Effects of constant rate infusion of anesthetic or analgesic drugs on general anesthesia with isoflurane: A retrospective study in 200 dogs

Abstract

Constant rate infusion (CRI) shows several advantages in balanced anesthesia, such as reduction of requirement for inhaled anesthetics and control of pain. The most commonly used drugs in these protocols are local anesthetics, dissociative, and opioids, which may be administered alone or in combinations. We evaluated the records of 200 dogs that underwent various surgical procedures with anesthetic or analgesic CRI in the perioperative period during 2011 and 2012 at the Veterinary Hospital of Franca University (Unifran), and identified possible complications during the transoperative period. Records evaluated included clinical state, laboratory tests, drugs used in premedication and induction, and CRI protocol. Acepromazine and morphine were the main drugs used in premedication. Propofol was used to induce anesthesia alone or in combination with other agents. We evaluated records of the 25 different CRI protocols. Fentanyl was the main drug employed in CRI, either alone or in combination. There were 128 episodes of anesthetic complications during CRI;the most common were hypotension, hypertension, and tachycardia, which occurred in 43 (32%), 35 (26.3%), and 19 (14.2%) dogs, respectively. Cardiac arrhythmia was reported in only 4 dogs. Signs of respiratory depression were present in dogs treated with 6 different CRI protocols. The consumption of isoflurane (vol %) reduced between 15.7% and 21.05% after 30minutes of the CRI in the fentanyl and fentanyl-lidocaine-ketamine CRI groups (p<0.05). In conclusion, CRI is a valid component of balanced anesthesia in dogs, safe, and has a low incidence of adverse effects. However, future studies are warranted to describe the results of the clinical use of CRI to better characterize and refine this technique. Key words: Continuous intravenous infusion, fentanyl, ketamine, lidocaine, morphine ResumoO uso de técnicas de infusão contínua (IC) possui inúmeras vantagens na anestesia balanceada, como a redução do requerimento de anestésicos inalatórios e controle da dor. Os fármacos mais comumente utilizados nestes protocolos são os anestésicos locais, dissociativos e opioides, que podem ser administrados isoladamente ou em associações. Foram avaliados os prontuários de 200 cães que foram submetidos a diversos procedimentos cirúrgicos com IC de anestésicos ou analgésicos no período perioperatório durante 2011 e 2012 no Hospital Veterinário da Universidade de Franca (Unifran). Foram identificadas possíveis complicações durante o período trans-operatório. Os registros avaliados incluíram estado clínico, exames laboratoriais, fármacos utilizados na pré-medicação e indução, e protocolos de IC. Acepromazina e morfina foram os principais fármacos usados na pré-medicação. O propofol foi utilizado para induzir a anestesia, isolado ou em associação com outros agentes. Foram avaliados os registros de 25 protocolos diferentes de IC. O fentanil foi o principal fármaco utilizado na IC, isoladamente ou em associação. Houve 128 episódios de complicações anestésicas durante a IC; os mais ...

Avaliação das complicações transanestésicas comparando a infusão contínua peridural versus analgésica em cães submetidos a neurocirurgias

“…Hypotension and hypoventilation were complications related by Cerejo et al (2013), which hypotensive episodes responded to vasopressor drugs or fluid therapy bolus, similarly to our study. According to the same author, there was an increase in end-tidal CO2 (> 50 mmHg) on 7.5% of evaluated dogs, differing from this paper with higher rates of animals with hypercapnia and absence of mechanic ventilation.…”

“…Apnea and cardiac arrhythmia (atrioventricular block and ventricular tachycardia) were also related in animals receiving FLK infusion (Cerejo et al, 2013), however, in this study, no animals exhibited these complications. Compared with other studies, where 25% of animals anesthetized with isoflurane for neurosurgeries showed bradycardia (Godoi et al, 2009), our study showed no difference in our evaluations (22.22%).…”

“…The use of different drugs in continuous infusion techniques produces several benefits on balanced anesthesia, such as a minor requirement from the inhaled anesthetic and better pain control. The most commonly used in these protocols are local anesthetics, dissociative drugs, and opioids, which can be administered isolated or in association (Cerejo et al, 2013). Moreover, these analgesic agents act on different stages of a painful process, such as transduction, transmission, and integration, blocking nociception in different points, therefore this pharmacological synergy favors drug biotransformation and also allows its dose reduction (Muir III et al, 2003).…”

Protocolo anestésico aplicado em procedimento cirúrgico de amputação de membro pélvico de um cão – relato de caso

“…Para controlar e/ou reduzir a dor faz-se o uso combinado de fármacos na anestesia, isso impede a ocorrência de eventos adversos durante o protocolo de analgesia balanceada (CEREJO et al, 2013), dentre os fármacos os mais utilizados são os anestésicos locais, dissociativos e opioides, administrados isoladamente ou em associações (DUKE, 2014).…”