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PFT 01
Spirometry
Question | Answer |
---|---|
Primary uses of PFT | quanitify changes in fxn and impairment. 2. screening of disease 3. assessment of post op 4. determination of pulm disability 5. evaluation of therapy effectiveness |
Basic pt types who are unable to do PFT | severe hypoxemia on room air 2. increased intracranial pressure 3. cardiac arrhythmias 4. inability to follow directions (age, disease) 5. untreatable TV or HIV |
Tidal volume VT | amount of air moved in and out of lungs during normal breathing |
Inspiratory reserve volume (IRV) | amount of air inspired from normal inspiration |
Expiratory reserve volume (ERV) | amount of air exhaled from normal exhalation |
Residual volume (RV) | amount of air left in the lungs after maximum exhalation |
inspiratory capacity (IC) | amount of air inspired from normal expiration |
Functional residual capacity (FRC) | amount of air left in the lungs after normal exhalation |
vital capacity (VC) | amount of air exhaled in one breath; the max amount of air that can be forcibly exhaled after breathing in as much as possible (max inhalation) |
Total Lung capacity (TLC) | amount of air in the lungs after max inhalation |
Info you need to get before testing | Gender, age, height, weight, race, exposure to chemicals, history of medicine, current symptoms, pack years of smoking |
Volumes and capacities that CAN be measured with simple spirometry | 1 Slow vital capacity (called enhanced spirometry) 2. FVC 3. Max voluntary ventilation |
Forced expiratory volume 1 sec | how much air pt can blow out in one second after they have taken a max breath |
forced expiratory volume 3 sec | how much air pt can blow out in 3 sec after they have taken a max breath |
Forced expiratory flow 200-1200 mL | machine disregards the first 200 ml that the pt exhales after max inhalation and then measures how fast the pt exhales the next 1000 mL (LARGE UPPER AIRWAY) |
forced exp flow 25%-75% | machine disregards the first 25% and the last 25% of the air that the pt exhales after max inhalation and then measures how fast the pt exhales (SMALL AIRWAY obstruction) |
Maximum voluntary ventilation | largest volume and rate that can be breathed per minute, in and out as fast as possible for 12-15 seconds (REPRESENTS STRENGTH OF RESP MUSCLES) |
PfTs are measured at | ATPS |
PFTS are reported at | BTPS |
Pt's who are candidates for methacholine challenge | asthma, fireman, assess severe of hyper responsiveness, to determine relative risk of developing asthma, to asses response to therapy |
How is methacholine delivered | dosimeter- only on inspiration and only 5 breaths of each dose level 25 mg/ml |
Substances that can be used for bronchoprovacation testing | histamine - 10 mg/ml 2. antigens 6-8mm wheel 3. cold air 4. exercise |
Avoid short acting bronch | 6-8 hours |
avoid long acting bronch | 48 hr |
avoid anticholinergic aerosols | 24 hr |
avoid tiotropium | up to 1 week |
avoid disodium cromglycate | 8 hr |
avoid nedocromil | 48 hr |
avoid oral beta 2 adrenergic agonist | 24 hr |
avoid theophyllines | 12-24 hr |
avoid leukotriene modifiers | 24 hr |
Pt that is candidate for exercise study | Dyspnea with exertion where past tests are normal.2 asthma and being athletic, 3. known exercise induced asthma |
AVERAGE tidal volume | Ve/f |
ATS criteria for PFT testing | Spirometer must be 8 liters, must be capable of measuring 0-14 L/s, all tests reported by BTPS, min of 3 acceptable FVC 8 max, FVC must be .2 L (150 ml) of each other |
Acceptable PFT | meets end of criteria, no coughing during 1st second inhalation, no closing of glottis, no leak, no obstruction of mouthpiece opening |