Pharmacology of general anesthetic agents in cardiac surgery: Pharmacokinetic and pharmacodynamic properties

INTRODUCTION: General anesthetic agents play a crucial role in cardiac surgery, providing analgesia, amnesia, muscle relaxation and control of autonomic responses. The appropriate choice of these agents is essential to ensure hemodynamic stability and minimize perioperative risks. Understanding the pharmacokinetic and pharmacodynamic properties of general anesthetics is essential to optimize anesthetic management in patients undergoing cardiac procedures. OBJECTIVE: This study aims to review and synthesize the recent literature on the pharmacokinetic and pharmacodynamic properties of the main general anesthetic agents used in cardiac surgeries, aiming to provide a knowledge base for clinical practice. METHODOLOGY: An integrative review was performed using the search terms "general anesthetics", "cardiac surgery", "pharmacokinetics" and "pharmacodynamics" in the SCIELO and PubMed databases, focusing on studies published in the last five years in Brazil. Sixty articles were initially identified, of which 35 were selected for detailed analysis based on their relevance and contribution to the topic. RESULTS: The main general anesthetic agents used in cardiac surgery include propofol, sevoflurane, and midazolam. Propofol, an intravenous agent, is widely used due to its rapid induction and recovery, as well as its antiemetic effect. Pharmacodynamically, propofol acts as a positive modulator of GABA-A receptors, promoting sedation and amnesia. Pharmacokinetically, it has a short half-life and rapid elimination. Sevoflurane, an inhalational anesthetic, is preferred due to its rapid induction and low blood solubility, allowing rapid adjustment of anesthetic depth. Pharmacodynamically, it reduces systemic vascular resistance and maintains hemodynamic stability. Pharmacokinetically, sevoflurane is eliminated predominantly by the lungs, with minimal hepatic metabolism. Midazolam, a benzodiazepine used as an adjuvant, provides anxiolysis and preoperative sedation. Pharmacodynamically, midazolam acts on GABA-A receptors, similar to propofol, but with a longer action. Pharmacokinetically, it has an intermediate half-life and is metabolized by the liver. CONCLUSIONS: The choice of general anesthetic agents should consider the specific pharmacokinetic and pharmacodynamic properties of each drug to ensure hemodynamic stability and patient safety during cardiac surgeries. Individualization of the anesthetic plan, based on the patient's clinical profile and the characteristics of the anesthetic agents, is crucial to optimize surgical outcomes.