Introduction Dexmedetomidine (DEX) and Acepromazine (ACP) are powerful sedatives with remarkable hemodynamic effects. High frequency ultrasound echocardiography provides best noninvasive measurement of cardiovascular function in mice. We investigated by High Resolution Echocardiography (HRE) the cardiovascular effects of DEX, of ACP and of their combination in isoflurane (ISO) anesthetized mice. Methods Forty five age-matched, sex-paired CD1 mice were randomly allocated to 3 groups undergoing 1.5% ISO anesthesia, followed by IP injection of either 5 mg/kg ACP, or 1 mg/kg DEX, or by their combination. Heart (HR) and respiratory (RR) rates were continuously recorded along with body temperature adjusting it to 36°C. An ECG synchronized high-resolution ultrasound imaging system (Vevo 770, VisualSonics, transducer frequency 40 MHz, focal length 6 mm, frame rate 30 Hz, spatial resolution 30 ?m) was used. Once 1,5% ISO steady state was reached left ventricle B-mode and M-mode images where taken at the level of the papillary muscles, recording basal ejection fraction (EF) and fractional shortening (FS) 10 and 20' before and at different intervals after treatments. A further measurement was made after reversing DEX by atipamezole (ATP). We compared HR, RR, EF and FS values at different times by paired non parametric Wilcoxon test and inter-groups differences by One Way Friedman ANOVA. When appropriate, a post hoc analysis by Mann Whitney test was made. Significance was set at P <0.05. Results RR decreased (P>0.05) in all groups compared to baseline values. ACP reduced FS (P<0.05) over time. DEX sharply reduced HR, EF and FS (P<0.001) showing a biphasic effect. ACP+DEX decreased (P<0.001) HR, EF and FS reaching steady values after 5 minutes (P>0.05); ATP always brought back such values close to baseline (P>0.05). Conclusions In mice ACP+DEX produced more steady hemodynamic values compared to those following single agents, lessening DEX biphasic hemodynamic pattern. HRE allows easy and accurate measurements of hemodynamic effects of different anesthetic agents in mice models. References 1. Alvaides RK, et al. Vet Rec 2008; 26: 852-856. 2. Janssen, B. J. A. et al. Am J Physiol Heart Circ Physiol, 2004. 4, no. 287, pp. 1618-1624. 3 Aldinger, K. A. et al. PLoS One 2009;4(3):e4729. doi: 10.1371/journal.pone.0004729. Epub 2009 Mar 6.
High resolution echocardiographic evaluation of hemodynamic effects of anesthetics in mice
Gargiulo S;Gramanzini M;
2013
Abstract
Introduction Dexmedetomidine (DEX) and Acepromazine (ACP) are powerful sedatives with remarkable hemodynamic effects. High frequency ultrasound echocardiography provides best noninvasive measurement of cardiovascular function in mice. We investigated by High Resolution Echocardiography (HRE) the cardiovascular effects of DEX, of ACP and of their combination in isoflurane (ISO) anesthetized mice. Methods Forty five age-matched, sex-paired CD1 mice were randomly allocated to 3 groups undergoing 1.5% ISO anesthesia, followed by IP injection of either 5 mg/kg ACP, or 1 mg/kg DEX, or by their combination. Heart (HR) and respiratory (RR) rates were continuously recorded along with body temperature adjusting it to 36°C. An ECG synchronized high-resolution ultrasound imaging system (Vevo 770, VisualSonics, transducer frequency 40 MHz, focal length 6 mm, frame rate 30 Hz, spatial resolution 30 ?m) was used. Once 1,5% ISO steady state was reached left ventricle B-mode and M-mode images where taken at the level of the papillary muscles, recording basal ejection fraction (EF) and fractional shortening (FS) 10 and 20' before and at different intervals after treatments. A further measurement was made after reversing DEX by atipamezole (ATP). We compared HR, RR, EF and FS values at different times by paired non parametric Wilcoxon test and inter-groups differences by One Way Friedman ANOVA. When appropriate, a post hoc analysis by Mann Whitney test was made. Significance was set at P <0.05. Results RR decreased (P>0.05) in all groups compared to baseline values. ACP reduced FS (P<0.05) over time. DEX sharply reduced HR, EF and FS (P<0.001) showing a biphasic effect. ACP+DEX decreased (P<0.001) HR, EF and FS reaching steady values after 5 minutes (P>0.05); ATP always brought back such values close to baseline (P>0.05). Conclusions In mice ACP+DEX produced more steady hemodynamic values compared to those following single agents, lessening DEX biphasic hemodynamic pattern. HRE allows easy and accurate measurements of hemodynamic effects of different anesthetic agents in mice models. References 1. Alvaides RK, et al. Vet Rec 2008; 26: 852-856. 2. Janssen, B. J. A. et al. Am J Physiol Heart Circ Physiol, 2004. 4, no. 287, pp. 1618-1624. 3 Aldinger, K. A. et al. PLoS One 2009;4(3):e4729. doi: 10.1371/journal.pone.0004729. Epub 2009 Mar 6.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
