The fascinating history of local anesthetics (LAs) began in South America with the herbal and traditional use of cocaine leaves by the indigenous peoples of Peru and Bolivia, the sacred plant of the Incas Erythroxylum coca. The use for anesthetic purposes dates back to 1884. Since then, the evolution of LAs has been closely related to research motivated by its efficacy and safety versus toxicity. According to their chemical structure, these drugs are classified into two main groups: esters and amino amides; however, there are three LAs with different characteristics: articaine, sameridine, and centbucridine. The pharmacological and toxic mode of action is primarily in the voltage-dependent sodium channels located in the cell membrane, which clinically produces analgesia, anesthesia, seizures, arrhythmias, and cardiac arrest. The quality of anesthesia and analgesia depends on the type of LA, dose, and application technique, while the deleterious effects are secondary to its plasma concentration. Nonanesthetic properties of LAs such as their antimicrobial, antineoplastic, antiarrhythmics, antitussive, and antiasthmatics effects have been described and are briefly reviewed.
Part of the book: Topics in Local Anesthetics
The shoulder joint and clavicle are innervated by the brachial plexus, the cervical plexus, and nerves to muscles around the joint and clavicle. Regional anesthesia is aimed at producing optimal surgical conditions, prolonging postoperative analgesia, being free of complications, reducing costs, and minimizing hospital stay. Regional upper extremity anesthesia can be achieved by blocking the brachial plexus at different stages along the course of the trunks, divisions, cords, and terminal branches. The gold standard of regional anesthesia for shoulder surgery is interscalene brachial plexus block plus cervical plexus block, but it is associated with a high rate of neurological complications and phrenic nerve block. The interest of the anesthesiologist has been directed towards regional blocks avoiding these complications; techniques that approach nerves more distally than interscalene block have been described. These approaches include supraclavicular nerves, upper trunk, suprascapular nerve by anterior approach, axillary nerve block in the axillary fossa, clavipectoral fascia block. The objective of this chapter is to describe the anatomy, sonoanatomy, technique, and the clinical utility of these accesses.
Part of the book: Topics in Regional Anesthesia
The globalized coronavirus pandemic 2019 has kept us on our toes. Although confusion is widespread and there is a trend toward normalization of almost all human activities, outbreaks remain frequent. The majority of patients with COVID-19 have a trivial to moderate clinical course; a small group develops severe pneumonia and other life-threatening complications. Vaccination against this virus has contributed to better control of the pandemic, but there are no antiviral drugs that have demonstrated efficacy; therefore, the management of surgical patients confirmed or suspected of this disease is a challenge for health care workers, including the anesthesiologists, as well as the non-COVID-19 patients who at a given moment could become carriers or sick. General anesthesia produces aerosols and risks medical and technical personnel being infected, especially those who manage the airway. On the other hand, regional anesthesia has advantages over general anesthesia because the airway is not handled; however, its limited duration is the most important concern. It is reasonable that regional anesthesia occupies a preponderant place in the safe management of all patients, as long as the type of surgery allows it, the anesthesiologist has sufficient skills and patients accept the proposed technique. At this time of globalized crisis due to COVID-19, the intrapandemic anesthetic management of patients undergoing surgery continues to be a changing task, a challenge that has been solved as new data based on solid scientific evidence arise, besides the development of drugs, safer vaccines, equipment, and health prophylactic methods. There is a clear tendency to use regional anesthesia whenever this is possible.
Part of the book: Topics in Regional Anesthesia