Patient warming during surgery is crucial to maintain the pet’s body temperature and prevent hypothermia due to the effects of anesthesia and other factors.

However, without proper use and monitoring, heating devices can cause serious burns, requiring ongoing care and in some cases proving fatal to the patient. Although warming elements are everyday essentials in veterinary practice, they require expert knowledge and care from team members who operate them.

There are many patient warming methods to choose from, including heaters embedded into the surgery table itself, separate warming devices, and insulating the patient. Here are some warming devices to consider, along with pros and cons and safety considerations.

Patient Warming Devices

Some of the most common options in small animal medicine include…

• Heated surgery tables. These tables have a warming element incorporated into the table itself, usually with more than one temperature setting. A surgical table heater can be a convenient way to warm the patient. But as with any heat source, caution must be used. 

• Forced-air warmers. The most well-known example is the Bair Hugger. These systems blow warm air through a delivery system—a special blanket attached to the machine. They typically have temperature settings and relatively even heat dispersal. For a while, these systems have been considered the “gold standard” by many practitioners because they are safe compared to many other warming methods. However, no system is foolproof, so these warmers also require precautions.

• Warm water blankets. These warmers do what their name implies—they send heated water through a blanket or mat to provide warmth. Often placed under a patient, these warmers can be very effective. But they can cause big problems if any malfunctions occur, such as leaking hot water (not unheard of due the patients’ sharp claws causing punctures), uneven temperature distribution, or overheating.

• Heated pads, mats, or blankets. Besides water or forced air, there are many heating elements powered by electricity. Some advertise advancements like even heat distribution, multiple temperature settings, and sensors that adjust to the patient’s heating needs or raise an alarm in case of overheating. These items are popular, with many brands, types, and sizes to choose from. As with any heater, they can malfunction or cause issues if not monitored properly.

• Microwaveable warmers. Common examples include rice-filled socks, IV bags, water-filled exam gloves, commercially sold warmers, and hot water bottles. These types of patient warmers, while very affordable, have largely fallen out of favor, due to higher risks of uneven heating and overheating. Plus, once liquid elements cool down, they might lower the patient’s temperature. Some clinics still use these warmers effectively with a standard microwaving protocol and vigilant monitoring.

Additional Warming Methods

While patient warmers are important during a surgical or dental procedure, additional measures improve warming efficiency. This can also mean less need for warmers to be on higher settings, which may help decrease iatrogenic burn risks. 

Consider the following…

• Cover the patient. This could mean towels or thick blankets, possibly just warmed in the dryer. Some vets have also successfully used insulating materials like bubble wrap to lock in warmth, or clothing such as baby socks on the paws.

• Keep the patient as dry as possible. Replace towels or blankets as they become wet. Try to let fluids (such as spray during a dental) drain away from the patient.

• Pre-warm the patient. Gentle warming for a short period of time prior to induction may help some patients, especially small ones.

• Use an IV fluid warmer. This might not be the most efficient or practical method for the average dog or cat. But if available, it can add a small warming boost.

• Use multiple methods. It’s common to have a heating element below the patient, combined with a Bair Hugger and towels on top of the patient, for example.

Safety Considerations for Veterinary Surgical Table Heaters and Patient Warmers

There are many great heating devices available for veterinary patients. But ANY of them have the potential to cause patient burns, if not used appropriately. 

Here are some tips to reduce this risk as much as possible…

• Always monitor the patient and the warming device(s). Sensors are helpful, but nothing beats hands-on monitoring for catching potential problems early and making any necessary changes.

• Maintain and check your equipment. Follow all the manufacturer’s guidelines for use, maintenance, and replacement timelines if applicable. Inspect warmers before each use for any problems and continue to check them during procedures.

• Always place an appropriate barrier between the patient and the heat source. Check to see if the patient’s position shifts during the procedure. Pay special attention to pressure points in contact with a warmer.

• Have standard operating protocols so team members understand and feel confident using these devices.

• Heating pads designed for human use aren’t recommended in veterinary practices.

The idea of accidentally burning a patient can be scary. No veterinarian wants to cause any harm. But warming is essential to patient well-being.

Fortunately, there are many different types of patient warmers available. Choosing the best ones for your individual clinic, and teaching everyone how to use them appropriately, can help empower the entire team to provide the best possible surgical care to your patients.

Written by: Dr. Tammy Powell, DVM