Continuous regional anesthesia and inflammation: a new target

Inflammation can be defined as the host response when confronted with an aggression. The purpose of the inflammatory reaction is the defense of the host for re-establishing the baseline homeostasis of the organism. Compared to the neuroendocrine changes associated to the stress response to injury, the inflammatory reaction is the major determinant of patient's recovery in the perioperative period. Perioperative inflammation is involved in the occurrence of various postoperative adverse outcomes other than only acute pain. By consequence, perioperative strategies which limit or control the inflammatory response might have beneficial effects on patient's recovery. The present review summarizes the current knowledges on the interactions between some of these strategies, specifically regional anesthesia (RA) techniques, and inflammation in the context of perioperative medicine. Regional anesthesia through its components i.e. local anesthetics and analgesic adjuvants like alpha-2 adrenergic agonists (clonidine, dexmedetomidine) modulates the inflammatory response consecutive to tissue injury by various mechanisms, at different levels. While experimental studies have shown that RA techniques modulate both local and systemic inflammatory reactions, in contrast, clinical findings are inconsistent as actual RA techniques fail to impact major patients' outcomes beyond immediate postoperative analgesia. The discrepancy between experimental findings and clinical observations asks questions and argues for a different view of perioperative inflammatory processes, in other words for an individualized management of the patients. Future developments of tools to quantify inflammatory and immune profile of patients might certainly lead to exciting findings and to major improvements in perioperative medicine.