关键词: 呼吸功能试验, 呼吸交换率, 心肺运动试验, 功率递增速率, 终止运动标准, Max试验, 安全与风险

Abstract: Objective　We analyzed the peak respiratory exchange ratio（RER） data of 102 symptom-limited maximal cardiopulmonary exercise tests（CPETs），in order to provide a reference for the determination of the appropriate RER for the stopping of the tests.Methods　Data concerning 112 CPETs performed with incremental protocols by 85 participants were collected from the Principles of Exercise Testing and Interpretation （Fourth Edition）．After the exclusion of 10 CPETs without RER because of inhaling pure oxygen，we analyzed RER related data of 102 CPETs.For CPETs with peak RER ≥1.10，1.15 and 1.20，we calculated and compared the differences of exercise duration，work rate （WR），systolic blood pressure（SBP），heart rate（HR），breath frequency（f），minute ventilation（V?E），carbon dioxide output（V?CO2），oxygen uptake（V?O2），oxygen pulse（O2P） and RER at the peak exercise and while the RER≥1.10，1.15 and 1.20 on the same CPET，using the paired-t test.Results　The mean peak RER of 102 CPETs was （1.21±0.16）（range：0.86-1.77）．Even though there were about one half to more than three quaters of CPETs with peak RER ≥1.10，1.15 and 1.20，there still were 7 CPETs with peak RER <1.0.For 77 CPETs with peak RER ≥1.10，there were significant differences for the parameters of exercise duration，WR，HR，f，V?E，V?CO2，V?O2 ，O2P and RER（P<0.05）．For 60 CPETs with peak RER ≥1.15，there were significant differences for the parameters of exercise duration，WR，HR，f，V?E，V?CO2 and RER（P<0.05）．For 50 CPETs with peak RER ≥1.20，there were significant difference for the parameters of exercise duration，WR，HR，f，V?E and RER（P<0.05）．Conclusion　Although more than half of the CPETs have a peak RER≥1.10，the remaining have a peak RER<1.0.In clinical practice，for ensuring the safety of symptom-limited maximal CPET，close monitoring is emphasized：the overall functional capacity of the patient would be underestimated if his exercise is stopped based on a peak RER reaching a certain level，and the the risk of over exercise would be posed to the patient if the maximal effort is denied based on a peak RER being below a certain level.So a fixed RER can not be used as the absolute predictor of stopping exercise，and we designed a special “Max”testing to identify the CPET as a maximal effort or not.

Key words: Respiratory function tests, Respiratory exchange ratio, Cardiopulmonary exercise testing, Work rate increasing rate, Standard for stopping exercise, Max testing, Saftey and risk