PFT 3rd year FDPS.pptx

concise ppt design for understanding of Physiotherapy graduates and post graduate students.

1. PFT By: Dr. Rekha Marbate

2. Content Introduction Method of pulmonary function test Normal values Interpretation

3. Introduction Pulmonary function tests (PFTs) provide the clinician with information about the integrity of the airways, the function of the respiratory musculature, and the condition of the lung tissues themselves.  A thorough evaluation of pulmonary function involves several tests that measure lung volumes and capacities, gas flow rates, gas diffusion, and gas distribution.  Based on the results of PFTs, pulmonary diseases may be classified into three basic categories: obstructive, restrictive, or combined.

4. Spirometry Spirometers may be of the traditional manual water-seal type, or they may be electronic computerized devices (e.g., pneumotachometer).  In either case, a spirogram of the lung volumes is typically produced to facilitate interpretation of the measurements .

5. Procedure: Subject position: Upright sitting Instruments: Nose clip, computerized spirometer device with mouthpiece. Procedure:  The patient should breathe normally into the spirometer (or other appropriate instrument) through a tight-fitting mouthpiece 

6. Instruction: Step 1: Breath in deeply and hold Step2: nose clip applied to avoid expiration Step3: Hold mouth-piece tightly in mouth and expired forcefully as fast and long as possible . Step 4: once further expiration end, remove mouthpiece. 

7. Test for lung volume and capacities IRV- inspiratory reserve volume[ 3300ml] TV- tidal volume[ 500ml] ERV- expiratory reserve  volume [1000ml];  RV- residual volume[ 1200ml];  TLC-  Total lung capacity [IRV+TV+ERV+RV=6000ml];  IC-  inspiratory capacity [ IRV+TV=3800ml] ; FRC- functional residual capacity [ ERV+RV=2200ml];  VC-  vital capacity[ TV+IRV+ERV= 4800ml]

8. Test for gas flow rate Tests that measure airflow rates during forced breathing maneuvers provide important information relating to the actual function of the lungs, the degree of impairment, and often the general location (large airways, small airways, etc.) 

9. Basic measures of airflow rates:  Forced vital capacity (FVC) is the maximum volume of gas the patient can exhale as forcefully and as quickly as possible. Forced expiratory volume in 1 second (FEV1) is the volume of air that is exhaled during the first second of the FVC and reflects the airflow in the large airways. 

10. Forced midexpiratory flow (FEF25-75) , previously called the maximal midexpiratory flow rate, is volume of air exhaled over the middle half of the FVC, divided by the time required to exhale it.  Maximum voluntary ventilation (MVV) is the maximal volume of gas a patient can move during 1 minute  Peak expiratory flow (PEF) is the maximum flow that occurs at any point in time during the FVC

11. Flow-Volume    Loop The flow-volume loop or curve is a way of graphically representing the events that occur during forced inspiration and expiration.  The flowv olume procedure simply records flow against volume on an X-Y recorder.  Following a period of normal, quiet breathing, the patient is instructed to perform a maximal inspiratory maneuver, to hold the breath for 1 to 2 seconds, to do an FVC maneuver, and then to do another maximal inspiratory maneuver. 

12.   A normal expiratory and inspiratory flow volume loop. 

13. A characteristic  flow­volume  loop  as seen in a patient with severe chronic airflow limitation caused by smoking. Notice the deeply scooped­ out appearance of the  expiratory limb of the curve, reflecting the pronounced flow limitation occurring at low lung volumes (predicted  flow­volume   loop in the red line).

14. C. A characteristic flow ­volume loop in a patient with severe lung restriction from pulmonary fibrosis. Notice  the patient’s relatively small lung volumes. Compared with predicted values, flow rates are relatively increased in relation to lung  volume (predicted  flow­volume  loop in the red line).  D, A characteristic  flow­volume  loop in a patient with a fixed tracheal stenosis  

15. This Photo by Unknown author is licensed under CC BY-NC-ND .