To address the problem of auditory alarms on anaesthesia monitoring and delivery devices whose signal is masked by the noises of other operating room equipment, a set of signals having the characteristics of spectral richness, frequency modulation, and temporal patterning were electronically generated, and were tested for detectability against operating room equipment noises in a laboratory setting. A set of signals was identified which can, under these circumstances, be detected with at least 93% accuracy at -24 dB signal-to-noise ratio.