Pulmonary Function Test 1 PFT AMI or PE

Pulmonary Function Test 1

PFT 的禁忌 沒有絕對禁忌 相對禁忌: 不明原因之咳血 氣胸 心臟血管功能不穩（AMI or PE） Aneurysms Recent eye surgery (e. g. cataract) Recent surgery of thorax or abdomen 2

Spirometry Vital capacity(VC maneuver) Forced vital capacity , Forced expiratory volume , and Forced expiratory flow 25%75%(FVC maneuver) Flow volume curve Before- and after-bronchodilator studies Bronchial challenge test 單位: L or ml, L/s or L/min, at BTPS ☆ BTPS: body temperature, pressure & saturation 3

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FVC maneuver 吸氣到最大, 之後用力呼氣到最大 Forced VC約等於 slow VC Forced inspiratory vital capacity(FIVC) 單位: L or ml, L/s or L/min, at BTPS Forced Vital capacity ( FVC ) Forced Expiratory Volume ( FEV 1) Forced Expiratory Flow 25%-75% 5

ACCEPTABILITY AND REPRODUCIBILITY CRITERIA Acceptable criteria(可接受性) 不可以有: 第一秒內cough or 閉氣, 隨興地吹氣, 漏 氣, 含管堵塞 好的開始: Vextrap< 5%FVC or 100 -150 ml, Time-to. PEF < 120 ms 好的結束: 6 s and/or 有plateau出現 Reproducibility criteria(重現性) 兩個FVC (或FEV 1)相差< 200 ml 最多 8個FVC動作 or 視病人情況而定 取 3個最佳動作 7

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FEV 1 mark 10

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Back-extrapolation of volume-time spirogram Extrapolated volume should be < 5% of FVC or 100 -150 ml 校正方法 因受測者用力呼氣開始的不夠快 12

5 -digit Error Code 0/1 0/1 0/1 FVC FEV 1 Vol Extrap End of Test Exp Time Two largest FVC’s were reproducible within 5% of one another 0 = O. K. Two largest FEV 1’s were reproducible within 5% of one another 5% FVC or 100 ml No measured volume change (< 40 ml) during the final 2 s 6 s, obvious plateau in V-T curve 1 = poor 13

判讀—FVC Healthy: VC 約等於FVC, 兩者差 < 200 ml Expiratory time: about 4~6 sec Obstructive: 呼氣時間變長 FVC ↓ 因air trapping Restrictive: FVC < 80% of predicted value 14

判讀—FEV 1 & FEV 1% Obstructive: FEV 1 ↓ & FEV 1% ↓, FVC不一定 FEV 1% < 75% FEV 1與prognosis & severity有關 Restrictive: FEV 1 ↓ & FVC ↓, FEV 1%不變 Senile change: FEV 1% 隨著年齡增加而些微下降 15

判讀—FEF 25 -75% Maximum mid-expiratory flow rate(MMEF) Reflecting the status of medium- to smallsized airways Young man: 4. 5 L/s; young woman: 3. 5 L/s; or > 65% of predicted value 隨著年齡增加而些微下降 It depends on FVC and good effort 提早停止呼氣 FVC↓ FEF 25 -75% ↑ In restrictive disease, small airway的直徑可能 因lung volume loss而變小, 造成FEF 25 -75%下降 16

Flow–Volume Curve Maximal expiratory flow-volume curve (MEFV): TLC RV Maximal inspiratory flow-volume curve (MIFV): RV TLC F-V loops: compared by superimposing Predicted vs actual Before vs post bronchodilator test For challenge test 17

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F-V Curve--判讀 Small airway obstruction: Concave(下凹) Large airway obstruction: FEF 50 & FIF 50 ↓ 漢堡狀 Restrictive disease: MEFV斜率不變 TLC ↓ 19

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Bronchodilator test To determine the reversibility of airway obstruction A FEV 1% less than predicted is good indication Use MDI or nebulizer Testing drug: ß-agonist(i. e. isoproterenol) Hold medication (i. e. theophylline…) 23

判讀 Positive: > 12% and 200 ml for FEV 1 or FVC Negative: No reversibility Poor effort inadequate deposition of drug Fatigue multiple FVC efforts 24

Bronchial challenge test To identify airway hyperactivity Provocative dose 20%(PD 20%): FEV 1下降20%時, methacholine的濃度 25

操作 Baseline spirometry Hold medications Diluent : usually normal saline Controlled FEV 1 Not reduced > 10% of baseline FEV 1 Smallest dose -> -> -> larger dose Reversal by bronchodilator Side effect: BRONCHOSPASM 26

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Lung Volumes (肺容積) 28

Lung volume—方法 測FRC: Open circuit method: Multiple-breath N 2 washout(氮) Close circuit method: Multiple-breath He dilution(氦) 29

Lung volume—方法 測RV: RV=FRC - ERV Slow VC maneuver (spirometry) ERV 測TLC: TLC=RV + VC TLC=FRC + IC 測RV/TLC % 30

Lung volume—判讀 影響因子: age, sex, height, race Other factor: body size, body position, time of day FRC > 120% of predicted pathologic TLC < 80% of predicted pathologic RV/TLC%: 正常值 20% ~ 35% 33

Lung volume—判讀 Obstructive lung: FRC↑> 120% RV/TLC% > 35% RV↑& TLC 不變 air trapping RV↑& TLC ↑ hyperinflation Restrictive lung: FRC, RV, TLC, VC通常一起下降 TLC ↓ < 80% FEV 1% 不變 TLC↓而 VC ↑: 以TLC為主 34

Thoracic gas volume VTG 可測肺部任何部位的體積 如: 由end-expiratory level測, 即為FRC 利用Boyle’s law Body plethysmography(body box) 35

VTG—操作 36

Body plethysmography PB = box pressure • 970 = (760 -47) 1. 36 = PFRC - PH 2 O 37

VTG—判讀 38

Diffusing Capacity Tests (擴散能力試驗) 39

DLCO --原理 41

DLCO –方法 44

DLCO –判讀 正常值: 25 ml/min/mm. Hg, STPD 影響因子: age, sex(M>F), height, lung volume, exercise, body surface area(BSA), ideal body weight(IBW) Other factors: Hb, Hb. CO, PAO 2, pulmonary blood volume/hemorrhage, supine position, altitude 45

Increase DL co Supine position Exercise Asthma Obesity Polycythemia Intra-alveolar hemorrhage Left to right intra-cardiac shunt 46

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Consideration 49