Emergence from anesthesia: a winding way back

The effect of aminophylline on the recovery profile after hysterectomy: A randomized controlled double-blinded study

Background and Aims

In anesthesia practice, aminophylline is clinically used to treat bronchospasm. However, due to its antagonistic effect on adenosine, studies have recently focused on the drug's ability to enhance the recovery profile. The aim of this study was to investigate the hypothesis that the administration of aminophylline leads to better recovery after general anesthesia in hysterectomy.

Methods

This randomized controlled double-blinded study, was conducted at Alzahra academic hospital in Guilan, Iran. During December 2022 to March 2023, 70 eligible women scheduled for elective abdominal hysterectomy were divided into two groups. Group A: received 3 mg/kg IV aminophylline diluted in 100 mL of normal saline and Group C: received 100 mL IV normal saline. The time to recovery of consciousness, tracheal extubation and discharge from post anesthesia care unit were recorded. In addition, heart rate, and mean arterial blood pressure were measured at 10 point times including; baseline (T0), immediately before the administration of aminophylline (T1), every 5 min until the end of the surgery(T2,T3,T4,T5,T6), and every 15 min in PACU(T7,T8,T9).

Results

There was no significant difference in terms of demographic data between the study groups. Comparing the two groups, the time of ROC was shorter in Group A than group C; 5.95 ± 1.12 and 8.5 ± 1.77 for Groups A and C, respectively (p < 0.001). The extubation time was shorter in Group A than group C; 7.79 ± 1.48 and 10.55 ± 3.02, for Groups A and C, respectively (p < 0.001). In addition, the discharge time was also shorter in group A than Group C; 30.17 ± 5.24 and 37.57 ± 4.41 for Groups A and C, respectively (p < 0.001). Not serious side effects were reported among 71.4% of cases in Group A and 51.4% in Group C (p = 0.086).

Conclusion

Administration of aminophylline at a dose of 3 mg/kg IV improves the recovery profile after abdominal hysterectomy without serious adverse effects.

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

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.

Awareness during emergence from anesthesia: Features and future research directions

The anesthesia awareness with recall (AAWR) phenomenon represents a complication of general anesthesia consisting of memorization of intraoperative events reported by the patient immediately after the end of surgery or at a variable distance from it. Approximately 20% of AAWR cases occur during emergence from anesthesia. Clinically, these unexpected experiences are often associated with distress especially due to a sense of paralysis. Indeed, although AAWR at the emergence has multiple causes, in the majority of cases the complication develops when the anesthesia plan is too early lightened at the end of anesthesia and there is a lack of use, or misuse, of neuromuscular monitoring with improper management of the neuromuscular block. Because the distress caused by the sense of paralysis represents an important predictor for the development of severe psychological complications, the knowledge of the phenomenon, and the possible strategies for its prophylaxis are aspects of considerable importance. Nevertheless, a limited percentage of episodes of AAWR cannot be prevented. This paradox holds also during the emergence phase of anesthesia which represents a very complex neurophysiological process with many aspects yet to be clarified.

Towards a better understanding of anesthesia emergence mechanisms: Research and clinical implications

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.