This prospective cohort study was conducted between March 2019 and January 2020 at KK Women’s and Children’s Hospital, Singapore. The study protocol adhered to the Strengthening the Reporting of Observational studies in Epidemiology (STROBE) guidelines and was approved by the SingHealth Centralized Institutional Review Board, Singapore (SingHealth CIRB Ref: 2018/2200), and registered on Clinicaltrials.gov (ID: NCT03685422).
Inclusion and Exclusion Criteria
Women aged 21 – 70 years old, American Society of Anesthesiologist (ASA) physical status I or II, with no visual or mental impairment and undergoing gynecological surgery were included in this study. Patients with severe motion sickness, significant respiratory disease or obstructive sleep apnea, oncological gynecology and obstetrics patients were excluded. Women who were unable to communicate in English or unable to understand the administered questionnaires were also excluded from this study.
Psychometric Assessment Tools Used
The State-Trait Anxiety Inventory (STAI) designed by Spielberger et al. has been used extensively in research and clinical settings . It has been used to measure the presence and severity of current symptoms of anxiety and a generalized propensity to be anxious. The tool consists of 40 items, 20 allocated each to state-anxiety and trait-anxiety. All items are rated on a 4-point Likert scale (e.g. from “Not at all” to “Very much so”; or from “Almost never” to “Almost always”).Test-retest reliability coefficients on initial development ranged from 0.31 to 0.86, with intervals ranging from 1 hour to 104 days .
The Hospital Anxiety and Depression Scale (HADS) is commonly used to assess the patients’ level of anxiety and depression during their hospitalization and is preferentially used as an indicator for global psychological distress . Each item on the questionnaire is scored from 0 to 3, thus a patient may have a total score from 0 to 21 for the anxiety and depression subscales, respectively. A score of 0-7 indicates normal level of anxiety/depression while 8-10 indicates borderline abnormal and 11-21 indicates abnormal. Validity of the HADS was deemed “good” to “very good”, with comparable sensitivity and specificity of longer scales including the STAI and the Symptom Checklist-90 anxiety scales . HADS has been validated in gynecological populations undergoing procedures, achieving good levels of internal consistency with Cronbach’s α of 0.78 and 0.84 for anxiety and depression subscales, respectively, and 0.88 for the whole instrument . As compared with conventional instruments that measure anxiety (e.g. STAI), the shorter HADS provides increased convenience for patients and allows for multiple measurements at different time points pre and post intervention.
The EuroQol 5-dimension 3-level (EQ-5D-3L) questionnaire  is one of the most widely used instruments for measuring health-related quality of life. It consists of a descriptive system on health state comprising five dimensions (5D) with three levels (3L) of self-reporting in each dimension: mobility, self-care, usual activities, pain/discomfort, and anxiety/depression; each dimension ranging from 1 to 3 to reflect level of impairment of “with no problem”, “with some problems” or “with severe problems”. The evaluation component involves a visual analog scale (VAS), asking to mark health state on the day of interview on a 20 cm vertical scale with end point of 0 and 100. Zero corresponds to "the worst health you can imagine" and hundred corresponds to "the best health you can imagine". For measuring patient satisfaction with regards to the VR intervention, a self-reported 4-point Likert scale with the following items: “Poor”, “Fair”, “Good” and “Excellent” was used. Pain score at rest was scored using a 0-10 Numerical Rating Scale (NRS).
Patients presenting to the day surgery service for a variety of minor gynecological procedures were initially screened by study investigators using the operative room surgical listing schedule. The investigators then evaluated the patient’s medical records to determine her eligibility. Patients meeting inclusion criteria were approached in a pre-operative holding area. Risks and benefits of the study were explained, and informed consent was obtained. No patient remuneration was provided in this study.
Pre-VR intervention assessments included demographic data, pain score and psychometric questionnaires (STAI, HADS and EQ-5D-3L; Figure 1). Patients were then given a Samsung Gear VR3 (Samsung Co. Ltd) headset and audio earpieces, fitted with a Samsung 8 smartphone (Figure 2A) running ‘Oculus Relax VR’ program (Figure 2C) . Disposable sanitary covers and earbuds were provided, that were discarded and replaced between each user (Figure 2B). Patients were given 11 immersive scenarios to choose from, and the experience was integrated with background meditation music and breathing exercises. The 11 scenarios included sceneries from a tropical beach in the Philippines, a rice terrace in the Philippines, wine glass bay beach in Australia, 12 Apostles in Australia, Fern Bern in New Zealand, a forest creek in Germany, a daisy garden in Germany, the Grand Canyon in the (United States of America) USA, watching northern lights in the USA, floating in the sky in clouds and being on the moon in outer space. The VR intervention was conducted with patients lying in bed in the fowler’s position with knees straight, in a quiet pre-operative waiting area. Patients were able to move their body freely in bed while on the headsets and were also instructed to discontinue the VR intervention if they experienced any side effects such as motion sickness or dizziness.
After the VR intervention, pain score, satisfaction score and psychometric assessments (HADS, EQ-5D-3L) were performed and collected. The VR intervention lasted for 10 minutes, with pre- and post-intervention surveys all done 1-2 hours before surgery. The patients subsequently underwent their intended surgical procedure under general anesthesia. Intra- and post-operative care provided adhered to standard hospital protocol. Data on intra- and post-operative analgesic use was also collected. Patients were all admitted to the day surgery unit in the hospital post-operatively before being further assessed to be discharged or for longer hospital stay. Data on analgesic use and pain score were also collected post-operatively in the recovery area.
The primary outcome for this study was the change in pre-operative anxiety as quantified by the HADS scale. The HADS anxiety scores pre- and post-VR were compared for data analysis. For secondary outcomes, EQ-5D-3L and patient satisfaction of the VR intervention were targeted and used for data analysis of the patient’s health state and anxiety levels.
Sample size calculation and statistical analysis
Tan et al.  reported difference in mean (SD) HADs anxiety between pre- and post-intervention in music experiences as 4.61 (4.08). The calculated sample size of 70 was based on the following assumptions: considering a conservative mean (SD) HADS difference of 2.0 (8.0), level of significance as 5% and power as 90%. After adjusting for 40% loss to follow up, ineligibility and withdrawal, a recruitment goal of 110 patients was targeted.
Categorical and continuous variables were summarized as frequency (proportion) and mean ± standard deviation (SD) respectively. Difference between pre- and post-VR experiences were compared using paired t – test and McNemar test for paired continuous and paired categorical data respectively. P-value < 0.05 was considered as statistical significance and all the tests were two – sided. Analyses were done using SAS version 9.4 software (SAS Institute; Cary, North Carolina, USA).