Do Noise Cancelling Headphones Reduce Patient Controlled Midazolam Requirements in Primary Knee Arthroplasty Patients Under Spinal Anaesthesia

The study is for patients undergoing elective primary knee replacement surgery under spinal anaesthesia. It is proposed that using music played on noise cancelling headphones will reduce the requirements for intravenous sedation in a randomised controlled trial of twenty patients. Spinal anaesthesia is commonly used for knee replacement. It provides loss of feeling from the operated limb but the patient remains awake. Orthopaedic surgery is very noisy. It is usual for patients to receive intravenous sedation with midazolam to reduce their awareness of surgery. Intravenous midazolam is effective but it depresses both the breathing and the circulation and may cause low blood pressure and reduced oxygenation. It is expected that by using noise cancelling headphones to reduce the awareness of noise during surgery, there will be a reduced requirement for intravenous midazolam. The study will measure the dose of midazolam required by patients randomised to receive either noise cancelling headphones playing music (intervention) or no headphones (control group). Patients will be followed up prior to hospital discharge to assess their awareness and recall of intra operative events and their satisfaction with intravenous sedation. This is a novel application of sound reducing technology capable of improving the patient experience during surgery whilst potentially reducing complications of intravenous midazolam sedation. Noise cancelling technology is readily available in commercially available headphones and it has the potential to eliminate background noise of surgical procedures. This study findings will be of interest for health professionals and patients involved in surgery or investigative procedures normally carried out with intravenous sedation.