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Impulse oscillometry By Dr/ Hossam EL-din mohamed Lecturer of chest diseases Ain Shams university.

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Presentation on theme: "Impulse oscillometry By Dr/ Hossam EL-din mohamed Lecturer of chest diseases Ain Shams university."— Presentation transcript:

1 Impulse oscillometry By Dr/ Hossam EL-din mohamed Lecturer of chest diseases Ain Shams university

2 Normal

3 Peripheral Airway Obstruction

4 Central Airway Obstruction

5 Restrictive Lung Disease

6 IOS Very simple to perform No special breathing necessary Minimal (no) co-operation Use with small children (down to 2 years) Even with animals No forced manoeuvre necessary No box necessary Peripheral and Central Resistance separated

7 Limits of oscillometry Detection of restrictive diseases is possible only in higher degree of the disease Differentiation between distal obstruction and restriction is only possible with additional determination of VC (Spiromety) or RV (body Plethysmography)

8 Recommendations Patient: Sitting in upright position while measured Head in neutral position or slight extension (not in rotation or flexion)Patient: Sitting in upright position while measured Head in neutral position or slight extension (not in rotation or flexion) Nose clipped Nose clipped Cheeks supported with hands to avoid the "Upper Airway Shunt"Cheeks supported with hands to avoid the "Upper Airway Shunt" To avoid artifacts in the mouth chamber: Mouthpiece (plastic) tight between teeth, Mouthpiece (plastic) tight between teeth, Tongue beneath mouthpiece Tongue beneath mouthpiece Lips firmly closed around mouthpiece Lips firmly closed around mouthpiece (even small gaps create remarkable pressure drops and therefore low or zero resistance)(even small gaps create remarkable pressure drops and therefore low or zero resistance) Take care on tight belts and clothes (increases peripheral resistance).Take care on tight belts and clothes (increases peripheral resistance).

9 Interpretation of IOS R5 total airway resistance normal if Lower than 150% of R5 pred. R20 poximal airway resistance normal if Lower than 150% of R20 pred. X5 Distal capacitive reactance normal if Higher than X5 pred – 0.2 kps/l/s

10 lung function is abnormal if either R5 or X5 or both parameters are in the abnormal range Assessment of bronchial hyperactivity R5 (50% increase = 20% decease of FEV1) Fres (40% increase = 20% decrease of FEV1) When 2 parameters pass threshold, terminate

11 Assessment of bronchial hyperreactivity (Dilatation) R5 Total respiratory resistance (20-25% decrease = 15% increase of FEV1) Fres Resonant frequency (20 % decrease= 15% increase of FEV1) As soon as one of these two parameters passes the threshold, the patient is hyperreactive


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