Sleep disorders are more common in critical care units (CCUs) due to factors such as noise, frequent rounding for interventions, and environmental disruptions. Sleep is essential for physiological and psychological recovery. This quasi-experimental study suggested that the effect of white noise on sleep quality in patients admitted to a CCU, where sleep disorders are prevalent due to environmental noise, would increase their sleep quality.
This quasi-experimental study investigated the effect of white noise on sleep quality in patients admitted to an inherently noisy CCU.
Researchers used a quasi-experimental design with a purposive sample of 60 patients. All patients were admitted to Shariati Hospital’s CCU. The inclusion criteria ensured that participants were at least 30 years old, stayed for at least three nights, were hemodynamically stable, and were not taking anesthetic or diuretic medications. Sleep data was collected using the Pittsburgh Sleep Quality Index (PSQI), which measures subjective sleep quality, sleep duration, disturbances, and medication use, with higher scores indicating worse sleep quality. There were 30 participants in both the control and experimental groups. For the control condition, sleep quality was assessed using the PSQI, and then CCU noise was measured throughout the night for three nights. Participants again completed the PSQI after three nights in the CCU. Next, after completing a baseline PSQI, a second group of participants were exposed to the experimental, white noise condition in the same CCU. The white noise was set to 40-50 dB and was administered to the experimental group for one hour each of three nights during peak noise times (8 p.m. to 9 p.m. at night and 11 to 12 p.m.). After three nights of the experimental condition participants were asked to complete a follow-up PSQI. To control for confounding variables, both groups were similar in demographics, and the same unit environment was used.
The control group showed a significant worsening in sleep quality over three nights, while the experimental group experienced a slight improvement. The primary finding was that white noise, used as an environmental intervention, masked unwanted sounds while significantly improving sleep quality in the experimental group compared to the control group. The control group, which did not receive the white noise intervention, showed a statistically significant (P<.001) decline in sleep quality over the three nights, with the PSQI score increasing from 5.20 (+- 1.8) to 11.23 (+-2.3), indicating worse sleep and highlighting the negative impact of environmental noise. The experimental group, exposed to white noise during peak noisy hours (2000 – 2100 & 2300 – 0000), showed a slight improvement in sleep quality, with the PSQI score decreasing from 5.17 (+- 1.66) to 4.53 (+-1.27). This change was statistically significant (P=.008), supporting the effectiveness of white noise as an environmental strategy to enhance sleep.
Although the total sleep time and the minutes to fall asleep did not show a significant change in either group, the overall improvement in sleep quality for the experimental group suggests that white noise helped to reduce the disruptive effects of the noisy CCU. These findings reinforce the importance of managing environmental conditions, such as noise, to improve patient outcomes and patient experience. White noise is recommended as a practical, non-pharmacological intervention for improving sleep by masking ambient noise.
Limitations include the short duration of the data collection periods, the inability to control all medication effects, and the use of sequential vs. concurrent data collection for the control and intervention conditions. While not mentioned in the study, another possible limitation is the age range of patients. Finally, a sleep log was mentioned but the authors did not note who recorded the log and it was not included in any of the final analyses.