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 nervous system and the hypothalamic-pituitary-adrenal axis, resulting in changes in vital signs and increased cortisol secretion. White noise is a non-pharmacological intervention that may mask environmental sounds and reduce auditory stimulation. However, evidence regarding its effect on an objective biochemical stress marker in patients undergoing gastroscopy under sedation remains limited.

This single-center randomized controlled trial will include 100 adult patients scheduled for elective diagnostic gastroscopy under sedation. Participants will be assigned to the white noise intervention group or the routine care control group using computer-generated block randomization, with 50 participants planned for each group. Before sedation, demographic and clinical information will be collected, baseline vital signs will be recorded, and participants will rate their anxiety and pain using 0-10 visual analog scales. A baseline saliva sample will then be collected for cortisol measurement.

Participants assigned to the intervention group will begin listening to white noise through headphones with disposable protective covers immediately before entering the endoscopy room, while they are still awake. The intervention will continue without interruption during sedation induction and throughout the gastroscopy procedure. Participants in the control group will receive routine care without an auditory intervention. Vital signs, including systolic and diastolic blood pressure, heart rate, respiratory rate, and oxygen saturation, will be recorded at baseline, during the fifth minute 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 be collected approximately 20-30 minutes after the procedure to account for the expected salivary cortisol response. Saliva samples will be maintained under appropriate cold-chain conditions and stored until cortisol concentrations are measured using an enzyme-linked immunosorbent assay. Changes in salivary cortisol, vital signs, anxiety, and pain will be compared between the intervention and control groups.

Inclusion criteria

• Aged 18 years or older
• Scheduled for elective diagnostic gastroscopy under sedation
• Able to communicate in Turkish
• Able to hear the white noise intervention and without hearing loss that would prevent its use
• Willing to participate voluntarily and able to provide written informed consent

Exclusion criteria

• Undergoing emergency gastroscopy
• Diagnosed psychiatric disorder or current use of psychotropic medication that may affect anxiety
• Hearing impairment that would prevent effective delivery of the white noise intervention
• Use of systemic, topical, or inhaled glucocorticoids within the previous month
• Diagnosed adrenal or pituitary gland disorder
• Pregnant or breastfeeding
• Active oral lesions, gingival bleeding, or severe periodontitis that may compromise saliva sample quality
• Smoking or consumption of caffeinated beverages within two hours before the procedure