A recent San Marino emergency response illustrates the value of starting heatstroke treatment before a patient reaches the hospital. Firefighters found a man unconscious in his car with a body temperature just under 106 degrees, placed him in a large plastic bag and cooled him with ice. His temperature had fallen to 99 degrees by the time he arrived at the hospital, where he was awake.
During a Thursday demonstration, firefighters showed how the department's field protocol works: Crews place a patient in a heavy-duty plastic bag and add ice over the torso while keeping the head elevated, according to KABC Television. The San Marino Fire Department keeps the treatment bags in paramedic vehicles and prepares coolers of ice during morning equipment checks, firefighter Andres Serrano said. Crews use the setup when extreme heat makes rapid cooling necessary.
Why Speed Matters in the First Half-Hour
The urgency behind the method is rooted in hard numbers. Classic non-exertional heatstroke can be fatal, and rapid cooling is important, according to StatPearls. Heatstroke can cause neurologic and organ complications. That same research notes mortality rates drop significantly when core temperature is brought below 102°F within 30 minutes — a critical early-treatment window for emergency responders.
Cold water immersion is considered the medical gold standard for treating severe heatstroke because it cools core body temperature three to five times faster than traditional methods like ice packs or fanning, per the American Heart Association and National Athletic Trainers' Association standards cited by iatroX. Extreme heat can cause deadly illness in the United States, the same source notes.
What local heat data can show
According to the Los Angeles County Department of Public Health, its heat dashboard tracks emergency-department visits for heat-related illness across the county from 2023 through 2026. The dashboard provides a way to monitor how visits change during periods of extreme heat, although the available context here does not specify a countywide total. The department identifies older adults, outdoor workers and people with chronic conditions or disabilities among the groups at higher risk of heat-related illness and death. Those risk categories help explain why rapid recognition and cooling matter beyond the individual emergency described in San Marino.
A Technique Born on Ambulance Stretchers
The body-bag immersion method itself isn't new to emergency medicine. Peer-reviewed research in JACEP Open described a single emergency-department case involving body-bag cold-water immersion and called it the first documented report of the technique, according to research indexed on PubMed. The setup allows paramedics to keep a patient's head elevated while surrounding the body with ice water, sidestepping the need for a hospital's dedicated cooling equipment.
Cold-water immersion is one option for rapidly cooling heatstroke patients. A commonly cited target is a core temperature below 102°F.
San Marino's Older Population Raises the Stakes
Older residents may be especially susceptible to classic non-exertional heatstroke during regional heat waves. Elderly residents often suffer from impaired thermoregulation, making them more susceptible to classic non-exertional heatstroke during regional heat waves, as reported by National Centre for Disease Control, Government of India.
The San Marino Fire Department responds to emergency scenes in the area. That local response is where crews can use the ice-bag protocol when needed.
San Marino Joins a Growing National Trend
San Marino isn't the first department to embrace ice-bag cooling in the field. Hoodline previously reported on a Camelback hiker's heatstroke fight after the Phoenix Fire Department became one of the first major urban EMS providers in the nation to equip all frontline emergency response vehicles with specialized ice bags, a move made systemwide following extreme desert heatwaves in 2024. A 2026 study published in Prehospital Emergency Care analyzed 183 heatstroke patients treated by firefighters using field ice-bag cooling and found significant core body temperature reductions, improved neurological recovery, and higher survival rates in cases evaluated among Phoenix Fire Department paramedics.
Some emergency medicine research has examined field cooling methods. Whether those methods or ice-bag immersion, the underlying goal is the same one San Marino firefighters demonstrated this week: getting a patient's core temperature down before organ damage sets in.
The San Marino response illustrates the department's effort to begin cooling at the scene, before a patient reaches hospital-based equipment. The recent case shows how that approach can be used during a life-threatening heat emergency.
