Anesthetic Agents and Their Clinical Applications

Introduction to Anesthetic Agents

The American Society of Anesthesiologists recommends the use of propofol for intravenous induction, volatile agents such as sevoflurane and isoflurane for maintenance, and various adjuncts including opioids, benzodiazepines, and neuromuscular blockers, each selected based on the specific procedure requirements and patient characteristics 1, 2

Propofol is characterized by rapid onset, smooth induction, and quick recovery due to its short half-life, and is considered safe for use in breastfeeding women with minimal transfer to breast milk (0.025%) 1
Thiopental is a rapid-acting barbiturate with very small amounts transferred to breast milk, requiring no waiting period before resuming breastfeeding 1
Etomidate provides hemodynamic stability during induction, with rapid redistribution from CNS and minimal amounts in breast milk 1
Ketamine is used for its sympathomimetic effects and analgesic properties, but should be used with careful monitoring as data on transfer to human milk is limited 1, 2

Nitrous oxide is often used as an adjunct to other agents due to insufficient potency to produce anesthesia alone, providing some analgesic effect and allowing reduction in doses of other agents, with rapid clearance after anesthesia by exhalation 1

Midazolam is a short-acting benzodiazepine commonly used for premedication and conscious sedation, with extensive first-pass metabolism resulting in low systemic bioavailability 1
Dexmedetomidine is an alpha-2 agonist used for sedation with minimal respiratory depression, but should be used with caution in breastfeeding women due to its half-life of approximately 2 hours 1

Succinylcholine is a depolarizing muscle relaxant with rapid onset and short duration, recommended at doses of 1-2 mg/kg for rapid sequence induction and intubation 1, 2
Rocuronium is a non-depolarizing agent commonly used as an alternative to succinylcholine, with higher doses (0.9-1.2 mg/kg) recommended for rapid sequence induction, and can be rapidly reversed with sugammadex 2

Fentanyl, remifentanil, and alfentanil are short-acting opioids commonly used during induction and maintenance, with remifentanil's ultra-short duration making it ideal for procedures requiring rapid recovery 1, 4
Morphine is the standard opioid for postoperative pain management 1
NSAIDs (ibuprofen, diclofenac, ketorolac) are used as part of multimodal analgesia 1, 4

The American College of Surgeons recommends either spinal or general anesthesia for procedures like hip fracture surgery, but not simultaneous administration due to risk of precipitous blood pressure drops 5
Rapid sequence induction is essential for patients at high risk of aspiration, such as those undergoing emergency laparotomy, requiring fast-acting muscle relaxant (succinylcholine 1-2 mg/kg or rocuronium 0.9-1.2 mg/kg) 2
Depth of anesthesia monitoring is particularly important in elderly patients to avoid excessive anesthetic depth, which may increase risk of postoperative delirium, with targeting lighter levels of anesthesia (BIS of 50 vs. 35) reducing postoperative delirium in older patients 2

Elderly patients require reduced doses of induction agents due to altered pharmacokinetics, and inhalational induction may be well-tolerated, allowing maintenance of spontaneous ventilation 5
Breastfeeding women can generally resume breastfeeding once they have recovered from anesthesia, as most commonly used anesthetics are considered safe with minimal transfer to breast milk 1, 6