About this trial
Virtual reality (VR) uses computer technology to create a three-dimensional environment which the user can explore and interact with. VR can be used to distract the patient during an operation and has been used to avoid sedative premedication, increase patient satisfaction and decrease pain during nerve blocks. VR used alongside spinal anaesthetic for hip, knee and ankle operations has shown a trend of less sedation being required with no decrease in patient satisfaction.
The most common type of anaesthesia given during total knee arthroplasty (TKA) is spinal. Spinal anaesthesia is given unless there are complications or other conditions present, and general anaesthesia is given instead. General anaesthesia puts the patient to sleep during the operation, whereas spinal anaesthesia allows the patient to stay awake, but numbs the lower half of the body so no pain is felt. Sedation is usually given with spinal anaesthesia to make the patient relaxed and sleepy. Light sedation will allow the patient to be awake but relaxed, whereas deeper sedation means the patient is more likely to be asleep and less likely to recall what happened during the operation. Sedation can cause a number of side effects including nausea, vomiting, headache, drowsiness, pain, confusion, memory loss and breathing difficulties.
In this study, all patients will receive spinal anaesthesia. Group 1 will receive VR and a light level of sedation, whilst Group 2 will not receive VR but will receive a deeper level of sedation (standard of care). When using VR during TKA, a lighter level of sedation should be required. This could help to reduce side effects and aid quicker patient recovery. This pilot study aims to investigate this further.
Eligibility criteria
This trial does not accept healthy volunteersQualifiers
Patients ≥ 18 years old who are American Society of Anaesthesiologists (ASA) grade 1 or 2 scheduled for routine primary elective knee arthroplasty.
Disqualifiers
Patients who are ASA grade 3 or 4.
Patients who cannot use VR e.g. those with dementia.
Patients with an existing diagnosis of delirium.
Patients with visual impairment if degree of myopia/hyperopia exceeds the corrective power of the VR headset.
Trial design
Parallel
Treatments tested in this trial
Virtual Reality
Procedure/Surgery* VR * Spinal anaesthesia * Limited propofol aiming for OAA/S of 4-5 (light sedation)
Treatment groups
Trial outcomes
Primary outcomes
Feasibility of using VR during total knee arthroplasty with spinal anaesthesia
Feasibility of using VR during total knee arthroplasty will be assessed by recruitment numbers to the study and staff and patients will be asked for their views of using the VR equipment.
Secondary outcomes
4AT
The 4AT includes alertness, Abbreviated Mental Test 4 (AMT4), attention and acute change or fluctuating course. A score of 4 or above indicates possible delirium and/or cognitive impairment, a score of 1-3 indicates possible cognitive impairment and a score of 0 indicates that delirium or severe cognitive impairment is unlikely.
Logical Memory subtest of the WMS-IV UK
The Logical Memory subtest of the WMS-IV UK will be used to assess memory recall pre-operatively, at 1 hour (+/- 30 minutes) in recovery and at 24 hours (+/- 2 hours) following skin closure. Logical Memory I assesses narrative memory under a free recall condition. Logical Memory II is a delayed condition assessing long-term narrative memory with free recall and recognition tasks.
Total Propofol during operation
Total propofol administered during the operation will be recorded in mg/kg.
E-entropy
The e-entropy system uses a disposable 4-electrode sensor on the patient\'s forehead to measure electrical activity in the brain before using a proprietary algorithm to process the electroencephalogram data and calculate a number between 0 (absence of brain electrical activity) and 100 (wide awake) providing an objective measure of the patient's depth of consciousness. The average e-entropy score during the operation will be recorded by calculating a mean of the trend data from the monitor log.
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