Analysis of ventriculo-arterial coupling in dogs: comparison of the effects of propofol and alfaxalone during anesthetic induction

This prospective, randomized, crossover clinical study aimed to evaluate and compare the impact of propofol and alfaxalone on ventriculo-arterial coupling (VAC) during anesthetic induction, with particular attention to the first 450 seconds after drug administration. The study involved 16 healthy dogs undergoing two separate anesthetic inductions for radiographic procedures, one with propofol (5 mg/kg over 30 s, followed by an infusion of 25 mg/kg/h) and the other with alfaxalone (2 mg/kg over 30 s, followed by an infusion of 10 mg/kg/h), each following premedication with butorphanol (0.2 mg/kg IV). Ventriculo-arterial coupling (assessed using a noninvasive echocardiographic approach), arterial elastance (Ea) and ventricular elastance (Ees), heart rate (HR), mean arterial blood pressure (MAP), aortic velocity–time integral (VTI), and the VTI×HR product were measured at baseline and at 30, 60, 180, 300, and 450 seconds following drug administration. Intra- and inter-treatment hemodynamic changes were analyzed using two complementary linear mixed models: a Δ-approach based on changes from baseline, and a continuous-time model including baseline as a covariate; statistical significance was set at p < 0.05. Propofol caused a more marked reduction in MAP (p < 0.001), whereas alfaxalone induced a greater increase in HR (p < 0.001). Aortic velocity–time integral decreased with both drugs, while the VTI×HR product increased more with alfaxalone (p < 0.01). Ea and Ees increased with alfaxalone (Ea: p < 0.001; Ees: p < 0.001) and decreased with propofol (Ea: p < 0.001; Ees: p < 0.001). VAC showed a significant deviation from baseline starting at 60 s for both treatments, with a significant difference between drugs only at 180 s (p < 0.001). Continuous-time model analysis showed similar trends for MAP, HR, VTI, VTI×HR, and VAC, whereas Ea and Ees showed opposite trends between the drugs (p = 0.026 and p = 0.023, respectively). In healthy premedicated dogs, induction with propofol or alfaxalone produces comparable hemodynamic changes; although differences were observed at specific time points, overall trends were analogous for MAP, HR, VTI, and VTI×HR. VAC was similar between treatments, with limited and clinically negligible variations, confirming that both anesthetics preserve ventriculo-arterial coupling during the early phase of anesthetic induction.