Decreasing Noise Levels in the ICU
Decreasing Noise Levels in the ICU
Abstract & Commentary
The environmental protection agency (epa) recommends that noise in hospitals not exceed 45 A-weighted decibels (dBA) during the day and 35 dBA at night. Kahn and associates found that peak sound levels were greater than 80 dBA in their ICUs. This level of noise pollution contributes to sleep deprivation and fragmentation in patients by causing more frequent arousal from sleep. Sleep deprivation affects mood, level of alertness, causes increased daytime fatigue, and can lessen task performance. Studies have shown that at least one-third of patients with sleep deprivation develop "ICU psychosis" syndrome. Sleep deprivation may adversely affect respiratory muscle function and ventilatory control, making ventilator weaning more difficult. Noise can contribute to hearing loss for both patients and staff. Studies have implicated noise levels in contributing to burnout in critical care staff.
Kahn et al have previously studied noise interference in the ICU. This study was conducted in two phases in the three-bed rooms in the medical ICU (MICU) and the respiratory ICU (RICU) of a large university-based teaching hospital. The first phase of the study identified the sounds responsible for high peak sound levels. These sounds were identified by a consistent observer and monitored with a sound level meter that was positioned where the patient’s head would be. Sound levels were recorded and measured in 15-second intervals for 10 consecutive minutes in 16 different sessions. Acute Physiology and Chronic Health Evaluation (APACHE) scores were calculated, the number of people in each room was noted, and noise-making equipment in the room was listed (e.g., ventilators, monitors, intravenous pumps, television, etc.). Sounds were counted and classified, both by loudness and as to whether they could be modified. For example, monitors and ventilators have preset alarm volumes for patient safety that cannot be altered.
Following this documentation and description of the current noise milieu, the second or behavior modification phase of the study began. The three-week behavior modification program was a comprehensive educational program involving nurses, physicians, respiratory therapists, and secretaries. The program included discussions about noise pollution and the impact on patients and staff. The purpose of the study was reviewed and the results from the first phase of the study shared. The causes of the loudest noise and the causes that could be reduced by changing behavior were pointed out to the participants. Handouts were distributed listing common sounds and their noise levels. Following the behavior modification program, postintervention observations were made, and the results were tabulated in six-hour blocks reflecting changes in noise level at different periods during the day.
The loudest noises that lasted the longest time were talking, television, and monitor alarms. (See Table.) The miscellaneous category included coughing, suctioning, banging, and less frequently occurring alarms. More than half of the offending noises identified could potentially be modified, especially talking and television. Suggestions for modification that were made included limiting loud and unnecessary bedside conversations that do not include the patient; turning off the television; placing beepers in vibrate mode; using the intercom only for emergencies; turning down the volume of overhead speakers; and adhering to visiting hours and limiting the number of visitors at the bedside.
The results of the behavior modification program were positive in significantly reducing the number and magnitude of peak sound levels. These levels were reduced from 80-83 dBA at baseline to 78-80 dBA following the behavior modification program. Although the peak sound levels that occurred were still far above the EPA guidelines, the logarithmic nature of the decibel scale translates into a noticeable reduction in noise. Accompanying the noise reduction, the number of sound peaks greater than 80 dBA were reduced from 1363 to 976 out of more than 2800 sounds noted in the observation period. (Kahn DM, et al. Chest 1998;114:535-540.)
| Table | ||
| Major Causes of Noise | ||
| Noise |
|
|
| Talking |
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|
| Beeper |
|
|
| Miscellaneous |
|
|
| Intercom |
|
|
| Oximeter alarm |
|
|
| Nebulizer |
|
|
| Telephone |
|
|
| Ventilator alarm |
|
|
| Television |
|
|
| Monitor alarm |
|
|
| Ventilator |
|
|
| IV alarm |
|
|
| Air conditioner |
|
|
| _________________________________________________________ | ||
Comment by Doreen M. Anardi, RN
This study raised a number of important issues regarding environmental noise. Clearly hospitals are too noisy, and the EPA guideline may not be an attainable goal. But, as this study demonstrates, individual hospitals and ICUs can evaluate their own noise patterns and institute actions to diminish the reducible noise. A three-week educational program was the intervention in this study, and a committed nursing unit that uses an educational program with periodic updates and monitoring of noise levels may be able to attain continuing reductions in noise level. This would seem to be an ideal continuous quality improvement (CQI) project that would benefit both patients and staff. An all-encompassing program could include housekeeping and dietary staff, and would potentially achieve greater noise reductions. One of the suggestions for limiting noise in this study was to limit visiting. The trend in many hospitals is to make visiting less restricted, so a noise reduction program would need to include educating visitors.
Noise reduction is appealing on its surface. Physiologic confirmation that it is a good thing could truly help to change practice. Future studies of noise reduction efforts could include patient response end points such as incidence of "ICU psychosis," time on the ventilator, use of sedatives, wound healing, and many others.
Noise can be an insidious presence. We can become accustomed to loud sounds and it is not until we leave the environment that we become aware of what we have been experiencing. This happens to me almost every day when I start my car and the radio is at "freeway-level" volume. While reviewing this article, that ubiquitous picture of the capped and white-uniformed nurse from yesteryear with her finger over her lips encouraging quiet was ever-present in my mind. Maybe it’s time to hang updated versions of that picture as a reminder to all staff and visitors to do what they can to reduce the noise level.
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