Discussion
colorectal cancer, CRF
COLORECTAL CANCER, CRF, SECONDARY, POSTOPERATIVE COMPLICATIONS
To our knowledge, the current study was the first study that aimed to investigate whether the selection of different CPET data-averaging intervals would translate into differences in mean values of CPET-derived variables in patients with colorectal cancer who performed CPET for preoperative risk assessment. As CPET-derived variables are used to preoperatively classify patients into having a low or high risk for postoperative complications based on their CRF, the secondary aim of the current study was to investigate whether potential differences in the numerical values of CPET-derived variables would lead to differences in preoperative risk classification. Based on the mean values of the CPET-derived variables there were only statistically significant differences for the variables VOFor VOThe main purpose of using data-averaging of CPET data is to reduce noise of breath-by-breath fluctuations and to aid CPET interpretation [Although the literature is scarce with regard to the influence of data-averaging intervals on the determination of CPET-derived variables (and only available for VOBased on the results of this study, the recommendation in the preoperative CPET guideline to use a breath-based data-averaging interval of 3–5 breaths or a time-based data-averaging interval of ~20 seconds seems plausible when evaluating the mean (group level) values. Nevertheless, caution should be taken when evaluating individual patients, as different data-averaging intervals caused substantial variation in the numerical values of CPET-derived variables within patients. As depicted in A limitation of the current study was that VOThe current study opens possibilities for clinicians to be flexible in the data-averaging interval that is used for interpretation of the preoperative CPET. Current CPET literature does not provide clear and consistent guidance for clinicians about the choice of a data-averaging interval [