10 MINUTES CAN SAVE YOUR LIFE
In 1997, National Fire Protection Association 1582, Standard on Comprehensive Occupational Medical Program for Fire Departments, recommended biennial exercise (treadmill) stress testing (EST) for all active firefighters over age 40.1 Since then, however, there has been no stampede of our aging brothers and sisters to be tested. Some departments adopted this standard; many have not.
Like our firefighters in question, EST has been around more than 40 years. It is a safe diagnostic method for detecting coronary artery disease (the number one killer of working firefighters). Treadmill testing was validated as a predictor for lethal coronary events more than 20 years ago in patients with no prior cardiac symptoms.2
The subject walks on a moving treadmill for three minutes in three progressive stages, with speed and incline increasing at each stage. His ECG (ECG and EKG are interchangeable, meaning 12-lead standard electrocardiograms), blood pressure, and pulse are continuously monitored for abnormalities. The actual “walk” takes about 10 minutes, but baseline (before) and cool-down (after) monitoring are essential for complete evaluation. The test takes at least 30 minutes to complete in most stress labs. The standard speed stages are 1.7, 2.5, and 3.4 miles per hour. The common grades are 10-, 12-, and 14-percent elevation.
Important findings are chest pain, cardiac rhythm changes, destabilized vital signs, or abnormal ECG rhythms during or immediately after the test. Test-induced pain or ECG changes are significant regardless of whether the patient was symptom-free or had a cardiac history before the test. Since these tests are performed on a standard protocol representing 40 years of validation and hundreds of thousands of patients, positive findings are credible and should not be ignored.
WILDLAND PACK TESTS
In June 2004, two firefighters died of cardiac arrest during or after their annual pack tests for wildland certification. The test involves exercise while carrying a loaded backpack. Witnesses say they were experienced firefighters in good physical shape. Their deaths brought the pack test death toll to nearly a dozen since this program began. One of this year’s victims had completed the limited test (no pack, one mile in 16 minutes or less). This level demands a one-mile walk on level ground at four miles per hour. Cardiologists compare such exertion to the middle stage of the stress test protocol (3 minutes on a 12-percent grade at 2.5 mph). The other victim was midway through the arduous level test (3 miles carrying a 45-pound pack in 45 minutes). This is still four miles per hour carrying 45 pounds. After the firefighter collapsed, he did not respond to resuscitative efforts. He had completed a health-risk screening questionnaire before taking the test.3
Pack tests don’t use cardiac surveillance; many fire departments deploy EMS standbys during any exercise-testing evolutions. There are few specific standards demanding advanced life support (ALS) standby crews during pack tests or other required local, regional, and state performance standard tests.
Medical standards dictate that a physician supervise the exercise during all stress tests. Oxygen, defibrillators, and resuscitation gear are immediately available. The subject is constantly monitored. Yet, unsuspecting firefighters turn out in droves at local high school tracks or city parks with flat terrain to do their pack tests. They don’t admit to or realize the similarity of cardiac risks involved. There is sad irony that the voluntary standard (NFPA 1582) and the pack test standard have each been on the books for about the same duration, six years.
Screening questionnaires alone are ineffective to assess cardiac risks. In our country, after 30 years of advanced EMS, only half of our civilian heart attack victims will call 911 for help. Initial ECGs show heart attack changes only about half the time. About half of our victims of angina or heart attack will admit only to indigestion, discomfort, aching jaw, or “heartburn” if they survive to give their medical history. They will still deny chest pain.
“Anginal denial” seems kind of a “Spirit of America” thing. A medical colleague showed up one night with a file folder full of old ECGs he had done over 16 months, each time he had chest discomfort. None were diagnostic of myocardial infarction, but none were completely normal. After recovery from his quadruple bypass, he went back in service. Another colleague got chest pains but interpreted his own ECG as nonspecific. He completed his weekend on-call duties and then came to the emergency room for a checkup. Within six hours he’d had a helicopter ride and an angiogram and received a vascular stent to open his coronary artery occlusion. Three days later, he was in his office seeing patients. Physicians are just as clever as firefighters at evading their own cardiac symptoms. In addition, at least half of our colleagues’ fatalities never had warning signs. That means no symptoms. There is no history to disclose on a questionnaire.
One brother was persuasive. He convinced his family, his coworkers, his personal physician, and his fire chief he was fit for duty after failing two exercise stress tests. His physician even wrote a note to his chief stating he was fit for duty. He could not be resuscitated from cardiac arrest his first day back on the job.
The down side for EST is a consistent history of producing false positive results for males (11 percent) and false positive tests in females (19 percent). This means about one out of five female firefighters and one out of 10 male firefighters may experience symptoms or ECG changes during the stress test that are never followed up by further studies proving cardiac pathology. Further workup is necessary, but this is frightening and expensive. This disadvantage must be weighed against a consistent fact: that for more than two decades, half of the hundreds of firefighters who suffered cardiac arrest had no warning sign of their risk of sudden cardiac death.
Cost is another consideration. This factor involves lots of geographic medical economics. In one neighborhood, a resting 12-lead ECG is billed at approximately $60, and a stress test performed in a private office by a qualified, experienced physician is billed at $200 (remember that, by definition, an exercise stress test incorporates a resting ECG). For a healthy, symptom-free firefighter, a normal “resting” ECG gives no hint or prediction of sudden death risk. In fact, such a normal resting ECG only confirms you are alive.
At least two western career departments will hire no new firefighters who haven’t passed an EST before reporting for training. Another career department has outfitted a red van as an exercise lab; it travels from station to station in the district, periodically testing its firefighters for cardiovascular fitness.
PUMP TEST METAPHOR
Exercise tests for individual firefighters are comparable to the annual engine pump tests performed on apparatus for the past 90 years. “The apparatus shall be subjected to a 10-minute overload test to demonstrate its ability to develop 10 percent excess power ….”4 An engine that fails its pump test is simply removed from service until the problems are fixed. Clearly, firefighters with valid EST abnormalities need to be out of service until further diagnosed or repaired.
Will Rogers observed, “You can’t legislate common sense.” In Tampa, Florida, earlier this year, The Firefighter Life Safety Sum-mit, sponsored by the National Fallen Firefighters Foundation and the United States Fire Administration, laid down a few no-nonsense objectives to reduce firefighter mortality. Of these objectives, “culture change” may be the most important concept to reduce cardiac fatalities.
Exercise stress tests can’t prevent all risks of sudden cardiac death. Neither will thermal imaging prevent all future building collapses. Individual firefighters and the collective fire service leaders must examine the realistic value of requiring exercise cardiac stress tests for all active firefighters. ■
References
1. NFPA 1582, Standard on Comprehensive Occupa-tional Medical Program for Fire Departments. Quincy, MA: National Fire Protection Association, 2000.
2. Giagnoni, E., et al. “Prognostic value of exercise EKG testing in asymptomatic normotensive subjects etc.,” N Engl J Med, 309:1085-1089, Nov. 3 1983.
3. Milstein M. “Man Who Led Crews Fighting Wildfires Dies During Fitness Test,” The Oregonian, June 9, 2004, C4.
4. NFPA 1901, Standard for Automotive Fire Apparatus, 11-2.2.2 (Pump Certification Test) from Isman, Warren E., Fire Service Pump Operator’s Handbook, (Fire Engineering, 1984), 236.
■ WILLIAM A. BOEHM, M.D., is a captain with the Dungan Volunteer Fire Department in Otero County, New Mexico, where he serves as a training officer and safety officer. He is a certified firefighter I and certified wildland firefighter. He has taught cardiac life support to firefighters and emergency personnel for more than 25 years. As firefighter, training officer, and EMS director, he helped initiate New Mexico’s earliest automated defibrillator deployments among volunteer fire departments.
 |
Notice how an ECG can change from normal on the left to ischemic (insufficient blood supply) on the right during strenuous exercise, with no symptoms of coronary artery disease. Necessary blood is just not reaching the cardiac muscle. The engine is overworked and running on lean. Changes commonly revert to normal as the patient rests after the test. These tracings explain the value of exercise stress testing for firefighters doing their job. These electro-physiological changes may be silently occurring during any pack test, hose carry, victim drag, or routine job essential to American fire services.
Adapted from Tavel ME, “Stress testing in cardiac evaluation: Current concepts with emphasis on the EKG review “Chest 2001:119;107.
