Cardiopulmonary Exercise Testing (CPET)

Cardiopulmonary exercise test is a kind of examination method. It reflects the cardiopulmonary function index of the human body in the exercise of increasing load. Through the comprehensive analysis of various parameters, the interaction and storage ability between the heart, lung and circulatory system are understood. Commonly used indicators of maximal oxygen (upper oxygen). (VO2max), metabolic equivalent (metabolicequivalent, MET), oxygen ventilation (VE/Vo2), anaerobic threshold (AT), maximum ventilation (MVV), heart Cardiac output (CO), stroke volume (SV), oxygen consumption per pulse (O2pulse), carbon dioxide emission (VCO2), ventilation per minute (VE), terminal tidal oxygen partial pressure (PETo2), terminal tidal CO2 partial pressure (PETco2), physiological dead space (Vd/Vt), dyspnea index (Dyspneaindex), alveolar-arterial oxygen partial pressure difference (PA-aDO2). Basic Information Specialist classification: Respiratory examination classification: pulmonary function test Applicable gender: whether men and women apply fasting: not fasting Tips: Acute myocardial infarction, acute tachyarrhythmia, pulmonary edema, severe aortic stenosis is absolutely contraindicated for this test. Uncontrolled hypertension, severe anemia, moderate aortic stenosis, and uncooperative patients are not suitable for this test. Normal value (1) VO2max (L/min) = 0.001 B × (61.45-10.7 Z - 0.372Y), wherein B is body weight (kg), Z = 1 (male) or 2 (female), and Y is age (years). (2) The fastest heart rate (number of times / min) = 210-0.65Y, where Y = age (years). (3) Maximum stroke volume (ml/stroke) = VO2max (ml/min) / fastest heart rate (number of times / min). (4) VEmax/MVV (%) <70%. (5) The fastest respiratory rate (number of times / min) = 35-50. (6) PA-aDO2 (kPa) < (11.4 + 0.43Y) × 0.133, where Y = age (years), and 0.133 = mmHg is converted to a coefficient of kPa. Clinical significance Clinical use is used to explore the physiological and pathophysiology of the circulation and respiratory system, to understand the extent of disease progression, to judge the efficacy and prognosis, and to be valuable for labor identification and rehabilitation. (1) In obstructive ventilatory dysfunction, due to VA/Q imbalance, Vd/Vt can be increased during rest, and it does not decrease during exercise. VE/Vco2, VE/Vo2, and PA-aDO2 also increase. The peak of VO2max failed to form a platform, the maximum oxygen volume per stroke decreased, and the fastest heart rate decreased. As the work of breathing increases, the efficacy is reduced and VEmax/MVV is increased. (2) In the case of restrictive ventilation dysfunction, the respiratory rate increases due to the decrease in lung compliance, especially after increasing the exercise load. The decrease in alveolar capillary bed and VA/Q imbalance caused an increase in Vd/vt and PA-aDO2. Due to hypoxemia stimulation of ventilation, VE/VCO2, VE/VO2 increased, other changes increased VEmax/MVV, VO2max and the fastest heart rate decreased. (3) In the case of chest wall disease, due to mechanical restrictions on ventilation, VEmax, the fastest heart rate and VO2max are reduced, and PaCO2 is increased. (4) In exercise-induced asthma, PEF and FEV1 were reduced 2 to 15 minutes after strenuous exercise due to bronchospasm. (5) In pulmonary vascular disease, due to the decrease of alveolar capillary bed and VA/Q imbalance, Vd, Vd/Vt, VE/VCO2, VE/Vo2 are increased, pulmonary artery pressure is increased, VO2max is decreased, and the fastest heart rate is normal or decreased. Precautions 1. Absolute contraindications: acute myocardial infarction, acute tachyarrhythmia, pulmonary edema, severe aortic stenosis. 2. Relative contraindications: uncontrolled hypertension, severe anemia, moderate aortic stenosis, uncooperative patients. 3. If the following conditions occur during the examination, the cardiopulmonary exercise test should be terminated immediately: (1) The appearance of acute damage is pale, sweaty, fearful, dizzy, confused. (2) Severe breathing difficulties and new cyanosis. (3) complex ventricular arrhythmia, supraventricular tachycardia, significant bradycardia. (4) There is pain in the precordial area, with ischemic ST, and the change is greater than 2 mm. (5) Severe hypertension (240/140 mmHg). (6) When the systolic blood pressure drops >10 mmHg. (7) Severe fatigue, severe leg pain, or intermittent squatting. Inspection process 1. Commonly used exercise equipment: Bicycle power meters and moving tablets are commonly used in exercise tests. The bicycle power meter has good safety, comfort and stability, and it is easy to observe and measure various physiological parameters, such as ECG monitoring, blood pressure monitoring and arterial blood extraction for blood gas analysis and lactate determination, and the patient's work volume is not related to body weight. The maximum oxygen uptake (maximaloxygenintake, VO2max) measured by the active plate is 10% to 15% higher than that of the bicycle power meter, but there is no bicycle power meter when collecting or measuring some physiological parameters, and the patient's weight and walking style. Etc. may affect the amount of work done. Bicycle power meters are commonly used as exercise equipment in respiratory diseases. 2. Common clinical exercise test methods (1) 6-minute walk test: Subjects walked for 6 minutes at their own walking frequency, recording the maximum exercise distance. The method is simple and easy, and is not limited by the site and the instrument. It is mainly used for the evaluation of preoperative and postoperative motor lung function in lung resection and lung volume reduction surgery; monitoring the response of treatment intervention; rehabilitation treatment of lung diseases; And predict the mortality and incidence of patients with cardiopulmonary disease. (2) Exercise stimulation test: mainly used for the diagnosis of exercise asthma and the evaluation of prevention and treatment efficacy. 1 Active plate method: The basic lung function was measured, and FEV1 was used as an observation index. The subject stood on the movable plate and the two-hand grips ran at the speed of the plate. Start at a lower speed and slope, and increase rapidly from 2 to 3 minutes until it reaches 70% to 80% of the maximum expected heart rate (220-age) or 40% to 60% of the maximum ventilation (FEV1×35). Maintain at least 4 minutes on the basis. The entire exercise process is best completed in 6-8 minutes. FEV1 was measured again at 1, 5, 10, 15, 20, 30 min after the exercise was stopped, and FEV1 was reduced to >15% before exercise as a positive standard. 2 Bicycle power meter method: Calculate the target exercise load (53.76 × FEV1-11.07) according to the FEV1 before the subject's exercise. After the start of exercise, at 1, 2, 3, and 4 minutes, the exercise load was 60%, 75%, 90%, and 100% of the target load, respectively. Heart rate and/or minute ventilation were also used to monitor whether exercise intensity was reached. After reaching the target exercise intensity, it is maintained for another 4-6 minutes. The time to measure FEV1 after the exercise was stopped was the same as above, and the maximum decrease value was >15%. (3) Cardiopulmonary exercise endurance test 1 Symptom self-limiting load-increasing exercise test: a commonly used method in clinical practice, the exercise load increases the load per interval for a certain period of time until the maximum symptom is self-limited. The exercise load is ramped up, and the increase varies depending on the patient's condition, ranging from 5 to 25 W per minute. It is ideal for patients to achieve maximum exercise in 8 to 12 minutes. The specific steps are as follows (take the bicycle power meter as an example): after taking the mouthpart, blood pressure cuff and ECG lead, rest for 3min, no load warm-up for 3min, the treadmill load is increased by 5~25W/min, the rotation speed is maintained. At 60r/min, until breathing difficulties, sore muscles in the legs, general fatigue, no further exercise or speed <40r/min, recovery at 0W for 2min. The maximum load level maintained for 1 min is defined as the maximum exercise load. 2 constant load exercise test: exercise load is maintained at a constant level for a certain period of time (usually 6min), heart rate, oxygen uptake and minute ventilation remain unchanged within 1min, then to reach a constant state, often with increasing load exercise test 70% of the maximum exercise load is used as its exercise load. Mainly used to evaluate the judgment of the therapeutic effect after treatment intervention. Not suitable for the crowd 1, absolute contraindications: acute myocardial infarction, acute tachyarrhythmia, pulmonary edema, severe aortic stenosis. 2, relative contraindications: uncontrolled hypertension, severe anemia, moderate aortic stenosis, uncooperative patients. Adverse reactions and risks (1) The appearance of acute damage is pale and sweaty, fearful and dizzy, confused. (2) New hair problems occur in severe breathing difficulties.