Retrograde amnesia after intravenous sedation and general anaesthesia in a dental hospital

Comparison of Effects of Stress and Midazolam on Retrograde and Anterograde Amnesia in Patients Undergoing General Anesthesia

Background

The identification of different factors affecting anesthesia and physiological changes during anesthesia can be effective in improving the quality of anesthesia. Midazolam is a benzodiazepine that has been used for many years for sedation under anesthesia. Stress is also an important factor affecting memory and other physiological changes, such as blood pressure and heart rate.

Objectives

his study aimed to investigate the effects of stress on retrograde and anterograde amnesia among patients undergoing general anesthesia.

Methods

This multi-center, parallel, stratified, randomized controlled trial was performed on patients undergoing non-emergency abdominal laparotomy. The patients were divided into high- and low-stress groups according to the Amsterdam Preoperative Anxiety and Information Scale. Then, both groups were randomly divided into three subgroups receiving 0, 0.02, or 0.04 mg/kg of midazolam. Recall cards were shown to patients at 4 minutes, 2 minutes, and immediately before injection to determine retrograde amnesia and at 2 minutes, 4 minutes, and 6 minutes after injection to determine anterograde amnesia. Hemodynamic changes were recorded during intubation. The chi-square and multiple regression tests were used to analyze the data.

Results

Midazolam injection was associated with the development of anterograde amnesia in all groups (P < 0.05); however, it had no effect on the development of retrograde amnesia (P < 0.05). Midazolam could decrease the systolic and diastolic blood pressure and heart rate during intubation (P < 0.05). Stress also caused retrograde amnesia in patients (P < 0.05); nevertheless, it had no effect on anterograde amnesia (P > 0.05). Stress and midazolam injection could not affect the oxygen levels during intubation.

Conclusions

The results showed that midazolam injection could induce anterograde amnesia, hypotension, and heart rate; nonetheless, it had no effect on retrograde amnesia. Stress was associated with retrograde amnesia and increased heart rate; however, it was not associated with anterograde amnesia.

Sevoflurane-induced amnesia is associated with inhibition of hippocampal cell ensemble activity after learning

General anesthesia could induce amnesia, however the mechanism remains unclear. We hypothesized that suppression of neuronal ensemble activity in the hippocampus by anesthesia during the post-learning period causes retrograde amnesia. To test this hypothesis, two experiments were conducted with sevoflurane anesthesia (2.5%, 30 min): a hippocampus-dependent memory task, the context pre-exposure facilitation effect (CPFE) procedure to measure memory function and in vivo calcium imaging to observe neural activity in hippocampal CA1 during context exploration and sevoflurane/home cage session. Sevoflurane treatment just after context pre-exposure session impaired the CPFE memory, suggesting sevoflurane induced retrograde amnesia. Calcium imaging showed sevoflurane treatment prevented neuronal activity in CA1. Further analysis of neuronal activity with non-negative matrix factorization, which extracts neural ensemble activity based on synchronous activity, showed that sevoflurane treatment reduced the reactivation of neuronal ensembles between during context exploration just before and one day after sevoflurane inhalation. These results suggest that sevoflurane treatment immediately after learning induces amnesia, resulting from suppression of reactivation of neuronal ensembles.

Patient perspectives on interventional pain management: thematic analysis of a qualitative interview study

Background

Chronic pain is a widespread problem that is usually approached by focusing on its psychological aspects or on trying to reduce the pain from the pain generator. Patients report that they feel responsible for their pain and that they are disempowered and stigmatized because of it. Here, we explored interventional pain management from the patient’s perspective to understand the process better.

Methods

A purposive sample of 19 subjects was interviewed by an independent interviewer. The interviews were transcribed into text and thematic analysis was performed.

Results

The subjects’ perceptions covered three key themes: themselves as objects; the caregivers, including the process of tests and retests, the encounters and interactions with professionals, and the availability of the caregivers; and finally the outcomes, including the results of the tests and treatments and how these inspired them to think of other people with pain. Linking these themes, the subjects reported something best described as “gained empowerment” during interventional pain management; they were feeling heard and seen, they gained knowledge that helped them understand their problem better, they could ask questions and receive answers, and they felt safe and listened to.

Conclusions

Many of the themes evolved in relation to the subjects’ contact with the healthcare services they received, but when the themes were merged and structured into the model, a cohesive pattern of empowerment appeared. If empowerment is a major factor in the positive effects of interventional pain management, it is important to facilitate and not hinder empowerment.

Trial registration

Clinicaltrials.gov 2013-04-24 (Protocol ID SE-Dnr-2012-446-31 M-3, ClinicalTrials ID NCT01838603).