Abstract OBJECTIVE Assessment of feasibility and proof of concept study for microvascular reactivity in anesthetized cats. METHODS 12, adult, healthy, purpose-bred cats were included. Cats were anesthetized and instrumented with a perivascular ultrasound transit time flow probe around the main pulmonary artery, a femoral arterial catheter, a central venous catheter, and a laser Doppler flowmeter with a heating unit. After a 20-minute stabilization period, microvascular reactivity, hemodynamic variables, and arterial and central venous blood gases were measured during 3 phases: (1) baseline, (2) hemorrhage, and (3) isotonic crystalloid bolus. Hemorrhage was induced by atraumatic blood loss of 20 mL/kg over 20 minutes. An isotonic crystalloid bolus at 20 mL/kg was administered IV over 20 minutes. RESULTS 6 cats were excluded from the analysis due to equipment errors or surgical complications. Microvascular reactivity decreased significantly after hemorrhage and remained below baseline after isotonic crystalloid bolus. CONCLUSIONS Microvascular reactivity assessment is feasible in healthy anesthetized cats. Hemorrhage decreases microvascular reactivity, and the administration of an isotonic crystalloid bolus did not reverse these changes. However, the small sample size may limit the external validity of the results. CLINICAL RELEVANCE This study demonstrated the feasibility of microvascular reactivity assessment in anesthetized cats. However, proper validation is warranted before clinical application.
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