DIFFERENTIAL AUSCULTATORY TECHNIQUE Prepared by LEE HOI LEONG

DIFFERENTIAL AUSCULTATORY TECHNIQUE Prepared by: LEE HOI LEONG YAP CHENG YEE ALICE LEE FONG LIN FOON JIA YIN SIN KIT YENG 091150431 091151529 091150076 091150269 091151302

Differential Ausculatory Technique • A cuff + a pair of pressure sensitive sensor • isolates the signal created each time the artery forced open.

Figure cited from Handbook of Biomedical Instrumentation by Khandpur, published by Tata Mc. Graw-Hill Education, page 224.

Differential Ausculatory Technique • No pulse generated when Systolic Pressure < Cuff Pressure • Artery ‘snaps’ open when the intra-arterial pressure exceeds the cuff pressure; pulse created

Figure cited from Handbook of Biomedical Instrumentation by Khandpur, published by Tata Mc. Graw-Hill Education, page 223.

Differential Ausculatory Technique Figure cited from Handbook of Biomedical Instrumentation by Khandpur, published by Tata Mc. Graw-Hill Education, page 224, figure 6. 30(a). • Signal A: • Comes from arrow A to sensor A • transmitted from the artery to both sensor and air bag in the cuff. • Consists of a slow, rising, low frequency (0. 5 - 5 Hz) with fast “pulse” (10 -80 Hz) superimposed on it.

Figure cited from Handbook of Biomedical Instrumentation by Khandpur, published by Tata Mc. Graw-Hill Education, page 224.

Differential Ausculatory Technique Figure cited from Handbook of Biomedical Instrumentation by Khandpur, published by Tata Mc. Graw-Hill Education, page 224, figure 6. 30(b). • Signal B: • Comes from arrow B • transmit from the air bag in the cuff to sensor B. • High frequency is being attenuated, left only low frequency signal. (Signal A being filtered by air bag)

Figure cited from Handbook of Biomedical Instrumentation by Khandpur, published by Tata Mc. Graw-Hill Education, page 224.

Differential Ausculatory Technique 1 st opening of artery occurs Last time artery forced open Figure cited from Handbook of Biomedical Instrumentation by Khandpur, published by Tata Mc. Graw-Hill Education, page 224, figure 6. 30(c). • Signal A – Signal B • Differential sensor eliminate signal B from signal A • Left only the higher frequency Korotkoff Signals. ( Korotkoff signals are isolated)

Differential Ausculatory Technique Summary Figure cited from Handbook of Biomedical Instrumentation by Khandpur, published by Tata Mc. Graw -Hill Education, page 224.

Thank You Q&A