We aim to assess, if placebo compared to preoperative administration of midazolam in elderly patients is equal in regard to the global postoperative patient satisfaction

Generalised premedication with benzodiazepines in all surgical patients has become questionable, regarding the risk-benefit assessment and the lack of evidence for this practice. Particularly, in elderly patients (≥65 years), a higher risk for adverse events is described.

Patients will be randomly assigned to one of the following two study groups. Preoperatively, group 1 will receive midazolam and group 2 will receive placebo.

Anaesthesia will be performed according to the clinical routine.

All possible side effects are described in the SmPC for midazolam. For the placebo-group, we do not expect any harm, as in the case of strong preoperative anxiety or agitation, additional midazolam application may occur on behalf of the attending anaesthesist at any time.

The sample size was calculated based on detecting a minimum of 5 unit difference in the primary outcome variable overall patient satisfaction measured with the EVAN-G. Setting a type 1 error of 0.05, a power of 0.8 and assuming the standard deviation of EVAN-G to be 14 units, 248 patients per group are needed to detect a 5 unit difference.

Considering a drop-out of 10% and a screening failure of 10%, we decided to include 614 patients in total.

The hypothesis of the study is that global patient satisfaction after surgery in elderly patients is similar after preoperative placebo application compared to midazolam application.

Inclusion Criteria:

1. 1. Only legally competent patients
2. Written informed consent prior to study participation
3. 65-80 years
4. Elective surgery
5. Expected surgery duration ≥ 30 minutes
6. Planned general or combined regional and general anaesthesia
7. Planned extubation at the end of surgery

Exclusion Criteria:

1. Age > 80 years
2. Age < 65 years
3. Non-fluency in German language
4. Alcohol and/ or drugs abuse
5. Chronic benzodiazepine treatment
6. Intracranial surgery
7. Local and stand by anaesthesia or solely regional anaesthesia
8. Monitored anaesthesia care
9. Cardiac surgery
10. Ambulatory surgery
11. Repeated surgery
12. Contraindications for benzodiazepine application (e.g. sleep apnoea syndrome, severe chronic obstructive pulmonary disease, allergy)
13. Allergy against any component of the Placebo (lactose monohydrate, cellulose powder, magnesium stearate, microcrystalline cellulose) or investigational drug (midazolam, lactose) or the capsules (gelatine, E171 titanium dioxide, E132 indigotine).
14. Expected benzodiazepine requirement after surgery
15. Expected continuous mandatory ventilation after surgery
16. Patients who explicitly request anxiolytic premedication
17. Patients with severe neurological or psychiatric disorders
18. Refusal of study participation by the patient
19. Parallel participation in interventional clinical studies within the last 30 days