Study questions current weaning criteria for ventilated dogs: full analysis

A retrospective study published online April 18, 2026, is adding nuance to how veterinary teams think about ventilator liberation in dogs. In 47 dogs mechanically ventilated for at least 24 hours, investigators found that 51.1% were successfully liberated, and 91.7% of those successfully liberated survived to discharge. Perhaps the most practice-changing finding was that many dogs succeeded even though they did not meet current veterinary criteria indicating readiness for a spontaneous breathing trial. (research.ed.ac.uk)

The study arrives as veterinary critical care continues to refine expectations around long-term mechanical ventilation. Historically, prognosis discussions around ventilated dogs have been shaped by high acuity, cost, and limited veterinary-specific evidence. But newer multi-institutional data published in late 2025 reported a 52.3% survival-to-discharge rate among dogs ventilated for 24 hours or longer, suggesting that once a patient gets through the first day of ventilation, outcomes may be more favorable than many teams and pet parents assume. (researchgate.net)

In the new study, McNally, Greensmith, and Cortellini reviewed medical records from 47 client-owned dogs and analyzed 48 liberation attempts in 30 dogs. Dogs were successfully liberated from several ventilator modes, including assist-control, synchronized intermittent mandatory ventilation, and pressure support ventilation. The investigators found that end-tidal CO2 was the only physiologic variable significantly different between successful and unsuccessful attempts, averaging 35 mm Hg in successful attempts versus 43.7 mm Hg in unsuccessful ones. Liberation success also did not differ based on whether dogs met veterinary criteria or two human readiness criteria sets when complete data were available. (research.ed.ac.uk)

One detail is especially relevant for ICU decision-making: among successfully liberated dogs with complete data, 55% did not meet current veterinary criteria for a spontaneous breathing trial. The most common reason was cardiovascular instability, usually tied to vasopressor use. The authors’ conclusion is direct: dogs should not necessarily be excluded from spontaneous breathing trials or liberation attempts simply because they are receiving vasopressors, provided other criteria are met. That does not prove vasopressor use is benign, but it does suggest current screening thresholds may be leaving some dogs on the ventilator longer than necessary. (research.ed.ac.uk)

Direct outside commentary on this specific paper was limited at the time of writing, but related veterinary literature points in the same direction: mechanical ventilation practice in dogs remains highly variable, and several adjacent studies are still defining which interventions truly change outcomes. A 2025 multi-center study on neuromuscular blockade, for example, found no significant survival advantage overall, underscoring how much of ventilator management in veterinary medicine still depends on local protocol and clinician judgment rather than robust prospective evidence. Meanwhile, recent work on ventilator-associated pneumonia in dogs highlights the practical cost of longer ventilation courses and the difficulty of applying human surveillance frameworks cleanly to veterinary patients. (frontiersin.org)

Why it matters: For veterinary professionals, this study could affect both bedside workflow and conversations with pet parents. If current veterinary liberation criteria are too conservative, especially around vasopressor use, ICUs may be missing opportunities to attempt liberation earlier in selected dogs. Earlier successful liberation could reduce sedation exposure, staffing intensity, complication risk, and cost, while giving teams a more evidence-based way to discuss prognosis. That said, this was a retrospective, single-center study with a relatively small sample, so it is better viewed as a signal to reassess protocol rigidity than as a mandate to liberalize extubation criteria across the board. (research.ed.ac.uk)

There is also a pet-parent-facing dimension. Earlier quality-of-life follow-up work suggests that dogs and cats surviving mechanical ventilation generally recover with minimal long-term quality-of-life impact, although patients ventilated for neurologic disease may have more persistent limitations. That context may help clinicians frame ventilation and liberation decisions less as isolated ICU milestones and more as part of a broader recovery trajectory. (rvc-repository.worktribe.com)

What to watch: The next step is likely prospective validation: larger, multi-center studies that test whether modified readiness criteria, especially around vasopressor tolerance and ETCO2 thresholds, can improve liberation timing without increasing reintubation or mortality. If those data emerge, veterinary ICUs may begin revising spontaneous breathing trial checklists and extubation protocols over the next few years. (research.ed.ac.uk)