Following the issue of Department of Homeland Security Presidential Directive No. 8, the term “first responder” has been redefined to include emergency personnel ranging from hospital-based providers to the more traditional firefighters.

The breadth of emergency responders on scene may now include public health, EMS, law enforcement and other non-traditional hot-zone workers. The fire service and hazmat teams are highly functional when scene management requires the use of personal protective equipment, but aside from the use of universal precautions for bodily fluids exposure, PPE isn't used routinely by these new hot-zone responders.

Whereas the fire service has a long-standing history of worker surveillance, health maintenance guidelines and injury prevention programs based on the risks of performing in hazardous environments, these new non-traditional users of PPE have been thrust into the fray with varying levels of protective gear, sporadic training, and near non-existent health screening and monitoring.

Although it's impractical to train and maintain all first responders to the level of hazmat technician certification, many of the same principles of scene monitoring must be maintained to ensure the safety of our emergency responders. Furthermore, rigorous screening and application of firefighter health maintenance standards, such as NFPA 1582, Comprehensive Occupational Medical Program for Fire Departments, and NFPA 1583, Health-Related Fitness Programs for Fire Fighters, must be adapted and applied to all responders who wear PPE.

NIOSH's firefighter fatality investigations provide a model surveillance service that may need to be replicated for all scene responders in PPE. Prior to committing the resources to perform these tasks, however, the differing needs, exposures, risks and injury patterns of the various first responders on scene need to be determined. It may be inappropriate at this time to simply apply the exhaustive firefighter literature to EMS personnel, or the military literature of PPE usage in soldiers, to the less-fit civilian population with higher risks for in-suit complications related to cardiovascular, pulmonary, and other heat-related illnesses.

Morbidity and mortality

The detrimental health effects of performing emergency response tasks while in PPE fall mainly within the three broad categories of cardiovascular stress, pulmonary compromise and environmental/exposure-related illness.

Preplanning and appropriate health screening of first responders tasked to perform in PPE will help to decrease the morbidity and mortality related to cardiovascular and pulmonary embarrassment, but little can be done to control the overall environment and climate in which a hazmat response is needed. Because of this, clinical signs of heat-related emergencies ranging from heat exhaustion and dehydration to heat stroke must be actively monitored during PPE use. Injury prevention and other environmental issues also can be mitigated before or identified during an event by training to and maintaining a high level of physical fitness.

In 2003, 45% of firefighter fatalities and 32% of injuries were attributed to overexertion or stress incurred in the line of duty. Strenuous activity, environmental heat sources, and use of PPE preventing heat loss to the environment all compound the thermal and cardiovascular stresses on the body.

Physiologically, the body responds to heat stress in several ways, including increasing oxygen consumption to maximum aerobic capacity (VO₂max) and increasing the loss of fluids through sweat. When primary cooling mechanisms, such as the evaporative heat loss that occurs with sweating, are hampered by PPE, core temperatures can increase to levels that can cause heat stroke and cardiovascular collapse.

The physical characteristics of PPE limit evaporative heat losses and increase the rate of heat storage. In addition, significant increases in core temperature will reduce work capacity, stamina, functioning and efficiency and can lead to individual morbidity and mortality. This also can affect others who are dependent on that individual on scene. These heat-related effects are well-known in traditional PPE users such as firefighters and hazmat providers, but they have not been well-described in non-traditional hot-zone responders, such as EMS workers.

Other disciplines

With recent acts of terrorism, there has been a strong push in educating health care providers on the early detection and treatment of biological and chemical disease states. One of the mainstays in this education is the prevention of cross-contamination of health care providers or other unaffected individuals. This prevention focuses on decontamination of the affected individual as well as protection of the health care provider with various levels of PPE.

Level C PPE includes a chemical-impermeable suit and a chemical-resistant hood with an air-filtration device; the suit is worn in such a way that the wearer will have a significant barrier to most contaminating materials. Unfortunately, this Level C PPE also has been subjectively reported to be quite physiologically taxing for the wearer. The firefighter literature is robust with documentation of the detrimental effects of combining job-related activities with heat exposure.

These trained professionals are not naïve to the use of PPE while performing fire control measures in the line of duty, but most EMS and hospital-based health care workers are “casual” users of this type of equipment and may be at greater risk for in-suit complications and heat injury due to lack of training and experience. Identification of EMS and emergency department workers at risk for heat-related illnesses is the initial step toward diagnosis. This requires an initial assessment of health care workers to determine if they're fit by certain professional and industry standards.

Many hazmat incidents also are crime scenes requiring police presence for the safety of both the responders and the public. For example, the city of Pittsburgh conducted a disaster drill in May in conjunction with DHS. In this drill, a terrorist attack was simulated at PNC Park, Pittsburgh's professional baseball stadium. More than 5,000 simulated victims were present, and 1,000 of these “victims” required decontamination and transportation to local hospitals. Weather conditions were humid, with an ambient temperature ranging from 64° to 69° F.

The officers from the Pittsburgh Bureau of Police Rapid Emergency Deployment team participated in the drill. This team of 24 police officers had been trained in the use of PPE and WMD response. During the drill they provided scene security and apprehended suspects in the decontamination line of the incident. All team members were medically screened at the beginning of the drill, and their baseline vital signs and weight were recorded prior to donning PPE.

Nine officers donned level C PPE (Tyvek coverall and air-purifying respirator) and were sealed with chemical-resistant tape according to local procedures. These officers also wore sidearms and portable radios. Two additional officers donned Tyvek coveralls and SCBA. These officers were designated as a rapid-intervention team in the event an officer in the decontamination line suffered an emergency and had to be assisted from the scene.

Officers entered the scene in two teams. The first team remained on scene in Level C PPE for 40 minutes while the second team made a 25-minute entry. After exiting the scene, the officers doffed their PPE and had their vital signs and weight reassessed. Even though these highly trained and physically fit officers performed tasks requiring minimal effort (decontamination security), marked tachycardia and weight loss were noted when the PPE was removed. The post-entry assessment revealed an increase heart rate of 18.7 ± 11.3 beats per minute and an average weight loss of 0.8 ± 1.2 kilograms. These field data indicate cardiovascular and thermal stress may occur while wearing PPE, even when working at low intensities.

This level of monitoring was not available for all non-hazmat responders during the drill, as EMS and other non-hazmat personnel are rarely medically screened and monitored for changes during a response to a contaminated scene. Just-in-time training can provide adequate instruction to provide the knowledge and the skills needed to perform tasks wearing PPE; however, health-related contraindications are poorly documented or not identified in individuals tasked to wear PPE on the spot.

Health screening

Strict NFPA and OSHA guidelines exist to limit the negative health consequences that can occur when individuals with known medical conditions must don PPE for emergency response. Certain conditions, even with strict control, are contraindications to performing any duties while wearing PPE. Other known medical conditions limit full, unrestricted activity in PPE, while some medical conditions, if under control or treatment, do not limit activity in PPE.

The following list can help to delineate the basic on-scene testing for no-go findings for casual or naïve PPE providers on scene.

1. History and physical examination:

   • Chronic vertigo or impaired balance as demonstrated by the inability to tandem gait walk
   • Lungs, for active tuberculosis
   • Cardiovascular, for coronary artery disease, including history of recent myocardial infarction, recent coronary artery bypass surgery or recent coronary angioplasty.
   • Renal, for renal failure or insufficiency requiring continuous ambulatory peritoneal dialysis or hemodialysis
   • Anticoagulation medications, such as Coumadin or Enoxaparin
   • Neurological, for seizure disorder
   • Endocrine, for poorly controlled insulin-dependent diabetes
   • Other, including claustrophobia or morbid obesity, defined by a Body Mass Index higher than 30

2. Vital signs: temperature, pulse rate, respiratory rate and blood pressure:

   • Severe uncontrolled hypertension, defined as systolic pressure >180 mm Hg, diastolic pressure >100 mm Hg

3. Pulse oximetry:

   • Hypoxemia, oxygen saturation < 90% at rest or exercise desaturation to < 90%

4. Peek expiratory flow:

   • Identification of reactive airway disease sub-clinical exacerbation

5. Weight:

   • Hydration determination before and after PPE usage

Other scene-related monitoring includes following established firefighting polices and procedures, implementing an adequate respirator maintenance program, establishing firefighter accountability on scene, and using personal alert safety system devices.

Technology and treatment

Gadgets, high-tech fibers and other equipment are available to protect first responders from heat-related injury. These come secondary to health maintenance, as one study of individuals categorized as moderately fit (VO₂max < 50ml/kg/min) or highly fit (VO₂max > 55ml/kg/min) reported that highly fit individuals performing light exercise during uncompensable heat stress had a longer time to exhaustion than the moderately fit individuals.

Microclimate cooling has been investigated for firefighting and military applications and has been shown to reduce heat strain and extend work time. Liquid cooling systems have been reported to be effective and have the advantage of reduced logistical requirements. Skin cooling, however, is not a trivial or benign task. Direct skin cooling can result in peripheral vasoconstriction and reduce convective transfer of heat from the core. While a technique known as intermittent, regional microclimate cooling can attenuate this physiological response, these devices all represent additional weight to be carried during work and are uniformly expensive. The sheer number of emergency responders who would be working in PPE at a disaster makes stocking sufficient quantities of these devices impossible.

Rehydration should attenuate some of these ill effects by maintaining circulating volume and reducing the rate of heat storage during exercise. Maintenance of circulating volume should augment skin blood flow, enhancing the transfer of heat from the body's core to the periphery. Current guidelines suggest athletes exercising in a temperate environment should consume fluids at rates equal to sweat loss and in excess of sweat losses when exercising in a hot environment greater than 86°F. In one study of fit individuals working in military PPE in a hot environment, however, oral fluid replacement during exercise failed to alter the rate of heart storage or the core temperature during heavy (running at 4.8km/hr at a 4% grade) or light (walking at 3.5km/hr on a level grade) exercise. Additionally, oral fluid replacement did not extend time to exhaustion in the heavy exercise condition. Thus, further mechanisms to replace fluids or provide cooling are necessary.

Other pre-hospital cooling techniques include fully undressing the patient to allow for evaporative heat loss. A tepid water mist accompanied by a continuous flow of air over the patient is the most rapid and effective means to dissipate heat. Full-body submersion in ice-cold water is contraindicated due to the lack of clinical monitoring that can be maintained, and because the peripheral vasoconstriction caused by the superficial cooling may actually trap heat at the core, where it continues to cause metabolic and cellular derangements. Rapid intravenous administration of one liter of cooled normal saline at 4°C also has been shown to effectively reduce core temperature by 1°C in healthy volunteers. This may be the most efficient and readily available pre-hospital intervention to treat and potentially prevent severe forms of heat illness.

When a more severe manifestation on the spectrum of heat-related illness affects a first responder, it's unlikely that the responder will be able to self-extricate from the scene. As a result, the first responder must undergo non-ambulatory decontamination and extraction from the PPE prior to Advanced Life Support intervention. Due to technical barriers while performing medical procedures in PPE, such as peripheral intravenous access, and exposure risks to the patient prior to decontamination, very few ALS interventions are performed in the warm zone.

However, due to the length of time non-ambulatory decontamination can take to perform, it may be beneficial to the patient to obtain intravenous access to provide fluid resuscitation and cooling during or prior to the decontamination procedure if it can be done quickly and with minimal exposure risks to the patient. In this situation, intra-osseous access using the EZ-IO from VidaCare Corp. or Bone Injection Gun from Waismed to obtain peripheral intravenous access while the responder is still in PPE may be reasonable options.

Finally, individuals wearing PPE are essentially functioning within a closed circuit of heat exchange, and the chances of rapidly progressing through the stages of heat illness are quite high. Unless specific goal-directed questions are asked and brief physical exams are performed periodically, the early and easily treated initial stages of hyperthermia will be missed.

Mechanisms and devices to monitor multiple providers regarding vital signs and potential stress during a deployment are available commercially. These devices can monitor responders in PPE at a distance while maintaining a continuous flow of vital sign information to the command post to determine the physiological stresses that the responders are experiencing in real time. If these devices, such as the LifeShirt from VivoMetrics, are used routinely, they may help to reduce the short- and long-term effects of performing routine duties while wearing PPE.

Ongoing efforts

In an attempt to study the emergency responder population as a whole, the Center for Emergency Medicine in Pittsburgh has developed the Emergency Responder Human Performance Laboratory.

The ERHPL is dedicated to conducting research and assisting in developing guidelines that improve the occupational health and safety of emergency responders. Current studies and research include:

• Physiological responses of EMS personnel working in Level C PPE.
• Effects of inducing mild hypothermia via peripheral intravenous fluids on core body temperature.
• Ergonomically sensitive adjuncts to provide ALS while working in Level C PPE.
• Practical and expedited on-scene medical screening for hazmat responders.

These ongoing studies should gain further insight into the potential detrimental health effects of performing routine duties in PPE and the means to address them in the field.

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Joe Suyama, M.D., is a faculty member of the EMS and Special Emergency Medical Response Divisions of the University of Pittsburgh Department of Emergency Medicine. He formerly was a member of the National Disaster Medical System as a medical officer for KY-1 based in Florence, Ky.

David Hostler, Ph.D., is an assistant professor of emergency medicine at the University of Pittsburgh and the director of research for the Affiliated Emergency Medicine Residency. A firefighter/paramedic since 1987, he is a founding faculty member for the Emergency Responder Human Performance Lab at the Center for Emergency Medicine.

For More Info

Contact the Emergency Responder Human Performance Laboratory, Center for Emergency Medicine, 230 Mckee Place, Suite 400, Pittsburgh, PA 15315; www.emsresearch.org/, or contact Joe Suyama at 412-647-8540, e-mail: suyamaj@upmc.edu.