As America comes to grips with hotter summer temperatures that already are seizing the nation’s Southwest, emergency medical responders in some areas are carrying new gear to treat heat victims: giant plastic bags to immerse people in ice water.
The tactic involves placing patients suffering from heat-related illnesses in zippered bags that engulf the body, then packing them with ice cubes and water, until they cool to safe levels.
It’s a technique that has been used for years to cool overheated soldiers or athletes facing heat stroke. Now the bags are being routinely deployed in some emergency rooms and on ambulance calls.
In Phoenix, where record-breaking temperatures last year killed 645 people, fire trucks and ambulances have been equipped with specially designed “immersion bags,” said Phoenix Fire Captain Todd Keller. Emergency responders fill the bags with water and ice at fire stations before heading out on heat-related calls, he said.
“Sometimes, when they get to the hospital, the ice is completely melted, the patient is so hot,” Mr. Keller said.
Patients typically stay inside 15 to 20 minutes or so, until their body temperature is reduced to about 101 degrees Fahrenheit. A pilot program using the therapy in Phoenix last summer proved successful enough that fire officials decided to deploy it across the entire department.
Last summer, Phoenix broke records with 31 straight days of the temperature reaching or exceeding 110 degrees Fahrenheit. Medical workers say it doesn’t take long to overheat in extremely hot weather, or even in temperatures that aren’t excessive if someone isn’t adapted to the heat.
Studies showing the efficacy of cold water immersion were carried out by the military in the 1990s. Yet there has been widespread fear that immersion could cool a body too quickly and provoke a stroke or heart attack. Instead, emergency responders were often advised to mist patients with water and to fan their bodies to cool them. More recent guidance has taught responders to put ice or cold water on a patient’s major arteries in the groin, neck and other areas.
But cold water immersion can bring down body temperatures eight times faster, with little risk of triggering other issues, particularly if body temperature is monitored closely with a rectal thermometer, said Douglas Casa, who studies heat-related illnesses and is the chief executive of the Korey Stringer Institute at the University of Connecticut.
The longer a person’s body temperature is elevated, the more likely the patient will face organ damage or other issues. (Using wet towels to cover as much of an overheated person’s skin as possible is a good alternative to immersing them in cold water, some researchers said.)
Until recently, cold water immersion hasn’t gained widespread adoption outside of ice tubs and dunk tanks that can be spotted in locker rooms. At foot races, sometimes kiddie wading pools are filled with ice water to cool off participants suffering from the heat. “It’s a shame this method has taken so long to permeate,” Dr. Casa said.
The fire department in San Antonio, Texas, last year started carrying ice, water and body bags to fire scenes to treat overheated firefighters, after working with researchers at nearby Brooke Army Medical Center and the University of Texas at San Antonio who were persuaded by the effectiveness of cold water immersion. “It’s not something we use often, but it’s a tool in the toolbox,” said Joe Arrington, a fire department spokesman there.
Fire departments elsewhere have also used the technique in the line of duty.
In Phoenix, the current heat wave could be a test for cold water immersion and other new tactics that the city is rolling out to avoid the same kind of grim outcome as last summer.
More cooling centers are open longer to help address rising overnight temperatures, and two of the centers will be open all day and night, said Melissa Guardaro, an assistant research professor in Arizona State University’s School of Sustainability who helps lead the state’s Heat Preparedness and Resilience Workgroup. More signs have been placed across the city to help make sure residents know about the centers.
“There’s no silver bullet,” said Ms. Guardaro. “But we learned an awful lot last year.”
Jerry Snow became convinced of the efficacy of cold water immersion after working in the city for seven years and watching people suffering from heat illnesses enter Banner-University Medical Center in Phoenix. “It is a safe therapy and it does improve outcomes in patients,” said Dr. Snow, an emergency department physician and medical toxicologist.
He considers Phoenix to be the nation’s epicenter of heat-related health issues. “Almost all heat-related deaths in the country occur in Arizona,” Dr. Snow said. “We really should be ground zero for treating these cases.”
Last summer as temperatures soared, he began visiting fire stations to train emergency medical workers in cold water immersion therapy. He plans to study the outcomes of the fire department’s use of the technique and said he will closely monitor future studies of cold water immersion.
Dr. Snow knows some patients may be too overheated for far too long to be helped by the method. But he said he was persuaded by results he’s seen so far.
“I’ve seen unresponsive patients, who are not responding to pain or to shaking them, but you start to cool them and in that 10-minute transport to the hospital you can already see dramatic improvement,” he said.
Last summer, responders employed cold water immersion using what they had: a tarp. They would pinch the ends and fold it in a banana shape so they could fill it with ice water and wrap patients in an ice bath inside.
The new bags in use this year work much better, medical workers said.
Another hospital in Phoenix, Valleywise Health Medical Center, also uses the technique. Doctors initially tried using rectangular, inflatable devices that looked like pools to immerse patients. But water splashed out of them and created slippery, unsafe conditions, said Dr. Geoffrey Comp, an emergency medicine doctor at Valleywise Health Medical Center. .
Now, the emergency department uses body bags, which are readily in stock at the hospital. The department’s freezers are filled with ice from the hospital cafeteria ice maker. For emergency responders, he said, body bags are also practical because space is tight in ambulances.
“There’s a stigma against term of body bag, but it’s a liquid-impermeable lightweight, cheap container we can use to put a patient in, and add cold water and ice,” he said.
Most heat patients who arrive at Valleywise have other health issues, Dr. Comp said, including people who are homeless or have addiction issues. He estimated that at least half the patients suffering from heat also have significant burns from skin contact with asphalt, which can get extremely hot in the sun. Last summer, he said, he treated a patient who had tumbled out of a wheelchair and suffered burns from falling to the ground.