Extradural anesthesia with lidocaine combined with fentanyl or methadone to ovariohisterectomy in dogs

Abstract

. Mentor. Responsible for intellectual and scientific content of the study; statistical analysis; critical revision. ABSTRACT PURPOSE:To compare the cardiopulmonary effects and the quality of anesthesia of the extradural lidocaine in combination with fentanyl or morphine in bitches undergoing ovariohysterectomy. METHODS:Sixteen female dogs, were sedated with intramuscular acepromazine (0.05mg kg -1 ), followed by anesthetic induction with intravenous propofol (4mg kg -1 ), to perform the lumbosacral puncture. The animals were randomly assigned to two treatments:T-F (n=8) extradural administration of fentanyl (5µg kg -1 ), T-M (n=8) extradural administration of methadone (0.3mg kg -1 ). In both treatment groups, opioids were combined with lidocaine, in order to make up a final volume of 0.4mL kg -1 . Heart rate (HR), respiratory rate (RR), systolic arterial blood pressure (SABP), intra-operative anesthetic supplementation, blood gases and adverse effects were investigated.RESULTS: HR, arterial pH and blood gases did not differ between treatments at any time point. RR and SABP decreased after epidural anesthesia, but the values were in terms of the physiological range of dogs. Intra-operative anesthetic supplementation was required in 50% and 62.5% of the fentanyl and methadone treated dogs, respectively. CONCLUSION:The extradural lidocaine in combination with fentanyl or morphine allowed cardiopulmonary stability, however sufficient sensitive blockade was not provided in 100% of the dogs.

An Update on Drugs Used for Lumbosacral Epidural Anesthesia and Analgesia in Dogs

“…Other combinations using local anesthetics and different opioids have been reported (e.g., methadone–lidocaine, morphine–ropivacaine, tramadol–lidocaine, oxymorphone–bupivacaine) but it seems that none of these protocols provided clear benefits over the administration of morphine–bupivacaine (64, 88, 127, 131, 132). However, they may be useful when the latter two drugs are not available.…”

Ropivacaína isolada ou associada à metadona ou à morfina, pela via epidural, em cadelas submetidas à ovário-histerectomia

“…A comparação do uso epidural da morfina isolada ou associada à bupivacaína, em cães submetidos a cirurgias ortopédicas, revelou menores valores de pressão arterial mediante a combinação de agentes, corroborando o estudo em pauta (Kona-Boun et al, 2006). Além disso, a avaliação da combinação de lidocaína associada ao fentanil ou à metadona, em cadelas submetidas à OH, mostrou redução significativa da PAS com ambos os protocolos, porém vale salientar que as médias permaneceram maiores que as deste ensaio, visto que os animais ficaram despertos durante o procedimento cirúrgico (Diniz et al, 2013). Tal fato ratifica a influência dos anestésicos gerais utilizados sobre a resistência vascular periférica (Adams et al, 1994) e a necessidade de considerar o uso de medidas terapêuticas para o controle da hipotensão diante das associações epidurais de opioides e anestésicos locais.…”

“…A crescente utilização de técnicas de anestesia balanceada visa primordialmente à obtenção de protocolos seguros, destacando-se a associação de fármacos opioides com anestésicos locais, seja no período pré ou transoperatório, objetivando-se ofertar analgesia e potencializar os anestésicos gerais, com redução de seus efeitos colaterais (Adami et al, 2012;Albuquerque et al, 2013;Diniz et al, 2013).…”

Preoperative epidural administration of lidocaine-methadone or lidocaine-fentanyl in female dogs undergoing elective ovariohysterectomy

“…All animals in the LF group and eight dogs in the LM group required additional propofol at the time of ovarian pedicle clamping. This result suggests that the cranial epidural spread of methadone and fentanyl was insufficient to achieve the innervation of the ovarian pedicle, which is located on the third and fourth afferent lumbar nerves (DINIZ et al, 2013), preventing the blockade of nociceptive stimuli from handling of ovarian pedicles.…”

“…The most painful stimuli during this procedure are believed to occur in the dermotomy and ligation of the ovarian pedicle. According to Ishiy et al (2002), epidural administration of 5 mg kg − ¹ lidocaine alone is not sufficient to produce anesthesia for ovariohysterectomy in dogs because it only blocks up to the fourth or fifth lumbar vertebra, whereas the ovaries are innervated by the third and fourth lumbar nerves (DINIZ et al, 2013).Thus, further research on the associations of analgesic drugs with lidocaine and their pharmacokinetics and adverse effects when administered epidurally is needed to obtain more effective anesthesia with minimal side effects.…”