CPET 心肺运动试验

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
Pulmonary

Peripheral


Ventilatory Respiratory muscle dysfunction Impaired gas exchange Reduced stroke volume Abnormal HR response Circulatory abnormality Blood abnormality
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 stress test CPET

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
Define terms: respiratory exchange ratio, ventilatory
equivalent, heart rate reserve, breathing reserve, oxygen pulse Pattern of CPET results COPD vs CHF
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
Karlman Wasserman
Coupling of External Ventilation and Cellular Metabolism
Adaptations of Wasserman’s Gears
General Mechanisms of Exercise Limitation
Peak VO2 <15 ml/kg/min

Peak VO2 <10 ml/kg/min

源自文库

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
Cardiopulmonary Exercise Testing
MITCHELL HOROWITZ
Outline
Description of CPET Who should and who should not get CPET When to terminate CPET Exercise physiology
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%

Cheaper Safer
Less danger of fall/injury Can stop anytime Independent of weight Holding bars has no effect

Direct power calculation



INCREMENTAL RAMP
WORK
WORK
TIME
TIME
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
Little training needed Easier BP recording, blood draw Requires less space Less noise Attain higher VO2 More functional
Advantages of treadmill
Incremental vs Ramp Exercise Test Protocol
CPET Measurements
Work VO2 VCO2 AT HR ECG BP R SpO2 ABG Lactate CP Dyspnea Leg fatigue
Exercise Modality
Advantages of cycle ergometer
Cardiovascular

Inactivity Atrophy Neuromuscular dysfunction Reduced oxidative capacity of skeletal muscle Malnutrition


Perceptual
Motivational Environmental
Ventilatory equivalent of carbon dioxide
Graphical determination of AT Fick Equation Oxygen pulse
Properties of Skeletal Muscle Fibers
Red = Slow twitch = Type I
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


White = Fast twitch = Type II


Sustained activity High mitochondrial density Metabolize glucose aerobically

Rapid burst exercise Few mitochondria Metabolize glucose anaerobically
What is CPET?
Symptom-limited exercise
test Measure airflow, SpO2, and expired oxygen and carbon dioxide Allows calculation of peak oxygen consumption, anaerobic threshold
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
Modified Borg CR-10 Scale
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
Peak VO2 >15 ml/kg/min

No significant increased risk of complications or death Increased risk of complications and death 40-50% mortality Consider non-surgical management