Pulmonary Function Testing PDF

Pulmonary Function Testing Graphics Interpretation Quality Control  INTRODUCTION In this section we will use graphics and charts to: Determine Acceptability of Tests Determine which Results to Report...

Pulmonary Function Testing Graphics Interpretation Quality Control  INTRODUCTION In this section we will use graphics and charts to: Determine Acceptability of Tests Determine which Results to Report Determine Good Effort Interpret Flow/Volume Loops Interpret Pre/Post Bronchodilator Spirometry Interpret FRC Graphics D Determining Acceptability Volume-Time and Flow-Time Graphs. Figure 1.29 and 1.30 D Acceptable: Unacceptable: 3 maneuvers, very close in range 3 maneuvers, no repeatability 2 maneuvers agree within 0.150 L Maneuvers do not agree within 0.150 L Acceptable or Not? looking for highest I sum curve 2 is best curve 2 - Figure 1.44 yes  What Is Reported? Effort 2 is considered the best because it has the highest sum Effort 1 Effort 2 Effort 3 FVC 3.55 3.50 3.53 FEV1 1.93 2.02 1.98 Sum of both 5.48 5.52 5.51 Largest Frc's Largest FEV, get reported-even if in diff maneuvers Frc - 3 55. FEVl : 2 02.  Determining Good Effort Figure 1.38 Two forced spirometry efforts, good and poor effort  POOR START OF TEST poor effort - poor effort ⑧ E SIGNIFICANT COUGHING VARIABLE FLOW EARLY TERMINATION FRC GRAPHICS Proper Technique: lines are straight and overlap Figure 02.12 FRC GRAPHICS Bad Tests: lines are bent and open in the middle Possible Causes: equipment issue Thermal drift temp not calibrated - Bad technique (panting too fast or too deep) Fig 02.13  Looking at Loops expiration - start end inspiration - Figure 1.39  Looking at Loops * usually caused Figure 1.43 by vocal cord paralysis  Looking at Loops Scoopy Skinny you aspirated a potato. Loop looks like a potato Kettering Comprehensive Review Study Guide  Pre/Post Bronchodilator only using FEV, % change is calculated using the FEV1 The formula is: 𝑃𝑜𝑠𝑡𝐹𝐸𝑉1 −𝑃𝑟𝑒𝐹𝐸𝑉1 x 100 𝑃𝑟𝑒𝐹𝐸𝑉1 a 12% change in FEV1 or a 0.2 L increase in FVC = a positive bronchodilator response We do not use the FEV1/FVC ratio to measure bronchodilator response Pre/Post Bronchodilator bronchodilator response. post-brown is less "Scoopy"  Pre/Post Bronchodilator Before Forced exhale to less after Scoopy + bronchodilator result FIGURE 01.47: SPIROMETRIC RESULTS IN FLOW–VOLUME GRAPH FORMAT. SHOWS FIVE MANEUVERS BEFORE BRONCHODILATOR (RX) AND THREE MANEUVERS AFTER RX.  Practice Does this test show a positive bronchodilator response? I - Table 1.9  Practice I Host-pre x10 218-202 X100 = about 8% alro did not have must have at least an appropriate. a. 2 change response in FVC. must be at leat 1270.  Practice Does this test show a positive bronchodilator response? 2 Table 1.10  Practice 2 post-pre - X 100 = pre 1 98 #. x 100 = 1 98. 0 25 X100 = 25% Q. = appropriate response  Practice Is this: A.Restriction B. Obstruction C.Normal D.Large Airway Obstruction E. Poor Effort -  Practice Is this: A.Restriction - B. Obstruction C.Normal D.Large Airway Obstruction E. Poor Effort  Practice Is this: A.Restriction B. Obstruction - C.Normal D.Large Airway Obstruction E. Poor Effort  Practice Is this: A.Restriction B. Obstruction - C.Normal D.Large Airway Obstruction E. Poor Effort  Practice Is this: Potato! A.Restriction B. Obstruction C.Normal - D.Large Airway Obstruction E. Poor Effort  Practice Is this: - A.Restriction B. Obstruction C.Normal D.Large Airway Obstruction E. Poor Effort  Practice This is most likely the result of: # A. B. C. Thermal Drift Excessive patient effort Poor patient effort D. Normal test E. Patient puffing their cheeks during testing  CALIBRATION CHECK Must be done every day of use A Use 3-liter calibration syringe * Inject at different speeds - but of the same volume Very slow to very fast to assess linearity Must document calibration checks Leak Testing - slowly sink over time Figure01.21  CALIBRATION CHECKS CONTINUED A Calibration check limit must be within ± 3%A 3L multiplied by 3% or (0.03) = 0.09 L or 90 mL We add 0.09 to 3 to find out upper limit (3.09 L) We subtract 0.09 from 3 to find our lower limit (2.91 L) A Calibration must be within 2.91 – 3.09 or you cannot use the equipment until it is serviced * Examples: - Calibration measuring 2.83 cannot be used. (possible leak) Calibration measuring 2.98 can be used Calibration measuring 3.15 cannot be used may be - an obstruction FIGURE 1.20: PHOTOGRAPH OF SEVERAL CALIBRATION (KNOWN-VOLUME) SYRINGES. Source: Printed with permission from: Hans Rudolph, Inc.  QUALITY CONTROL (QC) Biologic Controls Healthy non-smoking individuals Perform spirometry on each control a number of times Establish mean and standard deviation (SD) for FVC and FEV1 Values measured should fall within ± 2 SDs If values fall outside of ± 2 SDs, perform remedial action (e.g., call manufacturer) important  important QUALITY CONTROL (QC) Recorder Time Sweep CONTINUED If spirometer has a recorder with a time sweep, check the speed against a stopwatch A time sweep test allows for testing of degradation over time Range Check the spirometer over its entire range Or start at a point other than zero and check it against the chart paper Technologist Monitoring and Feedback Techs are measured for test quality and repeatability using a scoring system  CALCULATIONS REQUIRED TO REPORT RESULTS Temperature Correction Exhaled air from lungs is 37° C and is saturated with water vapor Air in room is usually 20-23° C There is a formula that uses barometric pressure and temperature to take the issue of water vapor out of the test results and ensure volumes read are reported at body temperature instead of room temp. Most analyzers perform this calculation internally A Correcting volumes in this manner is controversial and many studies have been done on its effects. However, correcting temperature is still the standard of practice  * important MAXIMUM VOLUNTARY VENTILATION (MVV) Patient breathes deeply and rapidly for 12 to 15 seconds Testing technique recommendations Tidal volume should approximate 50% of the VC Breathing frequency of approximately 90 breaths/min Obtain at least two MVV maneuvers, with a repeatability goal of ± 10%. If variability is > than 20%, obtain additional maneuvers Report highest acceptable MVV and MVV rate  MAXIMUM VOLUNTARY VENTILATION There are reference (predicted) values for the MVV Expired volume is extrapolated to 1 min A calculation or approximation of MVV can be made using the following formula: MVV = FEV1 x 40 MORE INTERPRETATION PRACTICE  WHAT IS THE BEST INTERPRETATION FOR THIS PFT? % predicted FEV1/FVC 45 ↓ FEV1 37 FVC25% 74 TLC 298 FRC 175 Asthma Pulmonary edema Sarcoidosis - Emphysema Normal  WHAT IS THE BEST INTERPRETATION FOR THIS PFT? to stage is FEV, predicted measured FEV1/FVC 82 46 FEV1 2.80 1.58 FVC 3.74 3.54 We aren’t given the %predicted. Now measured what? - Obstructive Fredictive Restrictive Mixed Normal 3 = 94 % 3 74.  WHAT IS THE BEST INTERPRETATION FOR THIS PFT? % predicted FEV1/FVC 87 FEV1 99 FVC 92 TLC 90 FRC 96 Mild obstruction superimposed on restrictive process Pulmonary edema Sarcoidosis Emphysema -Normal  WHAT IS THE BEST INTERPRETATION FOR THIS PFT? predicted measured % predicted FEV1/FVC 78 56 5470 FEV1 3.26 2.4 74 FVC 4.22 4.12 98 Restrictive Obstructive What degree of mild Obstructive severity? Mixed Normal  WHAT IS THE BEST INTERPRETATION FOR THIS PFT? measured predicted % predicted FEV1/FVC 48 70 4870 FEV1 1.5 3.1 48 FVC 2.1 3.8 55 TLC 6.5 4.9 133 - air trapping FRC 3.5 2.6 136 Restrictive Obstructive S - evere obstructive Mixed Normal  WHAT IS THE BEST INTERPRETATION FOR THIS PFT? predicted measured % predicted TLC RV 6.38 2.77 7.12 3.6 112 130 > air trapping DLCO 24.2 12.3 51 DLCO decreased Restrictive - Obstructive Mixed Normal  WHAT IS THE BEST INTERPRETATION FOR THIS PFT? measured % predicted FRC 1.86 67 TLC 3.99 67 RV 1.04 75 SVC 2.96 71 is low & Restrictive everything Obstructive Mixed Normal  WHAT IS THE BEST INTERPRETATION FOR THIS PFT? measured predicted FRC 4.26 3.80 112To TLC 7.71 7.02 1094 RV 3.49 2.02 SVC 4.22 5.04 Restrictive We aren’t given the ratios we expected -Obstructive or the %predicted. Now what? Mixed Normal