the Impact of Noise on Requirements of Anesthetics During General Anesthesia

Study Overview
=================
Brief Summary
-----------------
The investigators hypothesize that the noise level in the operating theatre influences the patients' requirements of anesthetics. Study subject are patients undergoing abdominal surgery in combined general and epidural anesthesia. Analgesia is maintained by epidural injections of sufentanil and ropivacaine whereas general anesthesia is maintained using the inhalational anesthetic desflurane. Desflurane requirements are adjusted using neuromonitoring (BIS-Index). Intraoperative noise levels are recorded. Patients are randomized to receive hearing protections or not.

Detailed Description
-----------------
All patients receive standardized anesthesia and monitoring according to the usual clinical care in the department. Placement of epidural catheters takes place before induction of general anesthesia. Thereafter, 10 ml ropivacaine 0.3% with 10 µg sufentanil are administered epidurally every 60 min to induce and maintain analgesia during surgery. Following induction of general anesthesia and tracheal Intubation, intraoperative hypnosis is maintained using desflurane.

Conditions
-----------------
Anesthesia

Intervention / Treatment
-----------------
* Device: hearing protection


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: full contractual capability written informed consent abdominal surgery in combined general/epidural anesthesia position during surgery: supine clinically normal hearing Exclusion Criteria: history of psychiatric disease history of intraoperative awareness clinically impaired Hearing contraindication for placing an epidural catheter

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Design Details

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


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Sham Comparator: Control<br>Patients of the control group receive a Sham hearing protection with no effect on noise attenuation. | Device: hearing protection<br>* Attenuation of hearing during surgery<br>* Other names: PeltorTM OptimeTM III H540A, 3M, Värnamo, Sweden;|
| Active Comparator: Intervention<br>Patients of the Intervention group receive a Hearing protection with a noise attenuation of 20-45 decibel. | Device: hearing protection<br>* Attenuation of hearing during surgery<br>* Other names: PeltorTM OptimeTM III H540A, 3M, Värnamo, Sweden;|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Requirements of the Inhalational Anesthetic Desflurane, Measured in Expiratory Volume Percentage, to Maintain a BIS-Index Triggered Depth of Anesthesia | Aimed BIS-index is 50, desflurane is measured in expiratory volume percentage | one hour | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Awareness Using a Structured Interview (Modified Brice Questionnaire) | Using a structured interview (modified Brice questionnaire) to detect episodes of intraoperative awareness | 1 day | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Anesthesia, Inhalation, Hearing, Noise, Occupational