Table 2.

Mean signal-to-noise ratio results

Parameter	Office			Emergency department			Intensive therapy unit			Operating theatre
	No PPE	PPE	PPE shout*	No PPE	PPE	PPE shout*	No PPE	PPE	PPE shout*	No PPE	PPE	PPE shout*
Background noise (dB)	45	45	45	55	55	55	65	65	65	70	70	70
Mean SNR (dB)	+2.9	+4.7	+16.4	−3.2	+4.1	+7.6	−5.8	−4.9	+2	−7.4	−7.4	+0.2

^*Raised voice whilst wearing personal protective equipment. PPE = normal voice with personal protective equipment; SNR = signal-to-noise ratio