Effect of continuous positive airway pressure helmet on respiratory function following surgical procedures in brachycephalic dogs: A randomized controlled trial.

Objective: To evaluate the effect of continuous positive airway pressure (CPAP) on respiratory function in the early postoperative period of brachycephalic dogs.

Study design: Prospective, randomized clinical trial.

Animals: A total of 32 dogs.

Methods: Dogs were assigned to recover with or without CPAP (control) and assessed at specific time points over 1 h. Treatment was discontinued for dogs with a CPAP tolerance score of 3 or more (from a range of 0-4). The primary outcome was pulse oximetry (SpO₂). Secondary outcomes were arterial O₂ pressure (PaO₂)/FiO₂ ratio (PaO₂/FiO₂), arterial CO₂ pressure (PaCO₂), and rectal temperature. For dogs that reached a CPAP tolerance score of 3 or more, only the data collected up to the time point before discontinuation were included in the analysis. The treatment effect (β) was analyzed using random effects models and the results were reported with 95% confidence intervals.

Results: Dogs were assigned randomly to each protocol. Baseline characteristics in both groups were comparable. Arterial blood gases were obtained in seven control group dogs and nine CPAP group dogs. Treatment did not affect SpO₂ (β = -0.1, -2.1 to 2.0) but affected the PaO₂/FiO₂ ratio (β = 58.1, 2.6 to 113.6), with no effects on PaCO₂ (β = -4.3, -10.5 to 1.9) or temperature (β = 0.4, -0.8 to 1.6).

Conclusion: In postoperative brachycephalic dogs, CPAP had no effect on SpO₂ but improved the PaO₂/FiO₂ ratio in brachycephalic dogs postoperatively.

Clinical significance: Continuous positive airway pressure offers a valuable solution to improve gas exchange efficiency, a prevalent concern in postoperative brachycephalic dogs, with the potential to enhance overall outcomes.