CPET心肺运动试验

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 equivalent, 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,Clinical Exercise Tests,6-min walk testSubmaximalShuttle walk testIncremental, maximal, symptom-limitedExercise bronchoprovocationExertional oximetryCardiac stress testCPET,Karlman Wasserman,Coupling of External Ventilation and Cellular Metabolism,Adaptations of Wassermans Gears,General Mechanisms of Exercise Limitation,PulmonaryVentilatoryRespiratory muscle dysfunctionImpaired gas exchangeCardiovascularReduced stroke volumeAbnormal HR responseCirculatory abnormalityBlood abnormality,PeripheralInactivityAtrophyNeuromuscular dysfunctionReduced oxidative capacity of skeletal muscleMalnutritionPerceptualMotivationalEnvironmental,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-limitedECGHRMeasure expired gasOxygen consumptionCO2 productionMinute ventilationSpO2 or PO2 Perceptual responsesBreathlessnessLeg discomfort,Modified Borg CR-10 Scale,Indications for CPET,Evaluation of dyspneaDistinguish cardiac vs pulmonary vs peripheral limitation vs otherDetection of exercise-induced bronchoconstrictionDetection of exertional desaturationPulmonary rehabilitationExercise intensity/prescriptionResponse to participationPre-op evaluation and risk stratificationPrognostication of life expectancyDisability determinationFitness evaluationDiagnosisAssess response to therapy,Mortality in CF Patients,Nixon et al; NEJM 327: 1785; 1992.Followed 109 patients with CF for 8 yrs from CPETPeak VO2 81% predicted: 83% survivalPeak VO2 59-81% predicted: 51% survivalPeak 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 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/minIncreased risk of complications and deathPeak VO2 10 ml/kg/min40-50% mortalityConsider non-surgical management,Absolute Contraindications to CPET,Acute MIUnstable anginaUnstable arrhythmiaAcute endocarditis, myocarditis, pericarditisSyncopeSevere, symptomatic ASUncontrolled CHFAcute PE, DVTRespiratory failureUncontrolled asthmaSpO2 200/120)Significant pulmonary HTNTachyarrhythmia, bradyarrhythmiaHigh degree AV blockHypertrophic cardiomyopathyElectrolyte abnormalityModerate stenotic valvular heart diseaseAdvanced or complicated pregnancyOrthopedic impairment,Indications for Early Exercise Termination,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 1 (CO2 production O2 consumption).Carbon dioxide regulates ventilation.Ventilation will disproportionately increase at lactate threshold to eliminate excess CO2.Increase in ventilatory equivalent 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: Fick 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 = (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 PrinceAm 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 ventilationAnaerobic thresholdHeart rate reserveBreathing reserve,Heart Rate Reserve,Comparison of actual peak HR and predicted peak HR= (1 Actual/Predicted) x 100%Normal 30%,Comparison CPET results,Normal CHF COPDPredicted Peak HR150150150Peak HR150140120MVV10010050Peak VO22.01.21.2AT1.00.61.0Peak VE604049Breathing Reserve40%60%2%HR Reserve0%7%20%Borg Breathlessness548Borg Leg Discomfort885,Cardiac vs Pulmonary Limitation,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% increasedDeconditioning 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 dioxide.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.,SUMMARY,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