Inter-observer agreement of preoperative cardiopulmonary exercise test interpretation in major abdominal surgery

Accurate determination of cardiopulmonary exercise test (CPET) derived parameters is essential to allow for uniform preoperative risk assessment. The objective of this prospective observational study was to evaluate the inter-observer agreement of preoperative CPET-derived variables by comparing a self-preferred approach with a systematic guideline-based approach.

Twenty-six professionals from multiple centers across the Netherlands interpreted 12 preoperative CPETs of patients scheduled for hepatopancreatobiliary surgery. Outcome parameters of interest were oxygen uptake at the ventilatory anaerobic threshold (V̇O_2VAT) and at peak exercise (V̇O_2peak), the slope of the relationship between the minute ventilation and carbon dioxide production (V̇E/V̇CO₂-slope), and the oxygen uptake efficiency slope (OUES). Inter-observer agreement of the self-preferred approach and the guideline-based approach was quantified by means of the intra-class correlation coefficient.

Across the complete cohort, inter-observer agreement intraclass correlation coefficient (ICC) was 0.76 (95% confidence interval (CI) 0.57-0.93) for V̇O_2VAT, 0.98 (95% CI 0.95-0.99) for V̇O_2peak, and 0.86 (95% CI 0.75-0.95) for the V̇E/V̇CO₂-slope when using the self-preferred approach. By using a systematic guideline-based approach, ICCs were 0.88 (95% CI 0.74-0.97) for V̇O_2VAT, 0.99 (95% CI 0.99-1.00) for V̇O_2peak, 0.97 (95% CI 0.94-0.99) for the V̇E/V̇CO₂-slope, and 0.98 (95% CI 0.96-0.99) for the OUES.

Inter-observer agreement of numerical values of CPET-derived parameters can be improved by using a systematic guideline-based approach. Effort-independent variables such as the V̇E/V̇CO₂-slope and the OUES might be useful to further improve uniformity in preoperative risk assessment in addition to, or in case V̇O_2VAT and V̇O_2peak are not determinable.