Before opioids became a staple in anesthesia practice in the late 1960s, achieving anesthesia involved inhaled anesthetics and/or high doses of Pentothal, which often led to hemodynamic instability and necessitated additional support due to their suppressive effects on hemodynamics.
The adoption of opioids introduced "balanced anesthesia," appreciated for its cardiovascular neutrality. Opioids enhance hemodynamic stability by suppressing the sympathetic system, making them a favored choice during induction for their potent analgesic properties and contributing to the concept of balanced anesthesia as an integral component.
The shift to opioids was particularly pivotal as earlier hypnotics were marked cardiovascular depressants, posing risks to patients with undiagnosed or untreated cardiovascular conditions. High doses of opioids allowed anesthesia providers to lower the required amounts of hypnotics and muscle relaxants, improving patient safety. Nowadays, the advancement in hypnotics and neuromuscular blocking agents allows for precise titration to achieve desired hypnosis and muscle relaxation levels with minimal cardiovascular risk. Furthermore, cardiovascular issues are generally diagnosed and managed before elective surgery in current practice.
Presently, alternatives like alpha-2 agonists (e.g., clonidine, dexmedetomidine), intravenous local anesthetics (lidocaine), and magnesium offer ways to stabilize the sympathetic nervous system, while agents like gabapentin reduce opioid needs by binding the alpha-2-delta subunit of voltage-gated calcium channels; gabapentinoids are structural analogues of GABA but do not act through GABA receptors. Employing these drugs in a high enough dose or in a multimodal strategy can reduce or even eliminate the need for intraoperative opioids, thereby minimizing sedation risks. This multimodal approach also significantly cuts down postoperative opioid requirements for analgesia, showcasing the benefits of diversified analgesic strategies in modern anesthesia practice.
