cpet心肺運動試驗

1、Mitchell HOROWitz,Cardiopulmonary Exercise Testing,Outline,Description of CPETWho should and who should not get CPETWhen to terminate CPETExercise physiologyDefine terms: respiratory exchange ratio, ventilatory equi

2、valent, heart rate reserve, breathing reserve, oxygen pulsePattern of CPET results COPD vs CHF,Rationale for Exercise Testing,Cardiopulmonary measurements obtained at rest may not estimate functional capacity reliably,C

3、linical Exercise Tests,6-min walk testSubmaximalShuttle walk testIncremental, maximal, symptom-limitedExercise bronchoprovocationExertional oximetryCardiac stress testCPET,Karlman Wasserman,,,,Coupling of External

4、 Ventilation and Cellular Metabolism,Adaptations of Wasserman’s Gears,,General Mechanisms of Exercise Limitation,PulmonaryVentilatoryRespiratory muscle dysfunctionImpaired gas exchangeCardiovascularReduced stroke v

5、olumeAbnormal HR responseCirculatory abnormalityBlood abnormality,PeripheralInactivityAtrophyNeuromuscular dysfunctionReduced oxidative capacity of skeletal muscleMalnutritionPerceptualMotivationalEnvironmenta

6、l,What is CPET?,Symptom-limited exercise testMeasure airflow, SpO2, and expired oxygen and carbon dioxideAllows calculation of peak oxygen consumption, anaerobic threshold,Components of Integrated CPET,Symptom-limited

7、ECGHRMeasure expired gasOxygen consumptionCO2 productionMinute ventilationSpO2 or PO2 Perceptual responsesBreathlessnessLeg discomfort,Modified Borg CR-10 Scale,,Indications for CPET,Evaluation of dyspneaDistin

8、guish cardiac vs pulmonary vs peripheral limitation vs otherDetection of exercise-induced bronchoconstrictionDetection of exertional desaturationPulmonary rehabilitationExercise intensity/prescriptionResponse to par

9、ticipationPre-op evaluation and risk stratificationPrognostication of life expectancyDisability determinationFitness evaluationDiagnosisAssess response to therapy,Mortality in CF Patients,Nixon et al; NEJM 327: 178

10、5; 1992.Followed 109 patients with CF for 8 yrs from CPETPeak VO2 >81% predicted: 83% survivalPeak VO2 59-81% predicted: 51% survivalPeak VO2 <59% predicted: 28% survival,Mortality in CHF Patients,Man

11、cini et al; Circulation 83: 778; 1991.Peak VO2 >14 ml/kg/min:1-yr survival 94%2-yr survival 84%Peak VO2 ≤14 ml/kg/min:1-yr survival 47%2-yr survival 32%,CPET to Predict Risk of Lung Resection in Lung Cancer,Lim

12、et al; Thorax 65:iii1, 2010Alberts et al; Chest 132:1s, 2007Balady et al; Circulation 122:191, 2010Peak VO2 >15 ml/kg/minNo significant increased risk of complications or deathPeak VO2 <15 ml/kg/minIncreas

13、ed risk of complications and deathPeak VO2 <10 ml/kg/min40-50% mortalityConsider non-surgical management,Absolute Contraindications to CPET,Acute MIUnstable anginaUnstable arrhythmiaAcute endocarditis, myocardit

14、is, pericarditisSyncopeSevere, symptomatic ASUncontrolled CHFAcute PE, DVTRespiratory failureUncontrolled asthmaSpO2 <88% on RAAcute significant non-cardiopulmonary disorder that may affect or be adversely aff

15、ected by exerciseSignificant psychiatric/cognitive impairment limiting cooperation,Relative Contraindications to CPET,Left main or 3-V CADSevere arterial HTN (>200/120)Significant pulmonary HTNTachyarrhythmia, bra

16、dyarrhythmiaHigh degree AV blockHypertrophic cardiomyopathyElectrolyte abnormalityModerate stenotic valvular heart diseaseAdvanced or complicated pregnancyOrthopedic impairment,Indications for Early Exercise Termin

17、ation,Patient requestIschemic ECG changes2 mm ST depressionChest pain suggestive of ischemiaSignificant ectopy2nd or 3rd degree heart blockBpsys >240-250, Bpdias >110-120Fall in BPsys >20 mmHgSpO2 <81

18、-85%Dizziness, faintnessOnset confusionOnset pallor,CPET Measurements,WorkVO2VCO2ATHRECGBP,RSpO2ABGLactateCPDyspneaLeg fatigue,Exercise Modality,Advantages of cycle ergometerCheaperSaferLess danger of f

19、all/injuryCan stop anytimeDirect power calculationIndependent of weightHolding bars has no effectLittle training neededEasier BP recording, blood drawRequires less spaceLess noiseAdvantages of treadmillAttain h

20、igher VO2More functional,Incremental vs Ramp Exercise Test Protocol,INCREMENTAL,RAMP,,,,,WORK,TIME,,,,,,TIME,WORK,,,,,,,,,,Physiology and Chemistry,Slow vs fast twitch fibersBuffering of lactic acid by bicarbonateCO2

21、production from carbonic acidRespiratory exchange ratioVentilatory equivalent of oxygenVentilatory equivalent of carbon dioxideGraphical determination of ATFick EquationOxygen pulse,Properties of Skeletal Muscle Fi

22、bers,Red = Slow twitch = Type ISustained activityHigh mitochondrial densityMetabolize glucose aerobically1 glucose yields 36 ATPRapid recovery,White = Fast twitch = Type IIRapid burst exerciseFew mitochondriaMet

23、abolize glucose anaerobically1 glucose yields 2 ATP and 2 lactic acidSlow recovery,Lactic Acid is Buffered by Bicarbonate,Lactic acid + HCO3 → H2CO3 + Lactate ↓ H2O + CO2,Respiratory Exchange Rati

24、o,RER= CO2 produced / O2 consumed= VCO2 / VO2,Ventilatory Equivalents,Ventilatory equivalent for carbon dioxide = Minute ventilation / VCO2 Efficiency of ventilationLiters of ventilation to eliminate 1 L of CO2

25、Ventilatory equivalent for oxygen = Minute ventilation / VO2 Liters of ventilation per L of oxygen uptake,Relationship of AT to RER and Ventilatory Equiv for O2,Below the anaerobic threshold, with carbohydrate

26、 metabolism, RER=1 (CO2 production = O2 consumption).Above the anaerobic threshold, lactic acid is generated.Lactic acid is buffered by bicarbonate to produce lactate, water, and carbon dioxide.Above the anaerobic thr

27、eshold, RER >1 (CO2 production > O2 consumption).Carbon dioxide regulates ventilation.Ventilation will disproportionately increase at lactate threshold to eliminate excess CO2.Increase in ventilatory equivalent

28、for oxygen demarcates the anaerobic threshold.,Lactate Threshold,,Determination of AT from RER Plot (V Slope Method),,,Determination of AT from Ventilatory Equivalent Plot,,Wasserman 9-Panel Plot,Oxygen Consumption: Fic

29、k Equation,Fick Equation:Q = VO2 / C(a-v)O2VO2 = Q x C(a-v)O2VO2 = SV x HR x C(a-v)O2,Heart disease,Heart diseaseLung diseaseMuscle diseaseDeconditioning,AnemiaLung disease (low SaO2),Arterial oxygen content

30、 = (1.34)(SaO2)(Hgb)Venous oxygen content = (1.34)(SvO2)(Hgb),Oxygen Pulse,Oxygen Pulse:“. . .the amount of oxygen consumed by the body from the blood of one systolic discharge of the heart.”Henderson and P

31、rinceAm J Physiol 35:106, 1914Oxygen Pulse = VO2 / HRFick Equation:VO2 = SV x HR x C(a-v)O2VO2/HR = SV x C(a-v)O2 Oxygen Pulse ~ SV,,Interpretation of CPET,Peak oxygen consumptionPeak HRPeak workPeak ven

32、tilationAnaerobic thresholdHeart rate reserveBreathing reserve,Heart Rate Reserve,Comparison of actual peak HR and predicted peak HR= (1 – Actual/Predicted) x 100%Normal <15%,Estimation of Predicted Peak HR,22

33、0 – ageFor age 40: 220 - 40 = 180For age 70: 220 - 70 = 150210 – (age x 0.65)For age 40: 210 - (40 x 0.65) = 184For age 70: 210 - (70 x 0.65) = 164,Breathing Reserve,Comparison of actual peak ventilation and pr

34、edicted peak ventilationPredicted peak ventilation = MVV, or FEV1 x 35= (1 – Actual/Predicted) x 100%Normal >30%,Comparison CPET results,Normal CHF COPDPredicted Peak HR150150150Peak HR150140120

35、MVV10010050Peak VO22.01.21.2AT1.00.61.0Peak VE604049Breathing Reserve40%60%2%HR Reserve0%7%20%Borg Breathlessness548Borg Leg Discomfort885,Cardiac vs Pulmonary Limitati

36、on,Heart DiseaseBreathing reserve >30%Heart rate reserve 15%,CPET Interpretation,Peak VO2 HRR BR AT/VO2max A-aNormal >80% 30% >40% normalHeart disease 30% 30% 15% 40% incr

37、easedDeconditioning 15% >30% >40% normal,SUMMARY,Cardiopulmonary measurements obtained at rest may not estimate functional capacity reliably.CPET includes the measurement of expired oxygen and carbon diox

38、ide.The Borg scale is a validated instrument for measurement of perceptual responses.CPET may assist in pre-op evaluation and risk stratification, prognostication of life expectancy, and disability determination.,SUMMA

39、RY,Cycle ergometer permits direct power calculation.Peak VO2 is higher on treadmill than cycle ergometer.Peak VO2 may be lower than VO2max.Absolute contraindications to CPET include unstable cardiac disease and SpO2 2

40、0 mmHg is an indication to terminate CPET.1 glucose yields 36 ATP in slow twitch fiber, and 2 ATP + 2 lactic acid in fast twitch fiber. RER= CO2 produced / O2 consumed,SUMMARY,Above the anaerobic threshold, CO2 product

41、ion exceeds O2 consumption.Ventilation will disproportionately increase at lactate threshold to eliminate excess CO2.AT may be determined graphically from V slope method or from ventilatory equivalent for CO2.Derived