The PRAM has been evaluated in dogs under steady-state hemodynamic conditions, and this study evaluated PRAM under dynamic circulatory conditions, created by infusion of sympathomimetic drugs.
Methods: Five Beagle dogs, weighing 11.3 ± 0.6 kg, were anesthetized with propofol and maintained under anesthesia with oxygen and PE´ISO of 1.3 X MAC. Esophageal temperature, PE´CO2 and PE´ISO, electrocardiography, pulse oximetry, and invasive ABP were recorded. Four treatments were administered in random order: Phenylephrine at 0.5, 1, and 2 µg kg-1 min-1, norepinephrine at 0.1, 0.5, and 1 µg kg-1min-1, and dopamine and dobutamine at 2.5, 10, and 15 µg kg-1min-1. Drug doses were administered in ascending order. An equilibrium time of 10 and 30 minutes was provided between different doses and drugs, respectively. At each data point, CO was obtained with PRAM, and thermodilution and SV were calculated. Bland Altman analysis was used to compare agreement between methods, and concordance was calculated to evaluate the trending ability of PRAM. P ≤0.05 was considered significant.
