Delirium is a common acute cognitive impairment characterised by confusion, disorientation and attention deficits, particularly prevalent in intensive care unit (ICU) settings. Given its significant impact on patients, caregivers and healthcare resources, preventing delirium in patients in the ICU is of paramount importance. This is the first randomised-controlled trial designed to evaluate the effects of a virtual reality-based sensory stimulation intervention on preventing delirium in ICU patients.

We employed a paired randomisation method to match eligible participants based on a validated delirium risk scoring model for patients in the ICU. The study will commence in September 2024 and conclude in June 2026. A consecutive sample of 324 patients in the ICU admitted to the study setting will be recruited. Eligible participants will be randomly allocated to receive either virtual reality-based sensory stimulation in addition to usual care or usual care alone. The virtual reality-based sensory stimulation intervention will last for up to 14 days, with all interventions administered by a research team. We define delirium-free days over a 14-day period as the primary outcome. The secondary outcomes will include delirium incidence, duration and severity; patients’ psychological well-being (post-traumatic stress disorder, sleep quality and ICU memory); patients’ clinical outcomes and other outcomes (quality of life, independence and cognitive function). Data will be collected at baseline, post-intervention and 6 months post-intervention. Two independent t-tests or Wilcoxon-Mann-Whitney tests will be used for continuous variables, while χ² or Fisher’s exact tests will be employed for categorical variables. The analysis will adhere to both the intention-to-treat and per-protocol principles. Additionally, mixed-effects models and subgroup analysis will be planned.

This protocol was approved by the Research Ethics Committee of Shenzhen Hospital of Southern Medical University (NYSZYYEC20230068). All participants or their family caregivers will provide written informed consent. Results will be disseminated through scientific publications, and presentations at local and international conferences.

ClinicalTrials.gov NCT06153472. Trial registration date: 22 November 2023.

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Delirium is a common acute state of cognitive confusion. Intensive Care Unit (ICU) delirium is highly prevalent, with an incidence ranging from 31%1 to 56%,2 and it can be as high as 81%3 in patients in the ICU undergoing mechanical ventilation. A preliminary analysis of data from 375 patients admitted to the ICU for more than 24 hours revealed an occurrence rate of 44% for ICU delirium.4 Moreover, delirious patients in the ICU had 1.33 times longer ICU stays and a 9.57-fold increase in mortality compared with non-delirious patients in the ICU.5 Patients in the ICU who experience delirium may suffer from post-traumatic stress disorder, anxiety, depression and cognitive impairment for up to 2 years.6

Non-pharmacological preventive measures aim to reduce one or more modifiable risk factors for ICU delirium.7 Previous research identified sensory stimulation as a key and effective non-pharmacological intervention in preventing ICU delirium.8 9 Sensory stimulation involves activating one or more senses,10 with visual and auditory stimuli being particularly effective for patients in the ICU.11 To further investigate the effectiveness of sensory stimulation in preventing ICU delirium, the research team conducted an initial study to assess the implementation of sensory stimulation in preventing delirium in the ICU and subsequently developed a sensory stimulation intervention plan.12 13 This plan involved daily sessions of 30 min each for 7 days, including visual stimuli (displaying personal or family photos) and auditory stimuli (playing recordings of family members). The results of the study showed that sensory stimulation reduced the duration and severity of ICU delirium but did not significantly decrease the incidence of ICU delirium.8 9 The limited effectiveness of sensory stimulation may be attributed to the narrow range of stimuli, insufficient stimulus intensity and inadequate dosing and implementation methods.9

In contrast, virtual reality (VR) technology, characterised by its three-dimensional and highly immersive qualities, has the potential to provide more effective sensory stimulation by immersing participants in three-dimensional dynamic environments.14 International research15–17 suggests that VR offers significant advantages in sensory stimulation and could be a promising approach for preventing ICU delirium. However, it is important to note that studies on the use of VR in this context are still in the feasibility testing stage. The DREAMS project at the University of Florida in the USA investigated the effectiveness of VR and found that 95.6% of participants found it very comfortable, 51.9% reported improved sleep quality and 81.5% experienced reduced pain.16 This team further conducted a study with 46 patients in the ICU, implementing a 7-day VR intervention, which resulted in reduced stress, pain, anxiety and improved cognitive function and attention in the participants.17 Additionally, Jawed and colleagues conducted a preliminary trial that showed VR could alleviate anxiety in patients in the ICU.15 However, since those studies were in the feasibility testing stage, they were unable to measure the effects on reducing ICU delirium.

The stress recovery theory and attention restoration theory explain the principles behind preventing ICU delirium using VR-based sensory stimulation.18 19 The stress recovery theory suggests that natural environments support positive changes in emotional states and psychophysiological recovery, primarily by relaxing the parasympathetic nervous system.19 In stressful ICU environments, cognitive and attentional resources can become fatigued, which is especially crucial for critically ill patients facing stressors. The cognitive demands and overstimulation in the ICU environment contribute to mental fatigue and stress responses.19 On the other hand, the attention restoration theory suggests that exposure to natural environments requires fewer cognitive resources and promotes a sense of disengagement from stressors, allowing attention to rest and recover.18 Therefore, VR-based visual and auditory stimuli, by immersing patients in relaxing VR environments, may provide a protective effect against environmental stress and support the recovery of physiological, emotional and attentional functions, thereby helping prevent delirium. Chirico and colleagues further elucidated the mechanisms of VR-based sensory stimulation in delirium prevention: exposure to VR-based natural environments can trigger a specific psychophysiological pattern activated by the parasympathetic nervous system, leading to intense emotional reactions.20 Emotion responses increase with higher levels of immersion, which can be used to alleviate symptoms like anxiety, pain and fear, effectively reducing patient stress, improving sleep quality and consequently reducing the incidence of delirium.20

This study evaluates a VR-based sensory stimulation for preventing delirium and improving patients’ psychological well-being (specifically post-traumatic stress disorder, sleep quality and ICU memory), patients’ clinical outcomes (including ICU length of stay) and other outcomes (such as quality of life, independence and cognitive function). It employs a rigorous RCT design, incorporating a VR-based sensory stimulation intervention within ICUs, which enhances the reliability and validity of findings. The methodological rigour of this design provides valuable insights into the effectiveness of such interventions in clinical settings. Previously, our primary outcome included both the incidence duration and severity of delirium. However, considering the recommendation to focus on a single primary outcome, we have designated delirium-free days as the primary outcome. Consequently, we have classified delirium duration and severity as secondary outcomes, and this update has been reflected in the trial registry.

In our study, our primary focus is on preventing delirium. However, if delirium does occur, physicians may prescribe antipsychotic medications. We will accurately document whether patients receive these medications and the dosage administered. Furthermore, we will maintain detailed records of the dosage of sedatives and analgesics administered to patients throughout the study. Additionally, in the intervention, family caregivers are involved through a ‘sample reorientation message’, which refers to a written communication provided to help them understand and navigate changes in care, treatment or environment. We acknowledge that family involvement may influence patient outcomes and could act as a confounding factor in our study. The observed effects may result from a combination of the VR intervention and changes in family behaviour. Due to the nature of the intervention, blinding was only possible for the outcome assessors, while blinding for the participants and those delivering the intervention was not feasible.

The study anticipates prompt availability of materials from family members and has contingency plans in place to ensure the timely initiation of the VR intervention. However, delays in obtaining materials from family members may occur, potentially impacting the initiation of the VR intervention. Additionally, the use of antipsychotic medications to manage delirium may influence study outcomes, and while their administration will be documented, their effects on study outcomes may not be fully controlled.

For patients in the ICU, obtaining informed consent can be a complex process due to the patients’ health conditions. When possible, and when the patient is capable of understanding and making decisions, we will seek written consent directly from the patient. However, for those who may be too ill to provide consent, we will obtain written consent from their legally authorised representatives, typically family members. We are committed to ensuring that all potential participants, or their designated representatives, are fully informed about the study’s objectives and procedures. This includes providing detailed information about the study, its potential risks and benefits, and the voluntary nature of participation.

We are dedicated to upholding the highest ethical standards in disseminating our research findings. Study outcomes will be shared through peer-reviewed publications and presented at academic conferences, ensuring that our work reaches the relevant professional and scientific audiences. We are steadfast in our efforts to safeguard the rights and confidentiality of all participants. To preserve individual privacy, all personal information will be anonymised, and the findings will be communicated in a manner that protects the identities of the participants.