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Spirometry, Rollercoasters, and Waterslides. Vinit K. Mahesh, M.D. CQN Chapter Asthma Expert April 15, 2010. Vinit Mahesh, MD Disclosure Statement.
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Spirometry,Rollercoasters,andWaterslides Vinit K. Mahesh, M.D. CQN Chapter Asthma Expert April 15, 2010
Vinit Mahesh, MD Disclosure Statement “I have the following financial relationships with the manufacturers) of any commercial product and/or provider of commercial services discussed in this CME activity:” Speakers’ Bureau: Merck and Astra Zeneca It is my obligation to disclose to you (the audience) that I am on the Speakers Bureau for Merck and Astra Zeneca. However, I acknowledge that today’s activity is certified for CME credit and thus cannot be promotional. I will give a balanced presentation using the best available evidence to support my conclusions and recommendations.”
Obstacles • What is it • How expensive is it • Who will perform studies • Who will interpret studies • How will this affect patient flow • Do we really have to do this • How do I get started
Spirometry Measurement of breathing
What is actually measured?? • Forced Vital Capacity (FVC) • Forced Expiratory Flow 1 sec (FEV1) • Maximum Expiratory Flow (PEFR) • Mid Expiratory Flow Rate (FEF25-75)
Forced Vital Capacity • Amount of air blasted out after maximum inhalation • Very effort dependent • Express in liters • Can only suggest restrictive lung disease
FEV1 • Amount of air blasted out in first second • Less effort dependent that FVC • Expressed as volume, but is a rate (per second) • FEV1/FVC useful parameter
Maximum Expiratory Flow Rate • Also known as peak expiratory flow rate • Similar to peak flows • Expressed as L/S • Peak flows expressed as L/min • Measure of larger airways or larger lung volumes
Mid Expiratory Flow Rate • Known as FEF25-75 • Rate of flow between 25% of FVC and 75% of FVC • Measure of smaller airways or lower lung volumes
Cost • $3000-$5000 initial cost • $3-$5 per study • Factor in personnel time for study • Procedure #94010 • Medicaid pays 39.00 • Blue Cross pays 46.00
Operator • Historically RT function • Nurses can perform • Initially, limit to one-two people to gain experience • Cheerleader personality
Interpretation • Percent predicted • Based on age, height, gender, race • > 80% predicted for FVC, FEV1, PEFR • > 40 % predicted for FEF25-75 • FEV1/FVC actual ratio 80-85% • Shape of curve
Utility • Picture paints a thousand words • Parameters not captured by peak flows • Normal in mild persistent asthma • Ultimate parameters are personal bests