BREATH SOUND MONITORING FOR APNEA

Abstract

Impedance respiratory monitoring is incapable of detecting obstructive apnea. We compared a microphone breath sound detector to an impedance monitor in 10 sleeping infants and children in order to determine its ability to detect normal respirations, central, and obstructive apneas and alarm for apneas greater than 10 seconds. Air flow was used as a standard for all measurements. Breath sounds detected 98.4% and impedance 98.9% of all normal respirations. There were a total of 42 central apneic pauses. Breath sound detected 40 and impedance 41 of these apneas yielding 95 and 98% respective rates of detection. Breath sound monitor alarmed for 5 of 7 central apneas and impedance monitor for 2 of the 7. There were 75 obstructive apneas. Breath sound detected 58 or 77% detection rate. The breath sound monitor alarmed for 5 of 13 obstructive apneas and the impedance monitor none. There were no statistical differences in either breath or central apnea detection between the two monitors. Air flow was statistically better than breath sound for the detection of obstructive apnea (p less than .05). Breath sound was statistically better than impedance for obstructive apneas (p less than .025). Our study suggests that a breath sound monitoring system may offer a practical alternative to impedance respiratory monitoring for the detection of normal respiration, central and obstructive apneas in infants.