Army Ranger School in the desert, mountains, and swamps of the southeast United States tracked effects of extreme sleep deprivation.
Infection: An Ongoing Challenge
Infection may be the greatest weapon of mass destruction. In 1519, six hundred Spaniards unintentionally brought smallpox to the Aztecs in Mexico. The disease helped in decimating a population of 20 million down to 1.6 million. The invisible weapon must have seemed to target the natives, since the Europeans, long exposed to the virus through livestock, were immune. Globalization has continued to fuel infection. Antibiotic-resistant gonorrhea, for example, spread from prostitutes in Vietnam to US servicemen and beyond.
Wartime infection works two ways: Invaders introduce pathogens and succumb to unfamiliar ones. "A soldier with hepatitis E moves to a new zone. If he doesn't observe strict hygiene practices or the new zone has poor sanitation facilities, the infection can be transmitted where it was nonexistent," explains Michelle Gayer, acting program leader for communicable diseases in complex emergencies at the World Health Organization. In contrast, says Gayer, "A soldier arriving in a malaria-endemic region who has not previously lived there is prone to contracting severe forms. Adults from the community are much less likely to develop severe malaria due to the buildup of immunity over time."
Chronic effects of infection linger long after troops depart. Endemic conditions appear and epidemics rage out of control where infrastructure has collapsed, Gayer says. Wonder drugs are only part of the equation in infectious disease control.
Careful monitoring can help identify soldiers at risk for posttraumatic stress disorder (PTSD), which manifests at least a month following a triggering event. Recognition of PTSD came gradually. "During the Civil War it was seen but didn't have a name, other than 'malingering.' Guys never came back to themselves after the war," says Freemon. Longer engagements made PTSD more common. "A soldier would be hunkered down in a trench, hearing explosions day after day, with little hope. After 30 days new guys would come in. But nobody put it together until after World War I," Freemon adds, when it was dubbed "battle shock." By World War II it had become "battle fatigue," then later "post-Vietnam syndrome" before PTSD.
Understanding PTSD means understanding its roots, and that's where biomonitoring may reveal the precipitating conditions. "Vietnam was a milestone. No nation had rigorously conducted an epidemiological survey of males and females in the theater," says Matthew Friedman, executive director of the National Center for PTSD and professor of psychiatry and pharmacology at Dartmouth Medical School. But scrutiny was delayed. "It was done in the mid-1980s, but the conflict raged in the 1960s and 1970s. For the first Gulf War, PTSD research began five years later," he adds.
Now researchers aren't waiting. The US military has already questioned 2,530 soldiers in Iraq and 3,671 in Afghanistan about PTSD symptoms pre- and postdeployment.4 The most telling finding, according to Friedman, is that only 23% to 40% of those affected sought help, fearing stigmatization. Since in the past symptoms typically peaked two years postengagement, current figures may be an underestimate.
QUESTIONS ABOUT INFERTILITY
Few questions of fertility surrounded the return of WWII veterans, who promptly seeded a baby boom. But in the wake of the Vietnam War, anecdotal reports of a link between exposures and infertility contradicted conclusions from the National Academy of Sciences. "Since 1975 I've seen hundreds of patients who thought they were infertile because of exposures in Vietnam, either to Agent Orange or sustained trauma, stepping on a mine, or an illness," relates Cappy Rothman, medical director of the California Cryobank in Los Angeles. And so in 1990 and 1991, Rothman offered soldiers discounted sperm storage. "Not many guys availed themselves of the offer," he recalls.
But this year, announcement of a discount brought hundreds of requests, and prompted other cryobanks to follow. The reasons: fear of chemical and biological weapons and a link, after all, between infertility and exposures in the Gulf.5
Noreen Maconochie, senior lecturer in epidemiology at the London School of Hygiene and Tropical Medicine, and colleagues queried 10,465 Gulf War veterans trying to conceive and 7,376 matched controls in the military but not the Gulf.3 Results revealed more infertility and delayed conceptions for the vets. "We collected data on a number of self-reported exposures, including petrochemicals, pesticides, depleted uranium, as well as information on multiple vaccinations and pyridostigmine bromide, an anti-nerve gas agent," says Maconochie. In the future, biomonitoring data teamed with information from particulate monitoring devices and biosensors for biological weapons will pinpoint threats to fertility.
Soldiers in Iraq describe the punishing heat; those in Afghanistan, the treacherous and frigid mountains. US Army researchers at the Natick facility are listening. "We are trying to develop a body of scientific knowledge so we have a basis for medical and operational guidelines in environmental extremes," says Michael Sawka, chief of the thermal, mountain, and medicine division. For example, effects of extreme temperature on ion-channel functioning are being assessed in human cortical neurons and in mini-swine. Research using hypobaric chambers identifies susceptibility to mountain sickness.
Modern research into adaptation to extreme environments began at the Harvard Fatigue Laboratory in 1927. "After World War I we realized there were military problems, such as working in high-altitude aircraft or in extreme hot and cold, and we needed experts. After World War II it was discontinued," explains Sawka. The field, which had morphed into exercise physiology, relocated to university laboratories and the Department of Defense. But it was a stretch. "A soldier fighting is not as simple a situation as an athlete running a marathon. The athlete is in good condition and knows the outcome. The soldier is exposed to the environment not knowing for how long, with minimal food and water. Soldiers suffer tremendous sleep deprivation, fear, hard work, and exposure to heat and/or cold," he adds.
The WPSM project is proceeding with these extremes in mind. A "sleep watch, for example, tracks wrist movements that foretell stage of awareness. A swallowed 3-ounce, jellybean-shaped pill continuously transmits core body temperature readings, courtesy of the space program. And the WPSM recently added to its evolving ensemble the respiratory component of VivoMetrics' LifeShirt System technology, which is already used in exercise physiology studies.
"It weighs 8 ounces, is machine washable, and feels like Lycra," says Elizabeth Gravatte, director of marketing. Embedded wires detect heart rate, blood oxygen saturation, blood pressure, carbon dioxide level, and coughing.
Just as WWII-era findings found their way to athletics and health care, so too will the fruits of biomonitoring in the battlefield yield valuable information on physiology under stress, even if it seems as if a future soldier won't be able to belch without setting off alerts miles away. But the incoming data may make the combat theater a safer place. Sums up Friedman, "Knowing what to do provides a better buffer against the debilitating effects of traumatic exposures."
Ricki Lewis (
1860–1865 Civil War
1866 – Italian monk Montegazza uttered idea for cryobanks: "A man dying on a battlefield may beget a legal heir with his semen frozen and stored at home."
1867 – Joseph Lister promotes carbolic acid as antiseptic
1900 – Karl Landsteiner lays groundwork for blood transfusions
1902 – United States begins manufacturing vaccines
Infection/combat deaths = 1:1
1930s Sulfa drugs
Infection/combat deaths = <1:1
Improved sanitation, better vaccines, whole-blood transfusions
1949–1953 Korean War
Helicopter evacuation, refined triage, cold-weather effects studied, plasma-volume expanders, mobile army surgical hospitals (MASH)
PROBLEMS: Quinine-resistant malaria MEDICAL ADVANCES: Recognition of "biological acclimatization" period of 6 weeks, trauma care in field, evacuation refined
1990–1991 Gulf War (Desert Storm)
PROBLEMS: Norwalk virus,
2003–? The War in Iraq
PROBLEMS: "Uxo" (unexploded ordnance), suicide bombings, beheadings on the Internet, blowing sand