Peak oxygen uptake in combination with ventilatory efficiency improve risk stratification in major abdominal surgery.

This pilot study aimed to evaluate if peak VO2 and ventilatory efficiency in combination would improve preoperative risk stratification beyond only relying on peak VO2 . This was a single-center retrospective cohort study including all patients who underwent cardiopulmonary exercise testing (CPET) as part of preoperative risk evaluation before major upper abdominal surgery during years 2008-2021. The primary outcome was any major cardiopulmonary complication during hospitalization. Forty-nine patients had a preoperative CPET before decision to pursue to surgery (cancer in esophagus [n = 18], stomach [6], pancreas [16], or liver [9]). Twenty-five were selected for operation. Patients who suffered any major cardiopulmonary complication had lower ventilatory efficiency (i.e., higher VE/VCO2 slope, 37.3 vs. 29.7, p = 0.031) compared to those without complications. In patients with a low aerobic capacity (i.e., peak VO2  < 20 mL/kg/min) and a VE/VCO2 slope ≥ 39, 80% developed a major cardiopulmonary complication. In this pilot study of patients with preoperative CPET before major upper abdominal surgery, patients who experienced a major cardiopulmonary complication had significantly lower ventilatory efficiency compared to those who did not. A low aerobic capacity in combination with low ventilatory efficiency was associated with a very high risk (80%) of having a major cardiopulmonary complication.