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World J Methodol. Oct 12, 2018; 8(2): 9-16
Published online Oct 12, 2018. doi: 10.5662/wjm.v8.i2.9
Towards a better understanding of anesthesia emergence mechanisms: Research and clinical implications
Marco Cascella, Sabrina Bimonte, Maria Rosaria Muzio
Marco Cascella, Sabrina Bimonte, Division of Anesthesia and Pain Management, Department of Supportive Care, Istituto Nazionale Tumori “Fondazione G. Pascale” - IRCSS, Naples 80131, Italy
Maria Rosaria Muzio, Division of Infantile Neuropsychiatry, UOMI-Maternal and Infant Health, ASL NA3 SUD Torre del Greco, Naples 80059, Italy.
Author contributions: Cascella M and Muzio MR contributed equally to this work, generated the table and wrote the manuscript; Bimonte S contributed to the writing of the manuscript.
Conflict-of-interest statement: All the authors declare no conflict of interest.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Marco Cascella, MD, Academic Fellow, Professor, Division of Anesthesia and Pain Management, Department of Supportive Care, Istituto Nazionale Tumori “Fondazione G. Pascale” - IRCSS, Via Mariano Semmola, Naples 80100, Italy. m.cascella@istitutotumori.na.it
Telephone: +39-81-5903586 Fax: +39-81-5903778
Received: June 29, 2018
Peer-review started: June 30, 2018
First decision: July 19, 2018
Revised: August 1, 2018
Accepted: August 26, 2018
Article in press: August 26, 2018
Published online: October 12, 2018
Processing time: 104 Days and 15.7 Hours
Abstract

Emergence from anesthesia (AE) is the ending stage of anesthesia featuring the transition from unconsciousness to complete wakefulness and recovery of consciousness (RoC). A wide range of undesirable complications, including coughing, respiratory/cardiovascular events, and mental status changes such as emergence delirium, and delayed RoC, may occur during this critical phase. In general anesthesia processes, induction and AE represent a neurobiological example of “hysteresis”. Indeed, AE mechanisms should not be simply considered as reverse events of those occurring in the induction phase. Anesthesia-induced loss of consciousness (LoC) and AE until RoC are quite distinct phenomena with, in part, a distinct neurobiology. Althoughanaesthetics produce LoC mostly by affecting cortical connectivity, arousal processes at the end of anesthesia are triggered by structures deep in the brain, rather than being induced within the neocortex. This work aimed to provide an overview on AE processes research, in terms of mechanisms, and EEG findings. Because most of the research in this field concerns preclinical investigations, translational suggestions and research perspectives are proposed. However, little is known about the relationship between AE neurobiology, and potential complications occurring during the emergence, and after the RoC. Thus, another scope of this review is to underline why a better understanding of AE mechanisms could have significant clinical implications, such as improving the patients’ quality of recovery, and avoiding early and late postoperative complications.

Keywords: Delirium; Anesthesia; Isoflurane; Propofol; Consciousness; Awareness; Electroencephalography

Core tip: Emergence from general anesthesia is not simply the reverse process of induction. The exhaustive knowledge of its complex neurobiological mechanisms is mandatory for avoiding or limiting a large number of anesthesia complications including altered mental status, and emergency awareness. Moreover, in a fascinating translational perspective, the study on this topic could provide new insights into the processes involved in cortical arousal, offering significant data to the research on brain arousal. On the other hand, research on the sleep-wake regulatory network, and on alterations in arousal processes could provide interesting suggestions for the general anesthesia research.