Lisa A. Pearse

Sudden Death in Young Adults: A 25-Year Review of Autopsies in Military Recruits

Context Sudden nontraumatic death in military recruits may offer insight into the causes and prevention of sudden death in young adults. Contribution Among 6.3 million military recruits age 18 to 35 years, sudden nontraumatic death occurred at a rate of 13.0 per 100000 recruit-years. Over half of the 126 autopsied decedents had an identifiable cardiac abnormality; one third had an anomalous coronary artery. More than one third of deaths had no explanation. Cautions This study had no control recruits who did not die suddenly. Implications Sudden nontraumatic death among military recruits occurs rarely. Whether more intensive screening would effectively prevent sudden death is unknown. The Editors Sudden death in healthy persons is uncommon and is usually due to previously undetected cardiovascular disease (1, 2). Most sudden deaths among apparently healthy young athletes occur during exertion and are most often caused by cardiac abnormalities (3-5). Gardner and colleagues (6) reported that 60% to 78% of exercise-related deaths in U.S. military personnel during 19961999 were attributable to a cardiac cause. Among young adults (persons 17 to 34 years of age), 50% of exercise-related deaths were attributable to preexisting heart disease (6). Maron and colleagues (7, 8) identified 158 sudden deaths in U.S. athletes younger than 35 years of age from 1985 through 1995 and found that 85% had a cardiovascular cause. In this and other studies of young athletes, hypertrophic cardiomyopathy, coronary artery anomalies, and cystic medial necrosis with a subsequent ruptured aorta were commonly associated with sudden death (3, 7, 9, 10). Uncommon causes of cardiac death in persons who exercise include myocarditis, floppy mitral valve, aortic stenosis, aortic dissection, and sarcoidosis (3, 11). Phillips and colleagues (12) identified 19 sudden cardiac deaths from 1965 through 1985 during Air Force basic military training at Lackland Air Force Base, Texas, the only training site for Air Force basic military training. The most frequent underlying cause of these deaths was myocarditis (42%), followed by coronary anomalies (16%). The frequency of sudden death in athletes younger than35 years of age is not clearly defined (13). Regardless of frequency, sudden death in young adults garners disproportionate attention from the media and raises important issues of legal liability (5). Deaths occurring during basic military training are of particular concern because they occur despite a preenlistment health screening program and have a substantial effect on the structure of basic training. The medical screening, conducted at a Military Entrance Processing Station, consists of a personal (but not family) medical history questionnaire and physical examination. The physical examination includes a clinical evaluation; blood and urine testing; and measurements of blood pressure, pulse, height, and weight. Cardiovascular screening is limited to heart auscultation. Electrocardiography is performed only if any abnormalities are identified. Cardiovascular diagnoses that prompt rejection for enlistment include valvular heart diseases, coronary artery disease, symptomatic arrhythmia, persistent resting sinus tachycardia, documented ventricular arrhythmias, left bundle-branch block, Mobitz type II second-degree and third-degree atrioventricular block, the WolffParkinsonWhite syndrome, hypertrophy or dilatation of the heart, cardiomyopathy (including myocarditis or pericarditis), history of heart failure, all congenital anomalies except for corrected patent ductus arteriosus, and hypertension. Disqualification for cardiac or vascular system abnormalities is very rare. In 2000, approximately 55 of almost 365000 enlisted applicants (0.15%) to military service were found to be unfit for military service because of cardiac or vascular disqualification. The duration of basic military training and the graduation requirements vary among the military services. In general, however, basic training may include basic rifle marksmanship; hand grenade, bayonet, and hand-to-hand combat training; unarmed combat training; physical fitness tests (that is, pushups, sit-ups, and a timed run); obstacle courses; live-fire exercises; foot marches (3, 5, 8, 10, and 15 kilometers); and field training exercises. Efforts to understand and prevent the rare, but tragic, occurrence of sudden death among these young adults depend on active surveillance of the population and accurate determination of mortality rates. However, published information on cause-specific mortality in this population is limited to isolated case reports (14-18), and population-based studies focused on a single military service (19) or specific cause of death (12, 20). To provide surveillance data specifically for recruit deaths, the Armed Forces Institute of Pathology implemented the Department of Defense Recruit Mortality Registry (DoD-RMR) in the Medical Mortality Surveillance Division at the Office of the Armed Forces Medical Examiner. This registry contains reports of every recruit death and autopsy. Recruit deaths described in the publications mentioned previously were included in the DoD-RMR. Descriptive analyses of nontraumatic and traumatic causes of recruit mortality derived from the DoD-RMR have been published elsewhere (21, 22). In the current study, we used data from the DoD-RMR to determine the cause of nontraumatic sudden death among military recruits over a 25-year period (1977 through 2001). Methods The Institutional Review Board of Brooke Army Medical Center approved this study. Nontraumatic recruit deaths were identified through the DoD-RMR. The registry reflects a review of military personnel records and investigative reports, death certificates and autopsies, and Armed Forces Institute of Pathology consultations and toxicology studies. The DoD-RMR considers a death to be a recruit death if the fatal incident occurred at a military training site before completion of initial training while the recruit was in an enlisted status in the Air Force, Army, Marine Corps, or Navy (22, 23). Of the nontraumatic recruit deaths that occurred from 1977 through 2001, cases were eligible for this study if they were categorized in the DoD-RMR as idiopathic deaths or deaths due to the following causes: cardiac, exertional heat illness, vascular, asthma, and all exercise-related deaths not elsewhere classified. We obtained demographic data and details about the circumstances of the fatal incident from the DoD-RMR because clinical histories were not consistently available from pathology reports from the military treatment facilities or civilian hospitals where these deaths were initially evaluated. The inclusion criteria for this study were a nontraumatic death with an available autopsy report for pathologic confirmation of the cause of death. We used the DoD-RMR to obtain and manually review records from each case that met the inclusion criteria. Cases were classified as sudden (cardiac, noncardiac, or idiopathic) and nonsudden. Sudden death was defined as an event resulting in death or terminal life support within 1 hour of the inciting event. Deaths were defined as cardiac in origin if the decedent had pathologically confirmed heart disease with clinical circumstances defined as potentially cardiac in origin. Idiopathic sudden death was defined as any sudden death unexplained by preexisting disease and without identifiable cause on postmortem examination. Crude mortality rates are presented as deaths per 100000 recruit-years (calculated by multiplying numeric death rates [number of deaths/number of recruits] by average training period expressed in years). The average training period was 8 weeks for the Army and the Navy, 6 weeks for the Air Force, and 11 weeks for the Marine Corps. We obtained population data from the Defense Manpower Data Center. Of the cases that made up this series, 5 have been discussed in detail in previous case reports (14-18), and 26 have had their sickle-cell status reported (without detailed discussion of causes of death) (12, 20, 22). We calculated CIs for mortality rates by using the Rothman binomial method (24), and we calculated P values for comparisons by using the MantelHaenszel method (25). We considered P values less than 0.05 to be significant. Statistical analysis was performed by using JMP Professional 5.0.1 (SAS Institute, Inc., Cary, North Carolina). Results The DoD-RMR contains 277 deaths identified from among 6.3 million recruits from 1977 through 2001. No recruit was noted to have preentry cardiovascular disease, and postmortem toxicology reports showed no evidence of illicit drug use. A family history of premature death or cardiovascular disease is not routinely gathered on initial-entry service members. Autopsy reports were available for 148 (97%) eligible nontraumatic deaths. The 126 sudden nontraumatic cases form the basis of the current study. The median age of the recruits was 19 years (range, 17 to 35 years), and 111 (88%) were male. The rate of nontraumatic sudden death was 13.0 per 100000 recruit-years, a figure that did not vary significantly over the 25-year study period (Table 1). Approximately half (64 of 126 recruits) of the nontraumatic sudden deaths were due to an identifiable cardiac abnormality, and slightly more than one third (44 of 126 recruits) were idiopathic (Table 2). A temporal relationship to exertion was noted in 86% (108 of 126 recruits) of events. There were 18 noncardiac sudden deaths: 6 from coagulopathy and hemorheologic causes (3 sickle-cell crises, 2 episodes of pulmonary embolism, and 1 internal hemorrhage), 5 from intracranial hemorrhage, 4 from pulmonary causes (respiratory distress due to asthma [n= 2], sarcoidosis [n= 1], and alveolar hemorrhage [n= 1]), and 3 from exertional rhabdomyolysis or heat stroke. Table 1. All-Service Nontraumatic Sudden Death Rates for Recruits by 5-Year Categories, 19772001 Table 2. Demographi

Causes of death in U.S. special operations forces in the global war on terrorism: 2001-2004

Background:Effective combat trauma management strategies depend upon an understanding of the epidemiology of death on the battlefield. Methods:A panel of military medical experts reviewed photographs and autopsy and treatment records for all Special Operations Forces (SOF) who died between October 2001 and November 2004 (n = 82). Fatal wounds were classified as nonsurvivable or potentially survivable. Training and equipment available at the time of injury were taken into consideration. A structured analysis was conducted to identify equipment, training, or research requirements for improved future outcomes. Results:Five (6%) of 82 casualties had died in an aircraft crash, and their bodies were lost at sea; autopsies had been performed on all other 77 soldiers. Nineteen deaths, including the deaths at sea were noncombat; all others were combat related. Deaths were caused by explosions (43%), gunshot wounds (28%), aircraft accidents (23%), and blunt trauma (6%). Seventy of 82 deaths (85%) were classified as nonsurvivable; 12 deaths (15%) were classified as potentially survivable. Of those with potentially survivable injuries, 16 causes of death were identified: 8 (50%) truncal hemorrhage, 3 (19%) compressible hemorrhage, 2 (13%) hemorrhage amenable to tourniquet, and 1 (6%) each from tension pneumothorax, airway obstruction, and sepsis. The population with nonsurvivable injuries was more severely injured than the population with potentially survivable injuries. Structured analysis identified improved methods of truncal hemorrhage control as a principal research requirement. Conclusions:The majority of deaths on the modern battlefield are nonsurvivable. Improved methods of intravenous or intracavitary, noncompressible hemostasis combined with rapid evacuation to surgery may increase survival.

Sudden Death in Young Adults: An Autopsy-Based Series of a Population Undergoing Active Surveillance

OBJECTIVES The purpose of this study was to define the incidence and characterization of cardiovascular cause of sudden death in the young. BACKGROUND The epidemiology of sudden cardiac death (SCD) in young adults is based on small studies and uncontrolled observations. Identifying causes of sudden death in this population is important for guiding approaches to prevention. METHODS We performed a retrospective cohort study using demographic and autopsy data from the Department of Defense Cardiovascular Death Registry over a 10-year period comprising 15.2 million person-years of active surveillance. RESULTS We reviewed all nontraumatic sudden deaths in persons 18 years of age and over. We identified 902 subjects in whom the adjudicated cause of death was of potential cardiac etiology, with a mean age of 38 ± 11 years. The mortality rate for SCD per 100,000 person-years for the study period was 6.7 for males and 1.4 for females (p < 0.0001). Sudden death was attributed to a cardiac condition in 715 (79.3%) and was unexplained in 187 (20.7%). The incidence of sudden unexplained death (SUD) was 1.2 per 100,000 person-years for persons <35 years of age, and 2.0 per 100,000 person-years for those ≥ 35 years of age (p < 0.001). The incidence of fatal atherosclerotic coronary artery disease was 0.7 per 100,000 person-years for those <35 years of age, and 13.7 per 100,000 person-years for those ≥ 35 years of age (p < 0.001). CONCLUSIONS Prevention of sudden death in the young adult should focus on evaluation for causes known to be associated with SUD (e.g., primary arrhythmia) among persons <35 years of age, with an emphasis on atherosclerotic coronary disease in those ≥ 35 years of age.

Incidence of primary blast injury in US military overseas contingency operations: a retrospective study.

Objectives:The present retrospective study was performed to determine the incidence and outcome of primary blast injury and to identify possible changes over the course of the conflicts between 2003 and 2006. Summary Background Data:Combat physicians treating patients injured in overseas contingency operations observed an increase in the severity of explosion injuries occurring during this period. Methods:This retrospective study included service members injured in explosions between March 2003 and October 2006. The Joint Theater Trauma Registry provided demographic information, injury severity score, and International Classification of Diseases 9 codes used to diagnose primary blast injury. Autopsy reports of the last 497 combat-related deaths of 2006 were also reviewed. Results:Of 9693 admissions, of which 6687 were injured in combat, 4765 (49%) were injured by explosions: 2588 in 2003–2004 and 1935 in 2005–2006. Dates of injury were unavailable for 242 casualties. Injury severity score (9 ± 10 vs. 11 ± 10, P < 0.0001) and incidence of primary blast injury (12% vs. 15%, P < 0.01) increased. The return-to-duty rate decreased (40% vs. 18%, P < 0.001), but mortality remained low (1.4% vs. 1.5%, P = NS). There was no significant difference in incidence of primary blast injury between personnel who were killed in action and those who died of wounds at a medical facility. Conclusions:Injury severity and incidence of primary blast injury increased during the 4-year period, whereas return-to-duty rates decreased. Despite increasingly devastating injuries, the mortality rate due to explosion injuries remained low and unchanged.

Chest Wall Thickness in Military Personnel: Implications for Needle Thoracentesis in Tension Pneumothorax

Needle thoracentesis is an emergency procedure to relieve tension pneumothorax. Published recommendations suggest use of angiocatheters or needles in the 5-cm range for emergency treatment. Multidetector computed tomography scans from 100 virtual autopsy cases were used to determine chest wall thickness in deployed male military personnel. Measurement was made in the second right intercostal space at the midclavicular line. The mean horizontal thickness was 5.36 cm (SD = 1.19 cm) with angled (perpendicular) thickness slightly less with a mean of 4.86 cm (SD 1.10 cm). Thickness was generally greater than previously reported. An 8-cm angiocatheter would have reached the pleural space in 99% of subjects in this series. Recommended procedures for needle thoracentesis to relieve tension pneumothorax should be adapted to reflect use of an angiocatheter or needle of sufficient length.

Fatal Airway Injuries during Operation Enduring Freedom and Operation Iraqi Freedom

Abstract Introduction. Airway compromise is the third leading cause of potentially preventable death on the battlefield. An understanding of the injuries associated with fatal airway compromise is necessary to develop improvements in equipment, training, and prehospital management strategies in order to maximize survival. Objective. To determine injury patters resulting in airway compromise in the combat setting. Methods. This was a subgroup analysis of cases previously examined by Kelly and colleagues, who reviewed autopsies of military personnel who died in combat in Iraq and Afghanistan between 2003 and 2006. Casualties with potentially survivable (PS) injuries and deaths related to airway compromise previously identified by Kelly et al. were reviewed in depth by a second panel of military physicians. Results. There were 982 cases that met the inclusion criteria. Of these, 232 cases had PS injuries. Eighteen (1.8%%) cases were found to have airway compromise as the likely cause of primary death. All had penetrating injuries to the face or neck. Twelve deaths (67%%) were caused by gunshot wounds, while six deaths (33%%) were caused by explosions. Nine cases had concomitant injury to major vascular structures, and eight had significant airway hemorrhage. Cricothyroidotomy was attempted in five cases; all were unsuccessful. Conclusion. Airway compromise from battlefield trauma results in a small number of PS fatalities. Penetrating trauma to the face or neck may be accompanied by significant hemorrhage, severe and multiple facial fractures, and airway disruption, leading to death from airway compromise. Cricothyroidotomy may be required to salvage these patients, but the procedure failed in all instances in this series of cases. Further studies are warranted to determine the appropriate algorithm of airway management in combat casualties sustaining traumatic airway injuries.

Deaths attributed to suicide among enlisted U.S. armed forces recruits, 1980-2004.

OBJECTIVE The purpose of this study was to describe the epidemiology of suicides among U.S. Air Force, Army, Marine Corps, and Navy recruits from 1980 through 2004. METHODS Recruit suicides were identified through the Department of Defense Recruit Mortality Registry. We calculated crude, category-specific, and age-adjusted mortality rates as deaths per 100,000 recruit-years. RESULTS There were 46 onsite suicides by gunshot (39%), hanging (35%), fall/jump (22%), and drug overdose (4%). An additional 20 recruits committed suicide from 1980 through 2004 after leaving the military training site. Methods included gunshot (70%), hanging (20%), fall/jump (5%), and poisoning (5%). Therefore, the overall recruit suicide rate was 6.9 (95% confidence interval = 5.4-8.8) deaths per 100,000 recruit-years. Only three (5%) suicides occurred among females resulting in a 3.5 times higher risk for males compared to females (95% confidence interval = 1.1-11.2). CONCLUSIONS Suicide rates among military recruits were lower than those of comparably aged U.S. civilians. However, the occurrence of any suicide during basic military training emphasizes the importance of routine evaluation of the effectiveness of each military services suicide prevention program as it applies to this population.

The use of electronic pharmacy data to investigate prescribed medications and fatal motor vehicle crashes in a military population, 2002-2006

The authors examined the association between prescribed medications and fatal motor vehicle crashes (MVCs) in an active duty military population between 2002 and 2006. Using a case-control design, MVC deaths were ascertained using a military mortality registry, and an integrated health system database provided information on health system eligibility, pharmacy transactions, and medical encounters. Cases and controls were matched on comparable observation time outside periods of deployment. Among selected categories, only one, antidepressant medications, was an independent predictor of fatal MVC (odds ratio, 3.19; 95% confidence interval, 1.01-10.07). Male gender, Black race, enlisted rank, service branch (Navy and Marine Corps), and selected co-morbidities were also independent predictors. Unexpectedly, the odds of younger age quartiles (< 27 years) and history of deployment were reduced for MVC cases. Although results need to be considered in the context of data limitations, the association between prescribed antidepressants and fatal MVC may reflect unmeasured co-morbidities, such as combined effects of prescribed and over-the-counter medications and/or alcohol or other substance abuse. Younger individuals, representing new military accessions in training or returning from deployment with serious injuries, may have fewer opportunities to operate vehicles, or targeted efforts to reduce MVC following deployment may be showing a positive effect.

Early mortality experience in a large military cohort and a comparison of mortality data sources

BackgroundComplete and accurate ascertainment of mortality is critically important in any longitudinal study. Tracking of mortality is particularly essential among US military members because of unique occupational exposures (e.g., worldwide deployments as well as combat experiences). Our study objectives were to describe the early mortality experience of Panel 1 of the Millennium Cohort, consisting of participants in a 21-year prospective study of US military service members, and to assess data sources used to ascertain mortality.MethodsA population-based random sample (n = 256,400) of all US military service members on service rosters as of October 1, 2000, was selected for study recruitment. Among this original sample, 214,388 had valid mailing addresses, were not in the pilot study, and comprised the group referred to in this study as the invited sample. Panel 1 participants were enrolled from 2001 to 2003, represented all armed service branches, and included active-duty, Reserve, and National Guard members. Crude death rates, as well as age- and sex-adjusted overall and age-adjusted, category-specific death rates were calculated and compared for participants (n = 77,047) and non-participants (n = 137,341) based on data from the Social Security Administration Death Master File, Department of Veterans Affairs (VA) files, and the Department of Defense Medical Mortality Registry, 2001-2006. Numbers of deaths identified by these three data sources, as well as the National Death Index, were compared for 2001-2004.ResultsThere were 341 deaths among the participants for a crude death rate of 80.7 per 100,000 person-years (95% confidence interval [CI]: 72.2,89.3) compared to 820 deaths and a crude death rate of 113.2 per 100,000 person-years (95% CI: 105.4, 120.9) for non-participants. Age-adjusted, category-specific death rates highlighted consistently higher rates among study non-participants. Although there were advantages and disadvantages for each data source, the VA mortality files identified the largest number of deaths (97%).ConclusionsThe difference in crude and adjusted death rates between Panel 1 participants and non-participants may reflect healthier segments of the military having the opportunity and choosing to participate. In our study population, mortality information was best captured using multiple data sources.

Drowning Deaths of U.S. Service Personnel Associated with Motor Vehicle Accidents Occurring in Operation Iraqi Freedom and Operation Enduring Freedom, 2003-2005

OBJECTIVE We examined common factors in vehicular drowning deaths that might lead to changes in equipment or training. METHODS Drowning deaths among service members deployed to Operations Iraqi Freedom or Enduring Freedom, 2003 to 2005, were ascertained using the Armed Forces Medical Examiner Tracking System database. Cases were linked to Army and Navy safety and investigative files. RESULTS Fifty-two cases of vehicular drowning deaths were identified. These occurred mostly at night, were almost always the result of a rollover, and were most frequently associated with a high-mobility medium-weight vehicle. Seat belts were rarely worn, but the majority of injuries should not have been severe enough to affect egress from the vehicle. These drowning deaths seldom occurred while engaged with the enemy and were rarely associated with bad road conditions or bad weather. CONCLUSIONS Effective preventive strategies might focus on training and equipment to reduce rollover events and on the expeditious extrication of victims.