The aim of this thesis is to develop apnea detection by using the sum of the respiratory inductance plethysmography of the chest and abdomen (RIP Flow) from a locally made amplitude modulation RIP (AM-RIP) and the standard instruments (Sleep Sense RIP). Our device consists of 1.Electronic circuit board. 2. RIP belts for the chest and abdomen. 3. A cable for Polysomnograph (CADWELL EASYII) connection. Both RIP Flow are obtained simultaneously. In five normal subjects, the ratios of air flow when breathing normally and during hyperventilation were compared against the spirometer. The flow ratios from AM-RIP and Sleep Sense RIP are always equal but do not match the ratio from actual flow measured by the spirometer with the Mean ±SD of 2.10 ± (0.62),2.28, ± (0.90) and 2.37± (0.74) accordingly. In five subjects with obstructive sleep apnea, Sleep Sense RIP and AM-RIP can detect total apnea of 1,138 and 1,125 accordingly with intraclass correlation coefficient = 0.998 at 95 % confidence level. The sensitivity 98.86%,false negative 1.14%. In conclusion, AM-RIP and standard instrument can detect apnea from the sum channel equally well. The RIP flow ratio do not reflect the actual flow ratio. This pilot study is limited by small sample size.
