Mitchell HOROWitz,Cardiopulmonary Exercise Testing,1,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 results COPD vs CHF,2,Rationale for Exercise Testing,Cardiopulmonary measurements obtained at rest may not estimate functional capacity reliably,3,Clinical Exercise Tests,6-min walk test Submaximal Shuttle walk test Incremental, maximal, symptom-limited Exercise bronchoprovocation Exertional oximetry Cardiac stress test CPET,4,Karlman Wasserman,5,Coupling of External Ventilation and Cellular Metabolism,6,Adaptations of Wassermans Gears,7,General Mechanisms of Exercise Limitation,Pulmonary Ventilatory Respiratory muscle dysfunction Impaired gas exchange Cardiovascular Reduced stroke volume Abnormal HR response Circulatory abnormality Blood abnormality,Peripheral Inactivity Atrophy Neuromuscular dysfunction Reduced oxidative capacity of skeletal muscle Malnutrition Perceptual Motivational Environmental,8,What is CPET?,Symptom-limited exercise test Measure airflow, SpO2, and expired oxygen and carbon dioxide Allows calculation of peak oxygen consumption, anaerobic threshold,9,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,10,Modified Borg CR-10 Scale,11,Indications for CPET,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 stratification Prognostication of life expectancy Disability determination Fitness evaluation Diagnosis Assess response to therapy,12,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% survival Peak VO2 59% predicted: 28% survival,13,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%,14,CPET to Predict Risk of Lung Resection in Lung Cancer,Lim et al; Thorax 65:iii1, 2010 Alberts et al; Chest 132:1s, 2007 Balady et al; Circulation 122:191, 2010 Peak 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,15,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 affect or be adversely affected by exercise Significant psychiatric/cognitive impairment limiting cooperation,16,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 cardiomyopathy Electrolyte abnormality Moderate stenotic valvular heart disease Advanced or complicated pregnancy Orthopedic impairment,17,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 block Bpsys 240-250, Bpdias 110-120 Fall in BPsys 20 mmHg SpO2 81-85% Dizziness, faintness Onset confusion Onset pallor,18,CPET Measurements,Work VO2 VCO2 AT HR ECG BP,R SpO2 ABG Lactate CP Dyspnea Leg fatigue,19,Exercise Modality,Advantages of cycle ergometer Cheaper Safer Less danger of fall/injury Can 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,20,Incremental vs Ramp Exercise Test Protocol,INCREMENTAL,RAMP,WORK,TIME,TIME,WORK,21,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,22,Properties 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 and 2 lactic acid Slow recovery,23,Lactic Acid is Buffered by Bicarbonate,Lactic acid