Regional anaesthesia has many advantages but it might be a stressful and painful experience. Usually, the anesthetist administers a pharmacologic intravenous sedation to achieve patient's comfort. Though, these medications are not benign, and disadvantages include unpredictable response, adverse effects, and interference with cooperation. The virtual reality hypnosis distraction (VRHD) could be a good non-pharmacological technique to improve patient's comfort, decrease anxiety and procedure related pain. This study is a prospective study where sixty patients scheduled for orthopedic surgery requiring regional anesthesia were randomized in three groups according to the use or not of VRHD during the regional procedure or before as a complementary premedication. The anesthetic management during the regional procedure and the surgery remained otherwise standard for each patient. The first endpoint is the proportion of patients receiving pharmacological sedation (in the VRHD groups compared to the pharmacological sedation group). .

The second endpoint is to determine if the VRHD increases the patient's satisfaction of their anaesthetic management.

The third endpoint is to study various parameters of use of this specific anaesthetic management: time required for the installation and operation time of the VRHD device; the variation of haemodynamic parameters between the separate groups; pain procedure-related and behavioural pain scale scores between the separate groups.

Background Regional anesthesia has many advantages but it might be a stressful and painful experience and the anaesthetist has to establish all the necessary measures to maintain patient's comfort and cooperation. In practice, this ideal situation may be the most challenging part of the regional anesthetic practice. Usually, the anesthetist administers a pharmacologic intravenous sedation, including opioids and benzodiazepines to achieve patient's comfort. These medications are not benign, and disadvantages include possible unpredictable response, adverse effects, and hindered cooperation.

Among the non-pharmacologic techniques which may be used to improve the patient's comfort, decrease anxiety and procedure related pain, hypnosis and virtual reality distraction are increasingly used.

In spite of the encouraging scientific and clinical findings, hypnosis for analgesia is not universally used in medical centers. Its widespread use has been limited by factors such as the advanced expertise, time and effort required by clinicians to provide hypnosis, and the commitment required by patients to engage in hypnosis. It is a challenge to make hypnosis a standard part of care in this environment.

Improvements in technologies made virtual reality (VR) distraction a unique practical tool to provide an immersive, multisensory and three-dimensional (3D) environment that creates a sense of presence which enables to modify the perception of reality and to capture a greater degree of attention. Several theories have been proposed to explain how distraction may inhibit or decrease perception of pain by capturing a greater degree of attention. The "virtual reality analgesia" (= analgesia produces by virtual reality) is a product of the attentional distraction. Hoffmann et al. explained that there is a limit to the conscious attentional resources humans have available to process large amounts of incoming information. Conscious attention is required for pain perception. Hoffmann et al. theorize that the more immersive the VR system, the more attention will be drawn into the virtual world, leaving less attention available to process nociceptive signals.

Until now, VR shows an interest in numerous clinical applications (to help treat anxiety disorders, control pain, support physical rehabilitation, and distract patients during wound care) VR technology guides the patient through the same steps used when hypnosis is induced through an interpersonal process. With attentional mechanisms as a common denominator, the attention-captivating qualities of virtual reality and the suggestion inherent in hypnosis, the potential for a synergistic effect between these modalities is significant.

Using a device which combined the advantage of VR technology and hypnosis could probably improve the patient's comfort, decrease his anxiety and procedure related pain.

The first endpoint consist in a significant minimal decrease of 50% of the requirement of IVS delivered to the patient throughout the regional performance, in comparison to the IVS group when using VRHD.

The second endpoint is to determine if VRHD increases patient's satisfaction concerning their anaesthetic management.

The third endpoint is to study various parameters of this specific anesthetic management: time required for the installation and operation time of the VRHD device; variation of haemodynamic parameters; pain procedure-related and behavioural pain scale scores.

Methods Our study is a prospective randomized study. The protocol was approved by the Independent Ethics Committee from Erasmus Hospital.

Written Informed consent was obtained from all participating subjects. Subjects were randomized by the use of a computer-generated random table. Sixty patients scheduled for orthopaedic surgery needing regional anaesthesia are randomized according to the used of VRHD during the regional procedure or before as a complementary premedication.

The patients and the anesthetist in charge of the patient were not blinded but the data collection and statistical analysis were blinded.

Anesthesia management The anesthetic management was standardized for each patient. All subjects were fasting from midnight and premedicated with 0,25-0,5 mg alprazolam per os one hour before the procedure.

During the regional block, the surgical asepsis was respected and the regional block was performed under ultrasound guidance (machine Epic or Philips…). A basic monitoring was installed (EKG (electrocardiogram), NIBP (non-invasive blood pressure), SpO2 (pulse oximetry saturation). A 18 gauge catheter was placed in a vein. To avoid hypoxemia, all patients benefited of a supplemental nasal oxygen (3l/min) if the SpO2 < 95%.

Intraoperatively, the patient was maintained under sedation or general anesthesia according to the surgical prerequisites.

In the postoperative period, standard care was provided to the patient at the postoperative care unit according the American society of anesthesiologists (ASA) recommendations.

Study protocol In the control group, the patient received the standard pharmacologic intravenous sedation before the regional anaesthesia (2 mg midazolam + 5 µg de sufentanil) without VRHD.

In the study group VRHD 1, the patient received the VHRD technique during the peripheral nerve block and received a pharmacologic intravenous sedation only if the patient's asked for it or if the patient shows some discomfort (behavioural pain scale score >3).

In the study group VRHD 2, the patient received the VHRD technique a first time before the regional procedure and a second time during the peripheral nerve block. The patient received a pharmacologic intravenous sedation only if the patient's asked for it or if the patient shows some discomfort (behavioural pain scale score >3).

Virtual reality hypnosis distraction protocol The VHRD technique is the program of OncomfortTM (Oncomfort Inc, Houston, USA). The OncomfortTM device include the hyper vision 3D virtual reality glasses and disposable single-patient-use headphones. The program is an immersive experience focused on inducing relaxation environment and this program exists in durations of 5,15 and 30 minutes.

In the group VHRD 1 and 2, the investigators use the program throughout the regional block. The duration chosen for the VHRD program was 15 or 30 min depending of the time required for the regional procedure.

In the group VHRD 2, the investigators use the program of 5 min for the session occuring before the regional procedure, followed by a 15 or 30 min program during the regional procedure.

Patients were coached by a separate practitioner aside from the regional anesthesiologist performing the regional block.

Study Outcomes The first endpoint consist in a significant minimal decrease of 50% of the requirement of IVS (opioids (µg) and benzodiazepine (mg)) delivered to the patient throughout the regional performance, in comparison to the IVS group when using VRHD.

The second endpoint is to determine if the VRHD increases the patient's satisfaction of their anaesthetic management.

The third endpoint is to study various parameters of this specific anesthetic management: time required for the use and installation of the VRHD device; variation of hemodynamic parameters between the separate groups, pain procedure-related and behavioural pain scale scores between the separate groups;

Statistical Analysis As the first endpoint is to determine if the VRHD decreases the need of pharmacologic intravenous sedation of 50%, the sample size (N=60) is determined by an intention-to-treat test (control group n=20, VRHD 1 n= 20 and VRHD n= 20).

Inclusion Criteria:

undergoing elective orthopedic surgery with regional anaesthesia (peripheral nerve block), were aged ≥ 18 years

Exclusion Criteria:

ASA (American Society of anesthesiologists) IV, spinal anesthesia, claustrophobia, blindness, deafness, unable to complete a satisfaction survey, previously documented history of neurologic disease, lack of written informed consent, urgent surgery, allergy to a drug used within the study, ongoing pregnancy, patient's infectious isolation

Patients were coached by a separate practitioner aside from the regional anaesthesiologist performing the regional block. The anesthetists in charge of the patient were not blinded, but data collection and statistical analysis were blinded.