Haemodynamic Effects of Pimobendan during General Anaesthesia in Healthy Senior Dogs: A Prospective, Randomised, Triple-Blinded, Placebo-Controlled Clinical Study

Abstract

Pimobendan is an inotropic and vasodilator drug with no sympathomimetic effects. This study aimed to evaluate the haemodynamic effects of pimobendan during anaesthesia in healthy senior dogs. A prospective, randomised, triple-blinded, placebo-controlled clinical study was conducted. Thirty-three dogs (median [range]: 9 [7, 12] years) were anaesthetised for surgical procedures. The dogs were randomly allocated into two groups: eighteen dogs received intravenous pimobendan at a dose of 0.15 mg/kg (PIMOBENDAN), and fifteen dogs received intravenous saline solutions at a dose of 0.2 mL/kg (PLACEBO). Data were recorded before, 1 min, 10 min, and 20 min after injection. Velocity-time integral (VTI), peak-velocity (PV), and mean-acceleration (MA) were measured using an oesophageal Doppler monitor (ODM). Heart rate and mean arterial pressure were also registered. The data were analysed using a two-way ANOVA for trimmed means. Statistical differences were considered if p < 0.05. Twenty minutes after injection, the VTI (13.0 cm [10.4, 22.3]), PV (95.0 [83.0, 160] m/s), and MA (12.6 [9.40, 17.0] m/s2) were significantly higher in the PIMOBENDAN group compared to the PLACEBO group (VTI: 10.5 [6.50, 17.4] cm, PV: 80.0 [62.0, 103] m/s and MA: 10.2 [7.00, 16.0] ms2). No significant differences were observed in the rest of the variables. Using pimobendan during anaesthesia increases VTI, PV, and MA, as measured by an ODM.