Masking Between Reserved Alarm Sounds of the IEC 60601-1-8 International Medical Alarm Standard: A Systematic, Formal Analysis

Auditory roughness: a delicate balance

Auditory roughness in medical alarm sounds is an important design attribute, and has been shown to impact user performance and perception. While roughness can assist in decreased signal-to-noise ratios (perceived loudness) and communicate urgency, it might also impact patient recovery. Therefore, considerations of neuroscience correlates, music theory, and patient impact are critical aspects to investigate in order to optimise alarm design.

Discriminating between simultaneous audible alarms is easier with auditory icons

When more than one audible alarm is heard simultaneously, discrimination may be compromised. This experiment compares near-simultaneous clinical alarms in two styles, the first are the tonal 'melodies' from the 2012/2006 version of a global medical device safety standard (IEC 60601-1-8) and the second are the auditory-icon-style recommended in the 2020 version of the same standard. Sixty-six participants were required to identify the meaning and priority of four different clinical alarms for one of the two styles of alarm (between-subjects). Alarms sounded both singly and in pairs (within-subjects). Results showed that the auditory icon alarms outperformed the tonal alarms on all measures except one, both for overall accuracy (recognizing both priority and function) and for partial accuracy (recognizing priority or function but not both). The results add to the growing body of evidence supporting the use of auditory icon alarms in clinical environments.

Delirium Variability is Influenced by the Sound Environment (DEVISE Study): How Changes in the Intensive Care Unit soundscape affect delirium incidence

Quantitative data on the sensory environment of intensive care unit (ICU) patients and its potential link to increased risk of delirium is limited. We examined whether higher average sound and light levels in ICU environments are associated with delirium incidence. Over 111 million sound and light measurements from 143 patient stays in the surgical and trauma ICUs were collected using Quietyme® (Neshkoro, Wisconsin) sensors from May to July 2018 and analyzed. Sensory data were grouped into time of day, then normalized against their ICU environments, with Confusion Assessment Method (CAM-ICU) scores measured each shift. We then performed logistic regression analysis, adjusting for possible confounding variables. Lower morning sound averages (8 am-12 pm) (OR = 0.835, 95% OR CI = [0.746, 0.934], p = 0.002) and higher daytime sound averages (12 pm-6 pm) (OR = 1.157, 95% OR CI = [1.036, 1.292], p = 0.011) were associated with an increased odds of delirium incidence, while nighttime sound averages (10 pm-8 am) (OR = 0.990, 95% OR CI = [0.804, 1.221], p = 0.928) and the ICU light environment did not show statistical significance. Our results suggest an association between the ICU soundscape and the odds of developing delirium. This creates a future paradigm for studies of the ICU soundscape and lightscape.