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Pulmonary Function
(PFT)
Term | Definition |
---|---|
Indications for (PFT) | - presence of lung disease - how much of the lung is damaged - the amount of damage due to the disease - progress of the disease - nature of the disease - evaluate the therapy given - response to therapy |
Pulmonary Function Equipment | - Spirometer - Electronic Spirometer - Pneumotachometer - Peak Flow Meter |
Spirometer | are used to MEASURE FLOWS and FLOW RATES |
Pneumotachometers | measures flow, and volume |
Peak Flow Meters | - measured at bedside - patient exhale forcefully which moves the indicator - read directly from the device - |
Peak Flow Meter Values | Low Range: 300-400 L/min Typical: 10L/sec= 600L/min High Range: 600-800 L/min |
Peak Flow Meters Personal Best | - record peak flow everyday morning and noon for 2-3 weeks when asthma is under control. - should be recorded after (SABA) |
Plethysmograph (Body Box) | - Boyles Law - Measure Thoracic Volume = FRC ( more accurately) Raw (airway resistance) |
Calibration and Quality Control of Equipment | must meet ATS-ERS standards tests are done by large volume syringe( Super Syringe) 3.0L Accuracy +/- 3.5% (2.895-3.105) L using flow = 2 and 12 L/sec |
To Calibrate Flow | use rotameter |
Gas Analyzer calibration | are calibrated = 0 = running a gas that doesn't contain the gas you are calibrate (i.e. 100% oxygen reads 0 on a He/ N2 analyzer) |
Gas Analyzer Troubleshooting | Galvanic- fuel cell Polarographic : replace batteries |
Pressure Manometer MIP/ MEP | MIP= < -20 = inspiratory muscle weakness MEP=< + 40 = poor ability to clear airway secretions |
PFT Testing and Procedure (VC)vital capacity,(SVC) slow vital capacity | patient is instructed to take a maximal inspiration followed by maximal expiration WITHOUT force |
(SVC) Identify slow vital capacity | Restrictive look at SVC for restrictive disease DECREASED = RESTRICTIVE |
Vital Capacity indicator | Vital capacity is the BEST for RESTRICTIVE DISEASE INDICATOR |
Forced Vital Capacity | The volume of air that can be expired as forcefully and as rapidly as possible after a max inspiration |
Forced Vital Capacity Identify | Identifies= FLOW RATES OBSTRUCTION |
Forced Vital Capacity | maneuver and procedure will provide important FLOW RATES to identify OBSTRUCTIVE DISEASES |
Flows that can be measured | FEV 1.0 FEF 200-1200 FEF 25-75 PEFR |
FEV 1.0 | The amount of gas expired in the 1st sec A decrease indicates OBSTRUCTIVE |
FEV/FVC | Value given as a ratio |
Decreased FEV/FVC 1.0 | The BEST indicator of OBSTRUCTIVE DISEASE |
Measurements and Minimum Accepted FEV/FVC | fev 0.5 = 60% fev 1.0 = 70% fev 2.0 = 94% fev 3.0 = 97% |
FVC | The FVC is not a FLOW its a VOLUME |
MVV | The largest volume and rate that can be breathe per minute voluntary effort performed for 12-15 secs |
Pre and Post Bronchodilator Testing | used to measure reversibility of an obstructive pattern Minimum increased 12% and 200mL All bronchodilators should be held 8 hours prior to test |
FRC | measures RV, TLC |
FRC can be measured by | He dilution N2 was out (Open method) Plethysmograph (Body Box) (closed) |
DLCO | measures carbon monoxide NV = 25mL CO/min/mmHg/ (STPD) |
Decreased DLCO | All restrictive + Except Emphysema The only Obstructive |
Flow Volume Loops | A normal flow volume loop should look like a football |
Flow Volume Loop Obstructive | short and wide = Obstructive |
Flow Volume Loop Restrictive | skinny and tall |
Predicted Normal Values | All measured values are compared with the predicted normal values for that individual. Based on Age, Height, Gender |
Important Evaluation | look at the % predicted |
Classification of Interpretation | Normal = 80-100% Mild = 60- 79% Moderate = 40 - 59% Severe = < 40% |
Obstructive Disease | CBABE Cystic Fibrosis, Bronchitis, Asthma, Bronchiectasis, Emphysema |
Restrictive | EVERYBODY ELSE e.g. neuromuscular, pleural disease, thoracic deformities |