Technique known as cold-water immersion adopted by Phoenix hospitals after county saw 645 heat-related deaths last year

The season’s first heatwave is already baking the south-west with triple-digit temperatures as firefighters in Phoenix – America’s hottest big city – employ new tactics in hopes of saving more lives in a county that saw 645 heat-related deaths last year.

Starting this season, the Phoenix fire department is immersing heatstroke victims in ice on the way to area hospitals. The medical technique, known as cold-water immersion, is familiar to marathon runners and military service members and has also recently been adopted by Phoenix hospitals as a go-to protocol, according to fire captain John Prato.