The Effects of a Model-based Sensory Stimulation Intervention on Preventing Delirium Among Intensive Care Unit Patients: A Randomised Controlled Trial

Delirium incidence means the number of patients who are delirious.

First occurrence of delirium was defined as the first time that patients was delirium positive through CAM-ICU. The time to have the first occurrence of delirium was calculated from patients' admission to ICU to the first positive result of delirium assessment.

The delirium duration will be calculated when the patient is first considered to have delirium to the last time that patient is not supposed to have delirium based on CAM-ICU.

CAM-ICU-7 scores are further categorised as 0-2: no delirium, 3-5: mild to moderate delirium, and 6-7: severe delirium.

The 17-item PTSD Checklist (PCL) correspond to the DSM-III-R symptoms of PTSD (post-traumatic stress disorder), which is a self-reporting scale for assessing PTSD (Frank et al., 1993; Mollica et al., 1992). Patients were asked for their agreement to describe each item, from one (not at all) to five (extremely). PTSD-symptoms could be divided into re-experiencing (flashback, nightmare, emotional cue reactivity, and physical cue reactivity), avoidance and emotional numbing (avoidance of thoughts and reminders, amnesia, loss of interest, detachment, restricted affect, and foreshortened future) and hyperarousal (irritability/anger, sleep disturbance, difficulty concentrating, hypervigilance, exaggerated startle response). The total score was summed and ranged from 17 to 85

The 9-item Chinese version of Patient Health Questionnaire-9 (PHQ-9) will be used to measure patients' psychological well-being.Patients will be asked for their agreement to the description of each item, from zero (not at all) to three (nearly every day). All item scores are summed (total score = 27). A higher score indicates greater severity of the depressive symptoms.

Family satisfaction will be measured using the Critical Care Family Satisfaction Survey (CCFSS).CCFSS has 27 items and five dimensions: medical condition guarantee, access to information, acceptance, support, and comfort. Family caregivers will be asked for their agreement to the description of each item, from one (very unsatisfactory) to five (very satisfactory). All item scores are summed (total score = 135). A higher score indicates a greater level of satisfaction.

The level of anxiety of family caregivers will be measured by the Self-Rating Anxiety Scale (SAS). SAS has 20 items, with each item ranging from one (not at all) to four (very much so). The scale will use both positive and negative scoring, with a total score of 50-59 indicating mild anxiety, 60-69 indicating moderate anxiety, and ≥70 indicating severe anxiety.

The ICU-Memory Tool (ICU-M) was used to measure ICU patients' ICU experience (Jones et al., 2000). The tool includes 14 questions (five open-ended questions and nine closed-ended questions), mainly including three parts: memories before admission to ICU; memories during ICU stay and memories after transferring out of ICU. Memories during ICU stay has three subscales: factual memories (lights, alarms, voices, families, faces, breathing tube, suctioning, darkness, clock, tube in your mouth, and ward wounds), memories of feelings (being uncomfortable, confused, down, anxious/ frightened, panic, and pain), and memories of delusions (feeling that people were trying to hurt you, hallucinations, nightmares, dreams). We summed the number of memories in each of the three subscales. The Chinese version of ICU-M has a Cronbach α coefficient of 0.823 and a scale-level content validity index of 0.946, which confirms its good reliability and validity

The 9-item Chinese version of Patient Health Questionnaire-9 (PHQ-9) will be used to measure patients' psychological well-being.Patients will be asked for their agreement to the description of each item, from zero (not at all) to three (nearly every day). All item scores are summed (total score = 27). A higher score indicates greater severity of the depressive symptoms.