Abstract:
Background　Guidelines from various medical specialties have different definitions for maximum extreme exercise.By analyzing the data of cardiopulmonary exercise test （CPET） included in the fourth edition of Principles of Exercise Testing and Interpretation，we found that if a peak RER or a blood pressure reading is used as the termination criterion，some patients' functional indicators will be underestimated，or some patients will not reach the specific value.In the CPET，in order to objectively quantify and accurately ensure that the results of the CPET are accurate，the Max testing is feasible.Objective　To clinically verify whether the CPET is a maximum extreme exercise，and to design the Max test to verify the accuracy of the objective quantitative functional assessment of CPET results and whether it is feasible to use the specific value of a specific index as the criterion for stopping the exercise.Methods　Sixty cases from Fuwai Hospital were enrolled during December 2017 to June 2018，including 20 physcial examinees（control group） and 40 with cardiovascular diseases（patient group）．All of them first performed individualized symptom-limited maximal CPETs，during which 12-lead ECG parameters，oxygen saturation，noninvasive blood pressure level and pulmonary gas exchange were measured with PFT Ergo Omnia 1.6.2 produced by COSMED S.R.L，Italy.When the CPET ended，they had a 5-minute break，then underwent the Max testing，during which，they cycled with a velocity of ≥60 r/min，at a constant intensity equivalent to to 130% of peak oxygen consumption，until exhausted.The difference and percentage difference between the peak heart rate and the peak oxygen uptake were calculated.If the percentage difference between heart rate，and that between oxygen uptake are all less than -10%，then the participant's Max testing is thought to be succesful，otherwise it is failed.Results　Patient group's peakO2 （L/min，ml?min-1?kg-1，%pred），anaerobic threshold（L/min，ml?min-1?kg-1，%pred），peak VO2P（ml/time，% pred），peak RER，peak SBP，peak WR，peak heart rate，OUEP（ratio，%pred） were lower than those of the control group（P<0.05）．The E/CO2-lowest （ratio，%pred） and E/CO2 slope（ratio，%pred） were higher in the patient group than in the control group （P<0.05）．No adverse events occurred during the CPETs and Max testing in all cases.Among the healthy controls，16（80.0%） were successful in completing the Max testing.And CPET was proved to be maximum extreme exercise，non-maximum extreme exercise，and failed for 12 cases（75.0%），4（25.0%），and 4（20.0%），respectively.In the patients，Max testing was successful in 37 cases（92.5%）．CPET was proved to be maximum extreme exercise for 34 cases（91.9%），non-maximum extreme exercise for 3 cases（8.1%），and failed in 3 cases（7.5%）．Conclusion　For CPET with a low peak RER and a maximum challenge，the Max testing can be completed after 5 minutes to confirm the accuracy of the objective quantitative assessment of CPET.Max testing is safe and feasible，and deserves further research and clinical application.

Key words: Cardiopulmonary exercise test, Symptom limitation maximum extreme exercise, Respiratory exchange rate, Max testing, Blood pressure, Heart rate

摘要： 背景　症状限制性心肺运动试验（CPET）在不同学科指南中对于最大极限运动的定义不统一。若以某峰值呼吸交换率（RER）、某心率或某血压特定值作为终止试验标准，一方面会让部分患者的功能指标等被低估，另一方面会因达不到该特定值而产生危险，在进行CPET时，为了客观、定量、精准地验证患者的结果是准确的，Max试验可行。目的　验证临床受试者完成的CPET是否为最大极限运动，设计Max试验验证客观、定量功能评估的准确性及以某指标的特定数值作为停止CPET的标准是否可行。方法　选取2017年12月—2018年6月在中国医学科学院阜外医院完成症状限制性CPET后再次施加130%自身峰值功率完成Max试验的60例受试者为研究对象。前20例体检健康者（正常组）先尝试完成Max试验，后40例心脏疾病患者（病例组）进行Max试验。Max试验方法：在完成CPET恢复5 min后，先蹬车≥60 r/min，再次给予受试者130%自身峰值功率的个体化恒定功率，鼓励受试者运动至不能坚持的极限状态。计算Max试验摄氧量最大值、心率最大值与CPET峰值摄氧量、峰值心率的差值百分比。若摄氧量、心率差值百分比任一指标<-10.0%定义为Max试验失败，否则为成功。结果　病例组峰值摄氧量（L/min、ml?min-1?kg-1、%pred）、无氧阈（L/min、ml?min-1?kg-1、%pred）、峰值氧脉搏（ml/次、%pred）、峰值RER比值、峰值收缩压、峰值运动负荷、峰值心率、摄氧有效性峰值平台（OUEP）（比值、%pred）低于正常组，二氧化碳通气有效性平均90 s最低值（E/CO2-lowest）（比值、%pred）、二氧化碳通气效率斜率（E/CO2 slope）（比值、%pred）高于正常组（P<0.05）。正常组与病例组均安全无任何事件完成CPET和Max试验。正常组Max试验成功16例（80.0%），其中证明CPET为极限运动12例，为非极限运动4例；失败4例（20.0%）。病例组Max试验成功37例（92.5%），其中证明CPET为极限运动34例，为非极限运动3例；失败3例（7.5%）。结论　对于峰值RER低而被质疑的症状限制性CPET，在5 min后再完成Max试验可以证实CPET客观定量评估结果的准确性。Max试验方法安全可行，值得进一步深入研究和临床推广应用。

关键词: 心肺运动试验, 症状限制最大极限运动, 呼吸交换率, Max试验, 血压, 心率