SESSION TITLE: Critical Care Posters II
SESSION TYPE: Poster Presentations
PRESENTED ON: Saturday, March 22, 2014 at 01:15 PM - 02:15 PM
PURPOSE: Echocardiography is an important tool for evaluating cardiac and hemodynamic functions in small animals but requires sedation and immobility, which influences cardiac performance. Minimizing the hemodynamic effects of anesthesia is extremely important for improving applicability of animal models to the clinical setting, especially in models of shock. We aimed to evaluate the effects of isoflurane dose on myocardial function in a murine model, and to attempt to compare very low doses of isoflurane to a state in which the mice were off anesthesia.
METHODS: 36 echocardiographic studies were performed on 12 healthy male C57BL/6 mice. 3 different isoflurane anesthesia regimens were employed using heart rate (HR) as a proxy: deep anesthesia with an objective of HR between 350 and 400 beat per minute (bpm), light anesthesia with an objective of HR between 475 and 525 bpm, and just before the mice woke up (>575 bpm). Using a high-resolution ultrasound system, stroke volume, cardiac output, left ventricle dimension and fractional shortening were recorded.
RESULTS: Fractional shortening was not statistically different between the awake group and the light anesthesia group (49±5% in awake mice vs. 48±5%; p=0.62) whereas it was statistically different compared to the deep anesthesia group (31±5%, p<0.0001 compared to both groups). Similar results found for stroke volume (41.4±5.8 μL vs. 41.6±6.9 μL; p=0.81 and 35.01±8,27 μL; p<0.05 compared to both groups). Cardiac output was slightly lower in the light anesthesia group compared to the awake group (21.9±3.6 mL/min vs. 25.6±3.3; p=0.02) attributable entirely to a difference in HR difference (522±17 beats/min vs. 608±23 beats/min; p<0.0001).
CONCLUSIONS: Doppler echocardiography can be performed under very light anesthesia using small doses of isoflurane without influencing cardiac function compared to awake imaging after anesthesia.
CLINICAL IMPLICATIONS: This technique allows for accurate and reproducible assessment of cardiac function while minimizing hemodynamic perturbations.
DISCLOSURE: The following authors have nothing to disclose: Fabien Picard, François Depret, Sergio Zanotti-Cavazzoni, Steven Hollenberg
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