Dreaming During Anesthesia and Anesthetic Depth in Elective Surgery Patients Under General Anesthesia

Study Overview
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Brief Summary
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Dreaming is a common, enduring, and fascinating part of the anesthetic experience, but its cause and timing remain elusive. Patients typically report that they were dreaming during anesthesia, but the actual timing of anesthetic dreaming is unknown. The following evidence supports the hypothesis that dreaming occurs intraoperatively and is related to light or inadequate anesthesia: (1) The incidence of dreaming has decreased as anesthetic techniques have improved; (2) dreamers exhibit more clinical signs of light anesthesia or report more awareness than non dreamers; (3) dreamers may receive lower doses of anesthetic drugs than non dreamers and emerge more rapidly from anesthesia; (4) the content of dreams may involve surgical topics or events occurring during anesthesia; and (5) in one study, the incidence of dreaming was lower in Bispectral Index (BIS)-monitored patients. Alternatively, dreaming may occur during emergence from anesthesia, when the brain is still affected by sedative concentrations of anesthetic drugs and the patient enters a sleep state. Few studies have assessed the relation between dreaming and depth of anesthesia, and their results were inconclusive.Most recently, in the B-Aware Trial, no differences in depth of anesthesia, as measured by BIS, were detected between dreamers and non dreamers. However, the patients were at high risk of awareness, and BIS data were collected manually and were only recorded in the BIS group and during maintenance. No studies investigating the relation between dreaming and depth of anesthesia during recovery were identified. Why is the investigation of dreaming during anesthesia important? Dreaming is one of the most common side effects of anesthesia but remains puzzling and requires explanation. Dreaming is sometimes distressing to patients and may decrease satisfaction with care. Some patients who report dreaming fear that their anesthetic was inadequate and that their experience was, in fact, awareness. Indeed, in a minority of cases, dreaming may truly represent near-miss awareness. The investigators therefore tested the hypothesis that dreaming during anesthesia is associated with light or inadequate anesthesia, as evidenced by higher median BIS values during maintenance of anesthesia. The investigators also explored the depth of anesthesia until emergence, the form and content of dreams, the predictors of dreaming during anesthesia, and the effect of dreaming on quality of recovery and satisfaction with anesthetic care

Official Title
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Dreaming During Anesthesia and Anesthetic Depth in Elective Surgery Patients Under General Anesthesia

Conditions
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Dreaming, General Anesthesia

Intervention / Treatment
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* Device: deep anesthesia depth
* Device: light anesthesia depth


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: between 18 and 70 years with an ASA physical status of I or II Exclusion Criteria: presence of sleep disorders pain syndrome cardiovascular disease sleep apnea syndrome psychosis history of opioid usage history of abnormal operation or anesthesia recovery unwillingness to provide informed consent a patient with a language communication disorder

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 70 Years

Sexes Eligible for Study
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Female

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: BIS 40-50 Group<br>The anesthesiologist adjusted the intravenous speed of remifentanil and propofol to maintain the bispectral index (BIS, BIS monitor; Aspect Medical System, Newton, MA) between 40-50 | Device: deep anesthesia depth<br>* The anesthesiologist adjusted the intravenous speed of remifentanil and propofol to maintain the bispectral index (BIS, BIS monitor; Aspect Medical System, Newton, MA) between 40-50 and 50-60 during the operation.<br>|
| Experimental: BIS 50-60 Group<br>The anesthesiologist adjusted the intravenous speed of remifentanil and propofol to maintain the bispectral index (BIS, BIS monitor; Aspect Medical System, Newton, MA) between 50-60 during the operation. | Device: light anesthesia depth<br>* The anesthesiologist adjusted the intravenous speed of remifentanil and propofol to maintain the bispectral index (BIS, BIS monitor; Aspect Medical System, Newton, MA) between 40-50 and 50-60 during the operation.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Mean blood pressure | record mean blood pressure during the surgery. Systolic, diastolic, or both pressures don't need to be assessed during the study period. | 5 minutes after entering the operation room | 
| Mean blood pressure | record mean blood pressure during the surgery. Systolic, diastolic, or both pressures don't need to be assessed during the study period. | procedure (anesthesia induction) | 
| Mean blood pressure | record mean blood pressure during the surgery. Systolic, diastolic, or both pressures don't need to be assessed during the study period. | at the end of surgery | 
| Mean blood pressure | record mean blood pressure during the surgery. Systolic, diastolic, or both pressures don't need to be assessed during the study period. | procedure (anesthesia extubation) | 
| Mean blood pressure | record mean blood pressure during the surgery. Systolic, diastolic, or both pressures don't need to be assessed during the study period. | the time when leaving the operation room | 
| heart rate | record heart rate during the surgery | 5 minutes after entering the operation room | 
| heart rate | record heart rate during the surgery | procedure (Anesthesia induction) | 
| heart rate | record heart rate during the surgery | at the end of surgery | 
| heart rate | record heart rate during the surgery | procedure (anesthesia extubation) | 
| heart rate | record heart rate during the surgery | the time when leaving the operation room | 
| Bispectral Index (BIS) | record BIS during the surgery. The range was 0-100. We control the range of BIS in 40-60 during the surgery | 5 minutes after entering the operation room | 
| Bispectral Index (BIS) | record BIS during the surgery. record BIS during the surgery. The range was 0-100. We control the range of BIS in 40-60 during the surgery | procedure (Anesthesia induction) | 
| Bispectral Index (BIS) | record BIS during the surgery. record BIS during the surgery. The range was 0-100. We control the range of BIS in 40-60 during the surgery | at the end of surgery | 
| Bispectral Index (BIS) | record BIS during the surgery. record BIS during the surgery. The range was 0-100. We control the range of BIS in 40-60 during the surgery | procedure (anesthesia extubation) | 
| Bispectral Index (BIS) | record BIS during the surgery. record BIS during the surgery. The range was 0-100. We control the range of BIS in 40-60 during the surgery | the time when leaving the operation room | 
| Total dose of propofol | record total dose of propofol | at the end of surgery | 
| Dream | Dreaming during anesthesia was defined as any experience that was described by the patient as dreaming and was thought by the patient to have occurred between the induction of anesthesia and the first moment of consciousness after anesthesia.27 Awareness was defined as postoperative recall of intraoperative events. All patients who reported dreaming were considered to be dreamers for the purpose of the analyses, whether or not they could remember the narrative of the dream. However, only dreaming reports where the narrative was remembered were classified using five-point Likert scales as follows Emotional content (1 very negative; 5 very positive) ● Memorability (1 can't remember narrative of dream; 5 most memorable ever) ● Visual vividness (1 not at all vivid; 5 most vivid ever) ● Amount of sound (1 no sound; 5 most sound ever) | at the end of surgery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Postoperative adverse effects | record postoperative adverse effects | 24 hours after surgery |