Changing Role of General Versus Regional Anesthesia in Clinical Practice

Abstract

An analysis of local anesthesia in past, present, and future clinical practice indicates that local and regional anesthesia will regain some of its earlier importance. The first era, as you all know, was started by the introduction of cocaine as a topical anesthetic agent in ophthalmology in 1884. This was followed by the synthesis of procaine in 1905 and, later, tetracaine in 1931. The esters of para-aminobenzoic acid marked the beginning of clinical regional anesthesia, as they were less toxic than cocaine. It has been said that the second era in regional anesthesia began with the synthesis of lidocaine in 1944. Lidocaine presented a new chemical class of local anesthetic compounds — the amide derivatives of diethylaminoacetic acid. It possessed distinctive advantages over procaine in terms of its greater potency and over tetracaine because of greater penetrating properties and a larger therapeutic ratio. This made it the drug of choice for various regional anesthetic procedures. Only in subarachnoid anesthesia, where penetration does not represent a problem, where relatively small doses are required and where there is markedly reduced systemic toxicity, did the longer-acting tetracaine maintain its position.