Physiological Status Monitoring for Firefighters
Director of Business Development, Globe Manufacturing Company
Photo Globe Manufacturing Company
Over the past decade, the number of firefighter on-duty deaths has remained persistently high (about 100) despite significant improvements in Personal Protective Equipment. Providing better gear, although critically important, has had the unintended consequence of allowing firefighters to go in deeper and for longer periods of time which exposes them to even more risk.
To reduce firefighter fatalities, we have to look at the causes of on-duty deaths. The single largest cause resulting in nearly half (45%) of all deaths according to the U.S. Fire Administration is stress and overexertion. Physiological Status Monitoring (PSM) holds out the promise of identifying when a firefighter is in high risk physiological stress before he becomes a fatality.
Firefighters face a unique set of risk factors that are all associated with stress and overexertion. Among these as cited by a study conducted by the Orange County Fire Authority are:
• Sudden nervous system surges caused by unexpected alarms
• Rapid shifts from low to high levels of exertion
• Carrying, lifting, and wearing heavy protective gear and equipment
• Prolonged exposure to high temperatures
• Excessive fluid loss
And in firefighting, all of these risk factors are often present together.
When you break down the risk to a firefighter of a fatal cardiovascular event by activity according to the New England Journal of Medicine , you can readily see a pattern:
• 32% during fire suppression
• 17% returning from an alarm
• 13% responding to an alarm
• 9% non-fire emergencies
• 13% physical training
• 15% non-emergency duties
Although responding, engaging, and returning from an emergency takes a relatively small portion of the total time a firefighter is on duty, it makes up over two-thirds of all on-duty fatalities.
When you factor in the time spent in each activity, the odds of a fatal on-duty cardiac event is 10 to 100 times greater during fire suppression than non-emergency duty, 2 times greater than for police officers, and 3 times greater overall than all workers . It’s no wonder that the International Association of Fire Fighters, the International Association of Fire Chiefs, and the National Volunteer Fire Council are all strong advocates for health, wellness, and fitness programs for firefighters.
In addition, The National Fire Service Research Agenda Symposium identified several aspects of firefighter health, wellness, and fitness issues that need the highest priority for further research and action including candidate selection and assessment, health maintenance, identifying risk factors for cardiovascular disease, physiological effects of heat stress and incident response, and functional capacity evaluation. Physiological Status Monitoring is a tool that can be utilized in all of these areas.
Clearly, the fire service has recognized the problem and is aggressively looking for solutions.
An Innovative New Technology
Most active people today are aware of heart rate monitors that are used by runners and for fitness workouts. The object is to monitor your heart rate allowing you to spend as much time as possible in a heart rate “zone” which is typically a percentage of your maximum predicted heart rate based on age. These normally strap-based systems communicate through short-range signals to a watch-like device to monitor your workout.
These systems are a rudimentary version of Physiological Status Monitoring, but they aren’t sufficient to meet the needs of the fire service.
A new and more technically advanced PSM system is now being developed by a team led by Globe and Foster-Miller for use by the military and the fire service. It embeds a built in sensor system into a moisture wicking and fire resistant T-shirt that would be worn in place of the current, cotton T-shirts that are worn today by almost every firefighter. These sensors measure heart rate, respiration rate, skin temperature, activity level, and posture. This data is collected and transmitted in real-time as packets of information out to a tiny receiver plugged into a laptop computer. If the system detects a potentially dangerous condition, it can alert the individual and the incident commander to pay attention before it’s too late. And it can record this data for post-activity analysis if the need arises.
So how might such a Physiological Monitoring System be used in the fire service?
At one level, it could be used by firefighters as part of an individually tailored fitness workout program. An easy to use graphical user interface would show how you are doing and the data could be logged to see how you are progressing toward your fitness goals, and provide training history and analysis. And for any fitness program, seeing progress is motivational.
Another useful opportunity for a Physiological Monitoring System would be for use in Academy Training. Providing real-time monitoring of each member of the team and a visual and audible alert to situations requiring attention could provide a critical early warning of potentially dangerous levels of stress and overexertion. By quantifying in a training environment just what the members of the team were experiencing during the session, individuals would have a better awareness of the importance of conditioning. And as the need for training increases, the fire service can’t afford to lose anyone in training.
HazMat operations and training are also well suited for Physiological Status Monitoring. An encapsulated Level A suit is one of the most difficult protective ensembles in which to work, as the heat and moisture build up puts more strain on your body. Feedback from HazMat personnel during PSM system testing has told us that it is reassuring to know that someone is looking out for you and your buddy, allowing you to focus on the job and hand. And current metrics for the amount of safe working time in HazMat operations is based on estimates of temperature, workload, and exposure. Monitoring the actual workload and vital signs may let personnel stay in longer to finish a job or warn you to come out sooner.
Of course, Physiological Status Monitoring holds out the promise to reduce fatalities on the fire ground. During operations, the system can remotely alert the incident commander to situations that require attention. It can serve as an electronic back up to the current PASS devise. And it can provide immediate vital data for Rehab.
So how do we know that the PSM system works? The first step is to compare the data in a laboratory setting between the data collected and transmitted by the T-Shirt and a “Gold Standard” medical Capnograph during a workout session both with full firefighting gear and without. This testing revealed an excellent correlation between the two sets of data (over 90%) for both respiration rate and heart rate. Plotting these data point revealed that the T-Shirt data was likely to be even more accurate than the capnograph accounting for most observable differential.
Then it is on to preliminary field testing. Field trials have already been conducted during training exercises with the US Army Special Ops and HazMat Ops and with the Santa Ana Fire Department for Level A HazMat Ops. These trials validated wearability as a base layer under issued gear and functionality of sensors, signal, and programming.
In the near future, plans are in place to conduct more extensive operations field trials in the fire service for use in everyday firefighting duty with Oxnard (CA) Fire Department and Boston (MA) Fire Department. And many Fire Departments across North America have volunteered to conduct Beta Testing of these systems as we move forward.
Research is now focusing on using PSM in even more ways. In one project, Worcester Polytechnic Institute (WPI), Foster-Miller, Globe, and the Worcester (MA) Fire Department are working to integrate firefighter location with Physiological Status Monitoring. The goal of this decidedly futuristic concept is to wirelessly locate, track, and monitor individual crew members throughout multi-story structures in real time using a laptop with an intuitive graphical interface. It’s an ambitious project, but it is already demonstrating exciting potential in firefighter location and validating the ability of using the PSM system as the platform for additional functionality as these technologies become commercially available.
Another soon to be launched research project is looking at the physiological status of firefighters while on duty, studying the relationship of this status to the user’s fitness level, and using this data to set appropriate physiological parameters for firefighters.
Are You Ready?
As with most new technology, the question that is often asked is whether the fire service is ready to adopt it. A survey taken during the IAFF Redmond Symposium in 2007 revealed that more than 85% of this Health and Safety audience was willing or very willing to wear a T-Shirt incorporating PSM . A similar survey conducted at the FDIC 2008 conference showed that over 90% of this broader spectrum fire service audience was willing or very willing to wear a T-Shirt incorporating PSM .
We are at the cusp of understanding the root cause of firefighter on-duty deaths due to stress and overexertion. We have a working new technology, Physiological Status Monitoring, which holds out the promise of providing a warning before it’s too late. This technology can be deployed as easily as replacing a common T-Shirt with a technically advanced T-Shirt that incorporates unobtrusive sensors and a miniaturized transmitter. The system including the T-Shirt, sensors, transmitter, signal, receiver, and programming is being developed to work in military and firefighting applications. Research and testing is ongoing to provide important data about the physiological status of firefighters performing the range of actual fire service duties. And the fire service is willing to wear it.
No one expects that deploying this new technology will prevent all on-duty firefighter fatalities or disabilities due to stress and overexertion, but think of how important it would be to the affected individuals, their families, and their departments to identify even a few before it was too late.
Mark Mordecai has been at the forefront of performance apparel development spanning a wide range of specialty markets including Outdoor, Marine, Team Sports, Fitness, Law Enforcement, and Fire/Rescue.
He is currently Director of Business Development for Globe Manufacturing Company where he is responsible for driving Product Development and Marketing. Globe is the oldest and largest manufacturer of NFPA certified firefighter suits in the world and produces a range of premium performance personal protective equipment for fire, rescue, emergency medical and other first responders.
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