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Objective Design Setting Animals Interventions Measurements and Main Results Conclusions To evaluate the changes in flow velocities of the middle cerebral artery before and after a carotid compression maneuver using transcranial color‐coded duplex sonography (TCCD) in healthy anesthetized dogs under mechanical ventilation.Prospective study.University teaching hospital.Eleven healthy adult dogs.A 5‐second carotid occlusion maneuver was performed to evaluate cerebral autoregulation (CA).After 10 minutes of stable anesthesia, the middle cerebral artery was evaluated by TCCD. Dogs were positioned in sternal recumbency with the head raised to the level of the phlebostatic axis. The systolic peak velocity (Vp) was measured using pulsed Doppler mode. CA was evaluated through the transient hyperemia test (THT), which assesses changes in the Vp after a 5‐second transient compression of the ipsilateral common carotid artery and is expressed as the ratio between the Vp flow before and after carotid compression. The Vp before and after carotid occlusion was compared using the Wilcoxon signed‐rank test. The median Vp of the middle cerebral artery after the carotid compression maneuver was significantly higher than the median Vp before compression (median [interquartile range, IQR]: 47.7 cm/s [34.3] vs 64.1 cm/s [24.4]; P = 0.003). The median THT obtained was 1.20 (IQR: 0.37).The current study demonstrated a significant increase in the Vp of the middle cerebral artery after a 5‐second temporary occlusion of the ipsilateral carotid artery in healthy anesthetized dogs under mechanical ventilation. These findings suggest that the noninvasive TCCD methodology could be valuable for assessing CA in dogs. Additional studies using this technique in neurocritical animals are required to confirm its usefulness. [ABSTRACT FROM AUTHOR]

The use of transthoracic echocardiography (TTE) and esophageal Doppler (ED) for the measurement of hemodynamic variables in anesthetized dogs was studied. Fourteen mixed-breed dogs, without cardiac disease, undergoing general anesthesia for diagnostic or therapeutic procedures were included in this prospective preliminary study. Dogs were premedicated with dexmedetomidine (3 μg/kg) and methadone (0.3 mg/kg), intramuscularly. General anesthesia was induced with propofol intravenously titrated to effect and maintained with isoflurane in oxygen. Animals were positioned in dorsal recumbency. Transthoracic echocardiography was performed using a 5-2 MHz cardiac ultrasound probe placed in the subcostal window, whereas esophageal Doppler was performed using a CardioQ probe (MP50; Deltex Medical, Chichester, UK). Once an appropriate view of the aortic flow was obtained, the variables peak velocity (PV) and velocity-time integral (VTI) were measured. Agreement between methods was evaluated using the Bland-Altman method with single observation per individual. The bias and the limits of agreement (LOA) between the two methods were determined. Mean (± SD) PV was 99.46 cm/s (± 42.73 cm/s) and 110.29 cm/s (± 35.86 cm/s), and VTI was 13.24 cm (± 4.33 cm) and 13.05 cm (± 4.47 cm), for TTE and ED, respectively. Mean differences and LOA were 10.83 cm/s (range: -20.50 to 42.16 cm/s) and -0.19 cm (range: -3.32 to 2.95 cm) for PV and VTI, respectively. No statistically significant differences were determined in the variables measured between TTE and ED in anesthetized dogs without cardiac disease, positioned in dorsal recumbency. This could be of clinical relevance when an evaluation of the intraoperative hemodynamic status of anesthetized dogs is desired., (Copyright and/or publishing rights held by the Canadian Veterinary Medical Association.)