The virtual reality immersion in the night-shift anesthesiologist trial is a randomized controlled, single-center clinical trial using a crossover design with a washout of 1 week. Anesthesiologists will be randomized in a 1:1 allocation to either undergo immersion relaxation using VR or not. Anesthesiologists undergoing VR intervention will undergo immersion relaxation via VR twice during the night shift: the first session will occur at 23:30, and the second session will occur at 07:30 the next day. The anesthesiologists will be able to choose VR content and enjoy themselves for 20 minutes. Anesthesiologists in the control group will not watch VR videos during the night shift. The design of the study is presented in Fig. 1.
The primary outcome of the study will be the NASA Task Load Index (NASA-TLX) at 07:30 of the next day, which consists of six dimensions rated on a 100-point scale in each dimension (physical demand, mental demand, temporal demand, effort, performance, and frustration), and is widely used to measure the mental workload[22, 23]. Secondary outcomes will be the Chinese Perceived Stress Scale (CPSS), perceived stress scores (Visual Analogue Scale (VAS)) and Multidimensional Fatigue Inventory (MFI-20) scores; the level of satisfaction among participants; heart rate (HR); blood pressure (BP); incidence of arrhythmia, chest tightness, headache, and palpitations at all the recorded timepoints. The CPSS was used to assess the severity of participants’ psychological stress as earlier reported. Perceived stress score was assessed via the VAS score, which was defined as the length in millimeters from 0 (no stress) to 10 (unbearable stress). The MFI-20 score was used to quantify the impact of fatigue, including five independent subscales of fatigue: general fatigue, mental fatigue, physical fatigue, reduced activity and reduced motivation.
The study will be conducted in the Third Affiliated Hospital of Sun Yat-sen University, a large comprehensive hospital in Guangzhou, China. The hospital is a tertiary medical facility that serves as a teaching hospital for Sun Yat-sen University, including 65 anesthesiologists in the Department of Anesthesiology, and the age of the front-line clinicians is 25 to 45. Besides, each anesthesiologist only undergoes one night-shift each arm and works from 17:30 to 8:00 of the next day.
Ethical approval and registration
The study protocol will be carried out in accordance with the principles of the Declaration of Helsinki, approved by the Institutional Review Board (IRB) of the hospital (approval number:  02-021-01), and registered with the Chinese Clinical Trial Registry at www.chictr.org on March 21, 2020 (registration no. ChiCTR2000031025). All the items of the WHO Trial Registration Data Set (TRDS) can be found in the protocol. The trial is currently active and ongoing, and any amendments to the protocol can be reported to and approved by the IRB. The participants can voluntarily withdraw from the study after providing informed consent.
Inclusion and exclusion criteria
To be eligible, participants must meet all of the following inclusion criteria: 1) participants who work for the hospital; 2) aged 25–45 years; 3) the patients they are managing are class I or class II according to the American Society of Anesthesiologists (ASA); 4) each operation takes 2 to 4 hours. The exclusion criteria are as follows: 1) participants who refuse to sign the informed consent form; 2) participants with serious cardiopulmonary diseases; and 3) participants who had experienced physical discomfort, such as seizures, severe dizziness, eye twitching, or blackouts triggered by light flashes when they wore a VR headset.
Following informed consent, participants will be randomized in a 1:1 allocation to either the VR immersion group (intervention group) or the routine night-shift group (control group), basing on a computer-generated random number that are concealed via a sealed envelope. One of the researchers conducts this step. The allocation will not be disclosed to the other researchers who conduct the trial until the participant is enrolled and assigned. In addition, researchers who perform the statistical analyses will be blinded to the group allocation.
Intervention group: virtual reality immersive relaxation
Participants in the VR immersion group (intervention group) will be asked to wear the VR headset (Pico G2 4K; Pico Technology Co., Ltd.; China) and choose the 360-degree panoramic videos on natural scenery around the world at https://vr.iqiyi.com/ based on their preferences to relax themselves in the resting room. Considering the limitation of resting time in clinical practices, participants experience VR immersion for only 20 minutes for each time and they will be asked to watch videos for twenty minutes at 23:30 and at 07:30 of the next day. The timepoints are chose based on our preliminary data that most first-line anesthesiologists would feel stress and overworked after 23:00, and the handover time of the nightshifts (08:00 of the next day). They will complete the NASA-TLX, CPSS, VAS and MFI-20 before and after watching the videos. When the participants are watching the videos, anesthesiologists with the same qualifications will take over their work until the VR immersion is complete.
Control group: the routine night-shift group
Participants in the control group will undergo a routine night shift without the VR immersion experience.
The participants’ general characteristics, including sex, age, body mass index (BMI), heart rate (HR), blood pressure (BP), and electrocardiogram (ECG) data, will be collected. To assess the effect of VR immersion on stress among night-shift anesthesiologists, data will be collected from participants in the intervention group at six time points: baseline status (07:50 am, T1), initiation of night shift (17:30, T2), before first VR immersion (23:30, T3); after first VR immersion (23:50, T4) on the day that they work the night shift and before second VR immersion (07:30, T5), after first VR immersion (07:50, T6) of the next day. At each timepoint, participants will be asked to measured their stress status via completing the scales included NASA-TLX, CPSS, VAS and MFI-20. In addition, ECG will be measured using a mobile ECG recorder (CardioLearn; HeartVoice Medical Technology Co., Ltd, Anhui, China) at each time point following the manufacturer’s instructions. The mobile device has been widely used in China to simply measure the ECGs and automatically analyze their results based on a novel deep learning-based cloud service as earlier reported[27, 28]. Furthermore, the anesthesiologists will be invited to record their ECG whenever they feel discomfort during the night shift. The incidence of arrhythmia, level of satisfaction, and incidence of chest distress, headache or heart palpitations will also be recorded by the researchers. The data recording flow chart is presented in Fig. 2 and the SPIRIT figure is shown in Fig. 3.
Reporting of compliance and adverse events
To avoid possible bias, anesthesiologists who had experienced something very pleasant or sad during the washout time will be asked to report their own emotion status before the second enrollment. This would be recorded and judged by two independent psychologists and those who get married or promoted, whose child is born, or whose family member is dead would be excluded from the final analysis. It has been reported that young people are more vulnerable to physical discomfort, such as seizures, severe dizziness, eye twitching, or blackouts triggered by light flashes when wearing a VR headset, therefore, participants who wear the VR headset for the first time and experience any discomfort during the procedure, the trial can be stopped, and the participants will be treated accordingly. All these events are recorded. To ensure the safety of patients, anesthesiologists with the same qualifications will take over the participants’ work during the VR immersion.
Sample size estimation
The sample size for this study was estimated using the PASS program 15.0.5. Based on our preliminary data from 14 subjects, the mean±SD of the NASA-TLX was 65.5±16.8 before the intervention and 55.7±18.2 after the intervention, and the SD of the difference was 12.1. According to tests for the difference between two means in a 2x2 crossover design, assuming a two-sided α of 0.05 and a statistical power of 80%, 26 participants are needed. To account for a potential dropout rate of 10%, we aim to recruit a sample size of 30 participants in total, and thus, 15 participants are needed in each group.
All data analysis will be performed using SPSS for Windows V.16.0 (SPSS Inc., Chicago, Illinois, USA). To avoid bias, the data analyst will be blinded to the data.
The analysis will include standard descriptive statistics, and both intention-to-treat and per-protocol analyses will be performed. The missing data will be handled by single imputation whereby the last observation will be carried forward and used as a surrogate for the missing value, as previously reported.
The Kolmogorov-Smirnov and Shapiro-Wilk tests will be used to test the normality of continuous data. Normally distributed data will be presented as the mean±SD and nonnormally distributed data will be expressed as the median (interquartile range). All quantitative data will be analyzed using methods applicable to between-group (intervention group compared with control group), within-group (post-intervention data compared with pre-intervention data within the intervention group and the control group, respectively) and between-consequence comparisons. Differences are considered significant when a two-sided P value is less than 0.05.
Analysis of the primary outcome
Our primary outcome, the score of the NASA-TLX, will be compared between the two groups, two periods and two consequences using one-way analysis of variance for 2X2 cross-over design.
Analysis of the secondary outcomes
The effect of VR immersion on the CPSS, VAS and MFI-20 scores will be compared using one-way analysis of variance for 2X2 cross-over design. Spearman’s rank correlation test will be used to analyze the association between work hours and scores on the scales. The age, BMI, HR, MBP and the level of satisfaction between groups will be analyzed by student t test or the Wilcoxon rank-sum test. The gender, incidence of arrhythmia, chest distress, headache and heart palpitations between groups will be analyzed by the Pearson χ2 test or Fisher’s exact test.