Marcos De Simone Melo

Hemodynamic changes in lipid emulsion therapy (SMOFlipid) for bupivacaine toxicity in swines

PURPOSE To evaluate the hemodynamic changes following SMOFlipid emulsion therapy with after bupivacaine intoxication in swines. METHODS Large White pigs were anesthetized with thiopental, tracheal intubation was performed and mechanical ventilation was instituted. Hemodynamic variables were recorded with invasive pressure monitoring and pulmonary artery catheterization (Swan-Ganz catheter). After a 30-minute resting period, 5 mg.kg(-1) of bupivacaine by intravenous injection was administered and new hemodynamic measures were performed 1 minute later; the animals were than randomly divided into two groups and received 4 ml.kg(-1) of saline solution or 4 ml.kg(-1) of SMOFlipid emulsion 20%. Hemodynamic changes were then re-evaluated at 5, 10, 15, 20 and 30 minutes. RESULTS Bupivacaine intoxication caused fall in arterial blood pressure, cardiac index, ventricular systolic work index mainly and no important changes in vascular resistances. SMOFlipid emulsion therapy was able to improve blood pressure mainly by increasing vascular resistance since the cardiac index had no significant improvement in our study. Hemodynamic results of the use of lipid emulsion in bupivacaine intoxication were better than the control group. CONCLUSION The SMOFlipid emulsion is a option for reversing hypotension in cases of intoxication by bupivacaine.

Hemodynamic changes with two lipid emulsions for treatment of bupivacaine toxicity in swines

PURPOSE To compare the hemodynamic changes following two different lipid emulsion therapies after bupivacaine intoxication in swines. METHODS Large White pigs were anesthetized with thiopental, tracheal intubation performed and mechanical ventilation instituted. Hemodynamic variables were recorded with invasive pressure monitoring and pulmonary artery catheterization (Swan-Ganz catheter). After a 30-minute resting period, 5 mg.kg-1 of bupivacaine by intravenous injection was administered and new hemodynamic measures were performed 1 minute later; the animals were than randomly divided into three groups and received 4 ml.kg-1 of one of the two different lipid emulsion with standard long-chaim triglyceride, or mixture of long and medium-chain triglyceride, or saline solution. Hemodynamic changes were then re-evaluated at 5, 10, 15, 20 and 30 minutes. RESULTS Bupivacaine intoxication caused fall in arterial blood pressure, cardiac index, ventricular systolic work index mainly and no important changes in vascular resistances. Both emulsion improved arterial blood pressure mainly increasing vascular resistance since the cardiac index had no significant improvement. On the systemic circulation the hemodynamic results were similar with both lipid emulsions. CONCLUSION Both lipid emulsions were efficient and similar options to reverse hypotension in cases of bupivacaine toxicity.

Methadone and Morphine during Anesthesia Induction for Cardiac Surgery. Repercussion in Postoperative Analgesia and Prevalence of Nausea and Vomiting

BACKGROUND AND OBJECTIVES Pain is an aggravating factor in postoperative morbidity and mortality especially in large size surgeries. Methods to effectively fend pain collide with elevated costs and for this reason they are not accessible in every service. The option would be the use of an opioid with long half-life, such as methadone. The objective of the present study was to compare the requirements of postoperative analgesia in patients who received methadone, morphine, or placebo during anesthetic induction, besides the prevalence of postoperative nausea and vomiting. METHODS Fifty-five patients scheduled for cardiac surgery were divided into three groups and they received during anesthetic induction 20mg of methadone, 20mg of morphine, or placebo. At the end of surgery, patients were transferred to the ICU where the following parameters were evaluated: duration of anesthesia, time until extubation, time until the need of the first analgesic, number of doses required in 24 hours, assessment of analgesia by the patient, and prevalence of nausea/vomiting. RESULTS Differences in the duration of anesthesia and time until extubation were not observed. The first dose of analgesic in patients who received methadone was administered later than in patients in the other two groups. The need of analgesics in the methadone group was lower, quality of analgesia was better, and prevalence of nausea and vomiting was also lower. CONCLUSIONS Methadone during anesthetic induction was effective for analgesia in large size surgeries. Lower incidence of nausea and vomiting was observed in the methadone group and therefore it is a low cost option available among us that should be stimulated.

Lipid Therapy with Two Agents in Ropivacaine-Induced Toxicity: Experimental Study in Swine

BACKGROUND AND OBJECTIVE Compare hemodynamic changes after ropivacaine-induced toxicity followed by treatment with two lipid emulsions in swine. METHODS Large White pigs were anesthetized with thiopental, followed by intubation, and kept on mechanical ventilation. Hemodynamic variables at rest were recorded with invasive pressure monitoring and pulmonary artery catheterization. After 30 minutes, 7mg.kg(-1) ropivacaine were injected intravenously and new hemodynamic measurements were performed within one minute. The animals were then randomly allocated into three groups and received: 4mL.kg(-1) saline solution, or 4mL.kg(-1) lipid emulsion with long-chain triglycerides, or 4mL.kg(-1) lipid emulsion with longand medium-chain triglycerides. Hemodynamic changes were reevaluated at 5, 10, 15, 20 and 30 minutes. RESULTS Ropivacaine-induced toxicity mainly caused a drop in blood pressure and cardiac index without significant changes in vascular resistance. Therapy with lipid emulsions restored blood pressure primarily through increased vascular resistance, as cardiac index showed no significant improvement. Lipid emulsion with medium-chain triglycerides caused a greater increase in vascular resistance, particularly pulmonary. CONCLUSION In groups receiving lipid emulsions, hemodynamic results were better than in control group. There were no differences in systemic arterial pressure and cardiac index between animals receiving lipid emulsion with long-chain triglycerides and mixed long- and medium-chain triglycerides.

Hemodynamic changes with high infusion rates of lipid emulsion. Experimental study in swine

PURPOSE To evaluate hemodynamic changes caused by sole intravenous infusion of lipid emulsion with doses recommended for treatment of drug-related toxicity. METHODS Large White pigs underwent general anesthesia, tracheal intubation was performed, and mechanical ventilation was instituted. Hemodynamic variables were recorded using invasive blood pressure and pulmonary artery catheterization. Baseline hemodynamic measurements were obtained after a 30-minute stabilization period. An intravenous bolus injection of 20% lipid emulsion at 1.5 ml/kg was administered. Additional hemodynamic measurements were made after 1 minute, followed by a continuous intravenous lipid infusion of 0.25 ml/kg/min. Further measurements were carried out at 10, 20 and 30 minutes, when the infusion was doubled to 0.5 ml/kg/min. Assessment of hemodynamic changes were then made at 40, 50 and 60 minutes. RESULTS Lipid infusion did not influence cardiac output or heart rate, but caused an increase in arterial blood pressure, mainly pulmonary blood pressure due to increased vascular resistance. Ventricular systolic stroke work consequently increased with greater repercussions on the right ventricle. CONCLUSION In doses used for drug-related toxicity, lipid emulsion cause significant hemodynamic changes with hypertension, particularly in the pulmonary circulation and increase in vascular resistance, which is a factor to consider prior to use of these solutions.

Comparação das alterações hemodinâmicas na intoxicação aguda com bupivacaína e ropivacaína por via venosa em suínos

JUSTIFICATIVA E OBJETIVOS: A ropivacaina apresentada na forma levogira pura foi introduzida para proporcionar alternativa mais segura que a bupivacaina nas anestesias locorregionais. O objetivo deste estudo foi comparar as repercussoes hemodinâmicas apos injecao por via venosa dos dois agentes em suinos, simulando intoxicacao que pode ocorrer durante anestesia locorregional em humanos. METODO: Suinos da raca Large-White foram anestesiados com tiopental, realizada intubacao traqueal e instituida ventilacao controlada mecânica. As variaveis hemodinâmicas foram medidas atraves de monitorizacao invasiva da pressao arterial e cateterizacao de arteria pulmonar. Apos periodo de repouso de 30 minutos os animais foram aleatoriamente divididos em dois grupos e receberam por via venosa 4 mg.kg-1 de um ou outro agente sem conhecimento do pesquisador. Os resultados hemodinâmicos foram avaliados em repouso e 1, 5, 10, 15, 20 e 30 minutos apos a intoxicacao. RESULTADOS: As repercussoes hemodinâmicas da intoxicacao aguda com bupivacaina foram mais importantes e mais prolongadas do que as com ropivacaina. Com bupivacaina o indice cardiaco teve diminuicao maior e mais prolongado, a pressao arterial media e a frequencia cardiaca diminuicoes mais prolongadas, a pressao venosa central aumento mais prolongado e a pressao capilar pulmonar aumentou mais e por mais tempo. O impacto no indice de resistencia vascular sistemica mostrou que a vasomotricidade foi parcialmente mantida, houve aumento nos dois grupos e, paradoxalmente, maior e por mais tempo com bupivacaina. CONCLUSOES: Em suinos a ropivacaina causou menos repercussoes hemodinâmicas do que a bupivacaina quando as mesmas doses foram injetadas por via venosa.

Comparison of Hemodynamic Changes in Acute Intoxication with Intravenous Bupivacaine and Ropivacaine in Swine

BACKGROUND AND OBJECTIVES Pure levorotatory ropivacaine was introduced to provide a safer alternative to bupivacaine in regional blocks. The objective of this study was to compare the hemodynamic repercussions after the intravenous administration of both agents in swine, simulating the intoxication that can be seen during regional blocks in humans. METHODS Large-White swine were anesthetized with thiopental, followed by endotracheal intubation and controlled mechanical ventilation. Hemodynamic parameters included non-invasive blood pressure and catheterization of the pulmonary artery. After 30 minutes, animals were randomly divided into two groups, and 4 mg.kg-1 of one of the agents was administered intravenously without the knowledge of the investigator. Hemodynamic parameters were evaluated at rest and 1, 5, 10, 15, 20, and 30 minutes after intoxication. RESULTS The hemodynamic repercussions of acute bupivacaine intoxication were more important and prolonged than in ropivacaine intoxication. With bupivacaine, the cardiac index showed greater and more prolonged reduction, mean arterial pressure and heart rate had more prolonged reduction, central venous pressure showed a more prolonged increase, and pulmonary wedge pressure increased more for more prolonged time. The impact on the systemic vascular resistance index showed that vasomotricity was partially maintained, increased in both groups, and, paradoxically, was greater and longer-lasting with bupivacaine. CONCLUSIONS In swine, ropivacaine caused less hemodynamic repercussions than bupivacaine when the same doses were administered intravenously.

Terapia lipídica com dois agentes na intoxicação por ropivacaína: estudo experimental em suínos

OBJETIVO: Comparar alteracoes hemodinâmicas apos intoxicacao com ropivacaina seguida de terapia com duas emulsoes lipidicas em suinos. METODO: Suinos da raca Large White foram anestesiados com tiopental, intubados e mantidos em ventilacao mecânica. Variaveis hemodinâmicas de repouso foram registradas atraves de pressao invasiva e cateterizacao da arteria pulmonar. Apos 30 minutos, 7 mg.kg-1 de ropivacaina foram injetados por via venosa e novas medidas hemodinâmicas foram feitas em um minuto; os animais foram entao aleatoriamente alocados em tres grupos e receberam: 4 mL.kg-1 de solucao salina, 4 mL.kg-1 de solucao lipidica com triglicerides de cadeia longa e 4 mL.kg-1 de solucao lipidica com triglicerides de cadeia media e longa. As alteracoes hemodinâmicas foram reavaliadas aos cinco, 10, 15, 20 e 30 minutos. RESULTADOS: A intoxicacao pela ropivacaina causou queda da pressao arterial e do indice cardiaco, principalmente, sem importantes alteracoes das resistencias vasculares. A terapia com as emulsoes lipidicas restaurou a pressao arterial atraves, principalmente, do aumento das resistencias vasculares, uma vez que o indice cardiaco nao apresentou melhoria expressiva. A emulsao lipidica com triglicerides de cadeia media causou aumento superior das resistencias vasculares, sobretudo pulmonares. CONCLUSAO: Nos grupos que receberam emulsoes lipidicas os resultados hemodinâmicos foram melhores do que no grupo controle; nao foram observadas diferencas da pressao arterial sistemica e do indice cardiaco entre os animais que receberam a solucao com triglicerides de cadeia longa e a mistura de triglicerides de cadeia media e longa.

Lipídeos nas intoxicações por anestésicos locais

- Com o advento dos anestesicos locais de longa duracao, a anestesia locorregional ganhou grande impulso sendo cada vez mais utilizada. Novas tecnicas de bloqueios foram descritas e a tecnica e frequentemente associada a anestesia geral com o objetivo de proporcionar analgesia pos-operatoria. A contra-partida e a necessidade da utilizacao de grandes doses com risco de acidentes por injecao intravascular inadvertida; trata-se de complicacao grave sem tratamento especifico ate ha alguns anos. Em 1998 foi proposta a utilizacao de emulsoes lipidicas em animais e a partir de 2006 varios trabalhos demonstraram o interesse dessas solucoes nos casos de intoxicacoes por anestesicos locais com diminuicao da morbi-mortalidade. O objetivo desta revisao foi fazer um levantamento da metodologia, revisando os mecanismos, interesses, limites e as condutas preconizadas atualmente.

Metadona e morfina na indução da anestesia em cirurgia cardíaca: repercussão na analgesia pós-operatória e prevalência de náuseas e vômitos

BACKGROUND AND OBJECTIVES: Pain is an aggravating factor in postoperative morbidity and mortality especially in large size surgeries. Methods to effectively fend pain collide with elevated costs and for this reason they are not accessible in every service. The option would be the use of an opioid with long half-life, such as methadone. The objective of the present study was to compare the requirements of postoperative analgesia in patients who received methadone, morphine, or placebo during anesthetic induction, besides the prevalence of postoperative nausea and vomiting. METHODS: Fifty-five patients scheduled for cardiac surgery were divided into three groups and they received during anesthetic induction 20 mg of methadone, 20 mg of morphine, or placebo. At the end of surgery, patients were transferred to the ICU where the following parameters were evaluated: duration of anesthesia, time until extubation, time until the need of the first analgesic, number of doses required in 24 hours, assessment of analgesia by the patient, and prevalence of nausea/vomiting. RESULTS: Differences in the duration of anesthesia and time until extubation were not observed. The first dose of analgesic in patients who received methadone was administered later than in patients in the other two groups. The need of analgesics in the methadone group was lower, quality of analgesia was better, and prevalence of nausea and vomiting was also lower. CONCLUSIONS: Methadone during anesthetic induction was effective for analgesia in large size surgeries. Lower incidence of nausea and vomiting was observed in the methadone group and therefore it is a low cost option available among us that should be stimulated.