Inter-observer reliability of preoperative cardiopulmonary exercise test interpretation: a cross-sectional study

Abstract

BackgroundDespite the increasing importance of cardiopulmonary exercise testing (CPET) for preoperative risk assessment, the reliability of CPET interpretation is unclear. We aimed to assess inter-observer reliability of preoperative CPET. MethodsWe conducted a prospective, multi-centre, observational study of preoperative CPET interpretation. Participants were professionals with previous experience or training in CPET, assessed by a standardized questionnaire. Each participant interpreted 100 tests using standardized software. The CPET variables of interest were oxygen consumption at the anaerobic threshold (AT) and peak oxygen consumption (VO2 peak). Inter-observer reliability was measured using intra-class correlation coefficient (ICC) with a random effects model. Results are presented as ICC with 95% confidence interval, where ICC of 1 represents perfect agreement and ICC of 0 represents no agreement. ResultsParticipants included 8/28 (28.6%) clinical physiologists, 10 (35.7%) junior doctors, and 10 (35.7%) consultant doctors. The median previous experience was 140 (inter-quartile range 55–700) CPETs. After excluding the first 10 tests (acclimatization) for each participant and missing data, the primary analysis of AT and VO2 peak included 2125 and 2414 tests, respectively. Inter-observer agreement for numerical values of AT [ICC 0.83 (0.75–0.90)] and VO2 peak [ICC 0.88 (0.84–0.92)] was good. In a post hoc analysis, inter-observer agreement for identification of the presence of a reportable AT was excellent [ICC 0.93 (0.91–0.95)] and a reportable VO2 peak was moderate [0.73 (0.64–0.80)]. ConclusionsInter-observer reliability of interpretation of numerical values of two commonly used CPET variables was good (>80%). However, inter-observer agreement regarding the presence of a reportable value was less consistent.