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Interpretation. Normal Spirometry Obstructive pattern Restrictive pattern Mixed pattern Small airway obstruction Non-specific ventilatory pattern Probably normal pattern Upper airway obstruction pattern Neuromuscular diseases. Normal Spirogram. All parameters are normal
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Interpretation • Normal Spirometry • Obstructive pattern • Restrictive pattern • Mixed pattern • Small airway obstruction • Non-specific ventilatory pattern • Probably normal pattern • Upper airway obstruction pattern • Neuromuscular diseases
Normal Spirogram • All parameters are normal • Normal shape in VT and FV loop
A. Normal: both the FVC and the FEV1/VC ratio are normal. “Knee”
The severity of the abnormality is graded: - % Pred FEV1 > 100 = May be a physiological variant - % Pred FEV1 < 80 and > 70Mild - % Pred FEV1 < 70 and > 60Moderatesevere -% Pred FEV1 < 60 and > 50Moderately - % Pred FEV1 < 50 and > 35Severe - % Pred FEV1 < 35Very severe
The severity of the abnormality might be graded as follows: -% Pred FVC < LLN and > 70 mild - % Pred FVC < 70 and > 60Moderate -% Pred FVC < 60 and > 50Moderatelysevere -% Pred FVC < 50 and > 34Severe - % Pred FVC < 34 Very severe
Early small airway obx FV curve :upward concavity FVC, FEV1, FEV1/FVC :NL • FEF 25-75 ??? • ATS states that FEF25-75% should not be used to diagnose small airway disease or to assess respiratory impairment
Probably normal spirogram • Only FEF 25-75 • No small airway disease (ATS) • Only FEV1/FVC FEV1> 100% Probably Normal FVC>100%
Similar to restrictive pattern Normal TLC, RV & DLco Obesity Asthma COPD Normal variant Nonspecific ventilatory pattern
Indications for referral • FEV1/FVC less than %75 and FEV1 less than %80 • FEV1/FVC more than %75 and FVC less than %80 • Significant reduction across time • Pulmonary symptoms or signs even with normal spirogram
Screening Spirometry • General health • Occupational health screening
Screening Spirometry in General Healthy Population • Baseline spirogram in all at 20-25 • Periodic spirogram depends on risk factors such as smoking each 1-5 yrs.
Occupational screening spirogram • In certain occupational exposures • Asbestos, silica, cadmium, cotton, coal, beryllium, wood dust,…. • Usually each 1-2 yrs
Comparison of periodic spirogram • Significant change in FEV1 or FVC • Cross-shift • Week-to-week • Year-to-year • Definition
Considerations in periodic spirogram • Using: • Similar reference values • Similar patient position • Similar time • Standard spirometer • Standard technique
Change in spirometric indices over time NIOSH : (0.85 .initial FEV1 or FVC) – (number of yr . 0.025) FVC FEV1 (value on time 1 – value on time 2 / value on time 1)× 100
In an ongoing annual surveillance of asbestos workers, a 24 year old woman is found to have an FVC of 3.59 liters. Her previous FVC was 4.17 liters. What is your interpretation? • Absolute change: 4.17-3.59 = .58 liters • She showed a loss of .58 liters. • Percent change: ((4.17-3.59)/4.17) x 100 = 13.9% • She showed a loss of 13.9% in her FVC.
Further investigation recommended for follow-up results if: • Decline in FEV1 or FVC > 15% in longitudinal screening. If the period is > 5 years, adjust for the decline due to aging (25 ml/year) • FEV1, FVC or FEV1/FVC < LLN at any time • >10% decline between pre and post shift screening
Case 1 A 71 yrs male Height :175 ,weight :88 FVC:45% FEV1: 31% FEV1/ FVC :53% FEF25-75 :15% TLC :142% very severe obx
Case 2 A 36 yrs female Height :162 ,weight :83 FVC:89% FEV1: 94% FEV1/ FVC :89% FEF25-75 :131% TLC :92% normal
Case 3 A 29 yrs female Height :165 ,weight :129 FVC:78% FEV1: 79% FEV1/ FVC :86% FEF25-75 :85% TLC :82% non specific ventilatory
Case 4 A 43 yrs female Height :61,weight :167 FVC:33% FEV1: 17% FEV1/ FVC :42% TLC :114% variable inthratoracic obx
Case 5 A 30 yrs male Height :186,weight :68 FVC:19% FEV1: 21% FEV1/ FVC :93% FEF25-75% :48% TLC :28% very severe restriction
Case 6 A 30 yrs male Height :175 ,weight :70 FVC: 88% FEV1: 69% FEV1/ FVC :66% FEF25-75 :38% VEXT : 90 moderate obx
Case 7 A 29 yrs male Height :179 ,weight :83 FVC: 95% FEV1: 84% FEV1/ FVC :67% FEF25-75 :51% VEXT : 120 Mild obx
Case 8 A 26 yrs male Height :177 ,weight :67 FVC: 97% FEV1: 77% FEV1/ FVC :66% FEF25-75 :48% VEXT : 60 mild obx