Cardiopulmonary effects of dexmedetomidine, with and without vatinoxan, in isoflurane-anesthetized cats

Effects of dopamine, norepinephrine or phenylephrine on the prevention of hypotension in isoflurane-anesthetized cats administered vatinoxan or vatinoxan and dexmedetomidine

“…In this study in isoflurane-anesthetized cats administered vatinoxan or a vatinoxandexmedetomidine combination, treatment was necessary to maintain normal arterial pressure (defined as MAP 70-80 mmHg), and higher plasma dexmedetomidine concentrations appeared to overcome the vasodilatory effect of vatinoxan. This is in agreement with a previous study in anesthetized cats (Jaeger et al 2019). In addition, norepinephrine and phenylephrine, but not dopamine, were effective at restoring normal arterial pressure.…”

“…Power analysis conducted using data previously collected in similar conditions in our laboratory suggested that six cats would provide a power > 0.8 to detect a 20% difference in CO between treatments, with the alpha level set at 0.05 (Jaeger at al. 2019).…”

“…However, the combination resulted in vasodilation and severe hypotension except at the highest plasma dexmedetomidine concentration studied, likely because of incomplete antagonism of dexmedetomidine-induced vasoconstriction (Jaeger et al 2019).…”

“…HR and rhythm (Lead II electrocardiogram; PowerLab; ADInstruments Inc., CO, USA), end-tidal isoflurane (FEIso) and carbon dioxide partial pressure (infrared spectrophotometer), and hemoglobin oxygen saturation (pulse oximeter) were continuously measured (Carescape B650; GE Healthcare, WI, USA). For FEIso measurement, end-tidal gas was collected by hand as previously described (Jaeger et al 2019). The spectrophotometer was calibrated each day with room air (isoflurane concentration of 0) and 4 secondary standards of known isoflurane concentration spanning the range of measurements (0.51, 2.04, 2.38 and 3.33%).…”

“…Pressure transducers were connected to a data acquisition system and software (PowerLab and LabChart; ADInstruments Inc.) and calibrated daily against a mercury manometer and zeroed at the level of the sternum. CO was measured by thermodilution as previously described (Jaeger et al 2019). Syringes containing dry heparin (PICO50; Radiometer America, CA, USA) were used to simultaneously collect 0.5 mL of arterial and mixed-venous (PA) blood to measure arterial and mixed-venous hemoglobin concentration [Hba] and [Hb𝑣̅ ], hemoglobin oxygen saturation (SaO2 and S𝑣̅ O2), pH, partial pressure of oxygen (PaO2 and P𝑣̅ O2) and carbon dioxide (PaCO2 and P𝑣̅ CO2) and lactate concentrations.…”