Nitrous oxide‐based vs. nitrous oxide‐free general anaesthesia and accidental awareness in surgical patients: an abridged Cochrane systematic review

Abstract

Summary Accidental awareness during general anaesthesia can arise from a failure to deliver sufficient anaesthetic agent, or from a patient's resistance to an expected sufficient dose of such an agent. Awareness is ‘explicit’ if the patient is subsequently able to recall the event. We conducted a systematic review into the effect of nitrous oxide used as part of a general anaesthetic on the risk of accidental awareness in people over the age of five years undergoing general anaesthesia for surgery. We included 15 randomised controlled trials, 14 of which, representing a total of 3439 participants, were included in our primary analysis of the frequency of accidental awareness events. The awareness incidence rate was rare within these studies, and all were considered underpowered with respect to this outcome. The risk of bias across all studies was judged to be high, and 76% of studies failed adequately to conceal participant allocation. We considered the available evidence to be of very poor quality. There were a total of three accidental awareness events reported in two studies, one of which reported that the awareness was the result of a kink in a propofol intravenous line. There were insufficient data to conduct a meta‐ or sub‐group analysis and there was insufficient evidence to draw outcome‐related conclusions. We can, however, recommend that future studies focus on potentially high‐risk groups such as obstetric or cardiac surgery patients, or those receiving neuromuscular blocking drugs or total intravenous anaesthesia.

Effects of Depth of Anesthesia Monitored by IoC on Patients Undergoing Laparoscopic Radical Resection of Colorectal Cancer

“…For instance, the accidental awareness during general anesthesia determines the success or failure of the surgery. 24,25 Previous research has revealed that the emergence of unintended awareness during the procedure of laryngoscopy is 1/25, and the collection of spontaneously self-reported awareness intra-operative of patients by the Royal College of Anesthetist Nation Audit Project showed that the incidence of surgical responsiveness was up to 1/800 in the United States in 2018. 26,27 BIS, which was previously considered as the most accurate anesthesia monitoring strategy, has been suggested to be affected by the variations in analgesic agents and patients' age, causing several complications such as hypertension, hypotension, hypoxemia, and accidental awareness during the surgery.…”

Regional versus general anesthesia for ambulatory total hip and knee arthroplasty

“…For most anesthesiologists a frequent conversation that occurs prior to surgery is one in which the patient requests that he or she ''does not want to hear or feel anything'' during surgery. Awareness under GA occurs very rarely [26], though it does occur. The level of sedation administered during surgery performed with regional anesthesia as the primary technique is variable with some centers opting for light or no sedation and others administering moderate to deep sedation.…”