Reduction of Intraoperative EEG Burst Suppression
- Conditions
- EEG With Abnormally Slow FrequenciesPostoperative DeliriumBurst Suppression
- Interventions
- Other: Treatment of hypotension and/or reduction of anesthetics
- Registration Number
- NCT03775356
- Lead Sponsor
- Technical University of Munich
- Brief Summary
Burst suppression (BS) is a not physiological pattern in the electroencephalogram (EEG). BS during general anesthesia is mainly seen as a sign for too deep hypnosis and may increase the risk of postoperative delirium (POD), a disturbance of consciousness arising within 24 hours after surgery. This monocentric, simple masked randomized study aims primarily to investigate, whether particular anesthesiological interventions reduce the occurrence of intraoperative burst suppression. The investigator initiated trial includes 66 patients (male and female) aged ≥ 60 years in two groups (intervention and control group). Secondary aims will be the correlation of burst suppression and mean arterial pressure, concentration of anesthetics and postoperative delirium.
- Detailed Description
Intraoperative burst suppression represents a non physiological EEG pattern. According to the literature and scientific knowledge, intraoperative burst suppression patterns might be caused either by hypotension resulting in a reduced cerebral circulation or by an oversedation of anesthetics correlating with a very deep level of hypnosis.
Some publications exist that discuss the occurrence of intraoperative burst suppression especially in elderly people (aged ≥ 60 years) as a predictor of postoperative delirium and postoperative cognitive dysfunction.
None of the studies however was able to prove a causal relationship between burst suppression and postoperative delirium. Contrary it might simply be an epiphenomenon.
Conducting this interventional trail primarily aims to prove whether specific anesthesiological interventions, such as the treatment of intraoperative hypotension in first line and/or the reduction of the concentration of anesthetics in second line, reduce intraoperative burst suppression. Hence it might be possible to investigate a possible casualty between burst suppression and postoperative delirium in a second trial.
Recruitment & Eligibility
- Status
- COMPLETED
- Sex
- All
- Target Recruitment
- 106
- Age ≥ 60 years
- Surgical interventions in general anesthesia (volatile or total intravenous anesthesia)
- expected surgery duration ≥ 1h
- American Society of Anesthesiologists (ASA) 1-4
- written informed consent prior to study participation
- Neurological or psychiatric disorders
- hearing difficulty
- deafness
- neurosurgical (intra)cranial surgery
- pregnancy
- expected continuous mandatory ventilation after surgery
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- PARALLEL
- Arm && Interventions
Group Intervention Description 2 - Unblinded Treatment of hypotension and/or reduction of anesthetics EEG and Entropy will be unblinded. The intervention starts with the start of a positive burst suppression rate. In the case of a concurrent hypotension the anesthetist treats the hypotension according to clinical standard operations in the first step. Hypotension means blood pressure values blow the baseline value which is defined by the lowest, preoperatively measured value. If after this treatment and a reevaluation of the BSR, BSR remains positive, the anesthetist is going to reduce the concentration of anesthetics in a second step. In case of positive BSR and a blood pressure value ≥ the baseline value, the concentration of anesthetics will be reduced as a first measure. The aim is to figure out whether one or both of these interventions can reduce to total, cumulative BSR.
- Primary Outcome Measures
Name Time Method Chance of the total, cumulative burst suppression rate. During general anesthesia and within the intervention The total, cumulative burst suppression rate (BSR) corresponds to area under the curve and is defined by the BSR (%) and the absolute duration of BSR (t).
- Secondary Outcome Measures
Name Time Method Burst suppression rate during maintenance. During maintenance within the intervention Rate of change of the burst suppression ratio during maintenance.
Postoperative delirium. Within the first three postoperative days Screening of the patients regarding a postoperative delirium by a brief confession assessment method (bCAM).
Burst suppression rate during induction. During induction within the intervention Rate of change of the burst suppression rate during induction.
Mean arterial blood pressure. During burst suppression within general anesthesia Evaluation of the mean arterial blood pressure with positive burst suppression rate.
Endtidal anesthetic concentration (ETAC) and infusion rate of propofol. During burst suppression within the intervention Evaluation of the mean ETAC and infusion rate of propofol.
Specific characteristics of the EEG frequency spectrum during burst suppression During burst suppression within general anesthesia Evaluation of specific EEG frequencies differentiating BSR caused by hypotension or oversedation of anesthetics.
Trial Locations
- Locations (1)
Klinikum rechts der Isar - Klinik fuer Anaesthesiologie und Intensivmedizin
🇩🇪München, Bayern, Germany