Effect of White Noise on Salivary Cortisol and Vital Signs During Gastroscopy

Gastroscopy may cause procedural stress due to uncertainty, swallowing of the endoscope,the gag reflex, and environmental noise. This stress may activate the sympathetic nervoussystem and the hypothalamic‐pituitary‐adrenal axis, resulting in changes in vital signsand increased cortisol secretion. White noise is a non‐pharmacological intervention thatmay mask environmental sounds and reduce auditory stimulation. However, evidenceregarding its effect on an objective biochemical stress marker in patients undergoinggastroscopy under sedation remains limited.This single‐center randomized controlled trial will include 100 adult patients scheduledfor elective diagnostic gastroscopy under sedation. Participants will be assigned to thewhite noise intervention group or the routine care control group using computer‐generatedblock randomization, with 50 participants planned for each group. Before sedation,demographic and clinical information will be collected, baseline vital signs will berecorded, and participants will rate their anxiety and pain using 0‐10 visual analogscales. A baseline saliva sample will then be collected for cortisol measurement.Participants assigned to the intervention group will begin listening to white noisethrough headphones with disposable protective covers immediately before entering theendoscopy room, while they are still awake. The intervention will continue withoutinterruption during sedation induction and throughout the gastroscopy procedure.Participants in the control group will receive routine care without an auditoryintervention. Vital signs, including systolic and diastolic blood pressure, heart rate,respiratory rate, and oxygen saturation, will be recorded at baseline, during the fifthminute of the procedure, and during recovery.The white noise intervention will be discontinued when the procedure is completed.Anxiety and pain will be reassessed after the procedure. A second saliva sample will becollected approximately 20‐30 minutes after the procedure to account for the expectedsalivary cortisol response. Saliva samples will be maintained under appropriatecold‐chain conditions and stored until cortisol concentrations are measured using anenzyme‐linked immunosorbent assay. Changes in salivary cortisol, vital signs, anxiety,and pain will be compared between the intervention and control groups.