Delayed Emergence from Anesthesia: What We Know and How We Act

Abstract

The emergence from anesthesia is the stage of general anesthesia featuring the patient's progression from the unconsciousness status to wakefulness and restoration of consciousness. This complex process has precise neurobiology which differs from that of induction. Despite the medications commonly used in anesthesia allow recovery in a few minutes, a delay in waking up from anesthesia, called delayed emergence, may occur. This phenomenon is associated with delays in the operating room, and an overall increase in costs. Together with the emergence delirium, the phenomenon represents a manifestation of inadequate emergence. Nevertheless, in delayed emergence, the transition from unconsciousness to complete wakefulness usually occurs along a normal trajectory, although slowed down. On the other hand, this awakening trajectory could proceed abnormally, possibly culminating in the manifestation of emergence delirium. Clinically, delayed emergence often represents a challenge for clinicians who must make an accurate diagnosis of the underlying cause to quickly establish appropriate therapy. This paper aimed at presenting an update on the phenomenon, analyzing its causes. Diagnostic and therapeutic strategies are addressed. Finally, therapeutic perspectives on the "active awakening" are reported.

Keywords: anesthesia emergence; delayed emergence; emergence delirium; general anesthesia.

Figure 1

Algorithm for delayed emergence management. In the case of delayed awakening, it is advisable to protect the airways and evaluate the level of consciousness (with any associated neurological signs). At the same time, it is necessary to begin to evaluate (and correct) the possible causes. In succession the most frequent causes must be checked (eg, dosage error, or residual effect of drugs). When no cause is clearly identifiable, it is appropriate to decide to carry out further diagnostic tests (eg CT scan). Legend: GCS, Glasgow Coma Scale; CT, Computed Tomography.