Agitation in adults after general anaesthesia

Fields A, Huang J, Schroeder D, Sprung J, Weingarten T. Agitation in adults in the post-anaesthesia care unit after general anaesthesia. Br J Anaesth. 2018;7(July):1–7.

“Fullness is always quiet; agitation will answer for empty vessels only.” – Amos Alcott.


Agitation after general anaesthesia is rare but can be associated with self harm and violence against staff. Postoperative agitation is also associated with hyperactive delirium.

Emergence agitation in adult surgical patients has not been as well studied as in children.


The aims of this study were to:

  • evaluate the prevalence of emergence agitation in adults after general anaesthesia
  • assess for potential associations between patient and perioperative factors and agitation
  • describe the postoperative course of adult patients who have had agitation episodes


The authors examined electronic case records for 207,569 adult patients undergoing surgery between July 2010 and September 2016 at the Mayo Clinic Hospital, MN, USA.  They identified 510 cases of agitation in this group that were matched to case controls by age and procedure.

Agitation was defined as a Richmond Agitation Sedation Scale (RASS) score of +3 / +4 or the administration of haloperidol.


The overall incidence of agitation was 510 patients (0.25%).

Variables associated with agitation were substance misuse, cognitive impairment, obesity, psychiatric problems, fall risk and the postoperative presence of an endotracheal tube, urinary catheter, nasogastric tube or chest drain.

Postoperative agitation was associated with postoperative delirium and pulmonary complications.


The authors suggest identification of risk factors for agitation will allow development of processes to ensure safe care.


Fields and colleagues have produced a retrospective case control study looking at perioperative factors associated with postoperative agitation.   We discussed the paper using the Critical Appraisal Skills Programme framework.

This paper is hypothesis generating but the methodology does not permit causative associations to be made.  We felt that several of the associations identified were plausible in line with our clinical experience.   The association of agitation with postoperative delirium and pulmonary complications is of clinical interest as postoperative morbidity is itself associated with reduced longterm survival.

The authors acknowledge in their discussion the likelihood of spurious associations being made when large numbers of variables are included.  Although we felt several of the associations were clinically plausible it is not possible to establish causation and there are likely to be unmeasured confounders.

Unfortunately the study design does not allow the association between agitation and age or procedure type to be established.

The primary outcome measure is agitation as defined in part by RASS score.  One of the criteria for RASS +3 is pulling at tubes.  We were not surprised therefore to see presence of tubes as a significant predictor of agitation.


This paper highlights the problem of postoperative agitation in a patient population similar to our own.  The methodology does not provide sufficiently robust evidence to recommend change in practice or policy at this time.

Summary by Dr Tom Salih




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