New perspectives in regional anesthesia: the use of ultrasound-past, present, and future

Abstract

EGIONAL anesthesia is enjoying a renaissance. New pharmacological agents (e.g. pure isomers - ropivacaine, additives - clonidine) and a broad spectrum of techniques (both single injection and continuous catheter techniques) allow anesthesiologists to facilitate most surgical procedures with regional anesthesia alone or in combination with a general anesthetic. Nevertheless, a huge number of different techniques for blockade (e.g., for the psoas compartment block more than 20 puncture sites are described) are confusing and may be a reason that skepticism remains regarding the broad use of regional anesthesia in daily clinical practice. Some anesthesiologists still continue to use techniques that do not allow precise localization of targeted neuronal structures or may expose patients to unnecessary risk, such as loss of resistance techniques, blind infiltration, and the deliberate elicitation of paresthesia. In this regard it is no wonder that, when strong criteria are used, the success rates of some regional anesthetic techniques are rather low. The use of ultrasonographic guidance offers the advantage of performing blocks with direct visualization of all involved anatomical structures. Despite our enthusiasm for the use of ultrasound in regional anesthesia, most of the initial findings with this new application of ultrasound technology need further scientific evaluation and validation. This point was recently made in an editorial by Denny and Harrop-Griffiths. 1 For example, outcome studies examining the relative safety of various techniques are extremely difficult to perform because of the rarity of serious adverse events and the necessity for large sample sizes. Until these studies are done, we will have to rely on the experiences, expert opinion, and direction of a few experts in the field. This article reviews the history and the present status of ultrasonography in regional anesthesia, one of the most exciting technical developments during the past years in our speciality, and tries to describe a view for the future. History and presence of ultrasonography in regional anesthesia