Delirium is an acute cerebral dysfunction syndrome characterized by acute fluctuating changes in consciousness, cognitive dysfunction, and disorientation. It's especially common in critically ill patients of emergency intensive care units and seriously threatens the survival and prognosis of patients and causes heavy economic burdens to the family, society, and medical service system. Impaired verbal communication, unfamiliar medical personnel, physical restraint, spatial-temporal disorientation, mechanical ventilation and sedation medication use can lead to a lack of adequate sensory stimulation and a high risk of delirium. Acoustic stimulation as a non-invasive non-pharmacological intervention can provide some sensory stimulation as a surrogate for critically ill patients. This research designs the content scripts from the needs of ICU patients and families for sound stimulation. The goal of this randomized controlled study is to test the effect of auditory stimulation by family voices in preventing delirium among sedative patients in emergency Intensive care units.

Patients are separated from their families and society under the closed management of the intensive care unit, the use of sedative drugs, mechanical ventilation, impaired verbal communication, physical restraint, environmental noise, and prolonged light exposure, which lead to a lack of adequate sensory stimulation, causing sensory deprivation in patients to some extent. In turn, sensory deprivation may cause multisensory perceptual confusion and hallucinations, affecting patients' orientation and thinking and triggering delirium, so providing appropriate sensory stimulation to critically ill patients may help to improve patients' orientation and attention, correct patients' thinking confusion and prevent delirium, and in clinical practice, sensory stimulation is considered as an important part of multicomponent delirium prevention programs.

Inclusion Criteria:

• transferred to the EICU from emergency admission
• no other history of emergency, surgery, or ICU admission history within 30 days
• no delirium in the first screening of Emergency Intensive Care Unit(EICU) admission
• with an expected length of stay in EICU longer than 24h and use of sedation medication

Exclusion Criteria

• Presence of hearing impairment, severe dementia, psychiatric disorder, or other severe brain dysfunction that hinders delirium assessment
• persistent coma or deep sedation (RASS score of -4 to -5)
• patients without a family member who can cooperate with the recording
• external ear disease or surgery that hinders earphone wearing