This randomized clinical study was conducted on patients with American Society of Anesthesiology (ASA) classification I and II undergoing vitrectomy surgery. After approval by institutional committee for ethics and clinical trial, and obtaining informed consent from the patients, all patients over 18 years of age who were referred to the operating room for vitrectomy surgery were included in this study. Patients with hearing impairments, mental health problems, prolonged use of tranquilizers or analgesics, and those with alcoholism or other illicit drug addictions were excluded from the study. None of the patients received anti-anxiety medication before surgery, and they were only taking medications related to their chronic conditions, such as diabetes and high blood pressure, on the day of surgery. Three patients were excluded from the study due to the use of hypnotics (benzodiazepines), two patients were excluded due to dissatisfaction, and finally, 50 patients were randomized into two equal groups of music (M) and white noise (W) [Figure 1].
As soon as the patients entered the operating room, they underwent standard monitoring with non-invasive blood pressure, electrocardiogram, and pulse oximetry. In addition, the bispectral index was used to monitor the depth of anesthesia and the BIS VISTA device (Aspect Medical Systems, Newton, MA USA) was used to monitor the depth of anesthesia.
General anesthesia was performed in all patients by the same method with intravenous injection of midazolam 0.02 mg/kg and fentanyl 2 micrograms/kg as premedication three minutes before induction. Intravenous injections of lidocaine 1 mg/kg, propofol 1.5 mg/kg, and atracurium 0.5 mg/kg were used for induction. The laryngeal mask was used for airway management in all patients and mechanical ventilation was initiated to maintain ETCO2 close to 30 mmHg. Propofol was used to maintain the BIS at about 50 throughout the procedure. After anesthesia induction, standard music player headphones (BT Trek, Stori Beat, and Move BT) were placed in the correct position for all patients, and the anesthesiologist blindly selected either the music files (M group) or white noise (W group) per random number from the table. Classical music was selected from a previous study. Kuan et al. suggested three unfamiliar relaxing music: Appalachian Spring: Ballet for Martha, by Copeland; Florida Suite: III Sunset-Near the Plantation, by Delius; The Birds: The Dove, by Respighi.[14 (link)] They are introduced as more relaxing than known music. So, we decided to use these three pieces and call them classical music. Loudness was verified using audio samples for patient comfort. To prevent possible hearing damage, the volume was turned up to a maximum of 85 dB by the recommendation of the World Health Organization. The headphones stayed in place until the end of the operation. At the end of the operation, the sound stopped and the headphones were removed. Blood pressure, heart rate, and BIS score were recorded at baseline and every 15 minutes during anesthesia. The amount of propofol used was recorded. Vital signs, pain intensity, the presence of nausea or vomiting, and restlessness were assessed in the recovery room. Pain intensity was measured on a 10-grade visual analog scale (VAS), from no pain (= 0) to maximal possible pain (= 10). Agitation was measured using the Riker Sedation-Agitation Scale [Table 1].[15 (link)]
Data analysis was performed using SPSS software version 17. Due to the normality of the statistical population distribution (confirmed by the Kolmogorov-Smirnov test), the Chi-square test was used to examine qualitative variables and the independent t-test was used to examine quantitative variables and the significance level was less than 0.05 in all cases.