Echocardiographic evaluation of rabbits submitted to continuous infusion of lidocaine sedated with midazolam

Author(s)

Ana Elisa Gregui Watanabe Marques

• Document type: Master's Dissertation
• Press: Araçatuba. 2019-07-05.
• Institution: Universidade Estadual Paulista (Unesp). Faculdade de Medicina Veterinária. Araçatuba
• Defense date: 2019-07-02
• Advisor: Paulo Sergio Patto dos Santos; Wagner Luis Ferreira

Abstract

Lidocaine is a versatile drug widely used in clinical practice. However, there are few studies that evaluate its effects on the heart. For this purpose, transthoracic echocardiography is a tool that allows an evaluation of the systematic and diastolic units in real time. The aim of the study was evaluate the effects of continuous rate infusion of lidocaine on systolic and diastolic functions of the left ventricle of healthy rabbits sedated with midazolam. Ten New Zealand rabbits, four males and six females, aged nine months, weighing 3.2 ± 0.3 kg were sedated with midazolam at the dose of 1 mg/kg intramuscularly and submitted to two experimental treatments (control and lidocaine) with a minimum interval of seven days. In the control treatment (CT), 0.9% sodium chloride solution (0.05 mL.kg-1 ) was administered in bolus followed by continuous infusion at a rate of 5 mL.hour-1 ; a 2% lidocaine bolus without vasoconstrictor at the dose of 1 mg.kg-1 followed by continuous infusion at the rate of 50 μg.kg-1 .minute-1 was first given in lidocaine treatment (LT). The main variables analyzed were: heart rate (HR), mean arterial pressure (MAP), peripheral vascular resistance index (PVR), Doppler cardiac index (DCI), shortening fraction (FEC), ejection fraction (EFJ), velocity of the wave S 'and relation E'/A'. All parameters were evaluated before the onset of the bolus (MB) and 20, 40 and 60 minutes after the start of continuous rate infusion (M20, M40 and M60). The studied variables were submitted to the ANOVA test with repeated measurements and post hoc Tuckey test using the software GraphPad Prism 6.01 There was no difference between treatments for the systolic function indexes FEC, FEJ and wave S ' for DCI and MAP. The E'/A' ratio and TRIV variables showed normal relaxation pattern. The results indicate that the use of continuous rate infusion of lidocaine (50 μg.kg-1 .minute-1 ) did not alter the systolic and diastolic functions of the left ventricle of healthy rabbits. Therefore, under established experimental conditions, lidocaine is shown to be safe from the cardiovascular point of view. (AU)

• FAPESP's process: 17/20513-3 - Ecocardiographic evaluation of rabbits sibmitted to continuous infusion of lidocaine sedated with midazolam
• Grantee: Ana Elisa Gregui Watanabe Marques
• Support Opportunities: Scholarships in Brazil - Master