JOHN YANG: With no end in sight to the extreme heat gripping much of the nation, the sizzling temperatures can quickly become hazardous and in some cases, deadly.

Ali Rogin reports on how emergency rooms are dealing with the influx of patients with heat related issues.

ALI ROGIN: Sweltering temperatures continue to scorch parts of the U.S. with millions under heat alerts coast to coast.

In Phoenix, Arizona, the heat has reached 110 degrees for more than 20 consecutive days, inspiring some creative challenges on social media.

WOMAN: Only eating foods I cook outside in Arizona for a day.

MAN: Into the oven you go.

See you tonight.

5 hours later.

MAN: Wow.

They're real cookies.

Warm.

Out of the oven.

Out.

Cheers.

ALI ROGIN: But the record highs can be dangerous for anyone exposed to the heat for too long.

In the past week, there have been thousands of heat related emergency room visits across the country.

Dr. Aneesh Narang is an emergency medicine physician at Banner University Medical Center in Phoenix.

Dr. Nareng, thank you so much for joining us.

Tell me about what you're seeing from patients who come in because of heat related conditions.

DR. ANEESH NARANG, Banner University Medical Center: Yeah, thanks for having me.

So we're seeing quite a spectrum of heat related illnesses, as we normally do this time of the year, and it really exists in a continuum.

So we have some that have mild, I would say heat related illnesses such as dehydration, cramps, heat, rash, swelling.

And then, unfortunately, now we're seeing several cases of patients presenting with the most severe form of heat related illnesses, which is a heat stroke.

And unfortunately, we are seeing many patients every day with us.

ALI ROGIN: Is it more than you've seen in previous years since you've been doing this work or has it been about the same?

ANEESH NARANG: Yeah, I think we're still waiting for the sort official numbers to come in, but I think there's some indications that pre-hospital calls for heat related illnesses are definitely up compared to last year.

And I would certainly say over the last several years, we're seeing a lot more of this.

No question.

I think last year was marked in the numbers we saw.

Unfortunately, you know, 425 people in our community died of heat related illnesses.

And now we're seeing numbers I think, that are very similar, if not more, to this point.

And we still have a long way to go.

ALI ROGI: Walk us through how high temperatures affect the body.

I think we all know inherently that's the case, but I'm curious if you can take us through how it works.

ANEESH NARANG: Yeah, I think at the sort of microscopic level, it is damaging cells and it's inactivating proteins and harming DNA.

So things that we need to live to breathe, to function.

How that manifests for symptoms is varied, of course, but I would say heat exhaustion is the first clue that something is wrong.

With heat exhaustion, you start to feel lightheaded, dizzy.

You have headaches.

You may be vomiting, you may feel like you're going to pass out.

And if you don't get into a cool environment quickly, get undressed, cool down as fast as you can.

Then you're really risk of developing heat stroke.

And really what's happening here is our body's ability to thermoregulate is in haired.

We are no longer able to do that when you reach temperatures that high, and certainly there's a lot of factors into that.

Your ability to sweat, dilating your blood vessels, all those things help promote heat loss.

And now you can't do that when you get to such high temperatures, and you can't get help right away.

And then heat stroke is the most severe form, unfortunately, of heat related illness.

By that time patients are used, they may not be able to talk to you, they may have seizures.

So that is what we're seeing, unfortunately, right now, every day.

ALI ROGIN: And what are the methods you use to treat these various things?

I would imagine that by the time they're coming to the ER, it's not simply about cooling people down.

ANEESH NARANG: Yeah.

So, certainly rapid cooling, though, is a huge intervention for us in what we focus on.

But while we're doing that, we also have to support their breathing.

We got to replace any fluid losses, and we have to treat any complications that come along the way.

So patients who have heat stroke, usually that's above 104 degrees, we are rapidly cooling them.

There's many ways to do this.

I would say the most effective way that we can do in a hospital setting is really we call, like, ice immersion therapy.

We are putting them in a bag.

We are pouring ice with some water that can rapidly cool their temperature back to normal core temperatures within minutes.

If we don't do that quickly, there's a greater chance of short term mortality, long term effects on your organ than your brain.

So that is our focus.

There are many other ways to cool patients down.

Ice packs in the groin, the axilla, the neck fans, spring with lukewarm water just promote evaporative cooling.

But I would say the most effective and quickest way is ice immersion therapy.

ALI ROGIN: How do you think emergency rooms should adjust their protocols for these sorts of emergencies, given that they seem to be on the rise?

ANEESH NARANG: Yeah, I think the most important thing, and luckily in the valley, here in Phoenix, I think we're all very prepared for the summer season is you have to have protocols in place for this to be effective.

You have to have everything in sort of one drawer or one area in the emergency room that you know you can reach to with the appropriate monitoring, with the ice, with the appropriate bags and equipment.

And you have to have a protocol in place before hyperthermia season kicks in.

And your staff, it takes a total team effort to make this effective.

Everybody has to be on board and understand the steps we have to do.

If you have any delay in rapidly cooling these patients, any delay of 20 to 30 minutes or more, now we become now we're behind the eight ball, and now we're talking about severe long term effects as well, or they may not make it, unfortunately.

So, if we protocolize things and have everyone in our staff understanding how this works, we are, you know, set up for success.

ALI ROGIN: And these record temperatures are expected to last through the rest of the summer.

So how can people stay safe?

ANEESH NARANG: Well, I think we always advise patients.

I think it's important for us in the medical community and the public health community to continue to educate the public.

If you need to be outdoors, go early in the morning, four in the morning, five in the morning when temperatures aren't so hot anymore.

But if you can stay indoors, if you don't have an air conditioning unit, go to the mall, go to the free public Library.

As much as time as you can spend in an air conditioned indoor space, the better off you will be.

You need to start off the day drinking water.

If you enjoy your cup of coffee, have a glass of water with it.

You have to continue to maintain your hydration throughout the day.

Wear loose fitting clothes, apply sunscreen.

Do everything you can, though, to not be outside during the peak hours in the day when the temperatures are scorching.

ALI ROGIN: Dr. Aneesh Narang with Banner University Medical Center in Phoenix.

Thank you so much for your time.

ANEESH NARANG: Thank you.