Health Innovation Case Studies

Parking Lot Freeze to Surgical Ease: Prewarming Case

The fall in our body tempreture during surgery is a much bigger problem than most people realize. When a patient’s core body temperature drops during surgery, it can lead to serious complications. They might bleed more because their blood doesn’t clot properly, take longer to recover because their body heals slower, or even develop infections because their immune system isn’t working as well. And on top of all this, patients often wake up feeling cold, shivering, and very uncomfortable—especially if they’re older or frail.

The issue comes from how anesthesia affects the body. When patients are put to sleep, their body loses the ability to regulate its temperature. Anesthesia also causes blood vessels to widen, which pulls warm blood away from the core to the surface, where it cools quickly. Combine this with the cold environment of the operating room, and most patients end up hypothermic, with a core temperature below 36°C (96.8°F).

For years, hospitals have tried to solve this problem by warming patients during surgery. But by the time the warming starts, the patient is already hypothermic. It’s like trying to dry off after you’ve already been caught in the rain. I started wondering—what if we could stop hypothermia from happening in the first place?

Started with myself

I have been prewarming myself when I needed to walk in the Cleveland winter. The winters were harsh and I’m not a fan of heavy coats, so every morning, I would blast my car heater for few minutes before stepping out and able to walk only in scrubs from parking lot to hospital. The same concept was for patients. Instead of waiting for them to get cold during surgery, we could warm them up beforehand while they’re still in the pre-operative area. By raising their core body temperature ahead of time, they’d have a “heat reserve” to protect them during surgery. Even when exposed to anesthesia and the cold operating room, their temperature wouldn’t drop below normal.

Testing the Idea

To see if this idea could work, we ran a study at the Cleveland Clinic with patients undergoing outpatient surgeries. These are shorter procedures where hypothermia can be especially tricky to manage.

Here’s what we did:

• Group 1: Patients in this group were prewarmed before surgery using a device that blows warm air over their body.

• Group 2: This group followed the usual care and didn’t receive prewarming.

• What we measured: We tracked their core body temperature, comfort levels, and overall satisfaction during and after surgery.

What we found

The results were:

1. No Hypothermia: Patients who were prewarmed maintained a stable core body temperature throughout their surgery. They didn’t experience the dangerous temperature drops seen in the other group.

2. More Comfortable: Prewarmed patients woke up feeling warm and comfortable. They avoided the shivering and cold discomfort that’s so common after surgery, especially for older or frailer patients.

3. Faster Recovery: These patients recovered faster and were overall more satisfied with their experience compared to those who weren’t prewarmed.

Why it matters

In surgery, keeping a patient’s body temperature stable is crucial. When a patient’s core temperature drops below 36°C (96.8°F)—a condition known as hypothermia—it sets off a chain reaction of complications. For starters, the immune system slows down, making it harder for the body to fight infections. This means surgical wounds are more likely to become infected, leading to longer recovery times, additional treatments, and even serious health risks. At the same time, hypothermia affects the blood’s ability to clot, increasing the risk of excessive bleeding during surgery. This often requires blood transfusions, which add complexity and carry their own risks.

Recovery also slows when the body is cold. Medications, including anesthesia, don’t work as efficiently, leaving patients groggy and taking longer to bounce back after surgery. But perhaps the most noticeable impact is on how patients feel immediately after surgery. Many wake up shivering and feeling miserably cold, which can be distressing—especially for older or frail patients, who are more sensitive to these temperature changes. The discomfort isn’t just physical; it affects how patients perceive their overall care experience, and no one wants their surgery to end with freezing shivers and frustration.

Traditionally, hospitals have tried to address hypothermia by warming patients during surgery, often with special blankets or devices. While this approach can help, it’s reactive—happening only after the patient’s temperature has already dropped. By the time the warming starts, hypothermia has already triggered many of the complications we try to avoid.

Prewarming offers a different path. Instead of reacting to the problem, it prevents it from happening at all. By warming patients before surgery—while they’re still in the pre-operative area—we create a reserve of heat in their body. This means that when anesthesia dilates their blood vessels and the operating room cools them down, their core temperature stays stable. There’s no dangerous drop, no increased bleeding, no infection risk, and no waking up cold and shivering.

What makes prewarming even more exciting is how simple it is. It doesn’t require major changes to how surgeries are performed or expensive technology. It’s a small, proactive step: warming patients before surgery using devices that gently blow warm air. This easy adjustment has a big payoff. Patients stay warm and comfortable, they recover faster, and they’re much more satisfied with their care. For hospitals, it’s a cost-effective way to improve outcomes and patient experiences, making it a win for everyone involved.