Penn Vet research on a voluntary head dunk for canine heat stroke: alternative techniques, contraindications, and what's next with Cynthia Otto

Cynthia M. Otto, DVM, PhD, DACVECC, DACVSMR, expands on research conducted by the Penn Vet Working Dog Center research. She walks through alternative techniques to the voluntary head dunk, explains when to avoid it, and shares what they're planning to examine next.

RELATED: Cynthia M. Otto reports research showing the benefits of a trained head dunk to prevent heat stroke in dogs

Transcript

Cynthia M. Otto, DVM, PhD, DACVECC, DACVSMR: It's not one size fits all. As I mentioned before, if a dog is already showing signs of heat injury—heading into heat stroke—or is mentally inappropriate, it's not going to be safe to attempt some of the techniques we've studied. Above all, it's about keeping the dog safe. If a dog is too hot and can't stop panting, they may not be able to tolerate dunking their head; that's when we need to hose them down or immerse them in a pool for complete immersion, and get them to veterinary care if indicated.

Most of the time, though, these methods are field cooling: cool them off, give them a break, and let them return to whatever they were doing. This is preventive care, not emergency care, and it's important to keep that distinction in mind when discussing cooling in the veterinary hospital.

If a dog has debris in their eyes or you want to flush their eyes, that's straightforward and useful. One group we haven't tested well are brachycephalic breeds; they may still benefit, but we don't yet have data. The dogs we've worked with so far are working-breed dogs—labs and shepherds—with more standard anatomy.

Water should be clean, and water temperature matters. We know the method is effective at about 72 °F. If the water is warmer, you won't get as much benefit because you need the water to be cool enough to allow heat transfer.

This past summer we ran a follow-up study because people asked whether you must train a dog to "head dunk," or whether other approaches—like a cold, wet towel wrapped around the head—would be similarly effective. That study is still under analysis, but our initial data suggest that the soaked-towel method is not effective at reproducing the cooling of a head dunk. We still need to finalize the analysis and publish the results.

We also compared colder water to room-temperature water. We tested approximately 59°F—basically groundwater from a well—versus 72°F, our room-temperature condition. We evaluated the head dunk at both temperatures, the towel at both temperatures, and pool immersion. We also looked at dogs standing in a pool versus lying down; not all dogs will lie down, and for total-body immersion we ideally want them to lie down, but many won't.

We also considered drinking. Does drinking cold water help? People naturally drink when they're hot, but dogs drinking excessive volumes raises concerns like bloat, so we need to analyze that data carefully. Questions such as whether 59 °F versus 72 °F makes a meaningful difference will be answered when the analysis is complete.

Another part of our ongoing work is how best to measure temperature. We evaluated subcutaneous (sub-Q) temperature chips, ingested temperature pills, and ear temperature...each has limitations. That raises the question of whether the absolute number matters as much as how the dog is responding physiologically. In many cases, the dog's clinical response and physiology will be more important than any single recorded temperature, because numbers can vary depending on the measurement method.