Induction and maintenance of general anesthesia: Recent advances and clinical implications

• DOI: https://doi.org/10.22533/at.ed.1595332520117

• Palavras-chave: general anesthesia; anesthetic induction; anesthetic maintenance; hemodynamics; preoxygenation.

• Keywords: general anesthesia; anesthetic induction; anesthetic maintenance; hemodynamics; preoxygenation.

• Abstract:

  General anesthesia consists of a pharmacologically induced state of unconsciousness, analgesia, amnesia, and abolition of reflexes, organized into the phases of induction, maintenance, and emergence. This study aimed to critically review recent evidence related to the main agents and techniques used in the induction and maintenance of general anesthesia, as well as their most relevant clinical outcomes. This is a narrative review of the literature, based on a search conducted in the PubMed database, including articles published in the last five years, available in full text and directly related to contemporary anesthetic practices. The findings demonstrate that induction remains a particularly critical stage, especially in elderly patients, in whom hemodynamic instability is frequent regardless of the agent used. Although remimazolam has been proposed as a more stable alternative, recent studies show no significant reduction in the incidence of hypotension compared to propofol. In the field of preoxygenation, modern techniques—especially the use of high-flow nasal oxygen (HFNO) associated with an elevated head position—effectively prolong the time of safe apnea and reduce hypoxemic events. Regarding maintenance, propofol and sevoflurane have their own profiles, with no defined clinical superiority in cognitive or recovery outcomes, although biomarkers indicate greater neuronal stress related to volatile agents. In the pediatric population, it is noteworthy that monitoring anesthetic depth using the bispectral index (BIS) significantly reduces the incidence of emergency delirium. It is concluded that contemporary anesthetic safety depends on the integration of individualized agent selection, the application of optimized ventilation and preoxygenation strategies, and the systematic use of advanced monitoring to reduce complications and improve perioperative outcomes.
  At the same time, the latest innovations in personalized approaches to anesthesia have deepened the understanding that successful anesthesia goes beyond the choice of medication. Integrated actions focused on improving blood circulation, such as adjusting the dose based on real-time data and using vasopressors with caution at the beginning of the process, have proven effective in reducing the occurrence of cardiovascular problems. Similarly, current studies emphasize the need for a thorough preoperative assessment, taking into account aspects such as the patient's physical condition, heart and lung disease, and the risk of mental confusion or memory problems after surgery. During anesthesia, recent results confirm the usefulness of goal-directed anesthesia plans, which promote less fluctuation in how the body processes medications and a more predictable recovery. In addition, current research highlights the importance of careful pulmonary ventilation to reduce respiratory complications during and after surgery, especially in more vulnerable individuals. Therefore, it is clear that the quality of anesthesia outcomes depends on a comprehensive strategy focused on individual patient analysis and supported by advanced monitoring, well-structured perioperative planning, and decisions based on solid information.