| Flap 1 |
Flap 2 |
| TLC Normal | total lung capacity 6000ml |
| VT Normal | tidal volume 500 ml |
| VC normal | vital capacity 4800 |
| RV normal | residual volume 1200 |
| Volumes that cannot be directly measured in a PFT | RV, FRC, TLC |
| Tests used for RV, FRC, and TLC | Helium dilution, Nitrogen washout, body box (most accurate) |
| PFT Equipment for measuring volume | water sealed spirometer (uses bell) bellows spirometer (most popular) dry rolling seal spirometer |
| Infection Control in PFT's | standard precautions fluids-hand washing, gloves, barrier filters. Infectious disease- personal respirator or close fitting mask (N-95 for TB). safe disposal, sterilize or disinfect equip between patients. |
| Why PFT's | identify and quantify changes in pulm function, epidemiological surveillance for pulm disease, assessment of post op risk, determine pulm disability, evaluate and quantify therapeutic effectiveness |
| Patient instructions for FVC | effort dependent, careful instructions, be sure Pt understands and will cooperate, demonstrate, enthusiastic coaching, sitting standing ok, nose clips on or off ok, 3 tests, best 2 must be within 5% ( convert atps to btps) |
| ATPS to BTPS | since ATPS can be 5 to 15% different that BTPS, adjustments must be made or test will be invalid. |
| FEV1 | forced exp volume in 1 second, Normal is 4.2 L...(<80%=obstructive), measured as volume it is considered a flow. Used as a measure of general severity with airway obstruction |
| FEV2 | forced exp volume in 2 seconds, normal is 4.6L |
| FEV3 | forced exp volume in 3 seconds 4.8L |
| PEFR | Peak exp flow rate, steepest point on curve on the "FLOOP", normal is 9.5L/sec (best identified on a flow-volume loop |
| FEF200-1200 | forced exp press between 200 and 1200, normal 8.5ml/second, measures large airway flow |
| FEF25-75 | forced exp flow between 25 and 75, normal is 4.5L/second, measures small airways |
| Measuring RV | Residual Volume, normal 1200, like the FRC & TLC it cannot be directly measured. alternative tests are, 1.Body box 2. Helium dilution 3. Nitrogen washout |
| Body Box | best method to measure RV, uses Boyles Law to calc RV, larger values because more accurate information |
| PFT Contra-indications | hemoptysis, pneumothorax, cardio problems, thoracic, abdominal or cerebral aneurysm, recent eye surgery, acute disease that may cause nausea or vomiting, recent ab or chest surgery |
| FVC Validity/Reliability | 3 acceptable tests must be given, best 2 should not vary by more than 5%, no cough, swallow or disruptions, smooth, continuous and complete, exhalation must be a minimum of 6 seconds |
| M V V | Max voluntary ventilation, normal is 160L/min, tested with Spirogram, fast and hard for at least 12 seconds, 2x-use best results, tests for strength of muscles, flow and capacity, tested pre-op/ make sure patient can get of vent post op |
| PFT Severity | normal 80 - 120, moderate 50-64, very severe <35 |
| Obstructive severity | check FEV1 & FEV1% |
| Restrictive Severity | check FVC, TLC & VC |
| DLCO | Diffusion of Lung Carbon Monoxide, normal is 40ml/min/mmHg, 0.3%CO & 10% He in air held in a single breath for 10 seconds. |
| Restrictive Disease | ↓ volumes & capacities, affects lung parenchyma and thoracic pump, ↓ inspiration, ↓CL, more vertical slope on PFT tracing than obstructive, restriction+diffusion=fibrosis |
| Obstructive Disease | ↓ Flows, ↑ CL, flatter curve on PFT tracing, affects airways, obstruction+diffusion=emphysema |
| FVC | Forced Vital Capacity, normal is 480 ml |
| FEV1% | FEV1/FVC, normal is 75 to 85 % (<70%=obstruction) |
| VC/TLC% | VC is normally 80% of TLC |
| Spirometery Value Factors | height, age, gender, ethnicity, sometimes for extreme weight and altitude (may be reduced 12 to 15 % for non-white) |
| FVC Tracings | obstructive curve is flatter, restrictive curve is more vertical |
| Conditions that ↓ DLCO | ↓ DLCO is associated with emphysema , Fibrosis, restrictive diseases, carbohemoglobin polycythemia, CHF, anemia, pulm embolism, exercise |
| Airway Obstruction Tests | FEF200-1200, normal is 8.5 L/sec, <80%=large airway disease. FEF25-75, normal is 4.5 L/sec,<80%=small airway disease. (FRC or RV >120%=airtrapping) |
| Patient Effort | Patient efforts insures validity and reliability of tests. Tests that are not valid or reliable, can lead to misdiagnoses, mistreatments and poor outcomes |
| Reversibility of airway obstruction | before and after treatment studies, FEV1 >15% indicates effective treatments |
| PFT categories (test types) | lung vol and cap, flow rates through airways, ability of lungs to diffuse gases (DL) |
| Nitrogen washout test | open circuit (non-re breather), exhaled gas measured for N2, Patient breaths until little N2 remains, 2-5 mins normal, COPD longer (perforated ear drum will scew test) |
| Helium Dilution test | measures RV,FRC,TLC...closed circuit, helium and O2, CO2 is absorbed by soda lime and )2 is added, Pt breaths until gas concentration is equalized 3-5 mins (20 mins in copd) |
| Fibrosis | restriction + diffusion |
| bronchoprovocation testing | methocholine induced asthma attack, positive response is FEV1 falls more than 20%, reversed with svn or mdi treatment |
