Effects of thoracolumbar epidural anesthesia with lidocaine on the systemic hemodynamics and hepatic blood flow in propofol anesthetized dogs

Abstract

General anesthesia reduces hepatic blood flow (HBF) from circulatory depression. Total intravenous anesthesia (TIVA) is associated with decreased circulatory depression compared to inhalation anesthesia, and epidural anesthesia using local anesthetics increases blood flow by blocking the sympathetic nerves and expanding blood vessels. We investigated the effects of thoracolumbar epidural anesthesia with TIVA on HBF in dogs. Six Beagle dogs had epidural catheters placed between T13 and L1 and were anesthetized with propofol and vecuronium. Physiological saline (control) or 2% lidocaine (0.2 ml/kg, followed by 0.2 ml/kg/hr) was administered at 1-2 weeks intervals. Heart rate (HR), cardiac index (CI), mean arterial pressure (MAP), and systemic vascular resistance index (SVRI) were recorded at 10-min intervals from before epidural injections (T0) to 110 min. Indocyanine green test was used to measure HBF during the awake state and until 90 min after epidural injections. HR and CI did not differ between treatments. MAP and SVRI after lidocaine were significantly lower than those of controls, and the lowest MAP value was 65±11 mmHg at T10. Compared to T0, after lidocaine treatment, HBF was significantly higher at T30, T60 and T90 (p<0.05); while, after control treatment, no significant change was evident at any time point. Despite a decrease in MAP by this technique, HBF was either maintained at pre-anesthetic levels or increased in comparison to controls, probably due to vasodilation of the hepatic artery induced by the selective blockade sympathetic ganglia.

Epidural Anesthesia versus General Anesthesia for Total Knee Arthroplasty: Influences on Perioperative Cognitive Function and Deep Vein Thrombosis

“…And despite the inhibitory action of GA on the activity of cerebral cortex and hypothalamus, it may not be effective in inhibiting traumatic stress and inflammatory indicators, which may exert adverse effects on patients' CF and induce DVT [ 12 ]. EA, as a local anesthesia method, achieves anesthesia by injecting analgesics into the epidural space to block sensory nerves [ 13 ]. Such anesthesia not only induces vasodilation in the occluded area to increase blood flow but also preserves the patient's consciousness and provides pain relief [ 14 , 15 ].…”

Low-dose epidural anesthesia decreases the use of intraoperative systemic analgesics in goats undergoing lower urinary tract surgery

“…12,13 However, sensory block is typically accompanied by sympathetic blockade, which may contribute to arterial hypotension. 12,14,15 We compared the vaporizer setting used in goats anesthetized for similar surgical procedures and found that the MAC fraction was lower when EA was used. While that difference was statistically significant, the clinical consequences of this MAC sparing effect is unknown, as the reduction in MAC was modest.…”