Pharmacokinetics in regional anesthesia.

Abstract

Purpose of review: Pharmacokinetics of local anesthetics are one of the main determinants of success and safety of regional anesthesia and comprise local and systemic distribution phases. This review aims to summarize the latest research findings on this topic in the context of various regional blocks performed for different surgeries and patient populations.

Recent findings: Research into local kinetics and systemic absorption of local anesthetics has chiefly been focused on novel fascial plane blocks, especially the erector spinae plane block, as these are increasingly adopted for regional anesthesia and pain management. As their clinical efficacy is very dependent on injection of large volumes of local anesthetic, doses over typically recommended limits are often administered.

Summary: Fascial plane blocks are the regional anesthesia techniques in need of the most pharmacokinetic characterization, not only to better understand their complex mechanisms of action but also to avoid harm from excessive doses of local anesthetics. Further mapping of risk factors for systemic toxicity from administration in different block sites is crucial. Extremes of age and pregnancy are vulnerable patient populations but in whom regional anesthesia, including novel techniques, has been performed with few complications.