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WSVA8-0064
ANESTHESIA
EVALUATION OF LIDOCAINE INJECTED INTO THE EPIDURAL SPACE VIA INTERCOCCYGEAL SITE PERCUTANEOUSLY IN RABBITS
B. Ong Huai Ern1, Y. Kaneko1, Y. Osada1, S. Yamamoto1, S. Mizutani1, Y. Kirino2, S. Torisu1, K. Naganobu1
1University of Miyazaki, Veterinary Teaching Hospital- Faculty of Agriculture, Miyazaki, Japan
2University of Miyazaki, Department of Veterinary Sciences- Faculty of Agriculture, Miyazaki, Japan
INTRODUCTION
Lumbosacral approach has been used for rabbit epidural anesthesia (Hughes et al. 1993). However, the technique was reported to cause intrathecal injection in all studied rabbits (Otero et al. 2012).
OBJECTIVES
To evaluate the effects of lidocaine injected into the epidural space via intercoccygeal site percutaneously in rabbits.
METHODS
Under general anesthesia with isoflurane following propofol induction, rabbits were placed in ventral recumbency with elevated hip. A 27-gauge spinal needle was inserted percutaneously at dorsal tail base in caudocranial direction. Correct needle placement in the epidural space was confirmed by contrast radiography using iohexol (0.05 – 0.1 ml/kg). Then, either 0.3 ml/
kg of lidocaine 2% (n=4) or normal saline (NS) (n=4) was injected randomly in blinded fashion. Pulse rate and blood pressure (non-invasive monitoring) were recorded before and after the injection. One minute after the injection, general anesthesia was discontinued. Neurological examination was performed in blinded fashion before and every 20 minutes after general anesthesia until all findings back to normal; and reassessed one week later.
RESULTS
Lidocaine group has significant longer recovery time
to normal anal tone, gait, conscious proprioception (CP), and deep pain perception (DPP) of hindlimbs, compared to NS group. No difference was observed for the recovery time of mentation and forelimbs’ CP and DPP between two groups. Blood pressure significantly decreased after lidocaine injection, but not changed after NS injection. No complications were observed during one week follow-up period.
CONCLUSIONS
Percutaneous lidocaine injection technique into the epidural space via intercoccygeal site may be used for rabbit hindlimb anesthesia.
Your Singapore, the Tropical Garden City
WSVA8-0023
ANESTHESIA
EFFECTS OF TRAMADOL AND TRAMADOL- LIDOCINE INFUSIONS ON THE MINIMUM ALVEOLAR CONCENTRATION OF SEVOFLURANE AND ENTROPY INDICES IN DOGS
N. Thengchaisri1, N. Koatsang1, C. Mahidol1
1Kasetsart university, Companion Animal Clinical Sciences, Bangkok, Thailand
INTRODUCTION
Previous studies indicate anti-nociceptive effects of tramadol and lidocaine infusions. However, the effects of intravenous infusion of both tramadol and lidocaine on minimum alveolar concentration (MAC) sparing effects of sevoflurane in dogs remain unclear.
OBJECTIVES
To compare the effects of continuous rate infusion (CRI) of tramadol and tramadol-lidocaine on MAC of sevoflurane and entropy indices in dogs.
METHODS
Eight, healthy German shepherds were induced and maintained with sevoflurane. A standard tail-clamp technique was used for MAC determination. The MAC was determined with only sevoflurane for MAC baseline (MACB), during infusions of tramadol (intravenous loading dose of 1.5 mg/kg and CRI of 2.6 mg/kg/hr; MACT), and tramadol-lidocaine (tramadol CRI of 2.6 mg/kg/hr and intravenous loading dose of 1.0 mg/kg lidocaine and CRI of 6 mg/kg/ hr; MACTL). Stated entropy (SE), response entropy (RE) and RE-SE difference were recorded at five minutes prior to and during tail-clamping.
RESULTS
The MACB was 2.4 ± 0.2%. Tramadol and tramadol- lidocaine decreased MAC to 2.2 ± 0.3% and 1.7 ± 0.3%, respectively. The MAC-sparing effect of tramadol- lidocaine was greater than tramadol alone (8.2 ± 8.9% vs. 30.1 ± 10.7%; p<0.01). All of SE, RE and most RE-SE difference were increased (all p<0.05) when subjects responded purposefully to the noxious stimulation. While no response occurred, all of entropy indices did not change compared to pre-stimulation data.
CONCLUSIONS
In dogs, a combination of tramadol-lidocaine infusion can reduce anesthetic requirements in higher degree than tramadol alone. Entropy indices may change associated with nociceptive responses in anesthetized animals.
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