1、Mitchell HOROWitz,Cardiopulmonary Exercise Testing,Outline,Description of CPET Who should and who should not get CPET When to terminate CPET Exercise physiology Define terms: respiratory exchange ratio, ventilatory equivalent, heart rate reserve, breathing reserve, oxygen pulse Pattern of CPET resul
2、ts COPD vs CHF,Rationale for Exercise Testing,Cardiopulmonary measurements obtained at rest may not estimate functional capacity reliably,Clinical Exercise Tests,6-min walk test Submaximal Shuttle walk test Incremental, maximal, symptom-limited Exercise bronchoprovocation Exertional oximetry Cardiac
3、 stress test CPET,Karlman Wasserman,Coupling of External Ventilation and Cellular Metabolism,Adaptations of Wassermans Gears,General Mechanisms of Exercise Limitation,Pulmonary Ventilatory Respiratory muscle dysfunction Impaired gas exchange Cardiovascular Reduced stroke volume Abnormal HR response
4、Circulatory abnormality Blood abnormality,Peripheral Inactivity Atrophy Neuromuscular dysfunction Reduced oxidative capacity of skeletal muscle Malnutrition Perceptual Motivational Environmental,What is CPET?,Symptom-limited exercise test Measure airflow, SpO2, and expired oxygen and carbon dioxide
5、Allows calculation of peak oxygen consumption, anaerobic threshold,Components of Integrated CPET,Symptom-limited ECG HR Measure expired gas Oxygen consumption CO2 production Minute ventilation SpO2 or PO2 Perceptual responses Breathlessness Leg discomfort,Modified Borg CR-10 Scale,Indications for CP
6、ET,Evaluation of dyspnea Distinguish cardiac vs pulmonary vs peripheral limitation vs other Detection of exercise-induced bronchoconstriction Detection of exertional desaturation Pulmonary rehabilitation Exercise intensity/prescription Response to participation Pre-op evaluation and risk stratificat
7、ion Prognostication of life expectancy Disability determination Fitness evaluation Diagnosis Assess response to therapy,Mortality in CF Patients,Nixon et al; NEJM 327: 1785; 1992. Followed 109 patients with CF for 8 yrs from CPET Peak VO2 81% predicted: 83% survival Peak VO2 59-81% predicted: 51% su
8、rvival Peak VO2 59% predicted: 28% survival,Mortality in CHF Patients,Mancini 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 et al; Thora
9、x 65:iii1, 2010Alberts et al; Chest 132:1s, 2007Balady et al; Circulation 122:191, 2010Peak VO2 15 ml/kg/min No significant increased risk of complications or death Peak VO2 15 ml/kg/min Increased risk of complications and death Peak VO2 10 ml/kg/min 40-50% mortality Consider non-surgical management
10、,Absolute Contraindications to CPET,Acute MI Unstable angina Unstable arrhythmia Acute endocarditis, myocarditis, pericarditis Syncope Severe, symptomatic AS Uncontrolled CHF Acute PE, DVT Respiratory failure Uncontrolled asthma SpO2 88% on RA Acute significant non-cardiopulmonary disorder that may
11、affect or be adversely affected by exercise Significant psychiatric/cognitive impairment limiting cooperation,Relative Contraindications to CPET,Left main or 3-V CAD Severe arterial HTN (200/120) Significant pulmonary HTN Tachyarrhythmia, bradyarrhythmia High degree AV block Hypertrophic cardiomyopa
12、thy Electrolyte abnormality Moderate stenotic valvular heart disease Advanced or complicated pregnancy Orthopedic impairment,Indications for Early Exercise Termination,Patient request Ischemic ECG changes 2 mm ST depression Chest pain suggestive of ischemia Significant ectopy 2nd or 3rd degree heart
13、 block Bpsys 240-250, Bpdias 110-120 Fall in BPsys 20 mmHg SpO2 81-85% Dizziness, faintness Onset confusion Onset pallor,CPET Measurements,Work VO2 VCO2 AT HR ECG BP,R SpO2 ABG Lactate CP Dyspnea Leg fatigue,Exercise Modality,Advantages of cycle ergometer Cheaper Safer Less danger of fall/injury Can
14、 stop anytime Direct power calculation Independent of weight Holding bars has no effect Little training needed Easier BP recording, blood draw Requires less space Less noise Advantages of treadmill Attain higher VO2 More functional,Incremental vs Ramp Exercise Test Protocol,INCREMENTAL,RAMP,WORK,TIM
15、E,TIME,WORK,Physiology and Chemistry,Slow vs fast twitch fibers Buffering of lactic acid by bicarbonate CO2 production from carbonic acid Respiratory exchange ratio Ventilatory equivalent of oxygen Ventilatory equivalent of carbon dioxide Graphical determination of AT Fick Equation Oxygen pulse,Prop
16、erties of Skeletal Muscle Fibers,Red = Slow twitch = Type I Sustained activity High mitochondrial density Metabolize glucose aerobically 1 glucose yields 36 ATP Rapid recovery,White = Fast twitch = Type II Rapid burst exercise Few mitochondria Metabolize glucose anaerobically 1 glucose yields 2 ATP
17、and 2 lactic acid Slow recovery,Lactic Acid is Buffered by Bicarbonate,Lactic acid + HCO3 H2CO3 + LactateH2O + CO2,Respiratory Exchange Ratio,RER= CO2 produced / O2 consumed= VCO2 / VO2,Ventilatory Equivalents,Ventilatory equivalent for carbon dioxide = Minute ventilation / VCO2 Efficiency of ventil
18、ation Liters of ventilation to eliminate 1 L of CO2Ventilatory equivalent for oxygen = Minute ventilation / VO2Liters of ventilation per L of oxygen uptake,Relationship of AT to RER and Ventilatory Equiv for O2,Below the anaerobic threshold, with carbohydrate metabolism, RER=1 (CO2 production = O2 c
19、onsumption). Above the anaerobic threshold, lactic acid is generated. Lactic acid is buffered by bicarbonate to produce lactate, water, and carbon dioxide. Above the anaerobic threshold, RER 1 (CO2 production O2 consumption). Carbon dioxide regulates ventilation. Ventilation will disproportionately
20、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
21、: 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 disease Lung disease Muscle disease Deconditioning,Anemia Lung disease (low SaO2),Arterial oxygen content =(1.34)(SaO2)(Hgb)Venous oxygen content =(1.34)(SvO2)(Hgb),Oxygen Pulse,Oxygen Puls
22、e:“. . .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 consumption Pea
23、k HR Peak work Peak ventilation Anaerobic threshold Heart rate reserve Breathing 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,220 age For age 40: 220 - 40 = 180 For age 70: 220 - 70 = 150210 (age
24、x 0.65) For age 40: 210 - (40 x 0.65) = 184 For age 70: 210 - (70 x 0.65) = 164,Breathing Reserve,Comparison of actual peak ventilation and predicted peak ventilation Predicted peak ventilation = MVV, or FEV1 x 35= (1 Actual/Predicted) x 100%Normal 30%,Comparison CPET results,Normal CHF COPD Predict
25、ed Peak HR 150 150 150 Peak HR 150 140 120 MVV 100 100 50 Peak VO2 2.0 1.2 1.2 AT 1.0 0.6 1.0 Peak VE 60 40 49 Breathing Reserve 40% 60% 2% HR Reserve 0% 7% 20% Borg Breathlessness 5 4 8 Borg Leg Discomfort 8 8 5,Cardiac vs Pulmonary Limitation,Heart Disease Breathing reserve 30% Heart rate reserve
26、15%,CPET Interpretation,Peak VO2 HRR BR AT/VO2max A-a Normal 80% 30% 40% normal Heart disease 30% 30% 15% 40% increased Deconditioning 15% 30% 40% normal,SUMMARY,Cardiopulmonary measurements obtained at rest may not estimate functional capacity reliably. CPET includes the measurement of expired oxyg
27、en 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
28、is higher on treadmill than cycle ergometer. Peak VO2 may be lower than VO2max. Absolute contraindications to CPET include unstable cardiac disease and SpO2 20 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=
29、CO2 produced / O2 consumed,SUMMARY,Above the anaerobic threshold, CO2 production 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 from the Fick equation, Oxygen Pulse = VO2 / HR, and is proportional to stroke volume. In pure heart disease, BR is 30% and HRR 15%.,
