Study suggests HFNOT lowers breathing effort in anesthetized dogs

High-flow nasal oxygen therapy may ease breathing effort in anesthetized dogs without changing systemic oxygen delivery or consumption, according to a new American Journal of Veterinary Research study published April 27, 2026. In a prospective, randomized crossover experiment, researchers at Seoul National University evaluated six healthy adult Beagles under alfaxalone total IV anesthesia and compared no HFNOT with HFNOT at 1 and 2 L/kg/min while dogs breathed spontaneously on room air-equivalent oxygen concentration. The team found flow-dependent increases in esophageal pressure, a surrogate for intrathoracic pressure, along with a lower respiratory rate at the higher flow, while arterial blood gas values and cardiac index remained unchanged. (vetlit.org)

Why it matters: For veterinary teams, the study adds physiologic evidence that HFNOT may reduce work of breathing even when it isn't being used to raise FiO2. That’s notable because prior veterinary literature has positioned HFNOT as a way to deliver warmed, humidified gas at high flow rates, generate some positive airway pressure, and support dogs that fail conventional oxygen therapy, especially in hypoxemic respiratory disease. This new paper suggests part of the benefit may come from unloading respiratory effort itself, although the findings come from a very small group of healthy, anesthetized dogs rather than clinical patients with respiratory compromise. (researchgate.net)

What to watch: The next question is whether the same reduction in breathing effort translates into better outcomes, clearer patient selection, or different flow-setting strategies in dyspneic dogs in clinical practice. (frontiersin.org)