A look at what first responders have to deal with as heat index reaches triple digits

North Texas is spending the first official day of summer under a heat advisory, with the heat index reaching temperatures of more than 105 degrees again.

From dispatchers to paramedics, MedStar is busy in the soaring temperatures blanketing the Metroplex.

MedStar crews responded to a lot of heat-related calls this week in Tarrant County, including a call about a child who was left in a hot car.

On Thursday, paramedics treated 21 patients for heat-related illnesses. Out of those, 15 were taken to the hospital, with two in critical condition.

The child in Tarrant County was rescued and did not need to be hospitalized. Another child in Aubrey wasn’t as fortunate and was unresponsive when airlifted to the hospital.

Any person outdoors in need of medical attention warrants response with lights and sirens, as MedStar has implemented its extreme weather response protocol.

FOX4 followed first responders as they were called out to heat-related calls on Friday.

One response took a crew to a woman who pulled over because she felt ill.

"She felt some dizziness, and rather than try to drive herself to the hospital, endangering herself and the public, she pulled over and called 911 so we could respond and help her," MedStar supervisor John Hamilton said.

The woman was treated in the ambulance and given steps to follow up with her physician.

First responders will continue to be on heightened alert to spot heat-related calls and respond to them quickly.

MedStar officials said heat exhaustion and heat stroke are common this time of year, but they can be prevented by drinking plenty of water and taking breaks if you are out in the sun.