Anestesia General Multimodal: Teoría y Práctica

Balanced general anesthesia, the most common management strategy used in anesthesia care, entails the administration of different drugs together to create the anesthetic state. Anesthesiologists developed this approach to avoid sole reliance on ether for general anesthesia maintenance. Balanced general anesthesia uses less of each drug than if the drug were administered alone, thereby... + Leer más

Balanced general anesthesia, the most common management strategy used in anesthesia care, entails the administration of different drugs together to create the anesthetic state. Anesthesiologists developed this approach to avoid sole reliance on ether for general anesthesia maintenance. Balanced general anesthesia uses less of each drug than if the drug were administered alone, thereby increasing the likelihood of its desired effects and reducing the likelihood of its side effects. To manage nociception intraoperatively and pain postoperatively, the current practice of balanced general anesthesia relies almost exclusively on opioids. While opioids are the most effective antinociceptive agents, they have undesirable side effects. Moreover, overreliance on opioids has contributed to the opioid epidemic in the United States. Spurred by concern of opioid overuse, balanced general anesthesia strategies are now using more agents to create the anesthetic state. Under these approaches, called "multimodal general anesthesia," the additional drugs may include agents with specific central nervous system targets such as dexmedetomidine and ones with less specific targets, such as magnesium. It is postulated that use of more agents at smaller doses further maximizes desired effects while minimizing side effects. Although this approach appears to maximize the benefit-to-side effect ratio, no rational strategy has been provided for choosing the drug combinations. Nociception induced by surgery is the primary reason for placing a patient in a state of general anesthesia. Hence, any rational strategy should focus on nociception control intraoperatively and pain control postoperatively. In this Special Article, we review the anatomy and physiology of the nociceptive and arousal circuits, and the mechanisms through which commonly used anesthetics and anesthetic adjuncts act in these systems. We propose a rational strategy for multimodal general anesthesia predicated on choosing a combination of agents that act at different targets in the nociceptive system to control nociception intraoperatively and pain postoperatively. Because these agents also decrease arousal, the doses of hypnotics and/or inhaled ethers needed to control unconsciousness are reduced. Effective use of this strategy requires simultaneous monitoring of antinociception and level of unconsciousness. We illustrate the application of this strategy by summarizing anesthetic management for 4 representative surgeries.

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Los autores se basan en principios anatomo-fisiológicos (E. Brown) para plantear que el control efectivo del dolor perioperatorio implica actuar no solo sobre un hipotético único circuito nociceptivo sino varios. Estos circuitos están modulados por sustancias muy conocidas por los veterinarios (NMDA, alfa-2, AINEs, lidocaína, pero también... + Leer más

Los autores se basan en principios anatomo-fisiológicos (E. Brown) para plantear que el control efectivo del dolor perioperatorio implica actuar no solo sobre un hipotético único circuito nociceptivo sino varios. Estos circuitos están modulados por sustancias muy conocidas por los veterinarios (NMDA, alfa-2, AINEs, lidocaína, pero también opioides).

En la práctica implica que el control de varios de estos circuitos será más eficaz que centrarse en uno solo, como podría ser el uso exclusivo de opioides, pero sin plantear eliminar a estos últimos fármacos sino, probablemente, ajustar sus dosis. En medicina humana ello es relevante porque la analgesia perioperatoria se ha basado a veces casi exclusivamente en el uso de estos fármacos. Sin embrago, en medicina veterinaria la menor disponibilidad de opioides ha favorecido durante años el uso de fármacos como la ketamina, los sedantes alfa-2, los AINEs y técnicas locorregionales. La conclusión que puede extraerse de este planteamiento, aparentemente novedoso en medicina humana pero no veterinaria, es que debemos seguir combinando los fármacos veterinarios disponibles en para obtener un control eficaz del dolor.

Un aspecto quizás más novedoso es que el control perioperatorio del dolor no se basa solo en el empleo de analgésicos sino que también fármacos considerados no analgésicos, como el propofol o el isoflurano, también participan de forma implícita en la nocicepción. De ahí que el empleo combinado de fármacos durante la anestesia se englobe en un concepto más amplio de “Anestesia General Multimodal’

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