Audibility and identification of auditory alarms in the operating room and intensive care unit

Abstract

The audibility and the identification of 23 auditory alarms in the intensive care unit (ICU) and 26 auditory alarms in the operating rooms (ORs) of a 214-bed Canadian teaching hospital were investigated. Digital tape recordings of the alarms were made and analysed using masked-threshold software developed at the Université de Montréal. The digital recordings were also presented to the hospital personnel responsible for monitoring these alarms on an individual basis in order to determine how many of the alarms they would be able to identify when they heard them. Several of the alarms in both areas of the hospital could mask other alarms in the same area, and many of the alarms in the operating rooms could be masked by the sound of a surgical saw or a surgical drill. The staff in the OR (anaesthetists, anaesthesia residents, and OR technologists) were able to identify a mean of between 10 and 15 of the 26 alarms found in their operating theatres. The ICU nurses were able to identify a mean of between 9 and 14 of the 23 alarms found in their ICU. Alarm importance was positively correlated with the frequency of alarm identification in the case of the OR, rho = 0.411, but was not significantly correlated in the case of the ICU, rho = 0.155. This study demonstrates the poor design of auditory warning signals in hospitals and the need for standardization of alarms on medical equipment.

Current equipment alarm sounds: friend or foe?

“…Momtahan et al 2 studied the audibility and identification of alarms in the OR and intensive care unit (ICU). OR staff including nurses, anesthesia residents, and anesthesiologists were able to identify between ten and 15 of 23 alarms and the ICU nurses were able to identify nine to 14 of 23 different ICU alarms.…”

Study of noise levels in a neonatal intensive care unit

“…In fact, Cropp, Woods, Raney & Bredle (1994), as well as Montahan, Hétu & Tansley (1993), concluded that the number and frequency of alarms that were set-off in the various intensive care units were too abundant for the staff to correctly discern them from one another. As a result, both these studies encouraged the reduction of noise in these ICUs by limiting the number of alarms, by finding alternatives to auditory alarm signals, by designing better units and by reducing the background noise levels.…”

Noise Levels in the Operating Room

“…Their purpose is to alert the provider when an unacceptable medical condition exists or when there is an equipment failure that can result in an unacceptable medical condition. The use of visual displays is not enough, as anesthesia providers are usually occupied by a number of other visual tasks in addition to the patient's monitor (Momtahan, Hetu, & Tansley, 1993).…”